Avimech International Aircraft, Inc.
THE DRAGONFLY o Core Competencies o Quality Assurance
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Avimech International Aircraft, Inc.
QUALITY ENGINEERING
The frame connections were analyzed with CATIA engineering standards. The skid assembly has been stress tested for all flight conditions.
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Avimech International Aircraft, Inc.
ROTOR HEAD ASSEMBLY
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ROCKET POWER HEAD
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Avimech International Aircraft, Inc.
VIBRATION & BALANCE TEST
Dragonfly decibels 72 at ground level Conventional helicopter decibels 115 at 2000 ft
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Avimech International Aircraft, Inc.
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Avimech International Aircraft, Inc.
ADVANCED TECHNOLOGY
PRECISION CNC
QUALITY MANAGEMENT SYSTEM
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Avimech International Aircraft, Inc.
NAVIGATION and COMMUNICATION
The EFIS is a valuable navigation tool and is part of the features of the Dragonfly DF1. It provides for a customized layout of up to 9 pages for flight data, airports, heliports, tower radio frequency, GPS, and more.
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Avimech International Aircraft, Inc.
EASE OF SHIPPING, TRANSPORT & STORAGE
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Avimech International Aircraft, Inc.
GLOBAL DEMAND
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Avimech International Aircraft, Inc.
A FASCINATING FLIGHT MACHINE
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QUIET, CLEAN & FAST !
Environmentally Responsible Aviation (ERA)
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Avimech International Aircraft, Inc.
QUALITY ASSURANCE The following subjects demonstrate the rigor applied to the entire design, manufacturing and testing of the Dragonfly's parts and components to ensure a final product that conforms to the highest standards in Aerodynamics, Safety and Engineering. The following details present the extent of quality and assurance built into the final product.
1 LOAD STUDY 1.1
Loads Cases
The load of the Frame is set as shown in the picture. Four major elements are considered: Main Rotor Head and Yoke Tanks Seat and Pilot Tail and Rear Rotor Each element have been assigned a percentage of Load according to the weight (See below)
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Avimech International Aircraft, Inc.
FRAME LOADS DEFINITION Reaction Loads from the Skid analysis are used to define the Loads on the Frame. Reaction Loads are calculated by Catia thanks to the clamp sensor function. Then, loads are transposed to the different application point with the following method:
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Avimech International Aircraft, Inc.
Frame Aerodynamics forces interacting with landing over the Skids, in order to decide material and techniques used.
Reference :
Dragonfly Stress Analysis ENGINEERING TESTS
DragonFly-ST-01 Page : 16 Revision : 1
After tests conclusions been satisfactory made, we pass to the next phase, such as welding structure.
2 FRAME STUDY 2.1
Material Material
Steel 4130
Young's modulus
2e+011N_m2
Poisson's ratio
0.266
Density
7860kg_m3
Coefficient of thermal expansion
1.17e005_Kdeg
R0.2% min yield strength
360MPa
2.2
Interface and Welding Connection
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Avimech International Aircraft, Inc.
2.3
Meshing
2.3.1 Global Meshing 2.3.1.1 Meshing: Entity
Size
Nodes
24399
Elements
73151
2.3.1.2 Element Type:
Connectivity
Statistics
TE4
69277 ( 94.70% )
BAR
588 ( 0.80% )
NSBAR
10 ( 0.01% )
SPIDER
3276 ( 4.48% )
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Avimech International Aircraft, Inc.
2.3.1.3 Element Quality:
Criterion
Good
Poor
Bad
Worst
Distortion (deg) 15146 ( 21.86% ) 16185 ( 23.36% ) 37946 ( 54.77% ) 61.823
Average 43.824
Stretch
63412 ( 91.53% )
5865 ( 8.47% )
0 ( 0.00% )
0.183
0.445
Length Ratio
64582 ( 93.22% )
4695 ( 6.78% )
0 ( 0.00% )
7.762
2.969
Due to the big size of the assembly, it is not possible to refine the mesh everywhere. But this first mesh gives a fair idea of the constraints localization and allows detecting the critical area of the structure.
2.3.2
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Avimech International Aircraft, Inc.
2.3.3 Bolt Connections 6 bolts tightening connection to model the link between G1F0133A and G1F0503.
2.4
Loads Cases
The following load cases are designed to match the certification CAP 750 Section VLH – Very Light Helicopters from November 2004. Sub section “VLH 725 Limit Drop test” and “AMC VLH 725” have been used. As defined in the certification document, the Main load needs to be calculated to match a drop height of 330mm (13 inches) from the lowest point of the landing gear to the ground.
Engineering Assumptions:
Maximum Weight for the Dragon fly is 350Kg Gravity acceleration is 9.81 m.s-2 The load generated by the drop from 0.33m height has been evaluated to 6900N This is the equivalent of a negative acceleration of 2 g = -19.62 m.s-2 Page 19 of 30
Avimech International Aircraft, Inc.
Clamps on the Frame interface
Vertical ground reaction along the bottom of both skids. Value equals to 6900N Ultimate load is 1.5 time limit load
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Avimech International Aircraft, Inc.
2.4.1 Symmetric Model When the Load cases are symmetrical, half of the structure is modeled. A symmetric constraint is applied on the center plane, restraining Displacement along Y axis and rotation around X and Z axis:
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Avimech International Aircraft, Inc.
2.5
Interface Connection
Connections used to link the different parts of the assembly are CATIA function, further details on these functions can be provided if needed
2.5.1 Seam Welding Connection This connection is used for the entire welded interface in the assembly. Line analysis connections are used as support for the welding connection.
For the skid support assembly, one line is used on each edge of the plates (G1F0705A and G1F0707A) and two lines on the interface between parts G1F0701 and G1F0703. A total of 10 welding connection are used for each support assembly.
On the clamps, welded connections are used for each edge of part G1F0905 in contact with part G1F0903. A total of 4 welding connection are used for each clamp.
The black lines on Figure1 represent the Line analysis connection; the Red sign represent the welding connection. Welding type is set as “Rigid”. The maximal Gap is set to 3mm and the Mesh step is set to 3mm.
Figure1
2.5.2 Bolt connection The modeling of the bolts on the skids support has been investigated on a small assembly. From this investigation, the “rigid connection” function has been chosen. This connection does not need the bolt itself Page 22 of 30
Avimech International Aircraft, Inc. to be in the model. It considers the bolt as a non deformable part. Regarding the difference of strength between the bolt steel and the tube aluminum, the assumption can be done. This connection constraint the axis from the tube and the axis from the skid support be remain the same as the loads are applied. For each skid support, a total of 5 rigid connections are used. The supports are composed by a general analysis connection.
2.5.3 Pressure fitting connection The clamps fixed on the cross tubes are composed by an aluminum part and a rubber part inserted between the cross tube and the aluminum part. The connection used to model this interface is a Pressure fitting connection. This connection allows setting an overlap between the rubber part and the aluminum part. This overlap is set to 0.65mm as this is the average overlap allowed by the model. The pressure fitting connection takes into account the elastic deformability of the interface. A total of 2 connections are used for each clamp assembly.
2.5.4 Contact connections Contacts connections are used for the interaction between the Tube (cross tube and Skids) and the skid support. The contact connections prevent bodies from penetrating each other and take into account the elastic deformability of the interfaces. Page 23 of 30
Avimech International Aircraft, Inc.
A total of 2 connections are used for each Skid support assembly.
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Avimech International Aircraft, Inc.
Blade airfoil and tip mount adapter shear force analyses.
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Avimech International Aircraft, Inc.
This analysis was made under assumption that blade is attached at the main rotor fitting only, and doesn't load leading edge beam at the end. Consequently the centrifugal force coming from the tip jet, tip jet bracket, upper and lower plates and bolts are being transferred by leading edge beam to the main rotor fitting. The moment coming from moving centrifugal force to the first row of the bolt group , is being transferred by the blade. Due to short arm the value of it is being considered as negligible.
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Avimech International Aircraft, Inc.
The Dragonfly DF1 AIRFOIL was tested by the NACA - National Advisory Committee for Aeronautics, as requested by The National Aeronautics and Space Administration (NASA). Our Blades are inspected, CNC aligned, X-rayed and performed a NDT - Non Destructive Test, then Static balanced and polished before be installed on the Aircraft, with all traceability documentation to satisfy the FAA - Federal Aviation Administration, and Avimech Q.A. - Quality Control enforcements.
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Avimech International Aircraft, Inc.
BLADE ELASTICITY TESTS, APPROVED BEYOND FLIGHT PARAMETERS.
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Avimech International Aircraft, Inc.
HOME OF THE DRAGONFLY
Environmentally Responsible Aviation (ERA)
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