William Wynne

"The Corvair Authority"
5000-18 HWY 17 #247
Orange Park, FL 32003 USA


Production News


A marathon welding session of four 12-hour days which will be complete today will bring us up to date on all orders for KR-2 and 601 Motor Mounts and Tray kits. Our friend and KR builder Glenda McElwee of Orlando stopped by yesterday on her way to the KR Gathering in Mount Vernon, Ill. Since we're on a roll and had the KR jig out, we made one more KR Taildragger Mount so she could take it to the Gathering as a demo. If you're a KR builder headed to the Gathering and would like to take this Mount home with you, call us at the hangar, (386) 478-0396, or send us an e-mail ASAP.

The long awaited batch of Safety Shafts will be in the mail tomorrow. If you're one of the builders who had their crankshaft nitrided, check the fit of your Safety Shaft in your crankshaft without Loctite on them. The machine shop tightened up the tolerances on the threads and they have a very close tolerance fit. Nitrided cranks sometimes have dusty threads, and the fit should be checked before doing the installation with Loctite.

We have quite a bit of products going out between now and Saturday. The two longest standing items on backorder are Distributors and Front Spinner Bulkheads. We continue to produce Distributors and are getting caught up, just not as quickly as we'd like. Spencer Gould worked with me on a redesign of the front crushplate, which eliminates the need for builders to do any drilling in the plate. These are now in the machine shop and we expect them shortly. The Fiberglas component of the Spinner Bulkhead is in production at our new composite subcontractor in Michigan. While they've taken a long time, there are significant improvements in quality. The old ones work, but the new ones will shortly be a cut above.

A reminder about the rewards of patience . . . We only sell products we've flight tested ourselves. Builders who are truly not held up for a part on order are often rewarded with a better part than the one we were making at the time of the order. Examples of this are that I'm filling all the Distributor orders with Dual Fuel Distributors; the KR mounts we finished yesterday have the new, slightly splayed lower tubes that allow far easier installation of the Motor Mount bolts; and the Spinner Bulkheads will come with all the countersunk hardware holes completed. Keep in mind that builders who truly need a part right away can always phone me. I can often hand fabricate one, walk the builder through making one, or source one through a builder who's already taken delivery but isn't using it yet.

We will have photos of a new development in Nosebowls in a few days. Until then, happy building and flying.

Action Update September 25, 2006
October California Corvair Meet


In a few weeks, we'll be at Zenith Aircraft Company's West Coast facility, Quality Sport Planes in Cloverdale, Calif. This facility is run by Michael Heintz. We have worked alongside Michael at Oshkosh and Sun 'N Fun for several years, and had long discussed the possibility of an event at his facility. The format of the October 6-8 event meets two needs: The first part is a small group workshop which is already booked. This format has worked very successfully for Michael. The second half of the weekend is an Open House that requires no reservations. This part is our traditional Corvair College style format that has always worked for us. We kicked around several ways to approach the organization of the event, and this combination without compromise should prove to serve all builders' needs. I'm looking forward to seeing a lot of our West Coast friends at the event. Sunday is also an Open House Fly In, so there will certainly be a number of aircraft to inspect and learn from.

You don't have to be a Zenith builder to attend. Everybody will be a Corvair fan, and I'm sure there will be a lot of Zenith builders, but Michael and I want all West Coast fans of the Corvair to feel welcome at the event. Because this is a long way from home, it would be difficult for us to run a typical College. The centerpiece of the event will be the installation of Woody Harris' Corvair engine on the front end of his 601. This is an excellent opportunity to learn, and I encourage everyone to ask questions and take notes, photos and video. I encourage people to bring their parts for inspection. Just like our home Colleges, I can cover a lot of ground in person, and generally quickly describe small fixes on parts or green light an engine for assembly. If you have photos of your project, please bring them. After 15 years of rabid building, I can offer builders advice on their airframes also. I'm looking forward to seeing all of you there.

For more information, visit the Qaulity Sport Planes Engine Workshops Page. As you contact him, please thank Michael Heintz for hosting this event. Although he's an aviation professional, it still takes a lot of effort to organize an event like this, and I want Corvair people to be known as fun, gracious and good company from coast to coast.

Hangar Happenings

In addition to our regular work, last week contained a fair amount of engineering and R&D work. The centerpiece of this was Mark Petniuas, the man behind Falcon cylinder heads. He spent a week working with us during the day, having fun in the evenings and planning the future of Corvair engines late into the night. One of the reasons I've chosen to work with Mark is that he's very farsighted. His work, knowledge and ethics will play a big part in the Corvair movement. Contrast this with other shops that did cylinder head work and had no interest in aircraft. When you meet Mark in person, you'll understand what an asset he is. He's also good company.

Above, Mark works on Gordon Alexander's cylinder heads. Gordon's engine is a 3,100cc conversion that was built in our shop and returned to get a nitrided crankshaft installed. Gordon purchased the engine as a kit from California, and we assembled it with him with the exception of the valve train. Gordon later called to say that this portion seemed very difficult. When the engine returned for a nitrided crank update, I discovered the problem: The heads that the California shop used on his engine had been severely overheated and should have been thrown in the junkpile. Instead, they did a thousand dollars worth of work to them because they had no other cores and they wanted his money. The tops of the rocker studs were misaligned by 3/8". The TBO on the valve guides would have been 50 hours. To fix it would require either a brand new start or a highly knowledgeable cylinder head guy and some tricky machine work.

The heads weren't Mark's problem and he's never met Gordon. Any guy who was just a businessman would have said "Too bad, the guy can buy a set of heads from me." But Mark is a fellow aviator, and approaches things from a practical viewpoint first. While at our shop, he took a full day to carefully machine the heads back into correct alignment and reassemble them. In the above photo he's cleaning and deburring them in the wash tank after the machine work. Mark's knowledge of motors go far beyond machine work and heads. As many of you know, Jan Eggenfellner, the Subaru guru, is our next door neighbor. Mark met him and talked to him in depth about electronic fuel injection systems from a hard-core field use perspective. It was enlightening to sit in on this because most conversations on the subject are a rehash of brochures and theory from people with no first-hand off-road experience.

Above, Mark works on the lathe while Arnold "The Repair" Holmes talks with Piper Aircraft engineer and Corvair builder Spencer Gould. Corvair builders who've been around a long time know that Arnold did a lot of flying with us in the early years, and today does all of our dynamic propeller and vibration analysis. He's recently returned from working on aircraft in the Ecuadorian jungle. Spencer is a comparatively new face whom many of you will get to know in the coming year. He's a Riddle graduate and his day job is in structures and powerplants. In our last update, I mentioned prepping our neighbor Jason Newberg's Pitts for its debut at the Reno Air Races. On short notice, Spencer built a wicked set of wingtips for it. The plane, named The Jamaica Mistaka, was a smash success and won the first place trophy in the Silver Biplane race. It turned its 72" metal prop 3,300 rpm near 200 mph. So much for old wives' tales about mach numbers and props and efficiency.

Here's Spencer with drawings of his Corvair powered project. It is an all composite, single seat taildragger. The photo in the notebook is the quarter scale model that he flew with a live video feed of the airborne tuft test on the wing. He built test samples, molds and tooling, and is now producing the parts. He has no commercial ambitions for it, only working to produce the right airplane for himself and expand his skills while doing so. A truly impressive, ambitious man.

Technical Note: The spring on the left, above, is a straight wound Corvair valve spring. It is 2" tall and is the correct one for the engine. On the right is a progressively wound spring that is listed in some catalogs as an acceptable Corvair spring. It has way too high seat pressure, on the order of 130 pounds, and at OT-10 full lift it will produce nearly 300 pounds over the nose. It is important not to use these springs in a plane. A racecar shop might recommend them, but they produce a lot of wear during cam break-in, and most importantly, when you run at cruise power for hours on end your exhaust valves will be far hotter than they would ever get in a car. In this situation, you want to use just enough valve spring to get the job done. The spring on the left is currently supplied by many sources; we get ours from Clark's Corvairs. It's the standard replacement spring.

We got several questions recently about battery location in a 601. Above is the Odyssey 680 battery mounted on the aft spar. This installation utilizes the Odyssey battery box. A small reinforcement keeps the rear spar steadied to the bottom of the baggage floor. Beside the battery is an aircraft grade continuous duty 12-volt solenoid. All power to the airplane goes through this, with the exception of a separate line that powers the fuel pumps and the coils. The master switch controls the solenoid and shuts off all the power not essential for flight. The battery cable is a #4. We never use a separate starter solenoid because the starter has one built into it. I've seen a number of builders use heavy ground cables. Metal airplanes don't require this. The plane itself is the ground.

After work, Gus took Mark flying in Dave's Wagabond. Mark is building a Murphy Rebel for his Corvair engine, and thus, the flight in Dave's airplane was an appropriate introduction. Mark is a graduate of the highly respected Spartan School of Aeronautics. He's been an EAA member for more than 25 years. He showed me a letter he wrote to the EAA in 1978 asking for information about Corvair powered aircraft. To understand what a different era this was, the response was personally typed and signed by Bonnie Poberezny, Paul's daughter and Tom's sister. When we visited Mark's shop, he showed us his personal Corvair that he's owned since he was 16. When he drove his '61 Corvair van to Oshkosh this year, I told him we looked forward to seeing his Corvair powered Rebel there next year.

Notes From The Net

We were forwarded a secondhand story about a builder who'd tried to put a gearbox on a Corvair. As the story was told, it worked but the builder quit because he could only get the geared engine to turn a 65 Continental's propeller 2,300 rpm, concluding that the Corvair's potential was the same as a 65. The person who relayed the story speculated that the engine might not be up to par.

Most 65 Continentals will not static a prop at 2,300. This is too close to the engine's redline. Thus, the man was getting more than 65 hp. But the engine was most certainly not running correctly. There's photos on our Web site and in our Conversion Manual of our own 1.39:1 Rinker box running on our test stand five or six years ago. It turned a 68x50 Sensenich 2,800 rpm. This is a giant difference in power output. Last year, one of the engines we built and test ran was standard U.S. rotation. The only prop available the day of the test run was the 72" Sensenich on Grace's C-85 powered Taylorcraft. The direct drive Corvair turned it 100 rpm more than the C-85. The 85 is a low rpm engine with a 2,575 redline. The appropriate prop for it lugs down a Corvair motor before it can climb up to its power plateau, but still, it did better.

When you read a story about a single test run by an individual builder, you have to balance it against photos like Dave's happily flying Wagabond, ready at the push of a button to take a trip around the pattern or across the country with a simple direct drive Corvair and a 64" prop, a combination many "experts" who write books rather than build airplanes tell you would never work. Fortunately, Dave did not read these books. Many of the same experts schooled legions of people to believe in low rpm prop efficiency. Our friend Jason didn't believe these people as much as his own testing. His reward is a big trophy and a fat check for first place from this year's Reno Air Races. As you're reading this at home, you'll make a conscious decision to take advantage of all of our testing and building over the past decades or not. Your work does not need to be and will not be a carbon copy of ours. But to succeed, the winners will take advantage of every successful proven piece of information at their fingertips. They'll discard every old wives' tale, marketing gimmick and story that starts with "I heard somebody tried that once." When you return to your workshop, your path will be set by the decision you make now.

It's late, and I have had too much coffee. I dictated the above paragraph to Grace, who doesn't ever drink coffee.I wanted it to be a golden passage which would stir the hearts and motivate the hands of Corvair builders everywhere. I want to believe she is yawning because it is late, but perhaps her glazed eyes have more to do with how many times she has heard a variation on this symposium. We are typing this on the old computer with the old version of Microsoft Word, and "Clippy" the paperclip icon is laying down and taking a nap in the corner of the screen, which makes it two to one in favor of quitting for tonight. The above message is a serious one, but it is written with more humility and less tone than many people would suspect at first read. My only agenda is to have builders spend their time and money wisely, avoid unnecessary risks, and have a good time with the fruit of their labor, be it flying alone at the end of a long day or sitting with friends by your planes at a fly-in.

Action Update
September 5, 2006


Above is Dr. Gary Ray's 601XL. He flew its maiden flight out of Pontiac (Mich.) Airport September 1, 2006. This is the latest 601 to take to the air on Corvair power. I saw the airplane in person just a few months ago, and I will attest to the fact that it is one of the nicest 601s ever built. Not bad for a guy who never built one airplane part before starting this project three years ago. If you're working on parts for your own first airplane, look at the photos closely, and think about Dr. Ray's success. It's all about the decisions you make and the persistence you show. I've said it many times before, but it bears repeating on this ocassion: Money, skills and time all take a back seat to simple persistence applied on the correct heading. Persistence will inevitably lead you to your own day in the sun.

The plane returning from its first flight, above. Gus happened to be on hand, as he was visiting his parents in Michigan. He called to say that he gave the airplane a brief inspection, and it showed itself to be a first class job. Dr. Ray flew the first flight without a hitch.

Through all our work with Dr. Ray, he has proven himself to be an absolute gentleman. He built the aircraft from a standard kit. He has a very active career, kids, a marriage and house like most of the people reading this. His project had to fit into the rest of his life. He built the plane in his garage at home, which Grace, Gus and I can attest is damn cold in the winter. He used a very modest collection of hand tools to complete the job. The plane features a glass cockpit, based on a Dynon D-10, and a very good looking interior. Almost everything on the plane, including panel, interior and paint work, are all Dr. Ray's craftsmanship. The firewall forward package contains virtually every item we offer for 601s. It's flying on an Ellison EFS-3A carb and a 66" Warp Drive prop. This great looking aircraft is certainly a tribute to its builder. When you see it in person, make sure to introduce yourself to Dr. Ray. He's a very outgoing, gregarious guy who will be glad to give you a personal tour. When you turn off your computer and head back to the shop to work on your own plane, just remember, persistence pays.

Pietenpol In Print


When you open up this months' Sport Aviation and turn to the "What Our Members Are Building" section, you'll lay eyes on a very, very sharp looking yellow and white Pietenpol. This is the very skilled handiwork of Texas Corvair builder Hans van der Voort. When I spoke to him on the telephone last week, he told me he now has about 50 hours on the plane. I had not yet seen the photo in the magazine. Fans of Pietenpols know that they're all treasured by their builders, but some are better looking than others, and you can tell this even from a small photo. Two experienced builders who saw the photo with me each said it made them want to go build a Pietenpol. This is a plane we're really looking forward to seeing in person.

Sharing success like this, even if your bird is not the prettiest in the flock, goes a long way toward putting our favorite engine in the positive light it has earned. I encourage everyone with a flying Corvair to send in a photo to Sport Aviation. Even if it flew a year ago, the EAA Publications staff is interested in how many hours it's logged, and any other comments you'd like to share.

Tech Notes On Props


Mark Jones of Wisconsin, who has been flying his Corvair powered KR-2 about a hundred hours, is using a 54x52 Sensenich prop. His aircraft is a little bigger and draggier than KRs built for smaller pilots. As a result, the plane's cruise speed is a little slower than smaller KR taildraggers. He recently asked if his plane would go faster with a higher pitched prop. He even considered something in the 60" pitch range. To understand my answer, consider this analogy: You're driving a 5-speed truck towing a trailer on the highway. You're in fourth gear with your foot to the floor and you've reached a stable top speed, but not nearly the redline of the engine. If you want to go faster, would you downshift to third or upshift to fifth? The obvious answer is you'd downshift to third. Upshifting would only reduce rpm and horsepower output, and you'd have even less power to apply to overcome the drag at your fourth gear terminal speed.

The 52" prop represents third gear. What is counterintuitive for most people is that engines with high rpm limits like the Corvair will actually fly faster on less propeller pitch. We used a slick customer KR-2 to test numerous propellers. It's currently flying with an identical 54x52 to Mark's plane. The 52 provides a very sharp climb rate, even out of small, hot, grass fields at heavy weights. It sacrifices only a few mph top speed over the highest pitch prop we tested. This information may stand in contrast to old wives' tales the benchwarmers at your airport tell, but it is proven with pure testing and it's true across the board.

At our airport, our friend and skilled aerobatic pilot Jason Newburg is prepping an S1S for the biplane class at Reno next week. The plane is a powerhouse, its 180 Lycoming turning a 72" metal prop. Although it's loud, with the prop turning 3,000 rpm, the speed was very impressive (actual speed classified till race day). In search of more speed, most people at our airport suggested more pitch. Only Jason and I knew the answer was just the reverse. Pitching down brought the rpm even higher, and picked up a gigantic chunk of speed. Its climb rate with a flat pitch prop is nothing short of phenomenal. Although the Pitts' prop is now louder than a T-6, it produces more thrust, speed and rate of climb than any other combination.

The same effect holds true for your Corvair powered airplane. The Sensenich on our own 601 was finalized with 4" less pitch than we first started with. This in spite of switching to our very powerful 3,100cc engine. The plane has a great rate of climb even on a 100F day with the largest of passengers. Its top speed is actually slightly higher than it was with 4" more pitch. Yes it's at more rpm, but it's not even beginning to get noisy, and the Corvair does not care about rpm.

KR/Vair pilot Joe Horton of Pennsylvania also has about 100 hours on his bird. He started with an Ed Sterba prop, but switched to a Sensenich 54x60. A 3,100cc Corvair powers his very slick plane. Joe made the observation that after it was reworked, Ed Sterba's prop was very close performance-wise to the Sensenich, and felt as smooth. There are good reasons for this: Ed Sterba is a very experienced, one-man prop shop. I included Ed's name in the first 5,000 Conversion Manuals we sold because he had built a number of good props for us before. But the bigger picture is this: Ed is known for reworking customers' props until they're right for a modest charge. Although they're handcarved, his props seem very smooth. The expanding world of Corvairs led me to search for a mass prop manufacturer that could produce extremely good props right out of the box in quantities that can serve the growing world of Corvairs. This is why other companies, like Sonex Ltd., also use Sensenich.

It's human nature to be impatient, and despite my warnings, we had more than one person fly a non-Sensenich prop that needed to be reworked in the past year. I recommend that builders take a CNC prop out of the box, put it on their engine, and tell me what the static rpm is because this gives me an instant gauge to determine if their engine's performing correctly. Ed's a good guy and will always produce some outstanding props, but I need props that work for everybody, not just specific instances after fine tuning.

A Word About Smoothness

Smoothness is very hard for humans to gauge. A prop can be unbalanced in two ways: the blades can be different weights or different aerodynamic shapes. Either imbalance will produce vibrations. However, the smooth nature of Corvair engines masks this. If you'd only flown 4-cylinder engines before, the roughest running Corvair would seem silky smooth to you. Even a significantly out of balance spinner is very hard for amateur pilots to detect by the seat of the pants.

On the other end of the scale is dynamic propeller balancing equipment with a skilled operator. Many of our propeller evaluations have included dynamic analysis by Arnold Holmes. Arnold earns 50% of his living doing this on hyper-expensive aircraft. He owns some of the nicest equipment, and because he's an old friend and fan of Corvair engines, has made this available to us many times. Our latest Flying DVD briefly shows him performing a test. A year-and-a-half ago, Bob Lester flew his KR to our hangar, and visually I suspected Bob's engine to be radically out of balance. It had vibrated enough to loosen his rear starter motor brackets. Yet, it was still fairly smooth compared to a four-cylinder engine. We had Arnold come over, and a quick test showed that the engine had full-scale deflection. This was traced to an out-of-track prop extension. When Bob questioned the accuracy of Arnold's machine, Arnold showed him that with the prop bolts that Bob was using with castelated nuts and cotter pins securing them, his equipment clearly was picking up the slightly loose cotter pins floating in the holes on a 2.5" radius.

When I use the term smooth in our description of props, it is a mixture of physical description from our years of experience with the engine, and the most sophisticated testing equipment available. Although Corvair engine builder John Kearney of Nevada worked on a simple homebrew accelerometer that was tested by several Corvair owners, this is not the same as calling on the professional expertise and equipment of Arnold, who's done hundreds of analyses. John's a very clever guy, but it's not possible for a simple system to be operated with consistent accuracy by builders in the field lacking standard mounting points and the ability to calculate the performance data based on rpm. I'm not critiquing anyone's questions, observations or contributions; I only want to remind people that we've really done our homework on this stuff, and when I make a prop recommendation, people can count on it to carry the full weight of our experience.

Speaking Of Corvair Powered KRs . . .


The KR Gathering in Mount Vernon, Ill., is just around the corner. Friends tell us that they're expecting 20-25 aircraft this year, four or five of which will be Corvair powered. If you're interested in this combination, I highly recommend you make plans for this event. In the back of my notebook, I've been keeping tabs on who will be among the first 10 KR pilots to log 100 hours behind a Corvair engine. So far, the list includes Steve Makish, Bob Lester, Mark Langford, John Martindale, Mark Jones, and Joe Horton. There are a number of good candidates to take the last three slots. When we reach the milestone, we'll plan something special to commemorate it.

Note that this list includes pilots in the modern era. Early in our work, we were contacted by Howard Hoops of California, an EAA Chapter 1 guy who was flying a Corvair powered KR-2. His plane was essentially a Bernie Pietenpol style hand prop conversion on a very basic KR-2. I submitted the photo of his plane, and it was published on the cover of Contact! magazine, back about Issue 50. I did not have the pleasure of meeting Howard, but Janette Rand told me in person that Howard was one of the finest gentlemen in the world of KRs. I always put work of independent pioneering guys like Howard in a special category. If anyone else from the KR community knows of any other early style Corvair conversions in the KR, we'd be eager to learn about them.


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December 2006 At The Hangar Part 1

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OSH, Illinois and SAA June 13, 2005

At The Hangar June 13, 2005 Part II

At The Hangar In May 2005

At The Hangar In April 2005


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