Jan-Feb 2010
Issue #100!
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CONTACT! ISSUE 100! PAGE 1
PO BOX 1382 Hanford CA 93232-1382 United States of America 559-584-3306 Editor@CONTACTMagazine.com
Volume 17 Number 5 January—February 2010
Issue #100! MISSION CONTACT! Magazine is published bi-monthly by Aeronautics Education Enterprises (AEE), established in 1990 as a nonprofit corporation, to promote aeronautical education. CONTACT! promotes the experimental development, expansion and exchange of aeronautical concepts, information, and experience. In this corporate age of task specialization many individuals have chosen to seek fresh, unencumbered avenues in the pursuit of improvements in aircraft and powerplants. In so doing, they have revitalized the progress of aeronautical design, particularly in the general aviation area. Flight efficiency improvements, in terms of operating costs as well as airframe drag, have come from these efforts. We fully expect that such individual efforts will continue and that they will provide additional incentives for the advancement of aeronautics. EDITORIAL POLICY CONTACT! pages are open to the publication of these individual efforts. Views expressed are exclusively those of the individual authors. Experimenters are encouraged to submit articles and photos of their work. Materials submitted to CONTACT! are welcomed and will become the property of AEE/CONTACT! unless other arrangements are made. Every effort will be made to balance articles reporting on commercial developments. Commercial advertising is not accepted. All rights with respect to reproduction, are reserved. Nothing whole or in part may be reproduced without the permission of the publisher. SUBSCRIPTIONS Six issue subscription in U.S. funds is $25.00 for USA, $35.00 for Canada and Mexico, $47.00 for overseas air orders. CONTACT! is mailed to U.S. addresses at nonprofit organization rates mid January, March, May, July, September and November. Please allow time for processing and delivery of first issue from time of order. ADDRESS CHANGES / RENEWALS The last line of your label contains the number of your last issue. Please check label for correctness. This magazine does not forward. Please notify us of your date of address change consistent with our bimonthly mailing dates to avoid missing any issues. COPYRIGHT 2010 BY AEE, Inc.
The fly-in season begins! And it begins for us with our 7th annual Alternative Engine Round-Up. For the fifth year running we’ll be gathering at the Jean Sport Aviation Center, in beautiful downtown Jean NV, which is pretty much a wide spot along I-15, just south of Las Vegas. The airport is certainly out of place with the infrastructure quality unrivaled for our use. Plan to spend the weekend of March 2628 in the warmth of the spring-time Nevada desert, partaking in the experimental aviation activities including educational forums all day Saturday, ending with an evening of great barbequed food and even better company.
We also look forward to reuniting with old friends in Florida when we attend Sun ‘n Fun. But this year we will be doing things a little differently, and this is very important to our friends who customarily renew at our booth— WE WILL NOT BE IN OUR USUAL LOCATION THIS YEAR! WE ARE MOVING TO A NEW BUILDING, ADJACENT TO THE BUS CIRCLE. We were offered a substantial discount to move to this location, which has the side benefit of being located next to the relocated FlyMart (which will no longer be located in the ultralight area.) Continued on page 23
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Our Founder Checks in.— Commemorating this, our 100th issue, Mick Myal remembers the beginnings.
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Jim Ewen.— Thom Sherwood’s short biography of graphic artist Jim Ewen, paying tribute to his contributions to CONTACT! Magazine over the years.
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Announcing the 7th Annual Alternative Engine Round-Up, Jean NV, March 26-28.— It's that time again, time for CONTACT! Magazine’s annual gathering. Join us this year for another outstanding weekend of good friends and experimental aviation.
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Tracy Crook’s Three-Rotor 20B RV-8.— Another successful rotary engine installation by renowned rotary guru, Tracy Crook.
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Bruce Sturgill’s Personal Cruiser, Part III.— The third in the series of brief articles detailing Bruce’s progress as he “beta-builds” his Personal (Corvair) Cruiser.
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Some Short Thoughts About Supercharging.— Paul Lipps asks and answers some simple questions about forced induction.
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The Artwork of Jim Ewen.
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Ken Miller’s 4.3L Chevrolet V-6 Powered RV-6A.— Stan Pitts updates us with this success story, detailing the complete disassembly and rebuild of the engine and PSRU, finding very little that needs replacing.
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Geared Drives New Subaru Redrive.— Phyllis Ridings reports on Bud Warren’s latest developments with his newest creation, a zero-offset drive, complete with its own oil pump and the ability to accept a traditional prop governor.
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Russell Sherwood’s Subaru EG-33 Powered Glasair 1RG.— Russell Sherwood recounts his journey to a successful auto conversion that took him through two PSRU’s and one hurricane. His simple approach to the design of his cooling system is quite revealing and somewhat amusing.
On the cover: Commemorating our 100th issue and 20 years, 1990 - 2010.
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Remembering the beginning By Mick Myal CONTACT! Magazine was created to respond to a change in EAA’s editorial policy. In its early years the Association publication relied on member contributions that made up its technical content. Among the many excellent papers I, too, had submitted several articles that were published, most notably “Ultimate Glue”. This formulation of epoxy wood glue (Hughes Glue) quickly replaced the FAA approved resorcinol in wood construction. For me, Sport Aviation was a must-read piece of mail each month, forgoing supper and any other news of the day. My habits have not changed with each monthly coming of CONTACT! Because of the changes to Sport Aviation’s technical content, in the late 1980’s I initiated a survey of EAA Chapters to determine what people in experimental aviation wanted in a publication. From it, I learned that EAA’s editorial practice had drastically changed in the 1980s, veering away from reliance on articles written by enthusiasts, designers and craftsmen. I learned that submissions from respected individuals, namely Molt Taylor, Ladislao Pazmany, Professor Ed Lesher, Bob Pauley and many others were being turned away. The survey suggested that a forum for experimenters was needed and welcomed. Nearing my retirement from General Motors, I made an effort to learn more about publishing techniques. At this early stage of computer development, newsletters were a lively topic of discussion. It seemed that a few organizations were converting from “key lining” (paste up of text and pictures) to on-screen composition. Digital photography was at that time not available to amateurs like me; however the advent of low cost ($49) publishing software (Windows Publisher) was the tipping point; I could do it! So my early issues of CONTACT! were a paste-up combination of digital text and 300 dpi positive images, converted to negative film for burning plates. I decided that the magazine layout would follow the SAE (Society of Automobile Engineers) report format and style. Each section would be announced by a headline word or phrase. This would give the reader a clue to the section content and act as an anchor point for a reader’s eyes. Illustrations would be accompanied by captions in a different font, again for visual separation. My keen interest in a specific airplane design was addressed by including its basic 3 view drawing (as per Jane's All the World's Aircraft) and a unique specification side bar on the edge of page 5, whenever possible. Readers could then collect and compare significant data. Continuity of text flow was a prime consideration for reader convenience; I would avoid the normal practice of “continued on page _”; that, to me, was irritating. Since the stories www.ContactMagazine.com
would flow without interruption I eliminated the usual table of contents page or section. I needed a distinctive feature to solidify issue composition and intent. My solution was the graphic bottom bar incorporating issue and page number. Next on my list was the matter of postage. The United States Postal Service (USPS) has various rates for magazines. The best rate is available to non profit organizations (501(c)(3)), like churches, clubs, charitable organizations, etc. The Internal Revenue Service (IRS) gave me a hard time to justify my eligibility. Many of their questions were based on the premise that CONTACT! was an established business. Long story short; I requested that they fill in the blanks but they couldn’t and finally decided to grant me a provisional IRS ID number for Aeronautics Education Enterprises (AEE). I needed 200 pieces to qualify for USPS bulk-mailing so two hundred undergraduate universities teaching aero and aerospace engineering were given complimentary subscriptions during the early years of publication. Next, the call for papers! The original premise was to provide a venue for experimenter articles dealing with a variety of aviation topics. The expected flood of articles did not happen! The first issue was relatively easy as I was living in Tucson AZ, the home town of Ross Aero. The feature article was penned by Chris Ross. I spent $500 to have an illustrator at Raytheon draw the centerfold of the Ross planetary redrive. However, Larry Brown kindly submitted his Pulsar story for Issue #2. George Pereira and his GP-4 were featured in #3. In order to get his story I traveled to Sacramento CA. While there, I also visited with George Morse of Prowler fame. His article would have been next but was not completed due to family illness. CONTACT! Magazine made its public debut in April, 1991 at Sun ‘n Fun. To look established we had the three issues spread all over the hangar booth, on rungs of two ladder-like parts connected like an A-frame. My aggressive method-of-operation was to snag passersby.
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It was not very polite of me so please accept my apology. Regarding the Oshkosh summer outings, some CONTACT! subscribers will recall our initial tailgate operation and later our 10 by 10 tent situated on the grass by the Fly Market or next to Jimmy Buffett’s amphibian. We ran a quarter-page ad in Sport Aviation and slowly picked up subscribers. Most of the aircraft design and powerplant articles we published over the years were the result of personal interviews and interaction. There were some tense moments when a submitter balked when asked for more information. Several articles never got published because of such reaction. Forums are essential to the dissemination of information and CONTACT! took the opportunity over the years to advance the alternative engine movement by enlisting experimenters to speak at forums about their experiences and developments. Over time, CONTACT! magazine became known as a primary source of alternative powerplant information. The publication fostered the development of various redrive and propeller combinations by experimenters, several of which became successful, home-grown businesses. To add focus we’ve published three volumes of “Alternative Engines” which contain exclusive reprints of past powerplant-related articles. Fellow GM retiree Jim Ewen gave his best to produce hand-drawn CONTACT! centerfolds for several key isBy Thom Sherwood Since its inception, CONTACT! Magazine has had the distinct honor of publishing some original aeromotive art from Jim Ewen. We thought it was high-time to honor this man and his talents, best known to our subscribers for his creative cutaway and technical illustrations, plus the occasional centerfold rendering. Jim Ewen is one of those rare, gifted individuals who found his calling early on. Always surrounded by cars in his father's repair shop (and later a Packard automobile dealership) in the tiny community of Chadron, Nebraska, Jim recognized a desire to sketch those beautiful road machines and sought out a career path to become a professional designer. After a stint in the military during the Korean War in 1953, Jim took advantage of the G.I. Bill to enlist in the Art Center School in Los Angeles and pushed himself to become part of the program's first graduating class in 1956. There, he met his wife-to-be, Rose, who worked in the school's front office. Immediately after graduation, Jim's first interview and job offer was with General Motors Design Staff. His career in Detroit began in the Advanced Research Studios, designing all those wonderful road machines he had dreamed about as a kid. The Firebird III and Cyclone were two cars from General Motors' Motorama years that Jim had a direct hand in developing. www.ContactMagazine.com
sues. Jim and I go back to 1957 when we were both hired by GM Styling, he as designer and me as technical stylist. We worked in different studios and our career paths never crossed. Jim was Chief Designer of GM South Africa at one point in his career. I left Styling to work in the international area for GM regulatory activities. We reconnected as recent retirees in Tucson in 1988. Jim was always available to help me add the special touches to articles and would travel with me to locations when his special talent was needed. I would be remiss not to mention the pleasures we experienced during our endeavors at SNF, OSH and COPPERSTATE over the years. To see a loyal subscriber again and again was always heartwarming. A few nonsubscribers could be counted on to come back and buy missing back issues. I always had at my side a willing partner and wife, Sue, to help me with driving, setup, sales/greetings, and record keeping. I couldn’t have done it without her!
Mick’s Picks: Significant Articles
Cessna Subaru- Reiner Hoffman— Davis DA-9- Leeon Davis— Pushy Galore- Bruce Bohannon— Detonation-Pre-ignition- Al Cline— Dieselis- Paul Lucas— Facetmobile-Barnaby Wainfan—
Issue #20 Issue #32 Issue #50 Issue #54 Issue #55 Issue #71
Jim's talents were then refocused in the up-and-coming Pontiac styling studios, working under Jack Humbert to refine the infamous "Wide Track" musclecars of the 1960s. Other duties included working alongside GM's Canadian engineers to design the unique Pontiac trim and emblems found on their distinctive north-of-theborder cousins. In 1969, Jim accepted a promotion to head-up a state-of -the-art GM styling studio in South Africa where various right-hand-drive cars were transformed into Chevroletbadged models for the local market. This three-year gig, upon ending in 1971, saw Jim return to the United States, where a whole new division was being formed back in Detroit. Jim then spearheaded the Transportation Division, where GM actively sought to research, design, and implement a variety of future-product commodities such as Mag-Levs, people movers, tractor trailers, and mass transit systems. Jim's tenure with GM lasted exactly 30 years and one day, where-after he and his wife Rose retired to Tucson, Arizona where he continues his freelance illustration work and stays active by regularly hiking in the desert. He will be a featured presenter this July at the (Pontiac) GTO Association of America's national convention in Wichita, Kansas. Jim’s artwork can be seen on page 12.
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For the past six years we have been hosting a gathering of alternative engine enthusiasts. The first two years we met at the Laughlin/ Bullhead airport in Arizona, and the last four years at the Sport Aviation airport in Jean, Nevada, just south of Las Vegas. The attendance has been pretty good and we hope to be able to keep doing this for a long time.
Forums have been well attended and well presented.
The forums are always well attended and seating is very comfortable.
The airport at Jean carries the name, “Sport Aviation Center” and it’s for good reason. The county has erected a 6,000 sqft building to be used for aviation related activities. In addition to being air conditioned, it has tables, chairs, and even a full kitchen. The building is easy to find, as it’s the only structure on the field. The airport is equipped with cardlock fuel, both 100LL and Jet A, at “reasonable” prices. If you’d like to attend via commercial flights, Las Vegas International (McCarran, LAS) should be a pretty cheap destination from just about anywhere. The Sport Aviation Center is also home to Vegas Extreme Skydiving and Las Vegas Soaring Center so while you are at the event, if you’d like to also log some glider time or experience free-fall, check with either of these operations. Mention that you are a part of our event for a substantial discount with the skydiving crew, and if you are either an EAA or AOPA member, look forward to a 20% discount with the soaring center. As for lodging, the Gold Strike Hotel and Casino has rooms for $49 (if you book early), and is literally walking distance from the flight line. But if you don’t feel like making the trek with your bags, a shuttle can be called from an outside phone and will be there within minutes. For reservations call: (800) 634-1359 As in previous years we have a few speakers lined up to give engine forums. Listing just a few are Paul Lipps of Elippse Propellers; Bud Warren and his daughter Phyllis; of Geared Drives; Jess Meyers of Belted Airpower; Jon Finley, builder of “Suber-Sonic”; and Gwen Maxwell of Maxwell Propulsions, all of whom have been featured in the pages of CONTACT! Magazine. We hope to have William Wynne of Corvair fame and at least one VW engine manufacturer represented. We have a list on our webpage which will be updated on a regular basis. www.ContactMagazine.com/roundup.html or you can simply call us and ask. If you are interested in presenting a forum, please contact us as well. I’m sure we can accommodate anyone who is interested.
Speaking of contact, please RSVP if you plan to attend. This is still a small venue and we’d hate to find out at the last minute that we have already outgrown the facilities. Use the web link on the previous page and click the RSVP button(s) or give us a call at (559) 584-3306 and ask for Pat. Last year we had a Subaru theme that was well received, but it gave us a reputation of being a Subaru gathering. Nothing could be further from the truth. Consider this an experimental aviation event with a strong slant toward alternative engines of all makes and all sizes. If you don’t enjoy engines or innovation, this is not the venue for you. But if you like all aspects of homebuilding and you’d like to spend a fun weekend around other like-minded aviation enthusiasts, this is your venue! We look forward to seeing you there this year, and with your support, we can continue to host this FREE event. Patrick Panzera Editor@ContactMagazine.com 559-584-3306
Al Gietzen’s stunning Velocity RG powered by a 3-rotor Mazda Wankel engine.
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Tracy Crook and his accomplishments with refining the Mazda rotary engine to a level of reliability comparable to certified engines of the same power, for a fraction of the price, were showcased in a special “all rotary” issue of CONTACT! Magazine. See issue #88. Not being content with proving the 13B and the Renesis, Tracy turned his efforts to the rare 20B “Cosmos” engine that was only available in Japan from 1990 to 1995.
Flight tests of 20B Powered RV-8; The case of the mismatched heat exchangers By Tracy Crook - Builder/Pilot tracy@rotaryaviation.com Real World Solutions 5500 NW 72 Way Bell FL 32619 (386) 935-2973 After 7+ years of building there was nothing left to do on the Mazda 20B powered RV-8 but flight test it. I have been flying an RV-4 powered with a 13B 2 rotor Mazda since 1994 and was anxious to see how the increased power of the 20B would affect performance. For those of you not familiar with the rotary engine, the 20B is a 3 rotor version of the 13B which powered the Mazda RX-7. The 20B makes about 300 HP in normally aspirated form, but it was turbocharged in the Japanese car it came from. I've been flying an RV-4 with the Mazda 13B two-rotor engine for 15 years, 1850 hrs. TT. Before getting into the flight test results, some explanation of the design choices and the intended mission of the airplane are called for. In addition to increasing the engine power about 50% above what is usually installed in an RV-8, I had extended both wings by about 18" so the wing loading and span loading are actually less than with my RV-4. Wing area was increased about 13% over stock; the extra 100 HP only added about 80 pounds. Nothing is free so these changes required a reduction in maximum G loading to 4.4 from the 6.0 G rating for the RV-8. This was considered acceptable in view of the intended mission. Most builders tend to go the opposite direction with wing length when adding more power (like the Harmon Rocket) but the mission for this plane called for maximum fuel economy on long cross country flights while still mainwww.ContactMagazine.com
taining a decent airspeed. The plane is equipped for IFR and I wanted to take advantage of the efficiency increase in flight levels above 18,000 feet. The extra area will allow the wing to stay in its low-drag angle of attack at these altitudes and the engine has enough reserve to have sufficient power left at high altitude. This was the primary reason for choosing the larger engine. At low altitudes and level flight, full engine power is not usable because the plane will more than exceed Vne. FIRST FLIGHT On the day of its maiden flight, it was hot—93 degrees Fahrenheit and high humidity. However, ground tests of the cooling system had gone so well that I was reasonably sure of good in-flight cooling as well. High-speed taxi tests had already been completed and the P-factor was no worse than the RV-4; in fact, I think it has less. This thinking may be premature since I have yet to make a full-throttle takeoff. The 20B was installed with 1.25 degrees right offset which I think helps a lot. My RV-4 has no offset. First flight was done without wheel pants or main gear intersection fairings. Just to make sure there were no surprises, takeoff was done at the same fuel flow as the RV-4 at WOT. I didn't note the manifold pressure but the throttle quadrant was barely over 1/2 throttle. Ground run on the -8 feels more stable than the -4 with considerably more rudder authority. The -8 is physically bigger that the -4 so this is really no big surprise. The plane broke ground at about the same point as the -4 but it feels like it levitates off rather than rotates off. This is probably due to the higher wing incidence on the ground than the -4 with its short gear legs but also due to the longer wing.
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The 20B demo run as part of the Rotary Roundup 2006 festivities. The 20B sounds very different compared to the 13B.
FLYING! Airspeed was increasing rapidly after liftoff but the airspeed indicator (ASI) was not matching the visual cues. Normally I expect to see 120 mph at the end of the runway (2700 ft) but ASI showed only 80. Too late to abort but the airplane was climbing and sounding very nice. I had been doing a lot of seat-of-the pants takeoff and simulated dead stick landings (in the -4) in anticipation of today's tests so I would feel comfortable in the event of partial or complete panel failure (Blue Mountain EFIS1 with only a standard ASI for backup). The climb to 1000 AGL feet felt effortless even after throttling back to 8 gallons per hour (GPH). I noticed that I was hunting for information and not absorbing much due to the very different instrument panel. Remembering that the EFIS1 displays primary airspeed in a ribbon format, I hunted for it and saw 0 MPH when I finally found it. The EM2 (our Real World Solutions engine monitor with backup ASI, VSI & altimeter) showed the same airspeed as the Van's steam gauge, now about 100 MPH. First squawk of the flight and this means I will do the first landing sans accurate airspeed information. I couldn't seem to locate the GPS ground speed on the display either. I'm glad I did all that practice. Time to settle in and start evaluating engine performance. I had taken off with the engine fairly warm so I was not surprised to see oil and water temps nearing 190 degrees F after climb out. I continue collecting data hoping the temps would start coming down but it soon became apparent that they were stabilizing at about 200 on both oil and coolant. Very disappointing, since they had been well below this on the ground when at the same fuel flow I was currently indicating; I had backed it down to 5.75 GPH by this time. The plane itself was flying beautifully. The aileron trim was able to trim out a slightly heavy left wing and the www.ContactMagazine.com
ship felt like it was gliding through the air, effortlessly. No surprise, the plane feels just like an RV (magnificent!). At this speed (guessing about 135 mph) the roll response was only slightly slower than the -4. The span of the ailerons were extended with the wing so the "RV feel" has been preserved. I completed a wide circuit of the pattern and was in position to make an approach so I throttled back and could immediately tell that the glide ratio is significantly higher than the -4. The longer wing is having more effect than I thought it would. I throttled up for a go around and the FBW (fly by wire) throttle responded well, no detectable throttle lag at all.
This -8 with the 20B ended up weighing about 70 pounds more than the average –8 equipped with an O-360 with a fixed-pitch prop, and about the same as one equipped with an IO-360 and a constant-speed prop. Empty weight (but with oil) is 1150 lbs. All the attention to weight control has paid off.
The higher than expected oil and water temps were distracting me from data gathering so I made a few more circuits of the field and set up for final approach. I cranked in more flaps early to kill off some airspeed and excessive L/D ratio and intentionally did not look at the ASI to avoid being confused. The wheel-landing touchdown was textbook perfect and as I glanced at the ASI, I saw 40 MPH. Obviously wrong, this is no LSA! When I investigated the ASI problem it turned out to be a broken pressure sensor in the Blue Mountain EFIS1 that caused a pressure leak which affected both the other backup airspeed instruments. All in all, a great first flight. The RV-8 is going to be exactly the airplane I was hoping for. Still a lot of testing and tweaking to do.
OIL COOLING EXPERIMENTS Cooling a liquid-cooled engine is frequently a challenge with alternative engines. The next several flights were spent trying to find out why the oil cooling was not working as well as expected based on the ground test results. Since the ground tests were done with the cowl off but with the radiator and oil-cooler inlets and diffusers in place, the obvious conclusion is that the problem had something to do with what happens inside the cowl. The most common problem is that back-pressure in the cowl restricts airflow through the heat exchangers. I have an instrument to measure that and it seemed to show very little back-pressure, but I tried many of the usual things known to improve outlet airflow anyway. Enlarging the cooling outlet, installing a cowl flap and adding louvers to the bottom of the cowl all had little effect.
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not adversely affecting water temperature. This was very confusing to say the least. The normal temptation is to keep changing the cooling outlet scheme until the internal cowl pressure is low enough to get the proper cooling. My belief is that this would lead to a very high-drag solution. After several more tests with no conclusive results I started to question my ground tests where the system cooled fine with the cowl off. Just to make sure I hadn’t missed something, I did a test flight with the cowl removed! The cooling was more than adequate in this configuration even though the drag was enormous. The fuel burn was 60% higher at the test airspeed of 130 mph. The only explanation that seemed to fit the test results was that the radiator (because of its relatively low airflow resistance) was hogging the airflow caAs viewed from standing in the cockpit: On the right is the radiapability of the cowl outlet. Or put another way, the tor, at the upper left is the oil cooler. Each has independent inlet radiator air flow was not as affected by the back diffusers that are proven, but each dumps into the common cowlpressure as the oil cooler was. The oil cooler is a ing which acts as the exhaust plenum. The relatively free-flowing air traveling through the radiator pressurizes the cowl, making it thick air conditioning (A/C) evaporator core that is difficult for air to enter the cowl from the oil cooler. very restrictive so with only a little decrease in pressure delta across it could cause a big reduction in airflow. The next experiment was to replace it with a On the theory that airflow patterns, rather than just presmuch less restrictive (to airflow) oil cooler. I found the sure inside the cowl, were potentially blocking airflow largest cooler that would fit in the same location as the A/ through oil cooler, I installed a partial exit duct behind the C core and I'm using the same diffuser as before (slightly radiator directing the airflow downward toward the cowl modified to fit the larger face of the new cooler). This outlet. It looked very restrictive but flight tests showed cooler is only 2" thick and core volume is 30% less than almost no effect on water cooling (which is okay) and a the A/C core. It is slightly larger in volume than an RX-7 significant improvement in oil cooling, but still not good cooler which is known to work well, at least on 13B enenough. I further restricted the airflow through the radiagines. Without any back pressure (flying with cowl off), tor by putting some roof ridge vent material inside the the A/C core had way more than enough cooling capaciinlet diffuser. This gave a tiny increase in water temp but ty (146 F oil temp on a 93 degree day) so I was hoping a further improvement in oil cooling. Long story short, that this smaller cooler would be enough. I will admit that after several more tests it became apparent that even a the idea of fixing an oil cooling problem by installing a small amount of back pressure under the cowl was havsmaller cooler seems counterintuitive. ing a major effect on the oil cooling even though it was
The Peterson oil filter gave Tracy the freedom to locate it in any available space. Here it’s shown with an Adel clamp mount on the gear drive adapter plate. The planetary PSRU is Tracy’s design and available from RWS, and can also be adapted to engines other than the rotary.
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The exhaust header was sent to Jet Hot for ceramic coating. Tracy chose the Jet Hot 2000 process (good up to 2000 deg F) instead of the more popular chrome-look version since that finish is only good to 1300 degrees. Rotary exhaust headers get a lot hotter than that. Hopefully this will reduce under-cowl temperatures significantly.
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I should point out another symptom. Power setting (and therefore airspeed) had very little effect on the cooling (i.e., it didn't get much hotter at high power as long as airspeed went up as well. Things got hot fast in climb however. This also indicated to me that cooling was limited by airflow through the system rather than by the oil cooler's ability to transfer the heat to the air. If the cooler is simply too small, more airflow will not help much. SKYWRITING A few weeks later the new oil cooler was in and ready for test (or so I thought). OAT was only 41 deg and it took a long idle time to warm up so I used that time to Tracy used another "shoe-box" style manifold (like he did on his RV-4) that limits the runcheck for oil leaks and saw ner length to around 11.5" If kept clean, this still gives good results. 16" would be better but room is always a problem. Notice the lack of throttle cable. The throttle body is from no signs. The pattern of oil an RX-8 and is fly-by-wire. FBW controllers will soon be available from RWS. The black and water temps during line leading to the plenum is the manifold pressure connection for the EC2. warmup looked good so I had high hopes. I monitored the temperatures closely sults in loosening the adapter-to-cooler mating thread as during takeoff and continued to see good numbers. you tighten the hose fitting. That's where the oil was Climbing out to 500 ft and turning left to downwind, I coming from. thought that I smelled a slight whiff of hot oil. Looking over my shoulder, I saw that I was sky-writing with a Although this was a very brief flight on a cool day, I could dense smoke trail so I throttled back to high idle and did tell from the trend of the oil and water temps that this a hard 360 to the right to set up for a downwind landing cooler was going to work much better than the old one (almost no wind). The only thing new was the oil cooler even though it is about 25 percent smaller in volume. so I was scolding myself for installing this cheap cooler-Size really isn't everything. Further tests with the AN while monitoring the oil pressure to see if this was going adapters properly installed showed a big improvement in to cost me an engine overhaul. Pressure stayed at 55 oil cooling. 60 PSI all through the landing so all was fine and thankfully the oil cooking off the exhaust system did not ignite. LESSONS LEARNED I wonder if the poor burning quality of synthetic oil is anThe significant thing I learned from all of this is that other good reason to use it? matching of the airflow characteristics of two different heat exchangers sharing a common cooling outlet is very On the ground it looked like there were a couple of important. quarts of Mobil 1 dripping off the bottom of the fuselage and left wing trailing edge. I popped the cowl top and the I use an air/fuel mixture monitor hooked to an O2 sensor entire engine compartment was drenched in oil EXCEPT in the exhaust system to make engine tuning easier. I for the oil cooler core itself, which was dry. The cooler noticed one other oddity during these tests. As soon as turned out to be OK. The leak was from the bottom fitting the O2 sensor got covered in oil, it quit working. These on the cooler. It came equipped with AN-10 male fittings sensors actually have to 'see' the outside air at the cold so I had installed -10 to -8 adapters to match the -8 hosend of the sensor. They compare the O2 in the air to the es in the plane. The tightening procedure needed on O2 in the exhaust and stop working when they can't. these adapters has some pitfalls. I am always careful to use two wrenches on these fittings so as not to put See ya at Sun 'n Fun! torque on the cooler and damage it. These adapters require that the adapter be put on first using the two Tracy Crook - Builder/Pilot wrench method followed by the hose fitting to the adapttracy@rotaryaviation.com er. BUT, one wrench needs to remain on the oil cooler Real World Solutions fitting and the other on the hose fitting. I mistakenly put 5500 NW 72 Way one on the adapter and one on the hose fitting. This reBell FL 32619 www.ContactMagazine.com
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Bruce Sturgill’s Personal Cruiser project first appeared in CONTACT! Magazine as a side piece to the cover story on Morgan Hunter’s Personal (Corvair) Cruiser, appearing in issue #88. As a continuation, in issue #91, Bruce reported on having Morgan to his home for some personal assistance in a builder assist program being offered by Pro Composites, the marketing force behind the Cruiser and the Vision, both designed by Steve Rahm. By Bruce Sturgill bruce@pursuitofflight.com
THE WORK CONTINUES
Canopy not cut in this shot, Bruce cut and tucked it away in the same box it was shipped in, for its protection until he’s ready to permanently attach it.
I thought that by now I would be a lot further along, but it seems like I haven’t gotten into a consistent rhythm for working on my plane since Morgan left. Having to hold up my end of the trade for having Morgan out for a builders assist week (my wife June got a new kitchen), took a little longer than we thought. The wife really likes her kitchen, and I have to admit it does look a lot better than the old one.
my worktable. Using this method I was able to get a much smoother fit between the other sections of foam, making for less sanding time.
The turtledeck, forward deck, and canopy are all cut to size even though I don’t have a picture with the canopy cut. It’s tucked away in a box for safekeeping. Since I won’t need it for a while, I’ll include details about its installation in a future update. I haven’t permanently attached the turtledeck or forward deck yet. I’m still working on the flight controls and the interior parts, and obviously it’s much easier to do that with them off. I have to admit, it’s very nice to have some moving surfaces that are attached to metal. I have the gear legs out from under the table and put on. The wings are covered; however, I need to cut out the ailerons and create my wingtips. I found that I was able to get a better fit of the trailing edge sections of foam by setting the leading edge of the wing in a cradle and working on a flat surface, thus the reason for me standing on
Clamps and straight edges to make sure the gear leg is attached properly. The blue sand bags are to help hold the gear up while the flox sets.
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Bruce’s unorthodox method of standing on his worktable microing the aileron section of foam in place. Photo by Victoria Sturgill
Turtle deck, forward deck, and cut for the canopy.
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The glassing of the wings is a time-consuming job and was made a little more challenging by not having a helper to hold the other end of the glass or mix epoxy. If I were to do it over, I’d purchase an epoxy pump instead of using a scale to get the correct ratios. The pump would make the process of the larger lay-ups go much quicker and smoother, though some builders are fine with using the scale method. I would agree that for the smaller parts the scale method is just fine; however, I think I have more waste with the scale method.
The bottom of the wing covered in peel ply, with a strip of carbon fiber on the section for the aileron. Straight edge to keep things straight, of course.
I would also enlist the aid of a helper; that was a lot of glass. I tried to take stills and video of the process, but it didn’t work out. I had my hands full just getting the large sections of fiberglass on straight and with the right amount of epoxy. I did spend a lot of time prepping the foam, making sure it was nice and smooth. It doesn’t look like I’ll need a lot of fill, especially with peel plying the surfaces. Glassing both wings was a big milestone that I was glad to have finished. Now that my work “busy” season is over, I hope to spend more time in the garage working on the plane.
Some Short Thoughts About Supercharging By Paul Lipps elippse@sbcglobal.net Supercharging is where a compressor increases the density of the charge entering an engine's cylinders. It does this by increasing the pressure of a known volume of gas, the cylinder's displacement. The compressor may be driven from the engine's crankshaft, by a turbine from the exhaust, or by a separate device such as an electric motor or another engine. This is how Will Matthews did it in his Reno Sport-Class race plane #43, White Lightning "Moonshine". He had a separate engine mounted in the rear seats driving a compressor. Unusual, but effective! Now you may assume that any time you are getting a certain amount of boost that the engine's power is increased proportionately. Not so! Let's suppose you have a turbo-normalized engine; that is, where the turbo-supercharger maintains a sea-level pressure of 30" up to a certain altitude where it no longer has the ability to increase the static pressure to 30". Will the power still be the same? After all, you still have 30" of manifold absolute pressure, right? Well, anytime you compress a gas, you also raise its temperature. The turbo -normalizer, at sea-level, is not compressing the gas above sea-level pressure, disregarding any pressure drop in the induction system. At 15,000 ' MSL, the standard static pressure is 16.9" and the standard temperature is 258.4K, 465.2R. The compressor must compress the air from 16.9" to 30". If the compressor's efficiency is 95%, the incoming air will be heated about 62C or 111F! Relative to sea-level standard temperature, the compressed air entering the cylinder will be 90% as dense as at sealevel, so all things being equal, the engine will have about 90% as much power as at sea-level. That's one of the reasons for using an intercooler on the output of the compressor. Another, of course, is to keep the combustion chamber temperature down to eliminate detonation. Now since the temperature rise is due to the amount of compression, that raises another consideration - induction pressure losses. I saw a racer at Reno with at least four feet of SCAT tubing from the inlets to the turbo-chargers of a dual installation. When I questioned the owner about the induction pressure loss this could give with the high resistance of this type of tubing and the high volume of flow, he just told me that the compressor would overcome this by sucking in the air. Yeah, but that pressure drop means the compressor is going to have to do more work on the air, which means more temperature rise, and more exhaust back-pressure. Secondarily, the cooling air-flow to the intercoolers will have to be increased to get rid of the extra heat, which means more drag!
Moments after arriving at EAA AirVenture 2007 Morgan Hunter, the builder of the prototype Corvair Cruiser, was invited to tie down under “the old brown arch,” the highest place of honor for any homebuilt visiting OSH.
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The moral of this: if you are using supercharging, minimize your induction losses by using smooth, large diameter tubing from the induction inlet to the compressor inlet, keeping the path as short and as straight as reasonable!
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By Stan Pitts stanpatair@nwi.net In CONTACT! Magazine issues #43 and #52, I chronicled the airframe and powerplant build-up of Ken Miller's RV-6A, N811KM. After eleven years and 700 hours of flying time, we decided to remove the engine and PSRU from This photo was shot in 1998. The plane still looks this good today. the airframe to see where we were as regards to possible unseen wear or damage. We had no indications of probPSRU LOOKING GOOD lems of any kind, but we felt it was time to see the inside On tear-down inspection, both the lower drive sprocket of the complete powerplant. The 4.3 liter (262 cubic inch) and the upper driven sprocket showed like new red hardChevrolet V-6 and Northwest Aero PSRU had performed anodizing in the tooth-to-belt contact area. The bearings flawlessly all these years without any leaks, belt adjustin the PSRU felt smooth, but we changed them, and the ments, or even an ignition tune-up. The original spark belt, because the drive manufacturer recommended we plugs were still clean, and looked good enough to last for do so. We very carefully examined and checked for many more hours. cracks in the PSRU plates, shafts, and fasteners. We found no cracks or signs of stress. We simply reWe had changed the accessory drive belts at five years, assembled it with the new components recommended by but had never changed or even had to adjust the PSRU the manufacturer. The PSRU is obviously well engibelt in all that time. The PSRU belt free-play, measured neered and well built. We have total confidence in it. at the prop tip, stayed at 5/8 of an inch from N811KM's early test flights until the day we disassembled the unit. It TOP END IN TOP SHAPE never showed any belt dust or detectable wear in the We are equally pleased with the condition of the engine. sprockets. The original belt literally looks as good as it Cylinder head removal disclosed a heavier than exdid when it was new. pected carbon deposit in the combustion chambers and on the piston tops. It was a soft bright tan colored carbon that I think is from the lead in 100LL aircraft fuel. Ken burns a mixture of unleaded auto fuel with approximately 25% 100LL added for its long-term storage stability, and to provide a little octane boost for added anti-detonation protection. The carbon on the piston tops went right to edge of the piston tops and was very dry, which means the piston rings are doing a good job. No oil is going by the rings to wash the carbon off. This carbon brushed off the piston tops easily with a soft brass bristle brush. There is no measurable wear in the cylinder bores, with hone cross-hatching still visible in the bores except right at the top of the ring travel. There are no signs of scoring on the cylinder bores or the piston skirts.
BOTTOM END INSPECTION Over-the-spinner view above the engine: Red SCAT hoses are carb heat ducts. Pulling the carb heat control on the panel closes ambient charge air door on the intake housing (air cleaner) bottom plate. This forces the carburetor to pull air that is pre-heated by passing through the radiator back through the radiator again. Induction air in the intake housing goes from ambient temp of 60 degrees to 110 degrees in a few seconds. No ice problems. This is with coolant at 180 degrees. Ignition and carb are protected from wind and rain by the PSRU unit. Red fire sleeve protects fuel supply line. Top radiator hose from thermostat housing to left of intake housing.
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Next I dropped the oil pan and was very pleased with how clean the sump was. I removed the main bearing caps and measured the lower main bearing shell thicknesses. I had measured and recorded the new bearing shell thickness when I built the motor, so now I could measure exactly how much wear there was in the bearings. The two center main shells had between 0.0001 to 0.0002 of an inch wear, and the end bearings had less than 0.0001 wear. This is next to no wear at all. I rolled the upper bearing shell of the rear main out to see if the belt load from the PSRU was wearing the upper bearing shell. I could not tell that the upper shell had been
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the stock pushrods, and the Crane roller rocker arms showed no signs of wear. The oil pump/distributor driven gear and the cam drive-gear were barely marked. The MSD distributor we use has a drilled oil passage directly from the main engine oil galley that keeps this gear interface well lubed and cooled. In addition to that, the steel GM roller lifter cam we are using has a cast iron coated drive gear that is easy on the oil pump/ distributor driven gear. No trick oil pump/distributor driven gears required. Other than gasket surface and bolt hole clean-up, that's all I had to do to the short block. Carb heat tubing can be seen routed into the side of the air cleaner. Prop is a groundadjustable, all composite, three blade Ivo.
touched by the crank. It looked like new, and measured same as new thickness, so I reinstalled the bearings in their original positions and re-torqued the main cap bolts. The main bearings looked so good that I decided not to pull any of the rod caps. The rear main seal was dry, so I did not disturb it either. There were several degrees of crankshaft rotation looseness in the original GM timing chain, so I installed a new Cloyes high-performance roller timing chain and gear set. I checked the cam-to-crank timing to make sure the new chain and gears were accurately marked. They were right on. The camshaft, the hydraulic roller lifters,
VALVE TRAIN
Next I disassembled the cylinder heads laying out everything in order so they could be re-assembled as they were originally. I cleaned the combustion chambers and the valves with glass beads and low pressure. There was little to no valve stem or valve guide wear. The Crane roller rocker arms, and the stock (original equipment) valve stem seals allowing a little oil to be drawn down the valve guides get the credit for this. There was so little valve seat or valve face erosion I did not face the valves or the seats in the heads. The cast iron heads with their induction hardened exhaust seats are holding up well. The valve springs lost only 5 to 10 pounds of seated pressure, and a 0.030 valve spring shim under each of the Crane valve springs brought them back to the original installed seated pressure of 115 to 120 pounds. The valve spring vibration dampers, valve keepers, and the valve spring retainers show no signs of stress or damage, which means the valve springs are doing a good job of controlling the valve train. Ken turns the motor a maximum of 4800 RPM, and then only when he's showing off. He cruises mostly at 3600 to 4200 RPM, so these high performance valve train parts are just jogging in there. I purchased a full Fel-Pro gasket set and re-assembled the engine.
IGNITION, INDUCTION and CHARGING
Right side under the cowl: Dual MSD ignition coils and automatic coil joiner. Cabin heater housing below coils. Easy access to oil filter. Nice exhaust fit– note that this header is designed to be on the other side of the engine.
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I also disassembled the distributor and cleaned up all the mechanical spark timing advance components, and checked the advance weights and springs for wear. All were in good shape, so I lubrication and re-assembly was all that was required to put the distributor back in great working order. All the MSD ignition components have performed flawlessly. We did the same to the Holley carb. Installed a kit, and bolted it back on. Same with the ND alternator. I took it to an automotive electrical shop for rebuild and they said the bearings were smooth
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and quiet, the brushes were good, and it put out over 40 amps at 14.4 volts, so we just bolted it back on. We even treated the motor to a new set of spark plugs.
COOLING SYSTEM About a year ago, during a preflight walk around, Ken noticed a small puddle of coolant under the airplane. This was the first indication that maybe we should get serious about looking deeper into this ten-year-old airplane. It was the original Edelbrock aluminum water pump starting to seep coolant from the shaft seal. Ken installed a new Edelbrock pump and flew for a few more months before we finally got around to taking the powerplant apart for this major inspection and rebuild. I re-used the water pump Ken installed last year.
Left side under pressure cowl baffle. New exhaust headers. Starter solenoid rotated down away from exhaust heat. Heat shielding on plug and electrical wiring. Fire sleeving on fuel supply lines. Coolant recovery bottle to the left of brake fluid reservoir. Lower radiator hose to water pump inlet behind coolant recovery bottle.
Ken took the radiator to have it checked and all they did was flush it out and pressure check it. They said it was as good as new. Cool! We changed all the cooling system hoses and the accessory drive belts. The original Robertshaw 180 degree thermostat was working well, so we also reused it. This brand of thermostat has never given us a minutes trouble. A thermostat maintains even temperatures throughout the engine which ensures that the clearances you take great pains to establish during assembly are stable. Running without a thermostat can create hot and cold spots in the engine which potentially could cause cracks in exhaust valve seat and surrounding areas and gasket failures due to uneven expansion and contraction of engine components. And piston to bore clearances change greatly from a cold area to a hot area which can cause a poor ring seal or a scored piston and cylinder wall. Who wants that to happen to their airplane engine? We use Texaco extended life coolant mixed 50/50 with distilled water under the control of a 16 pound radiator cap. I believe we have changed the coolant two other times over the last eleven years. No rust. No corrosion. Ken's cooling system works great.
EXHAUST While the engine was out we could see we were soon going to have a problem with the exhaust system I built. We had some hot spots that looked like blisters that would soon blow out. We learned that Sanderson Headers had available a “shorty block hugger” header set that looked like it might fit N811KM's tight engine bay. While I went through the engine, Ken ordered a set for us to try. After reinstalling the engine in the airframe, we tried the headers on and discovered that if we had two left side headers they would fit with only a minor modification to the header on the left side of the engine. Ken called www.ContactMagazine.com
Sanderson and they agreed to sell him a set of two lefts. I modified the left side header and Ken sent them both back to Sanderson. They made up another left side for him and then plated it and the one I modified with their ceramic coating. They fit fine and look great. It was relatively easy for us to modify the existing tailpipes to mate up with the new headers and still have the exhaust exit the cowl in the original location. The new exhaust system required us to re-route and re-shield the sparkplug wires, but that was relatively easy and turned out well. By the way, Sanderson headers feature a beautifully ground flat weld bead around each port and bolt hole so that they do not require exhaust gaskets. They don't come loose. They don't leak. Nice. I had run and tuned the motor on my engine stand before we installed the engine in the airframe, so after we bolted it in and wired it up and hosed it up and topped the cooling system up, it fired instantly. Everything is working as expected, and judging from past experience, we don't expect any problems. The new exhaust system sounds even better than the old system. N811KM sounds like no other airplane in this area. Smooth and crisp. I don't need to ride in it, just let me hear it fly over once in awhile. Ken flew over my work place a few days ago. I heard him coming even though I was in my office. I got outside quick enough to see him shoot over. It's a great looking airplane that flies beautifully, and sounds mean. Thanks, Ken, for letting me play with your airplane. Stan Pitts stanpatair@nwi.net
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Geared Drives was featured on the cover of CONTACT! Magazine, issue #89 and in the pages of #91. Their work with a simple, yet robust redrive for the small block Chevy is well documented in these articles. In issue #97, we reported on a Subaru redrive prototype of the same basic design, utilizing the same clutch configuration. With several hundred hours of flight testing completed, they have now come to market. CNC’d from billet, it’s a thing of beauty. I’ve been to the shop where the aluminum is milled and seen the workmanship, but it wasn’t complete enough to bother with photos. At this writing, no photos were available but the completed unit will be on display at the Jean fly-in on March 27th, 2010. ~Pat
By Phyllis Ridings Administrative Assistant to Bud Warren (936) 672-6639 www.GearedDrives.com Geared Drives has developed a spur gear PSRU that utilizes Bud Warren’s custom, centrifugal clutch assembly. A take-off of his larger unit designed for highhorsepower, this gearbox and clutch assembly was designed for any auto conversion engine in the 150 - 200 horsepower class requiring zero offset from crankshaft centerline. Applications include Subaru, Mazda, Suzuki, Ford (in-line and V’s) and others—including diesels—by use of an adapter plate bolted to the flywheel end of the engine. Like its larger predecessor, it features its own independent oil reservoir, oil pump and filtration system.
DOUBLE REDUCTION – VARIABLE RATIOS “This happened as part of a natural progression” said Bud. “Too many people requested that I design a PSRU for a Subaru. It became apparent that people were looking for alternatives.” Some were experiencing high gearbox operating temperatures, others reported intermittent thrumming and vibration of the airframe due to unresolved harmonics, and a couple reported incidents as dramatic as gearboxes locking up in flight. “I knew that if I could translate the features of our PSRU for high horsepower engines to a smaller and lighter double-reduction version with the centrifugal clutch, I had a good chance of solving a lot of their problems. Because the Subaru engines make their HP at higher RPMs I knew that I would not be able to achieve a reduction ratio that would be a one-size-fits-all answer.” Bud chose a double reduction gear configuration that would allow a wide range of ratios as well as providing the option of changing them out easily and inexpensively after the fact.
HARMONICS “The clutch is the key,” says Bud, “because it helps dampen harmonics. Operation is smooth, almost like an electric motor.” The clutch serves several other functions as well. Upon startup, the prop will spin due to the slight www.ContactMagazine.com
200Z-The zero-offset PSRU, retrofit/replacement. amount of friction and engine inertia. However, full engagement of the prop doesn’t begin until roughly 800 engine RPM, allowing the engine to start without the prop load, saving a great deal of wear on the starter. The harder the engine runs, the more firmly the clutch is engaged. At shut down, the prop winds down to a stop similar to that of a turbine, eliminating prop kickback. The clutch will not allow the prop to disengage until the engine RPM is reduced to well below 800 RPM. However, if the engine should quit in flight, the relative wind keeping the propeller spinning will keep the clutch engaged.
RETROFIT The 200Z- Zero Offset Geared Drives PSRU occupies a footprint slightly smaller than the Eggenfellner Gen III unit and requires no changes in thrust line or propeller. Use your existing electric constant speed prop, or any other prop you wish, including certified hydraulic. Geared Drives believes that there are distinct all-around performance advantages to using any constant-speed or cockpit-controllable propeller, and has built a hydraulic prop governor drive into this unit in order to facilitate that concept. Lubrication is provided by a built-in oil pump that serves the PSRU internals, prop, and prop governor. Engine oil is not used in the PSRU or prop governor. Retrofitting this unit to an Eggenfellner engine requires minimal machining. The center hole in the front mounting plate must be opened up to 10.5” diameter to accommodate the clutch assembly, and the spacers between the engine plate and the engine are replaced with longer ones to allow additional room for the Geared Drives clutch and flywheel assembly. Adapting this gearbox keeps the prop flange station in the exact same place as the Gen III unit and will not appreciably change the weight and balance. The prototype weighed slightly less than the Eggenfellner and the new CNC unit will weigh even less. Price will be the same for a retrofit or a new installation, just under $6,000.
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For a first-time builder, it seems that Russell has nailed it. With no formal aeronautical engineering training and admitting to failing at each initial attempt to create a new part, Russell embodies a “tinkerer’s spirit” with a tenacious attitude. After two or three attempts, he usually finds a way through just about any problem. His wife Rhea has been an instrumental key to the success of this Glasair, ready with ideas and loads of actual handson labor. Rhea has long wanted to live on a flying community airport and the couple has recently purchased hangar property on an airport near Fort Worth and are now in the process of building and moving there. This coming summer there are several air races in Texas that Russell hopes to compete in and get some real world performance numbers. A commercial rated pilot, Russell holds multi-engine and instrument ratings with 4,300 total flight hours logged. As of this writing, 323 of those hours have been in the Subaru EG-33 powered Glasair RG. By Russell Sherwood Houston, Texas (713) 542-9570 3sherwoods@comcast.net Powering my Glasair RG is a Subaru EG-33 automobile conversion. The EG-33 is a 230 HP, 3.3 liter, six cylinder engine and was removed from an SVX sports car. With the exception of the exhaust, intake manifold and the removal of unnecessary sensors and accessories, the engine is otherwise in the stock configuration.
PROPELLER SPEED REDUCTION UNIT My biggest headache has come from the gear box. The original was a Ross planetary drive with a 1.85 ratio. I had always planned on having frequent tear downs for inspection—about every ten hours—and extending that as confidence in the gear box grew. Chronic problems kept showing up, and I was never able to lengthen the www.ContactMagazine.com
inspection frequency. Some of those problems were: excessive planetary thrust washer wear; pitted gears; poor oil delivery to the planetary bearings; short planet bearing life; and movement of the planetary gear shafts. Poor design of the shaft keepers allowed the planetary shafts to move forward into the ring gear. If neglected, the planetary gear shaft movement could have resulted in a catastrophic failure. I finally discovered the source of some of these problems; poor oil delivery within the gear box. Even though plenty of oil was flowing through the unit, little was making its way to critical moving parts. Another big problem with the Ross was the extreme difficulty in doing a complete tear down and inspection. I was able to design fixes for most of these problems but, they came too late and at about 60 hours I was forced to ground the plane. In all fairness, I understand that the 2.17 or 2.85 PSRU ratio is more durable and reduction manufacturers prefer not to make the 1.85:1 ratio.
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keep all 230 of those thirsty ponies happy. Fuel tank selection is made with a remote electrically controlled valve from a 1980’s GM Suburban (part# 14029228). This valve switches both fuel going to the engine and excess fuel returning to the tank. Whichever tank is selected, the return flow is routed back to that same tank, helping eliminate cross-contamination. The fuel pumps and valve are located below the fuel tank level. If I accidentally run a tank dry, low pump placement allows the pump to reprime when the good tank is selected.
There is a lot going on, but Russell created a tidy package.
My second gear box is from GAP Industries of British Columbia, Canada www.gappsru.com (604) 820-9088. I questioned John, the CEO, on his design for oiling, ease of inspection, and vibration dampening. John also prefers the 2.17 and 2.85 ratios. After many phone calls and emails John agreed to make a one-of-a-kind 1.85 ratio for me. The GAP PSRU uses a planetary gear from a Ford C6 automatic transmission. The six-pinion gear set is tough enough for diesel-powered trucks. The propeller shaft and flange are machined from a solid billet of 4140 HTSR (hardened tempered stress relieved or heat treated, stress relieved) steel, as is the input shaft. The sun gear is shrink-fitted and silver soldered to the shaft. I did have teething pains with the GAP. Some companies seem to forget you the day after you buy their product but John welcomed my calls and we worked out solutions to the problems I incurred. He even called many times to check on his unit and I give John a gold star for his after-purchase assistance. I have about 240 total hours on this gear box. The planetary needle bearings have required replacing about every 25 hours because of signs of wear. In an effort to extend the bearing life, I tried several different bearings. On one occasion I made a set of plain bearings and developed a pressure oiling system for them. I built the bearings with a clearance of only 0.0005 inch. Oops...clearance should have been 0.0015 inch. The tight clearance did not allow adequate oiling at high power settings. Problems quickly arose on departure, an emergency was declared and a speedy return to the airport was made with only 63 seconds of flight time. I keep a video camera mounted in the plane and record every flight. If you would like to watch my bearing emergency, go to YouTube.com and do a search on my user name “ThrottleUpSVX,” then look for the video with “take off emergency” in the title. I failed to plug in the auxiliary microphone, so you won’t hear the engine monitor blaring out alarms or chatter between myself and other aircraft, but you can hear the engine sounds through the camera mic.
FUEL SYSTEM The stock Subaru fuel injectors are controlled by a stock Subaru ECU (engine control unit). Two MSD fuel pumps www.ContactMagazine.com
I ran premium auto fuel until the Houston area was forced to add ethanol. The Glasair, including the fuel tank, is made using vinylester resin. Curious about compatibility, I placed a small sample of the wing material in a jar with ethanol tainted fuel. Twenty four hours later the sample started feeling slimy. In 36 hours the glass fibers were starting to become free of the resin. Never put ethanol tainted fuel in a Glasair. I would advise anyone planning to use ethanol in your plane to carefully check its compatibility with your aircraft systems. For more ethanol horror stories, read Larry David’s article in CONTACT! Magazine issue #96. I now run Avgas, which makes the combustion chamber and exhaust a lot dirtier. With auto gas I could run my finger around the inside of the exhaust stack and come out with a clean finger—not the case with 100LL.
RADIATOR-COOLANT The radiator was built by Ron Davis Racing in Arizona. Final size and design was determined by a combination of Ron’s suggestions, available space, and findings during engine testing. The radiator core size is 16 x 15 x 2 inches and has 14 fins per inch. The radiator is mounted P-51 style and aft of the wing. Coolant must travel through 13 feet of 1 inch diameter tube to make the trip from engine to radiator and return again to the engine. I originally used ¾ inch diameter tubing. The cooling system was making about one cup of air for every hour flown. I feared water pump cavitation with the ¾ inch water pipe. At about 180 hours of flight time, I changed the water pipe to 1 inch diameter with no noticeable difference. I could have kept the ¾ tube. My radiator reveled it was carrying about 5% air and 95% water. Over several flights the cooling system seemed to never purge the air. The original air/water separator was a two inch diameter standpipe built to slow water flow to allow air bubbles to work their way up and eventually out the radiator cap. Hot water exiting the engine dumped directly into the standpipe at a point only 3 inches below the radiator cap. I built a clear mock-up of my standpipe and was able to watch the action of the bubbles. The problem with this design was the fast moving inlet water was too close to the cap and pulled the bubbles back into the water stream. I added two baffle plates between the incoming water and cap, which allowed a much better air/water separation but still needed more improvement.
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The fix was to rearrange the water routing and place the radiator cap in a location of stagnant water. This allowed air to collect under the cap and not be swept back into a high water flow area. Within the stagnant section I made a small pocket that holds air that does not purge when the cap pops, thus allowing the water to expand some without popping the radiator cap. The overflow bottle now fills a bit as the engine warms and coolant is then sucked back to the engine during cool down as it should. With my plastic airplane, the radiator, its aluminum piping, and the engine were all electrically isolated from each other. I measured a potential of about 0.7 volts between them. To help prevent galvanic corrosion I ran a ground wire from the engine to the piping and radiator.
P-51 STYLE BELLY SCOOP The P-51 style scoop has proven itself very well. Cool air enters the 33 square inch area scoop, and then has a 43 inch long run of gradually expanding plenum, opening to meet the 240 square inches of radiator area. The exhaust side of the plenum has a one-foot run to the control door hinge-line, after which the heated air is compressed down to about 84 square inches. As in a P-51, the exhaust air end of the plenum has a cockpit controllable door. This exhaust door can be closed to 11 square inches or opened to any position up to 77 square inches.
place an expansion cone over the hose, especially if that cone is angled at the rate we try to use in our cooling intakes, the water remains tightly bunched up. That is exactly what we saw happening inside the scoop. In an effort to expand and slow the incoming air, we duct taped cardboard turning vanes inside the scoop. After a bit of experimenting, the best location for the turning vanes was found and permanent turning vanes were then glassed in. The turning vanes did not cure 100% of the chaos, but it took care of the majority. The hot air outlet required no modification or turning vanes. Apparently the radiator plus the recompressing process does a good job of straightening and organizing the hot exhaust air. I believe that the turning vanes changed what may have been a marginally high-drag cooler to one that does rather well. With the OAT around 80 degrees F, normal departures and climbs can be made with the control door in the closed position or 11 square inches of exit opening. However the water temperature will slowly work its way up to about 215 degrees F in the climb. When departing and climbing with the door open to about 25 square inches, water temperatures remain near 195 degrees. In cruise, the door is positioned from 11 to 20 square inches. Taxi and ground operations can last all day even with power settings greater than normally needed. Now, with over 300 hours of flight time, I find the scoop intake opening area of 33 square inches to be a bit large. Plans are to build a slightly smaller intake opening, which may help reduce drag. Building the P-51 scoop was much more involved and time consuming than I had imagined. If you can cool your project with the radiator inside the cowl, you will likely save considerable time.
THE WIND TUNNEL My wife and I made numerous attempts at tufting the radiator scoop to watch the air flow—all were failures. We could not get both high volume and high speed at the same time, plus the air was entering the scoop in a very turbulent state. Frustrated with all the failures, I was near the point of giving up, but one summer day we happened to walk into a store that had several inflatable pool toys hanging from the ceiling. One toy was in the shape of an alligator and the snout on the ‘gator looked to be an exact fit for the scoop entry. We built a “poor man’s wind tunnel” and placed tufting yarn in the interior of the scoop. While watching the airflow through the scoop, we found that air does not like to turn. Air would generally hold the scoop intake shape and size until impacting the radiator face. After hitting the radiator, the air would make a 90 degree turn away from the shaft of incoming air. As the air moved outward, it went into chaos, tumbling and even traveling forward. If you take a garden hose and point it at a wall, the water stays in a tight group until hitting the wall. Even if you www.ContactMagazine.com
We bought one of the alligators and cut the tip of the nose off to match the scoop intake. The gator’s body was held wide and flat by internal parallel vanes that run the entire length of the body. The tail had a separate chamber from the body. I cut a bunch of quarter size holes in the wall that divided tail from body. Two leaf blowers were inserted in the tail section. When the blowers were turned on, magic happened. Air entering the scoop was straight, fast AND high volume. The gator’s internal vanes really straightened the flow.
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ternator fails, I should have ample battery life to make a safe landing. Every two years I put in a new battery and use the old one in my Dodge pickup.
WING TIPS
The “Gator Inflator” started life as a pool toy, worked out to be a valuable tool.
Plexiglas was placed over the radiator access hole and we could watch the tufting yarn within the scoop. A piece of yarn taped to the end of a stick allowed us to check airflow anywhere within the scoop. I had a small handheld airspeed indicator with a top speed of 25 MPH. When held near the radiator it would peg at 25. Calculating that out gave a speed of at least 175 MPH at the gator’s nose... Whoo Hoo! I have another video of the tufting and development of the scoop also posted on YouTube. The video dramatically shows air doing exactly the opposite of what I expected. Only with the addition of turning vanes was this condition corrected. Look for the video titled “Poor Man’s Wind Tunnel”.
OIL COOLER My Setrab oil cooler measures 6 x 4 x 2 inches. Oil temperature generally runs 5 or 10 degrees warmer than the water. A single three-inch diameter inlet near the prop allows cooling air into the cowl. That incoming air is split 50/50 between the PSRU and the oil cooler.
EXHAUST SYSTEM The six-into-one exhaust was originally built using mild steel. The intent was to use the cheap stuff for proof-ofconcept before spending money on stainless. The steel exhaust seemed to do just fine, but after about 100 hours I found a crack. That pushed me into building a new set from 321 stainless. The main difference with the new exhaust is a smaller diameter tail pipe, from 2.5 down to 2 inches. The exhaust was ceramic coated to help keep heat from nearby fiberglass.
ELECTRICAL POWER This aircraft has an all-electric system and is addicted to the juice. Flying with all systems operating (except lights, and heated pitot, which have not yet been connected) consumes about 19 or 20 amps. To feed this electron appetite, I have a single 45 amp Nippon Denso alternator. Instead of multiple batteries, a single Optima Red Top battery with a reserve capacity of 90 minutes stores the surplus electrons. The engine monitor warns of high or low voltage and excessive amperage draw. If the alwww.ContactMagazine.com
The stock Glasair wing tips looks like small versions of Piper Cherokee tips. I tuft-tested that tip and found that the vortex started peeling off the tip about 18 inches forward of the trailing edge. We made a custom set of bat type tips that add about 5% to the total wing area. The vortex has moved aft about one foot. Stall speed has decreased about 7 MPH without any noticeable penalty in cruise or top speed and the new tips also helped the sink rate. The Glasair used to sink like a Craftsman toolbox; now it sinks like a Craftsman toolbox with one of the wrenches removed.
FIREWALLS AND FIRE I must tell this story about my choice of material for the firewall. My friend Don was not a mechanical kind of a guy. Instead of building, Don bought a completed and flying Glasair. His plane was powered with a Lycoming with a remote oil pressure sender mounted on the firewall. The hose leading from engine to sender ran very close to the engine dipstick. The hose was easy to bump every time Don checked the oil level. One day Don had just departed when the tower called and told him that he was trailing smoke. An immediate turn and return to the airport was made. Fire trucks were foaming the plane before it had come to a full stop. Don estimated the total flight time was three or four minutes. Don’s firewall was made with an aluminum sheet installed over a sheet of Fiberfrax, mounted to the fiberglass firewall. Fiberfrax is a ceramic fire shield material that is rather fragile and is used to protect the fiberglass. The aluminum cover is to keep the Fiberfrax from damage, dirt, and breaking away. In the post-fire inspection, we found that when checking the oil Don must have accidentally loosened the oil sender hose enough for it to become disconnected and oil was now being pumped onto the hot exhaust pipes and caught fire. A few moments later the lower half of the aluminum firewall melted in the hot oil fire and the Fiberfrax was exposed to turbulent air within the cowl. The Fiberfrax began to flap around and disintegrate. Now, the fiberglass had no fire protection and the top layers were burned off. I doubt that the firewall would have lasted more than a minute or two more. Don was lucky that he got on the ground so quickly and was at an airport with a fire department. The fire in Don’s plane made my choice of firewall material easy. Stainless steel. Yep, stainless weighs a bit more, but at 10,000 feet and if the olfactory nerves detect that first whiff of something cooking up front, I’ll be glad I have stainless that will not melt so easily. The stainless remaining in place will allow the Fiberfrax to do its job and help keep the flames away from my body.
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The new Marcotte gear box and MTPropeller will rotate in the opposite direction of the original prop. Doing so requires that the engine be angled slightly to the right instead of to the left and this forces me to build a new engine mount. The new mount will require changes to— just about everything.
HURRICANE IKE In September of 2008, Hurricane Ike came up Galveston Bay and into the Houston area. My airport is about 15 miles west of the eye wall path. The Glasair was down for maintenance and could not be flown out of harm’s way. A company that I occasionally fly for was taking their aircraft to safer locations. Since I thought my hanger was poorly built and would not stand up to the coming hurricane, I moved the Glasair to that company’s larger stronger hanger. Dang. Bad decision. A large hanger door broke loose and fell on my plane.
While speaking to Guy Marcotte about my new gear box, he mentioned that Subaru balances their engines with the flywheel bolted to the crankshaft. That means if I put a non-original, perfectly balanced flywheel on my engine it may throw the engine slightly out of balance. Guy suggests that I balance the engine/flywheel combination without the prop and gear box, and then install the new prop/ gear box and balance the prop.
Q and A Anyone considering building a one-of-a-kind auto conversion should ask himself: 1. If a friend was building the same type of plane but used a Lycoming and is now flying, would I mind if I have another one to five years before the first flight? 2. Once flying, do I anticipate many trouble free hours of flying? 3. Will much of my flying be over territory with limited landing spots? 4. Would being a test pilot forever trouble me? These questions are aimed at improving the percentage of new projects that make it past a few flights. If you answered “Yes” to any of these questions, you may want to use a Lycoming or Continental in your plane. Automobile conversions can do quite well but they may require a greater commitment than one might imagine. With a oneof-a-kind automobile engine conversion it is highly likely that things will not turn out as you had envisioned and with lots of time will be spent correcting them.
The MT-Propeller blades took the full impact and were destroyed. The motor mount was tweaked a bit. Many of the airport bums commented on how well the plane took the impact of that heavy door. The irony is that my hanger had little damage, and the plane would have been fine if it had been left there. The hurricane damage has accelerated plans to make some needed changes. My gear box and propeller rotate in the unconventional or left hand direction, which narrows the selection of replacements for either. I have ordered a new Marcotte gear box. The Marcotte turns conventionally plus it raises the thrust line by almost two inches. With the planetary gearbox, the thrust line was about three inches lower than a Glasair with a Lycoming. The low thrust-line gave poor propeller-to-ground clearance and small pebbles would get picked up and ding the prop if too much power was applied before the plane had accelerated to 30 or 40 mph. www.ContactMagazine.com
Caution: A never-before-flown airframe powered by a never-before-flown engine puts the “X” in experimental; you will become a test pilot and need to get into that mindset. I grossly underestimated the amount of work required to get to this point. I knew that I would have to climb a few mountains; I just didn’t think I would have to cross the Himalayas! Now that I have a clearer picture, would I do it again? You bet, I love this stuff! Throttle Up! Russell Sherwood Houston, Texas 713-542-9570 3sherwoods@comcast.net
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If you are planning to visit our booth at Sun ‘n Fun this year, look for us in the new exhibitor’s building. Paper Pilot Certificates Expire March 31, 2010 Pilots who have not replaced their paper airman certificate with the required new plastic certificate risk being unable to exercise their privileges at the end of March. FAR 61.19(h) reads: “Except for a temporary certificate issued under §61.17 or a student pilot certificate issued under paragraph (b) of this section, the holder of a paper pilot certificate issued under this part may not exercise the privileges of that certificate after March 31, 2010.” To replace your airman certificate online, visit the FAA website: www.faa.gov/licenses_certificates/ airmen_certification/certificate_replacement To apply for a new certificate via the mail: Complete an “Application for Replacement of Lost, Destroyed, or Paper Airman Certificate” and send a signed, written request stating your: name, date and place of birth, social security number and/or certificate number, and the reason you need a replacement. Include a check or money order for $2 (U.S. funds), made payable to FAA, for each certificate you request. Mail your request to: Federal Aviation Administration Airmen Certification Branch, AFS-760 P.O. Box 25082 Oklahoma City, OK 73125-0082
ALTERNATIVE ENGINES VOLUME 3 Speaking of Alternative Engines, Mick and I collaborated on the publication of Alternative Engines Volume 3. In case you are not familiar with this series of books, approximately every five years, Mick has compiled all the www.ContactMagazine.com
CONTACT! Magazine engine articles from that time period and put them in book format. Volume 1 (the black book) contains the first five years, Volume 2, (the silver book) contains the next five years, and now Volume III (the gold book) contains the following five years worth of engine related articles. We sell these books through our website and at the various shows we attend for $42.00 each, but we usually bundle them with a subscription for a reduced rate. A special order form can be found in the back of the protective cover-wrap on the back of this magazine. A comprehensive table of contents will is published on our webpage. Visit: www.ContactMagazine.com/ Volume3.html If you don’t have internet access, either call me or drop me a letter and I’ll gladly send you a printed version. Anyone purchasing Volume 3 using that form will have their subscription advanced three issues as an extra thank you. See ya at Jean and Sun ‘n Fun! ~Pat
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