LT June 2013

JUNE 2013

Leonardo Times Journal of the Society of Aerospace Engineering Students ‘Leonardo da Vinci’

page 26

Airborne Aerospace

number 2

Interview with Business Development Manager Space

A new dean in town

An interview with the new dean, Professor Hester Bijl

T-Minus Engineering: a company in rocketry The start of a company in automated aerial and space vehicles

A career in aviation safety

Year 17

Revealing a multidisciplinary field of engineering at the cutting edge of aviation

Global environmental concerns call for future innovative products. Currently, the aircraft industry is seriously considering to install Contra-Rotating-Open-Rotors (CROR) on mid-range 150-200 seater aircraft by the year 2020. Today, NLR (National Aerospace Laboratory) specialists work in close coรถperation with aircraft & engine manufactures to investigate noise, vibration and safety aspects of these novel aircraft concepts.

www.nlr.nl Advertentie_NLR.indd 1

8-12-2009 15:59:05

Contents

04

Editorial

05

From Leonardo’s desk

06

Current affairs

08

A career in aviation safety

12

Interview - Airborne Aerospace

18

LVD - Safe Symposium

20

T-Minus Engineering: a company in rocketry

26

Interview - A new dean in town

30

Internship Report - Designing aircraft in Italy

32

RVD - The Planck satellite

34

Student Project - Delta Lloyd Solar Boat Team

38

Internship Report - Meet the Aggies

40

Aerospace Propulsion Products APP BV.

42

Noise synthesis

44

We vlogen met een zucht... - The Unmanned Aerial Vehicle

46

Column - Organizing safety

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Contents

Airborne designs and manufactures composite parts for a variety of industries. The Leonardo Times sat down with Airborne’s Sandor Woldendorp to answer the question ‘’How do they do it?’’.

There is a new dean in town since April 15: Professor Hester Bijl. The Leonardo Times decided to pay Professor Bijl a visit for an interesting interview.

11

European Patent Office

17

KLM

24

Thales

25

Atkins

36

Dutch Space

37

Aeronamic

48

Fokker

T-Minus Engineering: a company in rocketry

The start of a company in automated aerial and space vehicles The company T-Minus Engineering was started by four Delft alumni with an interest in rocketry. It is founded on the idea of doing what they love and do best: designing rockets.

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NLR

A new dean in town

An interview with the new dean, Professor Hester Bijl

Advertisement index 02

Airborne Aerospace

Interview with Business Development Manager Space

26

03

Cover articles

20

Table of contents

A career in aviation safety

Revealing a multidisciplinary field of engineering at the cutting edge of aviation From crash scenes to cognition; aviation safety is closer to the aerospace engineering studies than one might realize.

Frederik Mohrmann explains how aviation safety can be fascinating for young engineers.

JUNE 2013 Leonardo Times

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Editor’s letter Dear reader, You may have heard the story of the teenaged Chinese tourist who scratched a message on an ancient stone relief of the Luxor Temple in Egypt. This led to a fairly large share of media attention and the parents apologising for not raising their son properly. Other cases also prompted Chinese government officials urging tourists to behave.

This news followed the earlier discovery of something truly remarkable on the surface of Mars: in an apparent accident, one of the Mars Exploration Rovers left a set of tracks in such a way that it had actually drawn a certain part of the male anatomy. So, in essence: after years and years of research development, humankind started exploring Mars and at one point, one of the robot vehicles sent there accidentally drew some graffiti on the Martian surface, not unlike something one might find on the average toilet wall. It seems rather obvious that this is indeed accidental artistry, unless NASA has been holding out on some rather brilliant artificial intelligence that somehow made the rovers behave like teenagers.

Humans have the need to leave a mark and show that at some point, they were at a certain location. In the light of these recent events, I feel I should briefly address this, especially given the fact that this edition is the

Colophon June edition. Much like the government officials mentioned earlier, I would like to urge all the Leonardo Times readers to not engage in any sort of graffiti while on holiday. While the need to show others where you have been is perfectly understandable, there are better ways to go about this.

Year seventeen, number 2, June 2013 The ‘Leonardo Times’ is issued by the Society for Aerospace Engineering Students, the VSV ‘Leonardo da Vinci’, of the Faculty of Aerospace Engineering at Delft University of Technology. The magazine is issued four times a year with a circulation of 5500 copies.

The best way to let others know where you have been over the holidays is by sending the Leonardo Times a vacation photo of you with an edition of the magazine. You can send this photograph to the email address in the colophon, situated to the right of this editorial.

EDITOR-IN-CHIEF: Benjamin Broekhuizen

This particular edition would make an excellent travelling companion on your vacation.

The cover of this magazine is an artist’s impression of the Galileo navigation satellite system, for which the Dutch composites company Airborne produces the solar array panels. This edition contains an interview with the Business Development Manager Space Sandor Woldendorp. Another interview – and interviewee – of interest is the result of their Leonardo Times sitting down with the new dean of the faculty, Professor Hester Bijl.

Should you – or any of your friends and family – have any anxiety about flying, then reading the articles on aviation safety might set your mind at ease.

I hope you enjoy reading this edition of the Leonardo Times. On behalf of the entire editorial staff, I wish you all the very best for the holidays.

Benjamin Broekhuizen

Where will you take a photo with the Leonardo Times magazine?

FINAL EDITOR: Pattareeya Srongpapa EDITORIAL STAFF: Céline Dohmen, Aryadad Fattahyani, Konark Goel, Sushant Gupta, Robert-Vincent de Koning, Benedict Krautheim, Jules L’Ortye, Alisa Nevinskaia, Stefan Scortescu, Lubi Spranger, Jeroen Wink, Nout van Zon THE FOLLOWING PEOPLE CONTRIBUTED: Michael Arntzen, Benno Baksteen, Jasper Coosemans, Raoul de Jonge, Frederik Mohrmann, Hein Olthof, Anirudh Shukla, Merle Snijders, Nienke Tange, Martijn Tra, Mark Uitendaal, Bob Winters DESIGN, LAY-OUT: dafdesign, Den Haag PRINT: DeltaHage B.V., Den Haag Articles sent for publishing become property of ‘Leonardo Times’. No part of this publication may be reproduced by any means without the written permission of the publisher. ‘Leonardo Times’ disclaims all responsibilities to return articles and pictures. Articles endorsed by name are not necessarily endorsed editorially. By sending in an article and/ or photograph the author is assured of being the owner of the copyright.

‘Leonardo Times’ disclaims all responsibility. The ‘Leonardo Times’ is distributed among all students, alumni and employees of the Aerospace Engineering Faculty.

VSV ‘Leonardo da Vinci’ Kluyverweg 1, 2629 HS Delft Phone: 015 - 278 53 66 Email: VSV@tudelft.nl For more information the website can be visited at www.vsv.tudelft.nl At this website the ‘Leonardo Times’ can also be digitally viewed.

Remarks and/or questions can be emailed to the following address: LeoTimes-VSV@student.tudelft.nl

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Leonardo Times JUNE 2013

FROM LEONARDO’S DESK

Dear readers, When the last edition of the Leonardo Times was released a few highlights of the VSV-year had just taken place, for example the SAFE symposium by the aviation department and the yearly party Airbase.

Looking back both events were a great success. The SAFE symposium took place on March 5th. With the focus on safeguarding aviation in the future effectively we had a day filled with a great mix of national and international speakers. With almost 300 attendees we can look back on a very successful day. Only three weeks later Airbase was scheduled to take place at our faculty. On Friday March 22, one thousand students danced to hits by Lucien Foort or Bakermat until the early morning.

After Airbase most students started preparing for their exams which took place in the first few weeks of April. This exam period also meant that some familiar faces were back in the board-room of the VSV. When we, as the current board of the VSV, went on our holiday, the 67th board kept the VSV up and running. The holiday of the board gave us some time to relax and look back on our year so far.

So on April 5th we left Delft and headed to Schiphol, where we boarded the plane to Malaga. There a tour of Andalusia, a region in the south of Spain, awaited. The first few days were spent in Malaga where we got the first taste of Spanish culture and furthermore we were able to take a dive in the Mediterranean sea, a welcome

change from the 5 degree weather back in the Netherlands. After a few days in Malaga we rented a car and went on a nice road trip to Puerto Banús where we were greeted by Ferrari’s, Lamborghini’s and enormous yachts. After a quick stop we continued travelling inland through the mountains to the small but beautiful city of Ronda. This city is famous for the oldest bullfighting arena in Spain called ‘Plaza de toros de Ronda’. After a day of exploring the narrow streets of Ronda we were on the road again travelling to the Atlantic coast, where we stayed in the city of Cádiz. Apart from a nice swim in the Atlantic Ocean we learned a lot about the history of the city. After a very pleasant stay in Cádiz we continued to Seville, the capital of Andalusia, where we spent the last days of our holiday. Seville is famous for its large historical city centre and houses the largest cathedral of the world. We also visited the Alcázar, the royal palace of Seville. The mixture of Muslim and Christian architecture makes the Alcázar a very special and beautiful building. Apart from culture and sun we were also able to enjoy the fine Spanish cuisine and by the end of the week we all became tapas experts. Unfortunately ten days in Spain flew by and before we knew it we were boarding our Boeing 737-800 back to Schiphol Airport.

back to Delft with us. We arrived back in Delft just in time for a very special occasion. On April 15 Hester Bijl succeeded Jacco Hoekstra as dean of the faculty of Aerospace Engineering. During a nice ceremony on Monday afternoon faculty staff and students said goodbye to prof.

Hoekstra, who will continue as a professor of CNS/ATM , and welcomed Professor Bijl as the new dean of our faculty.

Fully rested we arrived back at the board room to start the last period of the academic year. Fortunately it seemed that the nice weather from Seville travelled

On behalf of the 68th board,

A week later, a day for all parents of the second year students was organised by the VSV in order to show parents what their children had been doing for the past two years and also show them around the facilities of our beautiful faculty.

Soon April changed into May and the three rowing teams of our society readied themselves for the Ringvaart Regatta, an endurance race over a distance of 100 kilometres. For the past year eighteen students have been preparing for this race which took place on May 29. I would like to congratulate them with completing this heroic task.

I want to conclude by wishing all of you the best of luck with the upcoming exams. After the exams most readers of the Leonardo Times will spread around the globe for a well-deserved summer holiday, enjoy!

Raoul de Jonge President of the VSV ‘Leonardo da Vinci’ JUNE 2013 Leonardo Times

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Current Affairs

AIRCRAFT ON IONS

03-04-2013, Cambridge, USA

XOMBIE RECORD HOP

25-03-13, Mojave, USA

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IT researchers say they found ionic wind thrusters may be a more efficient source of propulsion than conventional jet engines. The phenomenon occurs when a current passes between two electrodes, creating wind. If enough voltage is applied, the wind produces thrust. Researchers showed ionic wind produces 110newtons/kilowatt, compared to a jet engine’s two newtons/kilowatt. The thruster consists of a very thin copper electrode, a thicker tube of aluminum, and the air gap in between. Once voltage is applied, the field gradient strips away electrons in nearby air molecules, which are strongly repelled by the corona wire and strongly attracted to the collector. As the cloud of ions moves towards the collector it collides with surrounding neutral air molecules to create a thrust. Steven Barrett, in charge of the research, says these thrusters would cover the entire aircraft. (S.S.) MIT news

BOEING F/A-XX UPDATE

asten Space Systems’ XA-0.1B “Xombie’ vertical-landing, suborbital rocket demonstrator reached 495m, its highest altitude yet, during a test flight of a precision navigation system. The vehicle was controlled for the 80-sec. flight by Charles Stark Draper Laboratory’s Guidance Embedded Navigator Integration Environment (Genie) system developed under NASA’s Flight Opportunities Program. The agency is using the Xombie and Genie — a closed-loop planetary guidance, navigation and control system — to begin tests of prototype landing instrument for future missions to the Moon or Mars.

NASA adds that the flight, which included movement along a realistic planetary approach trajectory with a translation distance of 300m, “established a test-bed capability that will allow for landing demonstrations that start at much higher altitudes — several miles above the ground.” (S.S.) Aviation Week

UNSTABLE BUMBLEBEES

14-03-2013, Beijing, China

7-04-2013, Washington DC, USA

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oeing unveiled an updated version of its F/A-XX sixthgeneration fighter concept. The tail-less twin-engine stealth fighter design comes in manned and unmanned options. The design features diverterless supersonic inlets reminiscent of those found on the F-35. The concept also features canards, which is somewhat of a surprise because their motion is generally assumed to compromise a stealth aircraft’s frontal radar cross-section. But the lack of vertical tail surfaces suggests the aircraft would be optimized for all-aspect broadband stealth, which would be needed for operations in the most challenging anti-access/area denial environments.

Also of note in the manned version of the concept is the placement of the cockpit where rearward visibility appears to be restricted without the aid of a sensor apparatus. (S.S.)

B

umblebees are much more unstable when they hover than when they fly fast, according to Na Xu and Mao Sun from Beijing University of Aeronautics & Astronautic. They used a mathematical model to analyze the way bumblebees fly at different speeds, showing that the bumblebee is unstable when it hovers and flies slowly, and becomes neutral or weakly stable at medium and high flight speeds.The instability at hovering and low speed is mainly caused by a sideways wind made by the movement of the wings -- a ‘positive roll moment’. As the bee flies faster, the wings bend towards the back of the body, reducing the effect of the sideways wind and increasing the stability of its flight. According to the authors the results could be useful in the development of small flying machines like robotic insects. (S.S.)

Flightglobal

Science Daily

Leonardo Times JUNE 2013

Current Affairs

THE FIRST A350 ‘COMPLETE’

26/03/2013, Toulouse, France

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id-March, Airbus has fitted the Rolls-Royce Trent XWB engines to the first flying A350 prototype, and is also installing the aircraft’s auxiliary power unit.

A350 MSN1, as the first flying A350 prototype is called, will undergo ground tests and painting over the next few weeks before being handed over to the airframer’s flight-test team for ground runs. Although Airbus has yet to announce a maiden flight date, the company has stated it is aiming to fly the MSN1 “in the summer”.

With the installation of its engines and also the auxiliary power unit, MSN1 becomes essentially a ‘completed’ aircraft according to the aircraft builder. (J.L.) Flightglobal

GALILEO

14/03/2011, Noordwijk, The Netherlands

THE END OF THE X-48C PROJECT

04-18-13 - Lancaster, California, USA

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fter flying the remotely-piloted X-48C Blended Wing Body research aircraft for nearly six years, the joint NASA-Boeing X-48 project team recently completed a highly successful and productive flight test project at NASA’s Dryden Flight Research Center. The manta ray-shaped X-48 Hybrid Wing Body technology demonstrator flew a total of 122 flights. The last flight of the X-48C occurred on April 9, having first flown eight months ago on Aug. 7, 2012. “We have accomplished our goal of establishing a ground to flight database, and proving the low speed controllability of the concept throughout the flight envelope,” said Fay Collier, manager of NASA’s Environmentally Responsible Aviation project. “Both very quiet and efficient, the hybrid wing body has shown promise for meeting all of NASA’s environmental goals for future aircraft designs,” Collier said. (J.L.) NASA

PREDICTING AIRLINE DELAYS

05/04/2013, Detroit, MI, USA

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ow that a ground location can be determined using the first four operational satellites, Europe’s Galileo satellite navigation system has been declared viable. The 10-15m accuracy achieved at the ESA’s ground station in Noordwijk, The Netherlands, might sound rather inaccurate. However, this relatively low accuracy was as expected since only four satellites were in orbit.

The initial four satellites were launched between October 2011 and October 2012. However, a fast-track launch programme beginning this year will have 18 satellites in orbit by the end of 2014 for functional service and 26 satellites by the end of 2015 for near-global coverage. The full constellation of 27 spacecraft and three orbiting spares should be deployed by 2019. With only four satellites for the time being, the present Galileo constellation is visible at the same time for a maximum of two to three hours daily. (J.L.)

ost of the time, air travel is a seamless experience. However, if your flight is delayed and you miss your connection, this experience is rather tedious. But passengers aren’t the only ones suffering from these nuisances. Missed connections and annoyance cause pollution and frustration, costing airlines plenty of money. Arrival and departure are extremely hard to predict, as there are tons of variables to consider.

Weather, wind speed, emergencies and other factors can all conspire to make a fixed schedule useless. In order to improve predictions of flight times, General Electric teamed up with Alaska Airlines and the crowdsourcing challenge company Kaggle. Their objective was to find an algorithm able to predict arrival and departure times. Initial results show that their error rates - just a few minutes difference - are a 40% improvement over the industry standard, according to GE. (J.L.)

Flightglobal

Popscience

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JUNE 2013 Leonardo Times

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A CAREER IN AVIATION SAFETY Revealing a multidisciplinary field of engineering at the cutting edge of aviation

Being on the first passenger service ever of the 747-8 was a great way to start an internship.

“On October 18, 2011, around 1315 eastern daylight time, a Berger Waiex, N75654, was substantially damaged following a loss of aircraft control and collision with terrain near Washington, Georgia. The certificated sport pilot was killed. The aircraft wreckage, except for its “Y-tail” assembly, was found in a wooded ravine, about 2.3 nautical miles north of IIY. The Y-tail was found separated, near a dirt road, about 550 feet southwest of the main wreckage.” (NTSB, 2011) TEXT Frederik Mohrmann, MSc Student Aerospace Engineering, Control & Operations

A BLACK HOLE At this point all you have is a mangled wreck, some witness statements, and a deceased pilot. This is a very common starting point for an aviation accident investigator. From here, this case becomes a complicated puzzle involving everything from local weather patterns, to health certificates to maintenance records. Despite these challenges, investigators are societally charged with a paramount responsibility in determining the root cause of the accident; the essential first step toward preventing recurrence.

It is precisely this prevention of recurrence that instigates an imperative feedback process within aerospace engineering and innovation. However, the potential value of this process has in the past and the present been overlooked, or rather overshadowed by more pressing innovation; this again is partially attributed to a sense of technical accomplishment. In this article I will draw examples from my growing exposure to this discipline to illustrate how safety engineering is a truly warrant-

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Leonardo Times JUNE 2013

ed knowledge frontier in aerospace engineering, and why it suites our faculty’s academic ambitions so well.

In 2010 I was introduced to Professor John Stoop (ATO), in his courses Forensic Engineering and Safety Engineering. It didn’t take long for me to realize that there was much more to this discipline than National Geographic’s program “Air Crash Investigation” (although I highly recommend anyone to watch it!). I quickly rearranged my coursework and master aim toward safety studies, starting with an internship at the National Transportation Safety Board (NTSB) in Washington D.C.. Rekindling an old internship relationship between the faculty and the NTSB, I worked at the Department of Research and Engineering, Materials Division. I received components from field investigations to perform elemental, fractographic and certification analyses. It was a great opportunity to play an active and important role in these investigations; I was responsible for the complete laboratory investigations and the official NTSB lab reports.

Some investigation reports are already public. Others, such as the accident which introduced this article, are still being investigated. I was also able to work on the scene of a crash of a military helicopter, and pass the two week long accident investigation course given by the NTSB. All in all this was a fantastic opportunity to experience the dirty details of aviation safety. In retrospect, I can say that almost every single department at AE can in one way or another be technically involved in such an investigation: it is truly multidisciplinary. However, accident investigation is only a starting point, from which other safety questions arise.

CHANGES IN THE WIND The tremendous progress in flight safety that the aerospace sector has achieved in the past semicentury, is reflected in unfathomable statistics. In 2011, the accident rate was 1 in 2.7 million flights (IATA, 2012). Add to this the chance you survive such an accident is 95.7% (The Huffington Post, 2009). Put into perspective: you would

NTSB

Figure 1. My presentation at the ISASI seminar in Baltimore, in 2012.

need to fly every day, for almost 7,400 years, to be in a plane crash, and this isn’t even taking into consideration the survival rate.

And it’s only getting better; According to the Air Safety Network, 2012 was the safest year in aviation since 1945, when considering the number of accidents (ASN, 2013).

So you may wonder: “Why should I be worried about the feedback from accidents?”

Indeed it would seem things are fairly well under control. However, there are three reasons which may broaden your perspective: 1) Risk perception Consider the definition of risk. There are two main defining properties, the probability of an outcome, and the consequences of that outcome. In risk analysis, the quantification of these properties offers a platform for risk comparison and grading.

However, such risk scores require cognitive effort and knowledge, and therefore are not intuitively understood by people.

People have a limited sense of what they “feel” is risky or not. Probability is particularly vague when it drops below 1%, and long-term consequences, e.g., smoking, pregnancy, also often fade out of view.

On the other hand, short-term, acute consequences are more quickly understood, because of more vivid and explicit expectations, certainly fuelled by our increased exposure to media. Consider the lottery.

The lottery works because people cannot attribute value to the odds, but have a very intuitive thoughts on what they will

spend the 200 million euro on. The same goes for aviation accidents: the public has a much greater aversion to aviation accidents than to driving a car, because they disregard what they do not know (the probability), and base their judgement almost completely on a potential outcome.

For this reason, people will continue smoking and try the lottery, and aviation accidents will remain unacceptable in public perception despite the actual risk being smaller than many other activities that are regularly performed without hesitance.

2) Aviation growth During the SAFE symposium recently organized by the VSV, Captain Harry Nelson, Former Experimental Test Pilot, illustrated that if the current major accident rate were maintained until 2031, the world would experience one major aviation accident every three months. To prevent this, the accident rate in terms of flights must at a minimum decline inversely to the growth in traffic. However, more reduction must be achieved to decrease the rate in terms of time (the rate which improves public perception). A very real example is the explosive growth in air traffic in India and south-east Asia. The greatest safety concerns are overworked and underpaid flight crews due to a pilot shortage, and significant lapses in traffic separation and management due to lagging air traffic management infrastructure struggling to keep up with the huge traffic demands (India Today, 2013).

3) System dynamics This last aspect is the most novel, and most relevant to our engineering faculty.

In the past two decades commercial aircraft have become increasingly complex.

As more and more (sub-)systems are introduced to manage a safe, efficient and economical flight, pilots are being assisted by an ever increasing level of automation. In the past, the introduction of computers in aircraft systems facilitated crew workload reduction, which was relevant at the time.

However, more recent accidents suggest that this automation growth also dissociates the crew from actually performing the flight, and results in many having difficulties regaining flight and system control when an unexpected upset occurs.

The problem does not have a single root cause. Training, automation design, financial pressures on airlines, crew fatigue, etcetera; all contribute to the current state of the aviation system. From a holistic perspective, this emergent behaviour can be attributed the result of changing system dynamics and interactions. Reconsider crew workload reduction: the initial short term benefits are quicker crew recuperation and their allocation to secondary tasks, such as fuel optimisation. A less expected behaviour is “automation complacency”, which describes pilots casually accepting suggestions and trusting automation, biased by a low failure rate. Hence, active cross-checking, verification and understanding of the automated processes quickly goes by the board, resulting in questions such as “what is it doing now?”.

However, projects to identify these sysJUNE 2013 Leonardo Times

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NTSB

Figure 2. One of my NTSB cases, ID ERA12IA459: High-magnification striation patterns on the fracture face of an aluminium propeller of a Socata TB-10 aircraft indicate the presence of fatigue.

tem shortcomings are picking up speed.

ICATEE (International Committee for Aviation Training in Extended Envelopes), the NASA Ames Flight Cognition Laboratory and MAN4GEN (Manual Operations of 4th Generation Airliners) are strong examples of developments aimed at resolving this modern flight safety problem.

I was introduced to the MAN4GEN project after attending several interesting symposia, presentations and lectures on modern aviation safety. MAN4GEN is a European consortium including Airbus, Boeing, EASA, NLR, DLR and others, aimed at investigating flight crew operations in modern cockpits. My thesis literature work was already focussed on flight cognition and automation, and I was quickly able to start my MSc thesis internship in May 2013 at the head institute, the NLR. I will be investigating the role of automation in the provision of information to flight crews. My work will conclude how information provision affects the quality of the choices crews make during unexpected occurrences.

gator at the OVV, the Dutch Safety Board).

This annual scholarship from ISASI (International Society for Aviation Safety Investigators) permitted me to attend the annual week-long conference in Baltimore.

Next to learning from other speakers, I was given the opportunity to describe myself and my essay to the full audience of over 250 worldwide investigators. This was a fantastic time get to know and be known in this field. As part of my scholarship, I have also completed an SCSI training course in human factors, and in the near future will attend another course offered to me in the UK. There is a very clear demand for young engineers in aviation accident investigation. If you are interested in accident investigation and aviation safety, consult my references at the end of this article.

IMMERSE YOURSELF! My internship and thesis are only two examples of how an aerospace student can pursue his studies in aviation safety. There are many other ways to explore aviation safety. I will end with two other significant relevant activities I have undertaken.

In addition to my studies, I have recently immersed myself in Safety Management Systems. Currently, as the Safety Manager of the Delft Student Gliding Club, I am developing and implementing such an SMS as an EASA requirement for Approved Training Organisations, from 2015 onward. This work also introduces me to yet another cornerstone of aviation safety; prevention. At the moment, our SMS is a leading example within the Dutch general aviation community, and I look forward to improving the safety of our operations with it.

Parallel to my experiences at the NTSB, I was selected as a recipient of the Rudolf Kapustin Scholarship Award, the second Delft student to ever do so after Michiel Schuurman in 2003 (who is now investi-

In my experience the field of aviation safety is probably the most multidisciplinary study for aerospace engineers at the moment. I myself expect to further my studies toward human factors and cognition,

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as I believe it to be one of the most promising fields of aerospace engineering in the future. I would like to end with a quote which I hope will inspire other aerospace engineers to also explore aviation safety studies: “Take nothing for granted; do not jump to conclusions; follow every possible clue to the extent of usefulness… Apply the principle that there is no limit to the amount of effort justified to prevent the recurrence of one aircraft accident or the loss of one life.”

(Accident Investigation Manual of the U.S. Air Force) References NTSB; NTSB Identification: ERA12FA018; NTSB; 2011; http://www.ntsb.gov/ IATA; “Global Accident Rate Reaches New Low - Regional Challenges Remain”; IATA; 6 March 2012; http://www. iata.org/ Sherwood, B.; “The Three Myths About Plane Crashes”, The Huffington Post; January 15 2009; http://www.huffingtonpost.com/ ASN; “2012 exceptionally safe year for aviation”; ASN; 1 January 2013; http:// news.aviation-safety.net/ Maneesh, P.; “DGCA safety audit uncovers scary truths: Three year findings reveal facts on loose screws, fuel seepage and 83 drunken pilots on duty”; India Today; 26 March 2013; http://indiatoday. intoday.in/ MAN4GEN project: http://man4gen.eu/ ISASI website: http://isasi.org/

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Interview

AIRBORNE AEROSPACE Interview with Business Development Manager Space

Airborne Composites designs and manufactures composite parts for the Aerospace, Oil & Gas, Marine and other industries since 1995. They are involved in notable hightech projects, from the Galileo Satellites, to the Gulfstream aircraft for Fokker and the ALMA astronomical telescope. The Leonardo Times sat down to talk to Sandor Woldendorp, Business Development Manager, Space division at Airborne to get an insight in the question: ‘’How do they do it?’’.

TEXT Alisa Nevinskaia and Sushant Gupta, Students Aerospace Engineering, Editors Leonardo Times

LT: Can you tell us something about yourself and your position at Airborne?

SW: I am Sandor Woldendorp, Business Development Manager of the Space division at Airborne. I am responsible for the sales and business development of composite spacecraft structures. I started at Airborne seven and a half years ago as a stress engineer and grew towards project management. Since four years, I do sales & business development.

My study was at TU Delft at aerospace engineering. My thesis work was performed in the aerodynamics department and that was also my first job. I started working at NLR in the aerodynamics department. After 3 years, I moved to the

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engineering company Silver Aerospace, where I was part of the design team for a flap for the A380. After that I worked for Airbus in Germany for 9 months. In 2004, I joined Airborne and got the opportunity to build my career here.

LT: Airborne was founded by two Delft aerospace engineers. Could you throw some light on the background of Airborne?

SW: I am not one of the founders, but I know the story of our company. In 1995, the two founders had just finished their studies at the aerospace department in Delft and founded the company, focussing on aerospace and offshore markets.

Since then, Airborne has grown abun-

dantly in the number of employees (200+ personnel today), as well as in the range of activities. We now have production divisions at three sites: Ypenburg, IJmuiden and Girona, Spain. The growth was fueled by several processes. Firstly, the customers wanted to have a feel for the products: making prototypes was incorporated in the activities. After about ten years, a number of customers required serial production of parts. We had to move to The Hague facility to make that possible. At that point in time, metals were used for product manufacturing as well. Around 2005, we decided to focus on composite technology, as we experienced that that was where we had an added value to the markets. The company name was changed to Airborne Composites to ex-

AIRBORNE

AIRBORNE

Figure 1. Sandor Woldendorp, Business Development Manager, Space division at Airborne

press the focus that we chose. We do not do any metal designs anymore, but of course, most of the products still have a metal interface like bolted connections or bush fittings. The metals that we use depend on the specific products. In space, we use titanium and aluminium inserts. In marine applications steel is used, which has to be surface treated. All kinds of metals are still used, the choice depending on the application.

However, our expertise is in composites.

as the external communication, like our website, will also be structured in accordance with our market focus.

LT: Is this a marketing focus or does this change something internally in the company as well?

SW: Both actually. Oil & Gas is an example of this approach. It was launched two

dishes for astronomy and high-end parts for ASML (chip lithography machines).

For energy-related markets, we make big flywheels for storage of kinetic energy. If we see potential in a specific market, we choose to give that a greater focus and develop it into a separate unit. In Dutch, we call it a “Kraamkamer” – a nursery or incubator – for new business. The process was the same for the Marine unit, which was at first a new activity within Airborne Composites. In a few years, the Marine unit was vital enough to become a separate business unit. When products sprout in the “Specials” department and have significant growth potential, they might evolve into a separate business unit, if they represent a market in which we can play an important role.

“ Airborne was founded

LT: To what extent are the founders involved in Airborne these days?

by two aerospace engineering graduates.”

SW: The first four employees including the founders are still in the Board of Directors today. They do a lot of strategic decision-making. A recent decision that was made is to focus more on the following markets: Aeronautics, Space, Marine and Oil & Gas. This year we will make the transition in which Aeronautics and Space will be placed in a separate business unit: Airborne Aerospace. The same goes for Airborne Marine. This way, our clients will get more focus than they already had. The internal resources as well

years ago as a separate business unit in a separate location in Ijmuiden. There, our capabilities and expertise for the Oil & Gas market are concentrated in one place.

LT: Apart from Aerospace, Marine, Oil & Gas, you have a specials department.

Could you elaborate about what goes in “Specials” called Airborne X? SW: For instance, we make large antenna

LT: What are the challenges you face in the development, production and automation?

SW: When looking at automation, the challenges concern quality assurance and qualification. The processes that we handle by hand today could be handled automatically by robot tomorrow. What JUNE 2013 Leonardo Times

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AIRBORNE

Secondly, there is an ethical component.

Of course, we would not make weapons of mass destruction but also in general weapons, is not our business’’. Airborne is essentially a high tech company. There are many consumer products made from composite materials, from tennis rackets to polyester boats that is not our business. Products developed by Airborne are ‘’high spec’’.

Airborne likes to bring added value to the table, a real advantage for our clients, where our technologies enable our clients to obtain a unique position in their market. If there are a number of other companies that can accomplish the same task in the same way, a “no bid decision” can be made.

LT: What are the major arguments you have to put to clients to switch to composites in place of metals?

AIRBORNE

Figure 2. Galileo solar panel substrates manufactured by Airborne

Figure 3. Robot platform for composite manufacturing

needs to be proven is that the robots deliver the same or better quality. For example, Fibre lay-down can be accomplished by humans as well as by robots, but there are limitations to the capabilities of robots. On the others hand, robots make less mistakes than humans. Note that there are some processes that cannot be done by hand, for example fibre steering or advanced fibre placement, which can only be achieved mechanically. I cannot point out generic challenges to automation; each process has its own challenges.

gram in cooperation with our clients.

The first step is designing samples, after which a first article or prototype is made and tested in a laboratory. For spacecraft parts, the tests are performed in a simulated space environment. The testing sets challenges on our budget and resources.

It is a long path to operational life on a spacecraft for new products and technologies.

LT: What kinds of problems are faced in general, when you start discussing the manufacture of a certain product with clients?

SW: With every request from a customer approaching Airborne, a bid/no-bid decision is made. The selection is made on a number of criteria. First of all, the insight on whether a project is commercially attractive is acquired. As for any commercial company, the question: “Will we make a profit?” needs to be answered.

SW: For aerospace, an important aspect is that the product must be qualified for flight. Qualification is an intensive pro-

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LT: What are the criteria for a bid/no-bid decision?

SW: Well, usually our clients do not have to be convinced anymore. In the past we used to ‘preach’ why a client should choose composites over other materials. Fortunately, that is not the case anymore. Our clients usually know that they can reach better performance levels with composites: lower mass, higher stiffness, strength, less fatigue, no corrosion or a combination of these. If a client wants more information for making trade-off, we can provide that information as well.

What we do have to do is convincing the client about economic viability. Is it worth to pay the price for the benefits composites offer? Next to that, we have to proof that we can maintain the quality of the product in a series production. The serial production obviously reduces the price. Automation of the manufacturing process helps in that case.

LT: Could you provide some information about automation at the in-house Technology Centre?

SW: A number of processes have been robotized in-house. The trick for Airborne is that we do not make or buy a robot for a single process. It is common in Aerospace for Tier-1 supplier to go to a Robot manufacturing company to automate a specific process. The robot is designed to do exactly that and only that. We think that especially in Space and sometimes also in Aeronautics, the number of recurring products is too low to have one dedicated robot, which can cost a few million euros. In these cases, the cost of such a robot is not justified. Our concept is to have one flexible robot platform on which can place different heads, the so-called endeffectors, at the end of the robot arm.

In this way, theoretically speaking, we can have the robot do one process on

Monday, the other process on Tuesday, Wednesday etc. In addition, this flexible robot does not cost millions; it costs an order of magnitude less than that. This way we do not have high investments to automate a process for aerospace manufacturing. That is our cost-efficient solution for automation.

The development and programming of the head/actuator unit is done at the Airborne Technology Centre.

LT: This distinguishes you from your competitors.

aircraft for Fokker. Also recently, Fokker, manufacturing parts for Dassault SMS -a business jet - has selected us for production of empennage parts.

With our facility in Girona, we are working for years with Airbus and Eurocopter in qualification processes for programs like the A350.

LT: How do you see the future for composites in Aircraft Industry?

SW: Most of the aircraft can be made of

plexly shaped and highly loaded. Those are the parts where we want to play a major role in the ‘transition’ to composites.

LT: Are the high costs of Composites a disadvantage?

SW: Price of the composite part itself may be higher than of a metal part but if you include the cost for assembly, inspection and maintenance, it is beneficial in the long run. For instance, take the cost for inspection for fatigue: a composite structure may be initially more expensive to purchase, but at the end of its life, it may have cost less than a metal structure.

A stringer in thermoplastics might be more expensive, but then you do not need all these rivets, you can weld it.

The term used here is TCO: total cost of ownership. In general, the composite cost is initially more expensive than the metal part, but the clients are looking at the total lifecycle costs.

“ If there is no safe material today,

SW: Yes, we are not only development or only engineering or only a manufacturing company but we have all these capabilities in-house.

We can do the development, engineering, production, and qualification of composite products. This is not unique, but few companies can claim this in the high-end composites market, especially SME’s (small and medium enterprises).

it should have a safe alternative

tomorrow, that’s the philosophy.

LT: What are some projects that Airborne has been part of in the Aerospace Industry?

LT: What does relationship with the TU Delft entail?

SW: We have a good relationship with the TU Delft. Airborne was founded by two aerospace engineering graduates. After that, a lot of our employees came from the TU Delft, fresh graduates and people with experience. A big part of our management staff are Aerospace Engineers who have worked for other companies,

AIRBORNE

SW: We are proud of our involvement in the development and building of composite antennas for the ALMA astronomical telescope. We are involved in the Galileo Satellites, where we made all the solar panel substrates. In Aeronautics, we do serial production of parts for Gulfstream

composites in the near future. What you already see is that the Dreamliner has a full composite Fuselage. In the 1980’s, I recall that Beechcraft had already made a full composite business jet named the Beechcraft Starship. It was the first full composite jet with the wing as well as the fuselage made of composite. The new Airbus A350 will have a lot of composite.

The engines will be made of metal but most of the load-carrying structure will be composite. In this way, it reduces the mass, which is beneficial for fuel efficiency. Some of the metallic parts like load introduction ribs and brackets, are com-

”

Figure 4. Airborne personnel in front of ALMA telescope

JUNE 2013 Leonardo Times

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AIRBORNE AIRBORNE

Figure 5. Fibre steered space panel

and guidelines regarding harmful materials and chemicals according to REACH (Registration, Evaluation, Authorization and Restriction of Chemical substances), which is the European Community Regulation on chemicals and their safe use. ”If there is no safe material today, it should have a safe alternative tomorrow, that’s the philosophy’’. At the moment, Airborne is involved in the development of a new generation of solar panels in collaboration with Dutch Space. Selection of harmless materials and processes, with long-term availability, has its challenges.

New materials and smart processes are being researched and the focus is on cost efficiency and performance increasement with also sustainability in mind.

That includes the raw materials and how these are produced, so taking in account of what our company is buying and using.

On the other hand, it sometimes is simple to be eco-friendly. Our offices for instance all have motion sensors. When no movement is detected for a number of minutes, the lights are shut off automatically. This saves a lot of energy.

LT: What is your Marketing approach as a High-tech company?

Figure 6. Manufacturing of Galileo solar panels for Dutch Space

bringing in a lot of experience to Airborne. We get a lot of support especially in the Technology Centre where students do their internships and thesis work with us. There are a number of examples where we have seen that students are good in

of the TU Delft, specifically the Hechtingsinstituut, who are bonding experts. This was for an adhesive bonding of a composite part on a metal interface, which of course should survive in severe conditions at sea. We have some other development projects with TU Delft as a partner, where for instance numerical expertise is required.

“ The trick is not to tell the trick.” their work and have been offered a job.

In this way, we continue the relationship with the university. We cooperate with the university in other ways as well. For instance, the university has a test lab that we use on a regular basis to do some of our testing, a whole range of mechanical testing, including NDI. LT: Is Airborne involved in some projects together with the TU Delft?

SW: We developed a Marine propeller for the Navy, where we used the expertise

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LT: How do you look at being an Ecofriendly company?

SW: One element of Airborne’s mission statement is ‘’we care about our planet and our people’’. Caring about our people means that Airborne will provide an interesting and safe environment with challenges and opportunities for her employees. Caring about our planet is expressed in recycling the waste materials externally and following the rules

SW: Marketing, in terms of Airborne’s brand personality comes down to Expertise, Entrepreneurship and Visionary. Our website is currently undergoing an update that will express the company’s philosophy, products and goals. Next to that, the company takes a pro-active approach to reach potential clients. Our researchers at the Technology Centre develop a lot of interesting stuff, they give lectures, write papers and do presentations on influential technical conferences. The engineers attend SAMPE (Society for the Advancement of Material and Process Engineering) and JEC. It is a challenge to share knowledge on new technology with clients, competitors and other researchers, in a way that the proprietary information is not disclosed. The trick is not to tell the trick. Going to the right business events is another factor in marketing. Airshows in Paris, Berlin and Farnborough, job events like the ‘’Banenmarkt’’ in Delft, business to business meetings, etc. Then there is also the very direct approach, visiting our customers and potential customers. Media exposure is important as well, therefore this articles in the Leonardo Times is highly appreciated!

Later this year, Airborne will take part of the NASA exhibition – A Human Adventure in Utrecht.

Our social media team is available 24/7 Regardless of the time, where you are, or what your circumstances may be, someone from KLM is always available to help. Just contact us via facebook.com/klm or twitter.com/klm and we’ll respond within one hour.

KLM 24_7 210x297.indd 1

25-04-13 17:11

SAFE SYMPOSIUM Safeguarding Aviation in the Future Effectively

VSV ‘LEONARDO DA VINCI’

LVD

This year the Aviation Department had the honour of organising the annual symposium of the VSV ‘Leonardo da Vinci’ on the occasion of its 20th anniversary. On March 5, 2013 approximately 250 students and aviation professionals gathered in the Auditorium of Delft University of Technology to enjoy a day filled with inspirational lectures and educative discussions to gain a deeper understanding in the role that safety plays in the world of aviation.

TEXT Bob Winters, BSc. Student Aerospace Engineering, Symposium Affairs of the 20th Aviation Department

T

he world of aviation has always been aware of the risks involved, yet it has always been encouraging curiosity, looking for innovation and pursuing its challenges to fly even safer. With safety as trademark and top priority, the SAFE Symposium hosted discussions on the latest developments in the world of aviation with respect to safety.

The day was filled with lectures from an internationally respected ensemble of guests, all linked to the general theme of safeguarding aviation in the future effectively. Fred Abbink, former Technical Director of the National Aerospace Laboratory guided the audience through three sections of the day: Material and Maintenance, Air Traffic Management, and Flight Control. The day was concluded by an interactive debate led by Pablo Mendes de Leon.

MATERIAL AND MAINTENANCE Discussing safety in the future of aviation is impossible without a thorough understanding of materials and maintenance.

Is it possible to have large-scale innovation, with full composite aircraft whilst

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at the same time guaranteeing or even improving the overall safety of aviation?

What impact does a radical change in the use of materials or systems have, especially for the maintenance personnel?

Jan Verbeek, Partner & Senior Consultant of ADSE enriched us with a deeper understanding of this subject. He explained this subject with examples taken straight from the field and gave the attendees a clear insight in the practical issues that arise when implementing innovation. The title of his presentation “Innovation and Safety – a contradiction or two sides of the same coin?” was the perfect opener of the SAFE Symposium. His striking conclusion was that they are in fact part of “the same coin” and should be treated integrally rather than in competition. Furthermore the innovation of the complete certification process needs more attention to guarantee a successful deployment of the final product.

Steven Soederhuizen, Vice President Operations & Supply Chain of Fokker Aerostructures taught us that despite what most of the audience thought, Fokker is not only still alive but is alive and kicking.

Still over 500 Fokker aircraft are operated today and amongst many others, Fokker plays an important role in the construction of most business jets tails and the Glare panels of the A380. The type of business Fokker is delivering to the world even deserved its very own verb: AircraftING. The presentation was concluded with a direct call on the audience to join the Dutch aerospace industry.

AIR TRAFFIC MANAGEMENT The next challenge is to successfully handle all aircraft in the air. Ideally airplanes should be able to fly direct routes between destinations to minimise fuel burn and, thereby, the impact on the environment. Originally scheduled guest speaker Günther Matschnigg, Senior Vice President of IATA sadly fell ill just before the symposium and we were very fortunate that Giancarlo Buono, Assistance Director of Safety and Operations Europe from IATA was able to replace him so fast and so well. With traffic growth outgrowing capacity it is IATA’s vision to promote costeffective solutions that ensure the safety, capacity and efficiency of air travel. IATA

VSV ‘LEONARDO DA VINCI’

Figure 1. Jacco Hoekstra presents the Free Flight Project

promotes PBN (Performance-Based Navigation), something that has been spoken about for forty years already, but the realisation is only just occurring. PBN requires a transition from conventional navigation to area navigation.

One of the bodies responsible for air traffic management in Europe is EUROCONTROL. Tony Licu, Head Safety Unit at EUROCONTROL acknowledges all that was said before by Giancarlo Buono from IATA but with the subtitle: ”What do you need to know about future Risk and Safety Management and what you have not learnt in school.’’ He taught the audience how the industry should improve safety even more. Rather than focus on what goes wrong, focus on what goes right. After all, something that went wrong was supposed to happen correctly. It is therefore the trick to spot the things that gave the correct outcome, but in which the system might not function smoothly. Following Tony Licu was Jacco Hoekstra, the former dean of the Faculty of Aerospace Engineering of Delft University of Technology.

His approach to a safer and more effective air traffic management arose from a research project in cooperation with NASA, FAA and the NLR. This project named Free Flight is based on the assumption that airplanes have a 100% Airborne Separation Assurance and thus no Air Traffic Control

is needed for separation. This project strikingly concluded that with a relatively simple algorithm for separation Free Flight has the potential of increasing safety, capacity and efficiency. This out of the box project was a real eye-opener for the audience as it showed that potential solutions for the current problems exist but are not yet fully exploited.

FLIGHT CONTROL After lunch it was the role of Harry Nelson, Executive Operational Advisor to Product Safety and Former Experimental Test Pilot of Airbus, to focus more on the human (error) side of flight control. He gave the audience an overview on the improvement the aviation industry has made with respect to safety. Drawing on this own experience as a (test) pilot, he provided real-life examples on how several safety systems as we know them today, over time, came into existence and the respective philosophies behind the systems; it was truly an inspirational lecture.

Joram Verstraeten from the NLR ended the lecturing part of the symposium with a clear overview on the development of Unmanned Aerial Systems. Joram Verstraeten investigated the question whether people should step aboard an unpiloted flight. It can be answered with the formulation that as long as the system

INTERACTIVE DEBATE Concluding a day of interesting lectures it was time for the speakers and the audience to start debating. The audience was able to interact with the panel and moderator with help of a Twitter Wall.

Pablo Mendes de Leon, Director of the International Institute of Air and Space Law from the University of Leiden, hosted the debate. He proved to be the perfect neutral balancing factor with an outstanding knowledge on the subject to get the best out of each panel member respectively. It was the perfect opportunity for the audience to ask all remaining questions and start discussing on the lessons learned from the day. It is safe to say that ‘SAFE’ enriched the audience with the understanding of the role that safety plays in aviation and was received with great enthusiasm over the day.

Special thanks go out to the speakers, Committee of Recommendation, sponsors and volunteers for their contribution to the SAFE Symposium.

For further information visit www.safesymposium.com `

sponsored by:

supported by: Delft Infrastructures & Mobility Initiative (DIMI)

is not outperforming the human on all fronts, we need humans to fly the aeroplane. Or would you already step aboard on what may be everyone’s future?

Aviation Department The Aviation Department (LVD) of the Society of Aerospace Engineering Students ‘Leonardo da Vinci’ fulfills the needs of aviation enthousiasts by organising activities, like lectures and excursions in the Netherlands and abroad.

Sustainable solutions from a multidisciplinary approach

JUNE 2013 Leonardo Times

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T-MINUS ENGINEERING: A COMPANY IN ROCKETRY The start of a company in automated aerial and space vehicles

The idea started when a group of students from Delft Aerospace Rocket Engineering were sitting at the breakfast table of the Esrange launch base canteen, in the far north of Sweden. It was the day after the successful launch of the self-built Stratos rocket, that broke the European altitude record for amateur rockets. “This is what we love to do, and apparently we are good at it. Let’s try and make a living building rockets”.

TEXT Hein Olthof and Mark Uitendaal, Co-founders of T-Minus Engineering B.V.

T

he idea to found a real rocket company was thus born that day in Sweden.

The idea, however, was still very new, and the group broke up before it could really materialize. Mark Uitendaal graduated soon and went to work for the Swedish launch base. Eric Smit finished his study soon after that, and started working on the Delfi N3Xt satellite. Roel Eerkens and Hein Olthof were still following courses for their master’s degree. However, the idea remained, and in 2011 the company T-Minus Engineering was finally founded.

Given the background of the founders, who all graduated at TU Delft (aerospace engineering and electrical engineering) and have extensive experience in the design and operation of rocket systems, the perfect mix of skills and expertise was obtained to build high-quality rocket prod-

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ucts on a professional basis.

Only five hours after signing in at the chamber of commerce, and celebrating the founding of T-Minus with a nice dinner, two of the founders already flew to Glasgow, Scotland for the first mission: giving a workshop for the Scottish CanSat competition.

The CanSat competition is expanding rapidly in Europe. This project is set up in order to promote science and technology among high-school students, under ESA’s programme to promote STEM (science, technology, engineering and math) subjects. Several groups of four to ten students design and build a CanSat, a satellite the size of a soda can that is launched on a rocket to 1000m altitude, after which it descends through the atmosphere on

a parachute and carries out its mission.

Measuring temperature and pressure and transmitting these data in real time to a ground station is always the primary mission. But the secondary missions may be chosen by the teams themselves and therefore vary greatly. There are teams that just measure additional atmospheric properties, such as humidity or CO2 levels.

Others design a quadcopter to perform an autonomous descent.

T-Minus Engineering was involved in the European CanSat competition in a very early stage. At first, this involvement was only in the form of aiding in the organization of workshops and providing members for the CanSat jury. In 2012, two major contracts were signed with ESA: developing the CanSat starter kit and

organizing the 2013 European CanSat launch campaign. This led to the development of the first two T-Minus products: the T-Minus CanSat kit and the T-Minus CanSat launcher.

THE T-MINUS CANSAT KIT The T-Minus CanSat kit is designed to give the participating high-school students a quick start on building their CanSat. The heart of every satellite is its Master Control Unit (MCU). This is the part that collects all sensor data and distributes them to transmitters and storage units.

Therefore, the core part of the kit is an inhouse developed electronic circuit board that houses a powerful microcontroller, a power subsystem and all the necessary means to quickly connect sensors, storage devices and other necessary equipment. The board is electronically compatible with the popular Arduino experiment board, but the form factor is chosen such that it perfectly fits inside a soda can. Next to that, it also allows direct programming of the microcontroller, which greatly increases its flexibility. The board can not only be used for building a CanSat; it is much more versatile. For this reason, TU Delft already showed great interest in it,

T-MINUS ENGINEERING B.V.

T-MINUS ENGINEERING B.V.

T-MINUS ENGINEERING B.V.

Figure 1. Deployment of a CanSat as seen from the rocket

Figure 2. CanSat launcher in tower

and even facilitated its development.

Next to the MCU board, the kit contains an experiment board that is easily connected to the MCU. As the name suggests, it can be used for experimenting: soldering sensors, data storage devices, etcetera. Also two transceivers are included, so that a radio link from the CanSat to the ground station can easily be established.

To house all electronic components properly, the kit contains a simple structure on which the circuit boards can be mounted.

Finally, extensive documentation and lecture material on sensor usage, data processing and parachute design is included.

THE T-MINUS CANSAT LAUNCHER Of course, the most important and spectacular part of the CanSat project is the launch of the CanSats. For this, T-Minus Engineering designed a dedicated rocket: the T-Minus CanSat launcher. The key design elements for this vehicle are safety, operability and functionality.

The rocket is designed to deploy six CanSats simultaneously at an altitude of 1000m. It has a wide operation envelope, which means that it can be launched under a wide range of conditions. Wind speeds of 6m/s are no problem. It is pas-

sively stabilized by means of a fin set. The vehicle itself is 3.2m tall, with a diameter of 0.2m, and weighs 23kg when it is completely loaded. An in-house developed solid rocket motor delivers 1000N of thrust over a period of 4.2s, after which the rocket coasts to its apogee altitude.

Here, the CanSats are deployed after which the rocket is recovered under a parachute. In this way, the rocket can be reused with minimal refurbishment effort.

The vehicle is divided into two parts: a motor module and a payload module.

In order to minimize the safety risks during payload integration and the deployment shock on the payload themselves, the CanSat module does not contain pyrotechnic systems. Instead, it uses the T-Minus melter system for the payload deployment mechanism. This consists of a wire that supports the payload covers and a specially designed thermal knife. When the knife is activated, it melts through the wire and thus releases the payload covers, so that the payloads are deployed (Figure 5).

The maiden flight of the T-Minus CanSat launcher took place on March 4. Four liqJUNE 2013 Leonardo Times

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uid filled soda cans were installed in the payload bay as dummy CanSats, together with one real CanSat, made by T-Minus from one of the CanSat kits, and a video camera. After mounting the rocket on the launch tower, adjusting the azimuth and elevation, the countdown started: “T-Minus 10, 9, 8 … 3, 2, 1, Launch!” The rocket rapidly left the tower with a loud roar and in a thick cloud of smoke. According to the telemetry, all flight parameters were nominal. Twelve seconds into the flight, a critical event should occur: the opening of the hatches and deployment of the payloads. The telemetry stream from the rocket showed that the thermal knife was activated. Shortly after that, the payload deployment was visually verified, perfectly at apogee. Two seconds later, the parachute unfolded and the rocket descended gently down to the ground. This seemed to be a mission success. The rocket was quickly retrieved by military personnel and inspected by T-Minus engineers.

The parachute showed some degradation, due to the high deployment stresses caused by high dynamic pressure. The CanSat, however, could not be found immediately. This was already expected, as the impact terrain is quite rough. For this reason, the CanSat was equipped with a GPS tracker. Its exact location could therefore be pinpointed. Unfortunately, the military facility closed before it could be retrieved. A few days later, a phone call was received from the military: they had found the CanSat only one meter from its last transmitted GPS location. An

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inspection after the pickup showed that the CanSat was still in perfect condition.

A quick replacement of the battery and it immediately started to send its pressure and temperature measurements!

EUROPEAN CANSAT COMPETITION LAUNCH DAY Recently, the T-Minus CanSat launcher leapt into action on the launch event of the European CanSat competition.

Fifteen CanSat teams participated and waited anxiously for their CanSat to take flight. After their arrival in Holland, they had one full day to unpack their CanSat and perform some last-minute checkouts and updates at the facilities of TU Delft, under the watchful eye of the T-Minus experts. Compliance of each CanSat with the competition rules was checked. For some teams, this meant that their parachute had to be adapted in order to meet the required descent speed. Other teams had to actually shorten their CanSat, in order for it to fit inside the rocket. Finally, all teams were ready for the flight and went to Artillerie Schietkamp ‘t Harde by bus, early in the morning. Upon arrival at the military base, the CanSats were unpacked and per six, they were installed in their respective payload bays. The ground stations were set up and the radio links were checked. Then, the payload bays were taken to the launch ramp, fitted with the motor modules and installed in the launch tower. Four launches later, every CanSat had flown and performed its mission. Some of them even had the

T-MINUS ENGINEERING B.V.

T-MINUS ENGINEERING B.V.

Figure 3. Schematic representation of the DART vehicle

Figure 4. CanSat launcher in flight

chance to fly two times. Exhausted but happy, the students went back to Delft to analyze their results and prepare the final presentations that they had to give the next day. From these presentations, it appeared that the results of the teams varied greatly. Some missions were completely successful, while other teams had not managed to retrieve any data via their telemetry system. After an extensive discussion by the jury, in which a representative of T-Minus took part, the winners were chosen. They received a great applause and an impressive gift from ESA: a large telescope for use at their school.

Surely, this event has motivated a lot of students to pursue a carrier in science and technology!

FUTURE CANSAT ACTIVITIES Interest in the CanSat competition is growing within the European countries.

After the Netherlands and Norway, similar initiatives can be found in Italy, Spain, Belgium and Great Britain. T-Minus Engineering, being a partner in organizing the European competition, is planning to take part in all of these projects, either by providing the CanSat kit, technical support or arranging the launch event.

T-MINUS DART Although the CanSat project provides a great opportunity to operate launchers, the aim of T-Minus is always to go higher and faster. For this reason, the DART project is initiated. The concept of this system is simple. The layer of the atmosphere

between 50 and 120km is sometimes jokingly referred to as the ‘ignorosphere’, because no real means exist to perform insitu measurements of this layer in a cheap and easy way. Stratospheric balloons only reach altitudes up to 50km, and satellites can perform missions only above an altitude of about 200km because of orbit degradation due to drag. Sounding rockets can be used, but a sounding rocket launch is usually too expensive for performing frequent and relatively simple measurements. The DART system will provide the means to perform a quick flight to the ignorosphere with a small payload, at a cost substantially lower than the launch of a sounding rocket.

The DART consists of a powerful, short burning booster motor and a thin payload dart (Figure 3). The booster is powered by a high-performance solid rocket propellant; similar to the one used in the space shuttle boosters. The design is optimized for high propellant mass and volume fraction, which means that as much propellant as possible is fitted into a small combustion chamber that is as light as possible. For this reason, the combustion chamber wall is made of composite material. The booster propels the rocket in approximately three seconds to several kilometers altitude, where it reaches Mach 5. After booster burnout, the rocket separates under the influence of drag and the dart coasts upwards its apogee.

A possible use of the DART system is performing frequent measurements of gas concentrations (ozone, CO2, volatile organic compounds) in the higher atmosphere. If desired, multiple DARTs can be launched per day. This may provide valuable data for climate studies or pollution research. Another possibility is to use the DART for atmosphere probing prior to a large rocket launch. This can be a sounding rocket or, for example, a suborbital manned flight with space tourists. With the DART, wind speeds and directions at high altitudes can be mapped, so that the flight of the larger rocket can be predicted and planned more accurately. Several launch providers have already shown interest in using the DART vehicle for this type of mission.

OTHER ACTIVITIES Although the CanSat and DART consume much of the time of the company, some

other activities are undertaken as well.

Firstly, T-Minus cooperated in the development of the Delfi N3Xt satellite, developing and supporting the electronics for some of the subsystems. Next to that, DLR Bremen contacted T-Minus with the request to design and produce a special payload hatch for use on the REXUS sounding rocket. This task was completed in less than two weeks and the hatch performed well during the flight.

INCUBATION AT YES!DELFT Since the primary skills of the founders of T-Minus Engineering lie mainly in the field of science and technology, it was decided to find an institution that could provide assistance and advice on the other facets of running a company, for instance planning a strategy and product marketing. As for most technostarters in Delft, the incubation center YES!Delft is the place to go. After updating the businessplan and presenting it before a jury of experts, T-Minus was accepted in the YES!Delft program. This is a great chance for us to develop our company and make our dreams and ambitions come true.

FUTURE PLANS In the future, T-Minus is planning to develop more and more advanced (sub-)systems for sounding rockets, establishing its name as producer of high quality aerospace products. The ultimate goal is to have a completely in-house developed sounding rocket system within ten years.

T-MINUS ENGINEERING B.V.

The dart diameter is very small, approximately 30mm, in order to minimize the

influence of atmospheric drag during this coasting flight. This might be a possible drawback of the system, since it limits the available payload volume. However, with the current trend of miniaturization of electronic systems and the use of Micro Electro-Mechanical Systems (MEMS), many missions can be carried out within this small volume. Small sensor packages, such as a GPS receiver, pressure-, temperature-, humidity (PTU) sensors or acceleration sensors are a few examples. Also, radio transceivers are sufficiently small these days to be fitted inside the dart.

Figure 5. Deployment of the CanSats

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Interview

A NEW DEAN IN TOWN An interview with the new dean, Professor Hester Bijl

On April 15, Professor Hester Bijl was officially appointed the new dean of the Faculty of Aerospace Engineering. Succeeding Professor Jacco Hoekstra, she became the first female dean of the faculty. She is a Delft alumnus who has worked in both business and academia. Ample reason for the Leonardo Times to sit down for an interview with Professor Bijl.

TEXT Lubi Spranger and Benjamin Broekhuizen, Students Aerospace Engineering, Editor and editor-in-chief Leonardo Times

Congratulations on your appointment as dean of the faculty. Some time ago, you were a TU Delft student yourself, studying mathematics. In addition to that, you also studied English language and literature in Leiden. How did that come about?

Well, I started off with just studying mathematics here. I sort of liked everything at high school, so I had a hard time choosing. I like languages, but also maths, physics, chemistry, astronomy … I could not choose. I went to many open days and thought: maybe what I like on the ‘beta’ side is mathematics. It is the unifying part that is elemental to the whole of maths, chemistry and physics. I thought I would start there and maybe if I were wrong I could always easily switch, because mathematics is useful.

I visited all kinds of universities, but I really liked Delft. It was called ‘technical mathematics’ and it was very much applied mathematics. They presented how you could use maths to solve problems, instead of just proving theorems. After a couple of years of studying and I was sort of missing the language part. I loved

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to read, but I thought it would be nice to learn a bit more about it and talk with other people about what I had read. I then found out that for nothing extra, you could give it a try. I am not sure how it is know, you might have to pay, but in that time you did not have to pay a guilder extra.

I opted for the part-time version of English language and literature at Leiden University, which meant lectures on two evenings per week. I started there in my third year of my maths, sort of half way through the year, and finished it when I was doing my PhD. It was entirely different: the culture, the population. There was only one man in the entire class, which is the other way around from Delft. Poor guy! He left, actually, after a year. But there were a lot of older women who already had a job and started studying later, so I was much younger than the average age there.

What was your student life like? Were you involved in any societies or activities?

Yes, I was a member of de Koornbeurs. I

believe that still exists. It is more of a ‘jongerenvereniging’. I liked the fact that you could also be a member if you just lived in Delft and were not a student. So, it was an open society and I had quite a good time there. I was involved in some activities, like organising the Ontvangstweek and organising cultural events there, such as stand-up comedy, theatre and other things.

That is a busy schedule: Leiden, Delft, de Koornbeurs. Did you have time for anything else?

I think I still played the clarinet at that time. I stopped playing after I had children: I had no time to practice. I was there, arriving fifteen minutes late because of work, without having practiced. I could sort of catch up along the way, but I felt sorry for the orchestra. So I stopped doing that. I do salsa dancing now, which I can do at night when everyone sleeps. Nobody suffers!

After your studies in Delft, you went on to join the Boston Consulting Group (BCG).

Is there a specific reason for doing that?

After my studies I first did my PhD, also in Delft. I had several options, but I liked the Delft topic the most and I spent around at the NASA Langley Research Center for my PhD. After my PhD, I went to BCG. I really liked doing my PhD. I liked that it was tough, that you could dive into it.

But after a while, it did not seem like something for the rest of my life. You are rather on your own.

It depends a bit on your group now: in my group, people are less on their own, I think. But at that time, I was quite on my own. It was my promotor, a tutor and me.

It was four years on one project.

I then thought: maybe I like solving tough problems with other people, in a shorter time; a few problems a year instead of one for four years. That is why consultancy appealed to me: it is problem solving in shorter periods with teams, while going out into the world. I wanted to see something. Instead of only seeing university, have the opportunity to see companies and what they were doing.

You also get very good training there.

a long period of time. I also missed students, I really like working with students.

I thought that for the long term, this was not really my thing. For a couple of years, yes, but not my long-term career. I preferred the science career more: students, university. Then there was a position here at the faculty as an assistant professor at Aerodynamics. I saw that when I was sort

and I want to come back.” His response was: “Well, after two years you can come back: you can catch up, read papers and start again.” He was right. You do lose a bit: if I had done a post-doc and then went on, I would have been publishing all the time, whereas now there is a small hole in the publication list. But this is compensated by the skills and the experience I got at BCG. So, overall, it was fine and I could catch up here. The topic was slightly different from my PhD: it also concerned computational fluid dynamics, but now in a broader sense, also including challenging unsteady flows. It was nice we found a position with NASA for the first six months. I joined here, taught one course and then left to join the project at NASA on the same topic for six months in Langley, Virginia.

After that, I came back. It helped me getting into the topic quickly. And of course, it was aerospace engineering, which I really liked too. The mathematics side is nice, but it is like “I have a hammer, maybe somebody needs a hammer”. In my PhD, we had solved a problem for computing fluid flows which have both high and low speeds in different ranges. Normally, we had code for high speeds and code for low speeds: one wouldn’t work for the other. I made an algorithm and implemented it, so we could solve both. Then we thought: “Right, who wants to solve this?” We found that AkzoNobel at that time was producing fibres where they stretched the fibres with air and they had this problem. It is the other way around. Here at aerospace

“ I sort of liked everything at high school, so I had a

What was the reason to come back to academia?

I really enjoyed BCG and I would do it again, because it was a great step after my PhD. It was seeing and meeting people, learning different skills and seeing different companies. But I missed a few things.

I missed science: I missed thinking for

hard time choosing.” of in a dip and I thought: well, let’s apply.

Would you say that you still reap the benefits from being at BCG? Yes, I do. It’s hard to exactly pinpoint it, but you get very good training there and I think that still comes in very handy, writing and presenting for example. Also, you learn how to tackle problems and how to work in teams.

Was going back to academia a smooth transition after being outside your profession for some time?

I could have imagined working in consulting a couple of years longer, but when I left academia I had asked my promotor: “What do you think? I am planning to go out in the world, but maybe I am wrong

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fluencing the agenda. But we need to constantly strive to further improve ourselves and aim for even higher quality.

If you think about entrepreneurship, we have quite some successful start-ups like ISIS and Ephicas by aerospace engineers.

At some point the largest part of the Yes!Delft incubator was aerospace. The director has informed me that this is no longer the case, so that might be a goal!

With the budgetary constraints in mind, how is the money best spent in the faculty?

I think 99% of the cost paid from the first money stream – coming from the university – is fixed: salaries, labs. Your financial steering power is, therefore, quite limited. And I think that is also fair. Because if you are in a good position, you should not change things too much. On an educational level, you should avoid too many drastic changes as well. You need a very good reason for a major change as each change has strong implications for students. When possible you should change gradually.

Furthermore, we should not only focus on the money we receive from the central organisation, although you should fight for it. Most opportunities are outside, we should just go together outside. There is much more there: industry, EU projects, national research funds.

engineering, the challenge is out there. I can hear the wind tunnel whenever they switch it on. The challenge is there, you need to compute. I like that.

do first is get to know the other parts of the faculty better. I want to really make a tour, meet the other department heads, the people working at the departments, as well as the support staff.

Speaking of challenges, what do you see being your main challenges as a dean?

After all, it is quite a different job.

What I see for our faculty: I think our faculty is doing really well, we attract top students. We have a top educational programme on the really exciting topic of aerospace engineering. Our master was

Of course, I know the faculty quite well. I started working here in 1999 at Aerody-

“ I do salsa dancing now, which I can do at night when everyone sleeps. Nobody suffers! namics and have been, I think, the department’s chair for five or six years. For the last couple of years, I have been the chair of the department of Aerodynamics and Wind Energy and Flight Performance and Propulsion. I have spent time in the management team with the previous dean.

So I have some idea, but what I want to

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”

rated one of the best in the Netherlands and our students find jobs almost the quickest of the TU Delft. We do well on research and we have a lot of PhD students: almost 200 now. Our scientific output and impact is growing and also our stamp on the world. We are in EU committees now, not only part of projects, but actually in-

It is one of the things Jacco (Hoekstra, the previous dean) did really well: make that position very strong and not lose what we have. I think the large opportunities are outside. That is also why going together helps, so that would be theme one: going outside together. Not always and not everyone, but for instance aerodynamics and structures, or flight performance, aerodynamics and control on flow control, going out into the world, looking for outside partners.

That would be theme two: external relations. I think we’re doing really well and have a great position in the EU. If you look at what our researchers do, they have lots of relations. About a third of our budget already comes from outside: from subsidies, but also from company projects coming from outside. People are really busy acquiring money for PhD students, post-docs and projects, but I think we can do it more strategically: use me. Scientists working together with researchers from Airbus, DLR, Fokker, NLR and then I maintain relationships with the CEOs or CTOs of the companies, going out there to get stronger ties.

The third theme is education, which is actually number one. There’s nothing wrong with our educational programme, it is one of the top in the world I think. But we should keep it top of the world. Monitor

how students are doing.

Also important is our educational load. If you look at our faculty compared to other faculties, we have quite a high educational load for our scientific staff. So that you should also monitor. See if it is divided more or less equally. You can divide money, but you can also divide education.

You were the first female to be appointed professor and now the first to be dean so do you see a role for yourself in drawing more female students into engineering?

I certainly hope so. I really would like to have more female students. Because we miss out on a lot of talents. It’s 11% now and we come from 5 to 6% a couple of years ago. It has doubled in a couple of years’ time and I would like to see it doubling and doubling again.

dents how it is going and whether we can improve something for them. One thing that’s really nice at the TU Delft is the fellowship they have for assistant professors or associate professors. We keep a look out and ask the department chairs or professors to keep an eye out for high quality female scientists. And we have the Tinkerbell scholarship which Jacco started, which is for female PhD students. We have very good MSc women doing great research who would like to pursue a PhD, so

but also NOx and noise emissions will need to be reduced significantly.

In the space industry, there are several trends. One major trend is the ongoing miniaturisation of spacecraft and components, which leads to interesting new possibilities. Another exciting development is the advent of commercial space travel.

In the field of wind energy the major challenge is at sea: there is a need for robust offshore wind energy solutions that are significantly more cost-effective.

“ I really would like to have

more female students. Because

”

we miss out on a lot of talents.

In fact, female students at TU Delft currently perform better than the male students, but that is probably because we get the dedicated female top.

I think diverse teams work better. But how to do this? I read a few researches into that and I think one thing you can do is lead by example, to show it is possible. By being there and by being visible, girls can also think aerospace engineering might be for them. That is one thing I can do: whenever I can appear somewhere, I will do it.

Internally, there are several things I would like to do: of course talk to the female scientists, PhD students and regular stu-

I would like to support them as well. But I think it already helps being there, showing that it is possible.

Which future developments do you foresee in the aerospace industry and how will they influence the faculty?

If you take a look at what lies ahead for aerospace, I think this is a great time to be the dean of this faculty. There a number of major challenges.

The number of flight movements grows each year, but there environmental constraints become stricter and stricter. There is an enormous challenge: not only CO2,

All these developments will require smart aerospace engineers designing new solutions. In our strategy for the faculty, we took that into account.

If you could give one piece of advice to students, what would that be?

I would go for balance. In your student life, you can get so busy: studying, social activities, perhaps design activities in student teams. You might also have a job, so you can be short for time. Keep an eye on the balance and really make sure that your percentage of studies doesn’t go below a certain critical limit. Keep your studies going and then balance it with activities outside. But also, start immediately. I think students lose time and we might even lose students who wake up too late. It’s quite a change from high school to university.

The sooner you realise this and really start, the higher the chance of success is. And maybe I can do something there, too.

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Internship report

DESIGNING AIRCRAFT IN ITALY Internship at Piaggio Aero Industries

From October 2012 to January 2013, I went to the south of Italy to do my internship at Piaggio, the company famous for manufacturing the P.180 Avanti business aircraft.

The office where I was located was in Pozzuoli, a town just outside the city of Naples, in the shadow of Mount Vesuvius.

TEXT Jasper Coosemans, MSc Student Aerospace Engineering

P

iaggio Aero Industries is an Italian aircraft manufacturer with a rich history.

It was founded by Rinaldo Piaggio in 1884 and started as an outfitter for ocean liners.

The first Piaggio aircraft was the P.2 monoplane (1923), and the company became an important supplier of bombers and other aircraft during the Second World War. After the Allied forces destroyed most of Piaggio’s facilities, the company turned to a different business and came up with a new means of transportation intended to be cheap and easy to use: the world famous Vespa scooter was born. As the Vespa conquered Italy, Piaggio rebuilt its aircraft activities. Nowadays, Piaggio Aero is a completely separate company; the only thing it shares with the scooter manufacturer is its name. It is in the hands of some remarkable parties, among which are the Ferrari family, the government of Abu Dhabi and the Tata Group from India.

REDESIGNING THE AVANTI Currently, Piaggio is making its way back

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to the domain of military aircraft. Rather than designing completely new planes, it is taking the P.180 Avanti as a baseline for a range of surveillance aircraft. The Avanti is Piaggio’s signature aircraft, featuring two pushprops and a lifting front wing – Piaggio does not want to call it a canard, as it provides no pitch control.

An unmanned Avanti baptized HammerHead was presented earlier this year and is now undergoing ground testing. My internship, however, concerned another derivation, simply named Maritime Patrol Aircraft (MPA).

As the name suggests, the MPA will be used for surveillance in coastal areas. This type of mission is completely different from transporting business executives, so the original Avanti will need considerable revisions. The aircraft’s endurance is increased by nearly doubling the wing span and adding fuel tanks inside the fuselage, and some significant cut-outs are made in the fuselage such that additional

instrumentation, e.g., radar and cameras, may be mounted. From a structural point of view, this results in a nearly completely new design. Piaggio is sticking to a metal airframe, but the changes are so thorough that the MPA requires a lot of work in terms of design, analysis, testing and certification.

I came to Piaggio’s engineering office in Pozzuoli with very little experience in the art of finite element analysis (FEA), but as I was eager to learn it the proper way, my supervisor kindly agreed to give me the time and resources to familiarize myself with the method and software (PATRAN/ NASTRAN). During the three months I worked there, I got a fairly good idea of how the structural design process at Piaggio works. Starting from the aircraft’s global FEA model, which includes only a coarse representation of all structural parts, I created a fine model of the new structural in-board fuel tanks. This model allowed me to evaluate the stiffness and

TIBBOH

Figure 1. The P.180 Avanti serves as the basis for Piaggio’s military aircraft

strength of the proposed design, which is important because the fuel tank itself will not be pressurized, while the rest of the fuselage will.

In addition to this, I also performed some smaller tasks, like evaluating the torsional stiffness of the tail section after some large cut-outs had been proposed – an external company responsible for the analysis of this section claimed that the effect of the cut-outs would be small, but my supervisor did not agree and wanted a second opinion. Finally, I also tried to validate the FEA model of the tail section by comparing the contemporary results with the FEA results found for the original Avanti in the 1990s, and with test results performed when the Avanti was being certified.

Piaggio’s office in Pozzuoli is a small research facility consisting of just thirty engineers. The company’s large design offices and manufacturing plants are all located in the north of Italy. Consequently I did not see any factories or even Piaggio aircraft during my internship, but I did get what I came for: I learned how to use the Finite Element Method from skilled and experienced engineers who gave me a good insight in how they use the tool; from top-level global modelling to indepth detailed analysis.

HE WHO COMES TO NAPLES, CRIES TWICE Meanwhile, I enjoyed student life in Naples. Besides having visited the city for half a day during a high school trip, I only knew it for having trouble with collecting garbage, being the home of a mafia family and hosting the football club where Diego Maradona had the best years of his career. When I arrived, a local told me the city has a saying: “He who comes to Naples, cries twice: when he sees it for the first time, and when he has to leave.”

This told me that it was a place that takes some time before you appreciate it. Upon arrival though, Naples gave me very positive impressions. Besides the occasional stinky trash can here and there, the city is full of small streets which somehow succeed in mixing total chaos (mainly due to the crazy traffic) with a relaxed, laidback atmosphere brought by the numerous pedestrians who are just enjoying life.

Naples’s student population is enormous: the city has four universities, the biggest of which has just under 100,000 students.

Thanks to the Erasmus programme, there is also a large international student community, their backgrounds ranging from archaeology to mathematics and from Estonia to Portugal. I found it very easy to blend in with this group and with the

locals, who introduced me to the best places to eat (Naples is the home of the pizza!) and go out, and showed me where to find the best espresso.

Another good thing about staying in this part of Italy is that there is simply a whole lot to see and do. Naples itself is full of cultural beauty from the 18th century, but also contains some hidden treasures like the remains of a large Roman amphitheatre that can be found underneath the contemporary streets and houses. It is close to Pompeii, the Roman city that was covered in ash after Mount Vesuvius erupted in the year 79 AD. The whole area is still volcanic today, which gives some peculiar natural phenomena. From Naples, you can take a ferry to Capri, also known as “the island where the sun is always shining”, where you can admire the bright blue sea water and the white villas built on the rocks. The list goes on and on; however long you stay, it seems you will never get bored.

That left me with a feeling recognized by many students: the internship was an amazing time, but it was way too short.

With its unique atmosphere, delicious (and cheap!) food and drinks and a wide range of cultural and natural wonders, Naples is a city I will definitely visit again.

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RVD

SKYLON Potentially the new big thing in LEO transport

Space planes could very well be the ultimate aerospace engineering machine. These space planes are vehicles that function both as an aircraft when flying or gliding through the atmosphere, and as a spacecraft when orbiting around the earth. Well known examples of space planes are NASA’s space shuttle, which launches as a rocket, but re-enters as a glider, and XCORs Lynx, which takes off horizontally with four rocket engines, reaching suborbital flight. Since the twenty-first century, there is a new competitor on the market: Reaction Engines Limited (REL), with their space plane called Skylon.

TEXT Ivo van der Peijl and Marijn Veraart, Students Aerospace Engineering, President and Treasurer of the 27th Space Department.

SKYLON INTRO The ultimate goal for the Skylon is to replace all inadequate launcher systems that are used today with a more practical transport system. As current launchers are very expensive ($150M/launch) and unreliable (5% loss rate), a future launch vehicle as Skylon will require a low specific launch cost and should be genuinely easy to operate. This means that Skylon has to meet the following criteria: single stage in order to reduce development and operational costs; as reusable as possible; computer controlled as qualifying a vehicle for piloted flights increases development costs; simple launch and recov-

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ery procedures to minimize turnaround time; capable of aborted landing during ascent; an engine that uses existing aerothermodynamic techniques and materials; minimum maintenance between flights; provides an interface with other elements as it has to become part of an efficient transport system and the vehicle use environmentally friendly propellants to avoid atmospheric pollution. All these criteria can be met with the engine and structure concept for Skylon, described below. The REL company already received $350m in funding for the project as the first static tests of the newly designed engine’s precooler were successful.

SKYLON PERFORMANCE Skylon is designed to bring a payload of fifteen tonnes to Low Earth Orbit, without any pilots. It has a gross take-off weight of 275 tonnes, of which 220 tonnes propellant. The payload bay is 12.3m long, and 4.5m in diameter. Designed to be reusable for 200 flights, REL aims to provide a cheap solution for bringing payload into orbit. This payload may include either a standardized payload container, and passenger compartment. Control during atmospheric flight is provided by the moving tailfin, delta canard wings and ailerons along the wing trailing edge. Reaction control thrusters are present for the

space flight phase.

A retractable landing gear is attached to the fuselage, packed closely to save space and weight. Water tanks are used to dissipate of the heat caused by emergency braking during take-off. After successful take-off, the water is thrown out.

SABRE ENGINES The SABRE (Synergistic Air-Breathing Rocket Engine) is a hybrid engine, containing two operational modes. In both modes, liquid hydrogen is used as propellant. The air breathing mode takes oxygen out of the atmosphere, where the rocket mode uses its stored liquid oxygen. This is advantageous, because this eliminates the need for bringing oxygen as a first stage oxidizer, and with it the need for a heavy oxidizer container. SABRE is able to reach a thrust over weight ratio of 3 at burnout. Specific impulses of 3500 seconds atmospheric, or 450 seconds exoatmospheric are standard.

A precooler, consisting of thousands of small thin-walled tubes is present between the intake and turbocompressor. In air breathing mode, this precooler is used

to cool the air down from 1000°C down to -150°C in 1/100th of a second [4], by cooling it with a closed helium loop, that is cooled again by the liquid hydrogen fuel.

This is done to allow compression to the required 140 atmospheres without the need for extreme temperatures. The airbreathing mode can be used up to Mach 5, after which it is inefficient, so the intake will close and the rocket mode will take over.

A major problem for pre-cooled engines is water vapour in the atmosphere. Lowering the temperature of the intake air will freeze the water, blocking the engine.

A major testing programme has shown that this can be prevented, with provision made to stop the build up of ice.

FUSELAGE & STRUCTURE Skylon consists of a slender fuselage containing the propellant and payload bay, with a delta wing located midway along the fuselage with the engines mounted in the wingtips. The design evolved from the HOTOL airframe, which was derived from conventional rockets. The propulsion system is installed in the nacelles on the wing tips. This makes it possible to

place the empty center of gravity on the hypersonic re-entry center of pressure.

The payload bay is also coincided with the center of pressure, over the wing. This is to avoid disrupting trim with varying payload masses.

RE-ENTRY Re-entry occurs at relatively high altitude (approximately 10km higher than the Space Shuttle) due to the lower ballistic coefficient (mass per unit plan area). Temperature during this re-entry is kept down to 1100K by controlling the trajectory via active feedback of measured skin temperatures. As Skylon has an aerodynamic configuration that comprises a definite wing plus body, the wing does not fit within the body bow shock wave during re-entry, giving a rise to a localized heating problem addressed by actively cooling the wing.

Though will Skylon be the final breakthrough in Spaceplanes? Or, as can be concluded about all past Spaceplane projects from the 20th century, will it be postponed to our next generation. For now we will just have to wait and see.

REFERENCES http://www.aau.ac.uk/reactionenginesltd.htm http://www.reactionengines.co.uk/ sabre_howworks.html http://www.reactionengines.co.uk/ tech_docs/SKYLON_User_Manual_ rev1-1.pdf http://www.bbc.co.uk/news/scienceenvironment-20510112 Alan Bond, Richard Varvill, John Scott-Scott and Tony Martin: SKYLON – a realistic single stage spaceplane, Spaceflight vol 45 , april 2003 Skylon Unmanned Reusable Cargo Spacecraft, United Kingdom Richard Varvill, Alan Bond, The SKYLON Spaceplane, Reaction Engines Ltd,JBIS, VOl 57, pp.22-32, 2004

SPACE DEPARTMENT The Space Department promotes astronautics among the students and employees of the faculty of Aerospace Engineering at Delft University of Technology by organizing lectures and excursions.

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Student project

DELTA LLOYD SOLAR BOAT TEAM Sailing 30km/h with a solar-powered boat, using hydrofoils

Every two years since 2006, the Delta Lloyd Solar Boat Team builds a boat to participate in the World Cup for solar-powered boats, across the ‘Elfsteden-route’, the famous tour of the eleven cities in the Dutch province of Friesland. The upcoming year the team, consisting of a new group of students, will start designing and building the 2014 Solar Boat.

TEXT Martijn Tra, BSc Aerospace Engineering, Team member Delta Lloyd Solar Boat Team

O

ne of the greatest experiences of joining a DREAMteam is the cooperation of multiple studies and disciplines that exist within the TU Delft. The Solar Boat Team is one of those teams making this experience possible, making an extremely advanced machine that is fully designed by students.

HISTORY OF THE DELTA LLOYD SOLAR BOAT TEAM As mentioned before, the team builds a new boat every two years since 2006.

However, in 2005 a first set-up for the Delft Solar Boat Team was initiated by Professor Tom van Terwisga at the Faculty of Maritime Engineering. This was the very first time that the race was organized and it served as a pilot project to investigate the future possibilities of a Wold Cup for solarpowered boats. This pilot project ended up being a great success and in 2006, the first official race was organized. The team from the TU Delft designed and built a new boat within a year and were able to

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finish first, ending up ten hours before the second place in the overall ranking.

In 2008, the organization of the race was able to attract more teams, although none of them were able to beat us. This meant that the Delta Lloyd Solar Boat Team, again using a completely new boat, ended up first for the second time in a row. The difference with the competition was much smaller than in 2006, so the team decided to start work on a new innovation from 2010 onwards: hydrofoils.

The team started this innovation, which essentially entails sailing on wings that lift the hull out of the water, due to the great possibilities in optimizing the resistance of the boat. Working with this new technique, the team experienced some setbacks in the production, which in turn led to a very short period of time available for testing the boat. This lack of testing time caused a lot of time loss in the first few days of the race. The final days were a great success and the possibilities of the hydrofoils were confirmed by a top speed

of 36km/h (compared to 25km/h without the use of hydrofoils). In 2010, the team ended up third in the overall ranking.

In 2012, the team decided to continue working with hydrofoils, due to the great possibilities proven the race before. Due to some setbacks that had to be endured, the team ended up fifth in the overall ranking, but was able to incorporate a lot of improvements in the design. The design of this particular boat will be discussed in some more detail in the next section.

SPECIAL FUTURES OF THE 2012 SOLAR BOAT Some interesting futures of the 2012 Delta Lloyd Solar Boat will be discussed in this section, with a focus on the relevance to aerospace engineering. For additional information, the website www.solarboatteam.nl is available, or the team can be contacted via mail: info@solarboatteam. nl.

Figure 1. Render of the 2012 Delta Lloyd Solar Boat Team

General The Delta Lloyd Solar Boat Team is responsible for organizing everything related to building the boat and sailing the race. This includes matters such as taking care of the financial situation of the team, maintaining contact with the sponsors and the production of all the different parts of the boat.

Variety of students One of the special non-technical features of the 2012 Delta Lloyd Solar Boat Team was the variety of students participating: eight students from six different studies, including three aerospace engineering students. This great variety makes it very interesting to participate in a team like this and combine all the different disciplines.

Hydrofoils The hydrodynamic design of the hydrofoils shows a great similarity with designing wings for airplanes. Due to the background knowledge gathered during the first two years of the bachelor, this is a perfect job for aerospace engineering students. The focus for this design was improving on the stability properties of the hydrofoil design of 2010. The result of half a year of designing by two students can be seen in Figure 1.

Structures calculations There are two main components that require calculations on the structural loads: the hull and the hydrofoils. Both are produced using composites to achieve minimum weight.

When the hydrodynamic design of the hull was completed, one of our aerospace engineers performed calculations on the loading of the hull. The hydrofoil design required some more cooperation between the hydrodynamic design and the possible construction to search for the limits in loading the foils.

Use of composites In order to obtain a lightweight boat, the use of composites is very important. Using composites a high structural loading per weight can be achieved for the hull

as well as the hydrofoils. The hull is constructed using a sandwich construction: one layer of composite, a core of foam, followed by another layer of composites.

The boat was produced using wet hand lay-up and the weight of the hull ended up being 47kg.

The second main component produced of composites is the hydrofoils. These are produced using prepreg composites. An upper and lower skin are glued together with a core of foam in between.

INTERESTED? From September onwards, the team will start developing the boat for the race in the summer of 2014. Are you interested in the project? Are you considering joining the team? Please contact us via info@ solarboatteam.nl.

Table 1. Technical details

Weight:

155kg (excl. driver)

Length:

5.93m

Width:

1.8m

Solar deck:

7.92m2 GaAs solar cells

Max power solar cells:

1.75kWh

Weight of battery cells:

7.1kg

Max capacity of battery:

1.7kWh

Max motor power:

4kW

Top speed:

30km/h JUNE 2013 Leonardo Times

35

www.dutchspace.nl

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www.aeronamic.com/careers

01-05-13 11:53

Internship report

MEET THE AGGIES Internship experience at the Texas A&M University

“Welcome to the United States of America” the lines I had heard quite a few times in movies and sitcoms. Yet here I was listening to it, jet lagged and sleep deprived after roughly 24 hrs of flying, having just completed the immigration clearance at George Bush International Airport, Houston.

TEXT Anirudh Shukla, MSc Student Aerospace Engineering

FIRST IMPRESSIONS The thing that hit home immediately, or quite soon after exiting the airport on my way to the city of College Station and my accommodation for the next four months, was the sudden scaling up of things around me: the cars, the roads, the food portions, you name it. Hence, it came as no surprise to learn from the local students that the Texas A&M University campus was one of the largest in the US. Though, I probably should have asked that before trying to discover the campus on foot.

HISTORY & FOOTBALL FEVER Texas A&M started out as a college specializing in agricultural and mechanical studies with compulsory military studies.

This link to its past is retained by the ‘A&M’ in its name which stands for ‘Agricultural & Mechanical’. The region in Texas where the university is situated being dominated by agricultural farmland is referred to as ‘Aggieland’, thus, being the source of

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the nickname ‘Aggie’ for anyone from the Texas A&M university.

The military studies which were a compulsory part of the curriculum eventually became optional in the 60’s. However, the military tradition of Texas A&M is still very much intact, a fact which was most obvious during the football games on the weekends, where instead of having the usual cheerleaders we had yell leaders calling out special yells to get the support for the Texas A&M football team going. However, that was hardly a problem with pretty much the whole town of College Station gearing up for the weekend football games with the ‘Friday night yell’, when everyone gathered in the Texas A&M stands of the football ground to chant a series of yells, led by the yell leaders, to build up for the game.

I was lucky enough to be there at a time when Texas A&M had a football game with their biggest rivals UT Austin. Sadly,

I couldn’t watch the game in the stadium as the tickets were way too expensive due to the demand for them, as it was the first match between Texas A&M and UT Austin in the past two decades. This in no way meant that I missed out on the atmosphere of the game as we could hear the stadium full of spectators a good few kilometres away. Sadly, though Texas A&M lost in the dying moments of the game.

However, they were still great memories and made me into a bit of a football fan too, something I never thought I would say! The work I did there was just as exciting and interesting. I undertook work on applying the compatible spectral discretization method to beam bending problems which eventually developed into my master’s thesis.

EXPLORATION One of the best ways of discovering the US is by road. So weekend road trips were a great way to travel to neighbouring places such as San Antonio, San Marcos,

ANIRUDH SHUKLA

Austin and Houston. The best of these places for me was Houston for the simple reason that the Lyndon B. Johnson Space Centre was located there. It was an awe inspiring experience to be in the same place where the American space program took its first steps towards the moon and finally see firsthand the lunar modules and command modules used in the Apollo space missions, as well as the lunar rovers and of course the iconic Saturn V rocket, which seemed almost larger than life. Looking at the hardware used by the astronauts of the Apollo program and the desperately confined working environment it offered gave me a whole new appreciation for their bravery and ability, as some would say: they definitely had ‘the right stuff’.

Another highlight of being there was visiting the mission control at Houston and watching the live trajectory and images from the International Space Station (ISS), which was almost a surreal experience. It was quite interesting to learn about the tradition at mission control where the mission patches for all ongoing missions were hung on one wall of the mission control room and moved over and hung on the opposite wall on the completion of the mission. A small action signifying the

completion of a great event.

Keeping with the aerospace mood for exploration, I was fortunate enough to be able to visit the National Air and Space Museum in Washington D.C. The opportunity to finally see legendary aircrafts such as the SR-71 Blackbird, which was much smaller in size than I imagined, the Concorde, the Enterprise space shuttle and historically important aircraft such as the Enola Gay was the experience of a lifetime. Of course being surrounded by so much military aviation history I just had to take a go in the dogfight simulators there.

In my first ever and probably last ‘sortie’, I managed to shoot down four targets spending most of my time upside down, just one shy of becoming an ace, at least in my mind. Not too bad for a first ‘sortie’ I suppose.

TALKING ABOUT FOOD The exploration and experiencing of any new place is incomplete without discovering the local food, and Texas definitely had a lot to offer. Thanks to my local friends there, I discovered what a proper authentic cheeseburger tastes like and I have to admit that finding a cheeseburger

that good has been next to impossible in Delft. Of course this being Texas, a good old Texan steak was a must have and what a steak it was. The fact that they took their steaks seriously was obvious from the size of the serving, (see picture) which was the smallest serving. Due to the fact that Texas shares its border with Mexico, there is a rich culture of Mexican food there as well.

However, this was with a Texan twist to it giving rise to a new genre of food locally known as ‘Tex-Mex’.

Looking back, the time I spent at the Texas A&M University and the US in general was not only significant from the learning point of view for my masters but also discovering a new place, making some great friends and in the process acquiring lifelong memories of an overall enriching experience. Thus, not surprisingly, I would highly recommend an internship abroad to any fellow student considering it, be it Texas or anywhere, as the challenges of arranging one are far outweighed by the gains in experience and knowledge.

JUNE 2013 Leonardo Times

39

AEROSPACE PROPULSION PRODUCTS High-quality rocket ignition systems for the future

Aerospace Propulsion Products is the leading European company in designing and producing rocket ignition systems and spinoff products. One of their directors, Edwin Vermeulen, gave us an insight on the company and its future. He states that “whatever rocket technology is needed, we have the technology in house to provide the ignition systems”.

TEXT Nout van Zon and Alisa Nevinskaia, BSc Students Aerospace Engineering, Editors Leonardo Times

INTRODUCTION Last October we visited Aerospace Propulsion Products (hereafter referred to as APP) in Klundert, Brabant. Here we met Edwin Vermeulen, one of the two directors of the company specialized in rocket igniters. Mr. Vermeulen, a mechanical engineer, gave us a tour of the facility and provided his personal insight into the company and the market. Edwin Vermeulen started his career at DAF trucks where he spent seven years designing and simulating truck engines. After that he worked at Stork as a project manager on rocket ignition systems. When several years later the design activities of Stork were transferred to APP (where at the time only production was taking place), he became the director of engineering and marketing of the company.

ROCKET IGNITION SYSTEMS APP was founded by TNO in the 80s for the development of the Ariane 5 rocket engine ignition system. Due to the large scale of the project it was decided to move the activities from a TNO laboratory to the premises of a munition factory near Bergen op Zoom. The development of Ariane 5 rocket igniters was accomplished

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Leonardo Times JUNE 2013

together with TNO and Stork. The initial plan was to close the company after the project was completed. However, due to its succes, APP was not closed down and they continued to work on rocket ignition systems. In 2005 the company grew when Stork decided to incorporate all product development activities into the company.

In 2009 Stork decided to sell their shares of APP and therefore TNO is the single owner of the company. Nowadays, APP is a succesful company specialized in the development and production of rocket ignition systems and spinoff products.

WHAT MAKES APP COMPETITIVE? With over thirty years of experience in rocket ignition systems, APP has gained a lot of experience and managed innovations in both the production and design of these products. For example they provided the igniters for the first, second and third stages of the VEGA launcher that was launched just last year. This igniter uses novel carbon composite materials and parts that were made by additive manufacturing. Although this technology is still very new for space parts, APP already introduced 3D printing ten years ago in the production of their products. In general,

APP has created many smaller innovations in both the production and design that have contributed to their success in providing the rocket ignition industry.

APP WITHIN THE ESA OBJECTIVE APP has proven to be able to provide high-quality products to contractors such as Astrium, Avio, Snecma and ESA. However, being competitive is not the only requirement to succeed in the European space market. Any APP project for a European launcher also has to fit within the ESA objective that all the countries that have invested into space get some fair return for their industry. In the past, launcher projects have usually been developed entirely by a few large companies such as Astrium and Snecma. Edwin Vermeulen from APP believes it is more cost-effective to outsource work to specialized subcontractors. He states, “let us do it, it’s more cost efficient and you get better quality”. So far, APP has been very successful in providing these specialized products and the three big space companies (EADS Astrium, Snecma and Avio) are now their main customers.

AVIO/ESA

APP

APP

Figure 1. Turbinepump-igniter of the Ariane 5 Vulcain II motor

ESA MINISTERIAL CONFERENCE 2012 The ESA ministerial conference is held every couple of years during which the member states discuss strategic plans and budgets for the coming years. The last conference, held in 2012, mainly focused on the launcher debate. The big question for ESA member states was whether to invest in an improvement of the Ariane 5 launcher or a complete new successor (i.e., Ariane 6). Questions posed were how it would be financed and organized, and especially how the development and production could be performed at the most cost-effective way. The discussion was not finished during the last conference and was subsequently decided to be tabled until 2014. However Edwin Vermeulen is positive about the situation. He believes that any scenario, whether an improvement of Ariane 5 or a successor, will give APP opportunities for new products and developments. He optimistically notes that “whatever rocket technology is needed, we have the technology to provide ignition systems”.

APP OUTSIDE EUROPE It’s not easy to work outside Europe on rocket technology. First of all one has to understand the market differences on all levels. Second to that, it has to be a certainty that the exported rocket technology is only used for space applications. APP has established a business relation with South Korea ten years ago that is still ongoing.

Ten years ago an opportunity presented itself when both parties found themselves interested in the cooperation. As Mr. Ver-

Figure 2. Vega rocket motor test with APP igniters in Sardinia

meulen stated: ‘’We have done some work for the next generation launcher of South Korea, I’m not sure whether in the end it will be a commercial success for APP but we try at least.’’ Collaboration outside Europe is more challenging and time demanding, still APP explores and pursuits opportunities outside it’s boundaries. The other country that APP is doing business development in is India.

SPINOFF PRODUCTS & OPPORTUNITIES There are several ways in which APP applies its technology outside the space market. The civil market proved to have a need for the technology that APP has inhouse. The technology of producing hot or cool gasses, stored in solid state, can be used for different purposes depending on the device used. Hot gas generators are among others used for ignition, turbine start-up, emergency situations including valves and fire extinguishing.

The most successful spinoff product in this sequence is the gas generator for a dust explosion suppression system of the Belgian company StuvEx, which has been sold for over ten years. Together with TNO and a company called CGG Technologies (Cool Gas Generator), APP has developed a similar technology, the difference being that the resulting gas is at room temperature. Cool gas generators offer a whole new range of opportunities. They can be used for medical purposes (oxygen) or emergency actuation purposes (nitrogen, used for inflation, actuation, fire extinguishing, etc.). Edwin Vermeulen stated,

‘’Our vision is that in five to ten years more than half of our turnover comes from this type of more industrial products, not used in space’’.

APP has recently finalized the development of a new spinoff product in collaboration with TNO and ISIS (Innovative Solutions in Space). Since space debris is an increasing problem and launching nanosatellites is increasingly popular, there is an upcoming trend and a realization that nano-satellites need to have a means of de-orbiting as well. That’s why APP, TNO and ISIS have developed a small kickstage unit which can accomplish this task.

OPPORTUNITIES FOR TUDELFT STUDENTS There is always an opportunity for internships at APP. Master theses are not lying on the shelf at APP, but can be created for motivated candidates. Edwin Vermeulen stated, ‘’I would really encourage people to at least try and contact us if you would like to do an internship, master thesis or to have a job here’’.

APP would also like to make a contribution to the aerospace engineering study.

There is currently a discussion with some of the university responsibles about the possibilities for APP to support the university, for example by creating dedicated projects.

References APP website: http://www.appbv.nl

JUNE 2013 Leonardo Times

41

NOISE SYNTHESIS for the Virtual Community Noise Simulator Aircraft noise imposes restrictions on possible growth of airports. Noise mitigation measures can be based long-term predictive models but would benefit from high-fidelity simulation of the audible effects. To this end the NLR uses its Virtual Community Noise Simulator (VCNS). Several modelling steps and an application will be demonstrated in this article as to show the promising future of aircraft noise synthesis.

TEXT Michael Arntzen, PhD student aviation acoustics at the Air Transport & Operations department, executing his research at the NLR.

tional Aerospace Laboratory (NLR).

The simulation environment at the NLR is called the Virtual Community Noise Simulator (VCNS). In 2007, the NLR obtained the VCNS from NASA. At NASA the idea to presents audible flyover results emerged. They combined this with a virtual reality environment as to present the actual flyover results in a realistic setting.

In the VCNS, a test subject can experience flyover noise in a virtual reality environment. The system is based on the basis of seperately modeling the source noise and atmospheric propagation effects. In this article a quick introduction into the modelling steps, necessary for the functioning of the VCNS, is given.

SOURCE NOISE PREDICTION An aircraft has different noise generating parts. The two most prominent ones can be classified as the engine (jet mix-

MICHAEL ARNTZEN

INTRODUCTION Air traffic has been increasing steadily in the last decades, which had adverse effects on community noise near airports.

Noise mitigation measures are frequently studied based on contour maps showing a long-term averaged noise metric like the LDEN. Examining effects of noise mitigation measures based on such an averaged metric will exclusively allow determination of the average effects rather than local effects.

The local effect of a noise mitigation measure can be studied with more realism by using a high-fidelity simulation model that predicts the actual sound signature, instead of a noise metric, at a particular position. Developments to that end, predicting the audible sound at a reasonable computational time, are ongoing at both the National Aeronautics and Space Administration (NASA) and the Dutch Na-

Figure 1. The directivity pattern typical for a gasturbine engine in take-off conditions. The angle is measured from the inlet, i.e. 0 deg. means forward and 180 deg. means aft radiated sound.

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Leonardo Times JUNE 2013

ing and fan noise) and the airframe noise.

The source is represented in the VCNS as a compact source, i.e. all sound is assumed to be emitted from one position. This is a far-field assumption that is valid for the distances considered in typical flyover situations.

Airframe noise Airframe noise is generated by the turbulent wake coming from the gears, wings and high-lift devices. In general it is broadband of nature, i.e. containing a wide range of frequencies. Cavities on an aircraft, for instance the area behind an extended slat, are however known to produce tones as well. As cavities are different for every aircraft, airframe noise is usually very aircraft specific. Experimental and theoretical research is on-going in these areas and empirical models are made based upon these results.

Jet noise The engine is modeled from two individual noise generating components, the jet mixing noise and the fan noise. Jet mixing noise is generated by the mixing of the turbulent airstreams leaving the gas turbine. Sir James Lighthill was the first to describe this complex phenomenon from a theoretical perspective in 1952 thereby, single-handedly, starting the research field of aero-acoustics! Interested students are referred to [1] as to see what it takes to start a new research field.

One of his breakthrough results was that a jet exhausts emits noise that scales proportional to the velocity difference of the

jet and the ambient atmosphere to the eighth power. This is why today’s highbypass engines are quieter than their straight-jet counterparts.

Fan noise Whereas jet mixing noise is generally of a broadband nature, the fan emits both broadband as well as tonal components.

The main tonal component is caused by fluctuating aerodynamic forces resulting from unsteady wakes flowing of the fan rotor vanes onto the stator vanes. If the fan tip speed exceeds the speed of sound, shock waves occur on the fan rotor blades that result in tonal noise as well. For this noise generating mechanism, popularly referred to as Buzz-Saw noise, the fan must be spinning at a high speed. Consequently, this sound is usually present at take-off conditions and radiates almost exclusively forward. An example on the directivity of fan noise is presented by Figure 1.

SYNTHESIS AND PROPAGATION In noise synthesis, a distinction is made between the synthesis of the noise at the source and propagation phenomena.

Both are treated separately in the VCNS. Synthesis Having a source noise prediction is the start of the actual sound synthesis. Tonal components can be synthesized by applying the correct frequency and amplitude characteristics to a basic cosine wave form. This is called additive synthesis.

For broadband noise a different method has to be used since a wide range of frequencies are present. It is assumed that broadband noise is similar to white-noise, i.e. containing random phase and equal intensity for all frequencies. Since this is easily generated in the frequency domain, the predicted noise spectra for airframe and engine noise can easily be applied through convolution. Using an inverse Fourier transform, the acoustic signal in the time-domain is re-constructed.

MICHAEL ARNTZEN

MICHAEL ARNTZEN

NLR

Figure 2. Sound rays emanating from a source (flying left to right) in head-wind conditions. For clarity, the rays directly below the source have been omitted; the varying color refers to a different initial direction of the sound. The red part of the ground, where no rays reach the ground, is referred to as an acoustic shadow zone.

Figure 3. The synthesized signal of an aircraft (top picture) compared to a recording (lower picture).

Propagation If the synthesized signal at the source is known, it has to be propagated to the ground through the atmosphere. Using acoustic ray tracing, the effects of wind and temperature on the produced sound field are calculated. For instance, aircraft usually take off in headwind conditions.

This has an effect on the acoustic field as well. Ray tracing allows calculating how an acoustic wave-front propagates through the atmosphere. Due to wind and temperature effects the commonly assumed straight line path is not valid, as is visualized in Figure 2.

From Figure 2 it becomes clear that curved sound rays cause areas on the ground where no sound is present. This is accentuated by the red ground surface. In these acoustic “shadow” zones, less sound is present than would be predicted by a traditional straight-ray approach. Modifications like this are audible and have to be taken into account in noise synthesis. Examples of these calculations can be found in [2].

APPLICATION It is hard to show results of noise synthesis.

Probably the best way to visualize the data is to produce a spectrogram. A spectrogram shows, as a function of time (aircraft passage), the Sound Pressure Level (SPL) at different frequencies. Results of a recent synthesis effort are shown in Figure 3.

In Figure 3, the distinctive line at 2600 Hz is tonal noise that is both present in the synthesis as well as the measurement.

This tone is from fan rotor-stator wake interaction and starts around 2600 Hz after which it is Doppler shifted towards 1900 Hz as the aircraft flies over. Some differences remain between the synthesis and the measurement. The main elements are however nicely captured and confirm the promising possibilities of aircraft noise synthesis. Efforts are currently underway to assess where differences emanate from and which further improvements can be

made and will be published in the near future.

Furthermore, we would like to point out a recent study by NASA. [3] Rather than synthesizing regular aircraft they successfully synthesized a blended-wing-body to compare its noise reduction to a regular (Boeing 777) aircraft. These (audible) results are available on the internet together with movies of the virtual environment. [4] CONCLUSIONS Aircraft noise synthesis allows studying new procedures or aircraft designs without taking measurements. As such it becomes possible to hear future aircraft designs that are still on the drawing table or to evaluate noise mitigation measures without an extensive test campaign. Future research is directed towards making more realistic predictions and to further study atmospheric effects that modify the aircraft sound. If you have further ideas or want to contribute to this research as a graduate student, contact the author for further information.

References [1] Lighthill, M.J., “On sound generated aerodynamically I: General Theory”, Proceedings of the Royal Society of London, Series A: Mathematical and physical sciences, pp. 564-572, 1952.

[2] Arntzen, M., Rizzi, S.A., Visser, H.G., and Simons, D.G., “A framework for simulation of aircraft flyover noise through a non-standard atmosphere”, 18th AIAA/ CEAS Aeroacoustics Conference, AIAA 2012-2079, Colorado Springs, CO. [3] S.A. Rizzi, A. Aumann, L.V. Lopes, C.L. Burley, “ Auralization of Hybrid Wing Body Aircraft Flyover Noise from System Noise Predictions”, 51st AIAA ASM meeting, AIAA-2013-0542, Grapevine, Texas.

[4] Aircraft flyover simulation, http:// stabserv.larc.nasa.gov/flyover/, NASA, 2013.

JUNE 2013 Leonardo Times

43

“We vlogen met een zucht...”

THE UNMANNED AERIAL VEHICLE A small history of violence

At Aerospace Engineering, one can hardly miss the Unmanned Aerial Vehicle (UAV).

Many commercial purposes have been investigated in recent years. Also, unmanned reconnaissance and combat aircraft attract more interest; in hazardous regions, small aircraft can be deployed to do risky, but necessary jobs. And with success. But is the idea of using UAVs in locations where human lives are at stake really that new?

TEXT Robert-Vincent de Koning, MSc Student Aerospace Engineering, Editor Leonardo Times

O

f course, the answer is no. The history of unmanned aerial vehicles is almost a hundred years old. And although these UAVs are designed more and more for commercial purposes, their original goal was to gain an advantage in a war, without the risk of losing a valuable pilot. During both World Wars, the Vietnam War, the Cold War, the Yom Kippur War and lately the conflicts in the Middle East, many UAVs have been developed to fulfil that goal. They were not only used as tactical aircraft or flying bombs, but also as reconnaissance aircraft and even as decoys. But not all attempts met with success: in the process of learning this new technology of pilotless flight, many projects failed, were cancelled or were simply shot down.

But after decades of war, we are now finally able to use this technology for peaceful purposes as well. Let us first take a look at the violent history of UAVs. Using UAVs for combat dates back to as

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Leonardo Times JUNE 2013

early as 1916, a mere thirteen years after the first successful controlled powered flight. The engineer behind this unpiloted aircraft was A.M. Low, who was rather busy developing radar in order to beat the Fokker ‘Eindecker’ monoplane. He tried to incorporate his knowledge of radar into the unpiloted aircraft – or rather, the flying torpedo, as it was filled with dynamite – in order to remotely control the aircraft and send it to its target. Other companies, like Sopwith Co., got interested in this idea and developed their own unpiloted aircraft. Most of them crashed rather quickly or the aircraft was left abandoned in a shed. The problem with radiointerference due to the running engine seemed to be more difficult than building the actual aircraft itself. In 1918, the concept of using gyroscopes to guide the aircraft was used in the Curtiss-Sperry Flying Bomb. This was successfully tested and the aircraft flew for almost a kilometre.

This happened only once though, as all other tests resulted in crashes. However, the company of Sperry was quite successful and its gyroscope division is now part of aerospace giant Lockheed Martin.

It took until 1924 before the radio-interference problem was finally approaching a solution and a properly working remote-controlled UAV was built, which resulted in the Larynx in 1927: an aircraft that could travel for 450km with about 100kg of explosives on board. It was also quite fast for its time: with a top speed of 300km/h it was faster than most manned aircraft in those days. However, in practice it failed miserably (again), as the remote control was replaced by gyroscopes and all targets were missed.

Another remote-controled aircraft worth mentioning is the Radioplane by the Radioplane Company, which was the most sold (and most shot) remote-controlled aircraft during WWII: 15 000 were bought

US AIR FORCE

US AIR FORCE

Figure 1. The drone D-21 on top of the Blackbird.

by the US government to train anti-aircraft gunners. A UAV that was also meant to be shot at was the McDonnell Quail. Its purpose was to imitate the radar and heat signature of a B-52 bomber. Although the idea sounded rather well at first, radar improved and the Quail was quickly rendered obsolete.

A rather controversial UAV was introduced by the Germans, also during WWII: the Vergeltungswaffen 1, which translates to ‘reprisal weapon 1’, or V-1 in short.

Where the attempts in the 1910s failed, the V1 succeeded, as it really was a flying bomb. The V-1 was equipped with only simple control mechanisms for altitude and speed. It also possessed a counter mechanism, a vane, which measured the distance travelled. Once it flew its preset distance, it would descend upon its intended target, mainly London. Although notorious, the V-1 is a true predecessor of the modern cruise missile and it highly revolutionised the idea of warfare at a distance. The V-1 was a cost-effective way of targeting the Allies.

Although war is generally a bad thing, it does speed up technological progress and some impressive feats in engineering have been made in wartime. During the Cold War, there were some concerns about a secret nuclear test facility in Lop Nor, China. Because it was too far and too

risky for a U-2 spy plane, the CIA urged that a drone should be used. Lockheed engineered the D-21, a drone capable of flying at Mach 4. The D-21 was supposed to piggyback on a variant of the Lockheed A-12, the top-secret precursor to the SR71 Blackbird. It would then launch to a height of thirty kilometres and make pictures of Lop Nor. It would then proceed to fly back to the eastern coast of China and drop its film package by parachute, before plunging into the ocean and self-destruct.

The naval vessel below then had to be on the right location at the right time in order to acquire the descending film package. As always, there was a lot of bad luck involved: one parachute failed, one time the Navy messed up and two were lost on radar, never to be seen again. Fifteen years later, a CIA agent received part of a drone as some sort of Christmas gift from a KGB agent.

The American Firebee proved to be a successful UAV for both the Americans in Southeast Asia, as well as for the Israelis during the 1973 Yom Kippur War. While the Americans used it as a slightly stealthy reconnaissance aircraft during 34 000 flights (night or day) from 1964 to 1975, the Israelis found another purpose: decoy. Twelve modified Firebees were sent to Egypt, which then proceeded to fire ground-to-air missiles at the UAVs without

any luck. They either missed their target or were destroyed by the Firebees.

In this day and age, the US Air Force possesses more technically advanced UAVs than ever before. For example, the Predator built by General Atomics, which was introduced in 1995, is capable of battlefield reconnaissance and even carrying missiles, while the ‘pilot’ operates the aircraft back in the US. And, as opposed to most of its predecessors, it actually works.

Furthermore, the Lockheed Martin’s RQ170 Sentinel is a stealthy reconnaissance aircraft that was used above Iran in 2011.

The story of the Iranians claiming to have captured one of these aircraft through electronic warfare is well known and since then, electronic warfare on aircraft has become much more of an issue. Also, a new UAV of the US Navy was in the news recently. Northrop Grumman has successfully launched the X-47B from an aircraft carrier and its appearance largely resembles the B-2 bomber, also by Northrop Grumman. Meanwhile, Boeing is also building a stealthy flying wing, called the Phantom Ray. So although, over the decades, peaceful applications have been found for unmanned aerial vehicles, it also seems that they are still becoming increasingly important in warfare.

JUNE 2013 Leonardo Times

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COMPOSITESWORLD

Column

ORGANIZING SAFETY

TEXT Benno Baksteen, chairman of the Dutch Expert Group Aviation Safety

T

he most important component of a high-reliability organization is a Just Culture, a culture in which only criminal intent or gross negligence will lead to penalties. All other occurrences, whether they are accidents, incidents, mistakes or violations, both intentional and unintentional, should lead to analysis and system improvements. For a system to improve, you need to know what goes wrong and only in a Just Culture will people feel free to report what goes wrong, even if no damage was done, whether or not they were part of the sequence of events or perhaps even the key.

Next on the list is the set of rules and procedures that people have to work with.

These should represent best practices instead of, what is unfortunately rather common, distrust. Nor should the main purpose be to try to protect from legal and/or administrative penalties, sometimes referred to as CYA – cover your ass – rules.

The third ingredient is the acceptance of the fact that rules are tools. You can and should follow good rules and procedures almost all of the time, but it is not an automatic process that could be carried out by a robot. The first-line professional has

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to confirm each and every time, before applying a specific rule or procedure, whether or not it indeed applies in the specific situation and will lead to the intended outcome.

The final component, needed when you want to move from a high level of safety to a very high level, is the acceptance of the fact that the unexpected will happen.

Not everything can be covered with rules and procedures. The best bet here is resilience, both of the professional as an individual and of the organization as a whole.

A high-reliability system starts with the acceptance of the fact that safety is not an add-on. Safety is an integral part of normal everyday operation and of the whole of the organization. It is part of every decision. There will always be economic and other pressures competing with safety and that is just the way it is.

The actual level of safety will inevitably always be the result of a compromise. If you accept that, you should then be able to strike an optimal and accountable balance between safety and other goals. For that to happen on a daily basis, you need to organize counter-pressure against the pressure of, for instance, financial constraints. A good Safety Management

System (SMS) does just that. An effective SMS is not a one-time exercise: it is a continuous, dynamic and cyclical process.

It is not possible to ‘rule’ or ‘inspect’ safety in a system, other than at a very basic level. High levels of safety are only possible when the system generates rules and procedures that represent best practices. It’s what I like to call: solidified experience.

Bottom-up development based on what really happens is essential for that. Of course, you need at least two top-down elements, too. The initial framework needs to be established top-down, and even more important is the commitment of higher management to the bottom-up process. It is quite natural for people who are one or more steps removed from the daily operation to feel that the rules are excellent and that, if only the professionals would make no mistakes and would always adhere to the rules, there would be no problems. However, that is a fallacy.

The real world is too messy and most organizations are too complicated for that to work, let alone the fact that neither people nor systems will ever be infallible. www.advisory-council-degas.com

Come on board.

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