Corvair College History….in photos


Below are links to photo pages on all of the colleges we have held since #1 in the spring of 2000. This page is a work in progress, Because I still want to dig out some photos from the early events, San Antonio and the Canadian Corvair College in 2005, and put in pictures from #26 and #27.  Looking at the photos, it is a lot of engine building and learning, all mixed in with a lot of fun and friends. At the bottom we have a list of the 2014 colleges.

Although I am the only person who has made it to every college, we have a number of builders who have been at 6, and even a handful who have made it to 10 or more.  We have more than 25 people who’s first run happened on the stand at a college, who later flew the engine back in their plane. I look forward to reading comments from builders who have attended these events, it is a lot of good memories that I treasure.


Above, Tom Cummings of LA, on the left, stands with me in front of my Pietenpol at CC#1. The event was in May of 2000. Tom was the very first guy to show up at the very first College. Read the last page on the CC#17 link for a full story on Tom.


Click on any color link to see the photos and read the story


College#,  Location,  Local Host.

CC#1 – Spruce Creek FL  – William and Grace

CC#2 – Spruce Creek FL – William and Grace

CC#3 – Spruce Creek FL – William and Grace

CCJr – San Antonio TX – Oscar Zuniga

CC#4 – Sun N Fun, Lakeland FL – (2004)

CC#5 – Hanford CA – Pat Panzera

CC#6 – Edgewater FL – William and Grace

CC#6.5 – Edgewater FL – William and Grace

CC#7 – Alliance OH – Forest Barber

CC#8 – Edgewater FL – William and Grace

CC#9 – Edgewater FL – William and Grace

CC#10 – Edgewater FL – William and Grace

Corvair College Canada

CC#11 – Santa Rosa CA – Michael Henitz -QSP

CC#12 – White Plains SC – Ed and Val Fisher

CC#13 – Livermore CA – Rick Lindstrom

CC#14 – Lowell MA – Ken Pavlou

CC#15 – (Planned but not executed)

CC#16 – White Plains SC – Ed and Val Fisher

CC#17 – Orlando FL – Arnold Holmes

CC#18 – Livermore CA – Rick Lindstrom

CC#19 – Barnwell SC – P.F Beck and crew.

CC#20 – Hillsdale MI – Roy Szarafinski

CC#21 – Barnwell SC – P.F Beck and crew.

CC#22 – Georgetown TX – Kevin Purtee/Shelley Tomino

CC#23 – Palatka FL- Weseman’s and Wynnes

CC#24 – Barnwell SC – P.F Beck and crew.

Corvair College #24, reviewed in photos, part one.

Corvair College #24, reviewed in photos, part two.

Corvair College #24, reviewed in pictures, part three.

CC#25 – Leesburg FL – Arnold Holmes

Corvair College #25, In Photos

CC#26 – Mexico MO – Zenith Aircraft Co.

CC#27 – Barnwell SC – P.F Beck and crew.


2014 Corvair Colleges

CC#28 – Austin TX – Kevin Purtee/Shelley Tomino, Feb.

Corvair College #28 registration is open

CC#29 – Leesburg FL – Arnold Holmes, end of March

CC#30 – Mexico MO – Zenith Aircraft Co., Sept.

CC#31 – Barnwell SC – P.F Beck and crew., Novemeber

Oil Change interval, meeting the challenge

(If the picture does not come through, try hitting F5 at the top of the keyboard.)



I am a lucky guy. When I bring up a serious topic, I can always count on some close friends to send some supporting words of encouragement. Quite often, one of these letters will come from the illustrious mind of 601XL builder Ken Pavlou. (He is the guy who also takes care of the on line college registrations and the parking row at Oshkosh.) Because he was born in Greece, “Adonis” is one of his nicknames. “TTBL” is a reference to the film “Ted.”

” William, Hope you had a great Christmas with your family. I want to share with you that I
mounted both wings on my 601 today. It’s pretty exciting.
Being that I won’t win any awards or break records for quality or performance, I
 decided to try and break the record for longest oil change interval by going
86.5 hours. I just wish I knew of these records before I changed my oil at 0.5,
1, 5, and 10 hours. Oh well.

I wish you a happy and healthy new year. Below is photographic evidence of my progress.

TTBL, “Adonis.”

I hate to tell Ken that 86 hours is just the record for Break in oil, and he has already blown his shot at that. For all I know the longest time between regular changes may be even higher. Ken is a pretty competitive kind of guy, I am sure the will meet the challenge no matter what it is.

Corvair Oil Change interval….. Lessons part #1


Quick Quiz: William gets a little depressed around the holidays because:

1) That is an appropriate reaction to seeing masses people shopping, wandering around like zombies text messaging on I-phones and very few people considering what is really worth living for.

2) His birthday is the last week of the year, and when you’re in your 50’s it’s hard to pretend your 24 years old anymore and not pay for it the next day.

3) His private question “I am supposed to be a great engine teacher, What have I accomplished this year?” Must be reconciled with the actions of builders who made some really foolish mistakes this year.

If you chose any of the answers, you are correct, but if you chose answer #3, you are also getting to a topic that distresses me all year round. In this short series, I am going to cover examples of people who made mistakes with their engines.


Some basic rules on this: A) Make a mistake, even a dumb one, and I don’t use your name. B) Make the same mistake a second time, and I reserve the right to use your name in the story. C) If you go on the net and complain about the effect of your mistake, but don’t understand that it was your mistake causing this effect, 50% chance the story has your name in it. D) If you make mistakes all the time because you want to argue every paragraph on my website, but also complain that the engine doesn’t run like I said it would, then your name and photo are going in the eventual story.

Why this matters: Two fold, I need people to slow down, read and ask questions. Every time people make mistakes like this, It puts them at unnecessary risk and it gives Corvairs a bad name. Even if the guy doesn’t complain on discussion groups, every person at his home airport sees his issues and says ” That’s because it is a car engine”.  None of those observers look and understand that they were looking at a self-inflicted wound. The observers are the people who always say “We had a guy with a Corvair at our airport, nothing but problems.”

They never stop to think that the same guy would have had issues with any engine he had. Corvairs like to have the oil changes, but so do brand new O-200s. Some times peoples mistakes, their public demonstration of these self made problems and the stupid comments people make about them lead me to wonder “Where do I do to restore the reputation of my 25 years of work with the Corvair?” Unfortunately, the only answer is that reputations are a commodity that are built very slowly over time with a 1,000 good examples which are very easily destroyed by a few careless people. Everyone who takes their own life work seriously has challenges, and this is mine. It has no good nor easy solution, we are left with just stories about lessons learned.

For the serious builder, take heart. for every guy out there messing things up, there are two dozen having no problem at all. The most important thing to understand here is that these mistakes don’t strike builders at random. I am going to spend some time here showing that individual personalities, like being in a rush, not respecting details and thinking you are to smart to listen to me are all the root of these mistakes. They are not random, they have nothing to do with experience nor IQ. They have to do with personality traits that are poor matches to serious work like engine building and flying planes. That is what you need to take away from this.


2013 saw a long standing record broken in the land of Corvairs. This was done right at Oshkosh, in the row Ken Pavlou reserved for Corvair powered planes, right behind my display booth. I should be really happy about that right? Guess again. The record was Longest time flying on the break in oil that should have been changes at 30 minutes to 1 hour: The new mark, set by a builder who had flown in from the east coast is 86 flight hours on the break in oil. It had never been changed, and was several years old.  This took the previous record away from the person who set it in 2008, flying to a College with 56 hours on his break in oil.

Is this a Corvair issue? No, these guys would have done this to any engine they put in their plane. I have a hard time understanding how a person would spend the time carefully assembling and engine and they go about poisoning it. Both of the guys are smart enough to get paid a very good living, but they are both from the “Office building” world, and have little exposure to mechanical things that need some level of care. Both have busy lives and may not have focused attention on their operation. Although neither engine broke because of it, I am sure that the life spans of these engine was shortened by 50% or more.

Two years from now when they are overhauling their engines, and people at their local airport walk past and say to each other “Didn’t he just build that? I guess car engines don’t last.” These builders will not do me nor the Corvair the justice of hanging a sign outside their hangar which says ” Self inflicted wound. I tried to extend the recommended initial oil change interval by a factor of 100.” It is worth noting that neither of these builders thought they were doing anything wrong. It came up in conversation, so I don’t actually know how long they were going to go, it could have been 100 or even 200 hours. I try to be an optimist, but right now, I am sure we have a builder somewhere, who will not read this, who will try to break the 86 hour record.

Should Mr. “86 Hours” have known better?: Yes, I published this story: Notes on Corvair flight engine oils. about a month and a half before he left for Oshkosh. It specifies 25 hour intervals. Also, the plane was more than a year old, and should have had a yearly condition inspection by federal law. If the oil wasn’t changed, the inspection was bull shit. The A&P who did it needs his license jerked. If the builder did it himself, he needs his repairman’s certificate rescinded, and if he didn’t bother to get a Repairman’s cert for his plane or have an A&P look at it, the plane flew to Oshkosh illegally.

The Corvair is a very tough motor, and I changed the oil myself at Oshkosh at night. I cut the filter open and there was almost no metal at all to be found. I expected damage, but I was just guessing, because in all the testing I have done in 25 years, none of it included seeing how long I can run break in oil in an engine without making metal.

OK, what about Mr. “56 Hours?”: He should have known better also. lots of people claim that information was not easy to find on our webpages. OK, I took me 60 seconds to go to, go to the bottom of the page and type “Oil Change hours” into the search box and it spit out the 2007 story I have reprinted below. I am sorry if that was too hard.


From 2007:Above, Fred Roser’s engine on the dyno. The photo is a reminder that we prime, test run and operate Corvairs on  Shell Rotella T 15W40 oil. Although everybody has a favorite oil that’s served them well on projects years ago, several  industry experts have told me that the formulation of many favorite oils has been changed for environmental reasons, often  compromising break in qualities by eliminating metallic based additives. Since we test engines on Rotella all the time,  builders can be confident that the current formulation of this oil works well in our favorite engine. We change the  oil and filter at 1 hour, 5 hours, 10 hours and 25. As KRVair Builder/Pilot Steve Makish pointed out, he’s yet to see an engine hurt by  having the oil changed too often.”

60 Days until Corvair College #28


There are just about 60 days until CC#28 in Texas. If you are thinking about going, the time is now to get a plan together. Over the next few days I will be putting up many stories about Colleges. Ones in the past, how to prep for them, upcoming events, builders progress. Stay tuned, more info on the way:

1/2 of Our illustrious hosts for CC#28, Kevin Purtee, above, at CC#22. Kevin lives two lives in aviation: His day job is piloting an Apache helicopter and his passion is his Pietenpol and his part in that community. Yes, he will wear the “Sock Monkey hat of Power” at CC#28. 

“The registration form is live at:  “

Read more detailed information at this link:

College #28 registration is open

Letters from Pete and Steve


Two particular letters arrived in the past day from fellow builders and flyers Steve Makish and Pete Chmura. They were both sparked by the story ” Two Letters on Christmas eve. ” Each of the letters references the loss of their Fathers. The stories are tangential to flying, but they are important to me.  Aviators have strong feelings about flying, but also have them for many other aspects of their lives, such as family. In the world of Corvair builders, I have long made sure that we have space for men to share their strongest feelings on both.

People like to complain about “political correctness” , where social stigma is used to deter people from saying non-mainstream things.  Some of the off-beat things are worth sharing, most would simply be edited by taste or being considerate. However, long observation of the human condition has shown me the #1 form of “PC” behavior that people of all political perspectives engage in: refraining from acknowledging the struggles and wounds of others. People hide behind “being polite” when they are just really afraid of conversing and saying the wrong thing. To my perspective, if someone wants or needs to speak, then it is time to listen. When it come to saying something, almost anything said, even poorly worded, is far better than having a fellow human standing alone in a crowd of people.

A number of years ago a friend lost an adult child in an accident. Over time, he had innumerable arguments with friends and co-workers. All of these people quietly complained to each other. To a small group of these people I said “The man has a crippling emotional wound. The physical equivalent would be a six-foot spear stuck in his chest. Everyday, everyone politely walks past him and never mentions or notices the spear. It might just help if someone just said to him, ‘I don’t know what having a spear in my chest it like, but I think you’re doing a damn good job for having that kind of wound.’ Just say that you thought about his kid today instead of pretending they never existed.” When one of the friends said they couldn’t imagine doing that, I politely said I understood, but they were not really the man’s friend.

Above in the orange shirt, Steve Makish ( stands beside his Corvair powered KR2 at Corvair College #8, held at our Edgewater hangar. His friend Bob Lester is in the background with his Corvair powered KR2.


Steve sent the following note today:

“William I have not written for a year. this has been a bad year and I never thought I  would lose both my parents 13 months apart. Enjoy the time you have with your Mom and Dad and cherish the moments. Happy New Year. Your friend, Steve”


From Pete Chmura, (petechmura@gmail) sent this letter:

“My Father passed yesterday at age 87. He flew Stearmans at Alameda NAS at the end of the war. He never flew after that. Last summer he said he wished he had “bought that plane” after he was discharged. I’ll be 54 next month. Time to get some wings.”

Pete’s letter made me think about the book above. Max Henderson was my instruments instructor at Embry-Riddle.  The book is his fathers coming of age diary from being part of a barnstorming team in 1935-36. Max found it after his father past. In 2000, Max was the Christmas guest speaker at my EAA chapter. He told a very moving story about how his dad had always downplayed his love of aviation when the kids in his family were growing up. After he passed, Max realized that his father had loved aviation as much as any man, but he had sacrificed his own ambitions to make sure that his kids got a better running start at higher education and their own times in aviation. When Max said this in front of 70 or 80 members of chapter 288, each of us thought of our own parents. There were few, if any dry eyes in the house.

Two Letters on Christmas eve.


I write this from my sister’s house in Charleston SC, where my family is gathering for Christmas this year. After driving to NJ for my Father’s 88th birthday, My brother-in-law, John and I drove Mom and Dad here to get them to a warmer setting for the holidays.  It is a long drive, but it is easier on them than airline travel, and they still like to get out and change horizons. On Memorial day I often tell people I have the ‘ultimate luxury’ of being able to speak with my Father by just picking up the phone any day. I am well aware of how few people my age still have both their parents, and this I am most thankful for on this Christmas eve.

On my mind are two letters that came in from people who are not so lucky, and I would like to share them with you because I found them very moving. The first one came from Randy Cary. It was written in response to my story about my Fathers 88th birthday last week, a story you can read at this link: William E. Wynne Sr. turns 88 today. Note that Randy’s Dad graduated from West Point on D-Day. It made me think about all the commencement speakers who have told graduates that they will ‘make a difference in the world.’  Randy’s Father and others of the Greatest Generation certainly did, in some cases at a terrible personal cost.

Have a great time with your Dad. There is no better way to spend the holidays than to be with family. My dad graduated from West Point on June 6, 1944 and went into the lines at Bastogne on Christmas Eve of 44 in the Battle of the Bulge. Like your dad, he didn’t want special treatment and always felt that there was someone who was worse off than he was. I lost him in 2000 and miss him every day. And to think that he was 23 when he went to war and when I compare him to a lot of similarly aged young people today, it just baffles me.
Count every day as a blessing for you, as I know you do. I have read you blog for three years now.  Merry Christmas to you, Grace and your families.

Randy Cary”


Above, Charles Poland Jr., 1947-2013.

The second letter came Aaron Poland. He wrote it about his father who sacrificed his own life to save other people’s children on January 29th 2013. If you read a single story I wrote this year, I would like it to be this one: Charles Poland Jr., An American of whom you could be proud. It is not possible to express how much the actions of Charles Poland moved me. Our world is sadly filled with people who make inaccurate judgements on the character of others based on surface issues like race, politics, appearance, professed faith or material wealth. I knew none of these things about Charles Poland when I read about the events of January 29th, and it shows you how none of these things reveal human character, only a man’s actions do. Everything you need to know about Charles Poland could be understood by considering how he chose to spend his last 60 seconds on Earth. The note I received from his son Aaron was very brief, just affirming the code that his Father lived and died by:

“I hope you where able to stop by in Newton, AL. Dad is buried in the local cemetery there. Dad was a helicopter crew chief in the US Army. Dad always believed to do the right thing at all cost and he proved it.”

This will be the first Christmas that the Poland family will have without their father. He was 66 years old, and they surely thought they would have him for many more years. As I type this, my own father sits in the next room sipping a cup of coffee with my mother by his side. Thankfulness for this drives me to acknowledge the losses of others less fortunate.

Later tonight, I am going to send a short E-mail To Aaron Poland simply saying that I think his Father was a real hero, and I was thinking of his family on this day.  If you would like to join me in this, Aaron’s E-mail address is: . I have never met him, don’t know anything about him except who his father was. I don’t know what ‘right’ thing to say is, but I will say something. I read an essay last year that said we don’t often face a choice between good and evil, but we continuously face choosing between doing something and doing nothing. To remember a father who instinctively chose to do something, at the cost of his life, writing a short note at Christmas seems like a small but important action.-ww

Basic Corvair information


Here as a basic breifing on Corvair flight engines for builders getting a first look at using one.

Above, A  3,000 cc Corvair flight engine. I built this particular one for the SPA Panther aerobatic aircraft, and has powered the prototype aircraft through it’s introductory season. The Corvair is a popular option on more than 20 different experimental airframes.


The Corvair is a General Motors designed engine, manufactured by Chevrolet.  1.8 million engines were built in the Tonawanda New York engine plant between 1960 and 1969. The Corvair has been flying on experimental aircraft since 1960, and I have been working with them as flight engines since 1989. It is a story of careful development and testing, a slow evolution to the engines we have today. It is ‘old and proven’ rather than ‘new and exciting.’


– Configuration:  The engine is a horizontally opposed, air-cooled, six cylinder configuration. We only promote its use as a simple, direct drive power plant. The engine configuration is very similar to Lycomings and Continentals.

Displacement: The engine is effective without a gearbox or belt drive because it has a comparatively large displacement. We have versions that are 2,700, 2,850 and 3,000 cc. The smallest of these are twice as big as a Rotax 912.

Power: Corvairs have three different power ratings. 100, 110 and 120 hp. These correspond to the three displacements. They make their rated power at 3,150 rpm. They have wide power bands, making 75% power at 2,650 rpm. All engines will exceed their rated power at higher rpm, and they can be continuously run at full power at 3,600 rpm without damage.

Weight: The engine weighs 225 pounds ready to run. This is effectively the same as a Continental O-200. It’s installed weight is 35 pounds more than a 912 Rotax, 25 pounds more than a Jabaru 3300. The Corvair is 40 pounds lighter than a Lycoming O-235. 3,000 cc Corvairs are slightly lighter than 225 lbs. because we have special cylinders made for them which make these engine 5 pounds lighter.

– Reliability: From the factory, the Corvair made up to 180 HP in the car and turned more than 5,500 rpm. The engine is reliable and long-lasting because we are only operating at 60% of these levels. Conversion engines that run at the car’s red line rpm historically have short lives and cooling issues.

Cost: We sell complete engines from $9,750 to $11,750. However, 90% of our builders assemble their own engines working from our Conversion manual, DVDs, parts and support and a rebuildable core engine they pick up locally. Typically, they budget $6,500-8,500 to build a first class, zero timed, engine.

Cooling: The Corvair has a factory cylinder head temp limit of 575F. This is the highest limit on any mass-produced air-cooled engine ever built. The engine as also the first mass-produced turbocharged car. GM engineered the motor to have excellent heat tolerance and heat dissipation. In aircraft the engine typically runs at 325 to 350 CHT.

Parts availability: Every wearing part in the engine has continuously been in production for 5 decades. The engine pictured above, only has an original pair of cases, and oil housing and cylinder head castings. All other parts in the engine, including the crankshaft, are brand new. Many of the parts in the engine, like the lifters and valve train, are common to Chevy v-8s. There is no part availability issue.

Ignition: The fleet of flying Corvairs is about 500 aircraft. More than 90% of them have a dual ignition system that I have built. Our system uses two redundant systems, one points based, the other a digital electronic system. The design has two of every part potentially subject to failure, but it utilizes one plug per cylinder. Six cylinder engines can fly on one cold cylinder, most 4 cylinder engines can not. Plug fouling is unknown in Corvairs because the ignition system is 40,000 volts and uses a plug gap twice as wide as a magneto system.

Fuel: The Corvair can use either 100LL or automotive fuel. It is not bothered by ethanol in the fuel.When Corvairs were designed, car gas was a lot like 100LL; for the last 35 years every mile driven by Corvair cars was done on unleaded car gas. Many engines like 912s and modern car engines do not have exhaust valves that can withstand the corrosive nature of 100LL. We use stainless and Inconel valves in Corvairs.

Maintenance: The Covair is low maintenance. The heads never need retorquing. The valves have hydraulic lifters and never need to be reset or adjusted. I dislike the term “maintenance free”, because it implies a “no user serviceable parts inside” disposable appliance mentality. The Corvair is a solid, robust, machine which holds its adjustments, but our program is aimed at teaching builders to be self-reliant owners.

Goals: If one of your goals is to be the master of your engine and airframe, the Corvair is an excellent choice. There are many engine options for people who just want to buy something. Our efforts are aimed at expanding the personal knowledge and skills of each builder.

Made in the USA: In an era where everything seems imported and companies like Continental have been sold to the Chinese Government, We have kept the “Made in the USA” option for builders who prefer to employ fellow Americans. Virtually every part in the engine, with small exceptions like the distributor cap (made in Mexico), are made by American craftsmen. Because we also sell engines outside the US, we are a Net Exporter, helping correct the trade imbalance.


Corvairs have proven themselves to serve a very broad variety of builders. Many alternative engine options are offered only as a “buy it in a box” import, more of an appliance than a machine, with little or no consideration of the builders, skills goals, needs, budget or time line. The Corvair has options to address these valid considerations, because your power plant should conform to you, not the other way around.

This said, Corvairs are not for everyone.  In the 25 years I have been in the EAA and working with builders, the Corvair has always been very popular with ‘traditional homebuilders’, the people who have come to experimental aviation to discover how much they can learn, understand and master.  The expansion of the EAA has brought more of these builders, but it has also brought a great number of people incapable of distinguishing between mastery of an aircraft or an engine and just merely being its buyer and owner.  People who’s consumer mentality and short attention spans are better suited to toy ownership than mastery of skills and tools in aviation. Corvairs, and perhaps experimental aviation, are a poor match for such people. Many salesmen in our field will gladly sell anything to anyone with green money. I am an aviator, not a salesman, and the gravity of the subject requires more frank discussion and ethics than many salesmen bring to the table.

If you came to experimental aviation to find out how much you can master, not how little, then you are among the aviators who follow Lindbergh’s timeless 1927 quote: “Science, freedom, beauty, adventure: what more could you ask of life? Aviation combined all the elements I loved.”  Even if you are brand new to aviation, I am glad to work with you. I have a long history of working with builders of all skill levels. We have a number of successful builders out flying who are the masters of both their airframes and engines, who had never changed the oil in a car before building their plane.  If you got into experimental aviation just to buy stuff, then any salesman will do just fine for you. If you got into experimental aviation to learn, develop your own skills and craftsmanship and make things with your own hands, then who you work with really matters. You can’t become and old school homebuilder / motor head by buying things from salesmen. They have nothing to teach you. What you will do in experimental aviation is not limited by what you already know. It is only limited by what you are willing to learn, and selecting experienced people to learn from.  If you are here to learn, I am here to teach. It is that simple.


Click on the color links below to read more on this topic


a) – Complete Lindbergh quote is here: The Quote, 1927, C.A.L.

b) – Explanation of machines vs appliances : Machines vs Appliances Part #2

c) – Story of real engines vs ‘ideal’ ones: Unicorns vs Ponies.

Testing and Data Collection reference page


I am collecting stories on testing we have done here. Virtually every month for the last 24 years has brought some type of testing or data collection on the Corvair flight engine. Some tests are fairly simple, such as building a new manifold and testing the output of a simple 1 barrel automotive carb, others like building and dyno testing EFI systems were more complex. This goes on continuously. Many of the tests go undocumented, or show themselves to be fruitless or economically unusable. Many test only provide a puzzle piece that is useful on another project years later.

Most alternative engine outfits are only interested in selling stuff, and more often than not, they did almost no testing before going to market. Many companies start selling engine before the first example has flown 100 hours, and I can think of a number of now defunct companies that sold engines long before even a single example had left the ground. The common element with all of them was viewing testing as just some useless overhead that cuts into quick profit margins. We are just the opposite. Remember that teaching builders about their engine is our primary goal. A a learning focused company, reasearch, testing and evaluation has provided the very material our program is made of.

Below are links to several stories that give a glimpse of the practical testing that has always been integrated into my work with the Corvair. Just stop and think about how many time you have read in a magazine article or sales brochure that the horse power output was from “Dynamometer tests”, yet, how many times have you ever seen a picture of any of these engines actually on a dyno? Personally I have seen at least 200 claims of HP output alleged to be measured on a dyno, yet I have only seen pictures of 4 different engines on an actual dyno run. In an era were virtual everyone has a cell phone, and every one of them is a camera, why do you think that 196 companies didn’t end up with a photo of their engine? Just maybe, the only “dyno” run they did was an imaginary one for the brochure.

I have said it before, If your goal is to Buy something, any salesman will do. If you goal is to learn, build and fly, to be the master of what you are doing, they you need someone you can learn from. I am willing to share what we have learned in many years of reasearch and testing with anyone who came to experimental aviation to learn and build.


Above, the EFI 2,700cc Corvair in 2007, at power on my dyno. The urethane wheel directly reads foot pounds of torque off the digital scale.


Click on any title below to read the full story of that test.



Dynamometer testing the Corvair and O-200


Dyno testing Corvairs, 2008


Turbocharging Corvair flight engines, Pt #1


Turbocharging Corvair Flight engines Pt. #2


Torque, HP and Thrust tests


Thrust testing 85 and 100 hp engines


Testing Turbo Corvair and Rotax 912S.


Panther Engine propeller test


Ignition system, experimental “E/E-T”


In Search Of … The Economical Carburetor


Dyno testing Corvairs, 2008


Below is a story from the spring of 2008, taken from our ‘Hangar Update” on our main page It is a good indication of how testing is integrated  everything we do. I am sure than many other companies headed to Sun-n-Fun that year focused their attention on getting spiffy polo shirts ready and glossy brochures. Not us, we were out on the ramp in front of the hangar testing engines.

In the second part of the story, we are running a test on a perfect “standard day” These are set of circumstances that rarely occur in real life, but which all dynos are supposed to be corrected for. By running the test on that day we developed very accurate correction factors for our testing. It is taking the time to do things like that, and not ow you dress that makes testing valid.

The story was shot in front of our house and hangar in northern Florida. Mark Petz and Kevin Fahy are prominently featured. Mark still builds outstanding Corvair flight heads at, but Kevin a member of our original “Hangar Gang” is long since retired. Shortly after this story he He married a very attractive woman with a PhD in Aerospace Engineering who long worked for NASA at Huntsville AL.  Kevin  made a tee-shirt that said “Trophy Husband” and set out to lead a life of quiet leisure.

A few days before Sun ‘N Fun, Kevin came up to give us a hand readying the display engine for the show. Above, he’s prepping our Fifth Bearing engine for its run on our Dynamometer We have run more than 50 engines on this dyno. The the run stand we had before the dyno broke in and test ran about 75 more. Research, testing and years worth of study and learning make our recommendations valid.

A week prior to the show, Mark Petniunas of Falcon Automotive drove down from Wisconsin to our North Florida hangar to give us a hand assembling and test running our Fifth Bearing test engine. I told him on the phone I thought it was a day or two away from running. Late into the sixth 18-hour day of his visit, Mark said: “I’m going to have to fire my travel agent. I have yet to see one girl in one bikini on one sunny sandy beach. This Florida vacation is nothing like the brochure.” Above, Mark on the right confers with Kevin right after the first start up of our Fifth Bearing Motor.

Above is our Fifth Bearing Engine at power on the Dyno. The natural aluminum CNC billet Bearing Plate is between the case, Ring Gear and the Gold Prop Hub. It is intended to address both thrust and bending issues.
I came up with this design myself, but the CAD modeling was done by our aeronautical engineer Spencer Gould.  Sharp eyes will notice that this utilizes All Our Regular Production Components. The added 1″ round spacer in front of the CNC Starter Bracketshows the length of the engine. The engine has a Gold Billet CNC Pan on it.

The day after Sun ‘N Fun we were back at our North Florida Hangar conducting more tests and unloading and unpacking the trailer after the show. Here, Kevin, myself and Mark on the other side use all hands on a run of The Fifth Bearing Engine.

Above is the balancer on The Fifth Bearing Motor. The timing scale on the back of the Corvair engine shows 0 to 16 degrees. The length of this scale can be transferred to the balancer to show 16 and 32 degrees BTDC (before top dead center).
As stated in my conversion manual, the proper way to set the timing on your Corvair engine is to know what the full advance is at full static rpm. I have long told people to tie down the tail of their airplane and check the timing advance at its full static rpm. Installing the distributor and not setting the timing this way is foolish. All aircraft engines, including those with magnetos, have their timing checked at maximum advance.

The difference is that aircraft with magnetos have their timing set statically at full advance, and then their impulse couplings retard their timing. The Corvair engine can have its timing set statically at idle for an idle setting, but it must be run to its full static rpm to have the timing checked because distributor ignition has mechanical advance, not retard.

If you’re a builder and you didn’t know this, that’s perfectly okay. That’s why we issue instructions. If you hold an A&P license and you don’t know this, you can stick the powerplant section of your license in an envelope and mail it back to Oklahoma City. This is a good example of how I’ve intentionally patterned the Corvair engine to philosophically duplicate the proven aspects of Lycomings and Continentals.

Dyno calibration after Sun ‘N Fun.
Above, you’ll notice Kevin and I are wearing jackets. We’re waiting just before sunset for a rare weather phenomena to occur: a perfect standard day of 59F 50% relative humidity and a pressure of 29.92. Any time you read a dyno report and it says “corrected horsepower,” they’re making a calculation, sometimes accurate and sometimes not, to adjust for their test conditions not being at standard atmosphere. Because we live in Florida near sea level, there have actually been three occasions in the past four years when these conditions were met during daylight hours on testing days.

Our dyno relies on the super accurate optical Prop Tach for the rpm measurement and it will only reliably pick this up in daylight. A few minutes after the photo above was taken, we made a dyno run which required no correction. By testing the same engine later in the week, we reconfirmed our correction factors for this particular dynomometer and we retained accurate measurements all year round.

As the post Sun ‘N Fun work wound down, we stopped for a photo op with Grace’s Taylorcraft. From left above: Dan Weseman, Mark Petniunas of Falcon, Kevin, myself, Grace and Scoob E were on hand for the last hour of tests. Although it marked the end of another Sun ‘N Fun as it became a collection of good memories, friends and fun, the talk already centered on what we were going to do this summer, plans for Oshkosh and good times ahead.
The pace of the Corvair Movement affords little time for reflection. And certainly the best of times are ahead of us. If you are new to the land of Corvairs, there’s time to express creativity, make your mark, enjoy new friends and join the adventure.

Testing Turbo Corvair and Rotax 912S.


Here is a story about thrust testing two engines from our time at the Edgewater hangar. This work was the start of our efforts with turbos on Corvairs. The testing below lead directly to flying a turbocharged 2700cc engine in our Stitts Skycoupe test aircraft the following year. The StolGlass aircraft had a very nice 912S rotax in it, with an inflight adjustable prop on it.

If legends, hangar flying stories and old wives tales were to be mistaken for testing and data, the Rotax would have delivered great numbers, which it didn’t.  Few people understand that if the gearing on the Rotax was for maximum performance, it would be in the range of 1.8:1, but the gearing the factory selected is far higher, 2.54:1, and this is driven by the need for the engine to meet very stringent European noise restrictions.

Turbo Corvair and 912S Thrust Testing

July 2004


At the hangar, we do testing all the time. It’s not a special process, but rather integrated at every opportunity. In these photos, you’ll see two tests that we ran during the summer. The photo above shows a direct drive 164cid Corvair engine we used as a test mule for our simple turbo setup. Our previous tests have more photos of this same engine, but here we’re testing a 72″ two-blade Warp Drive propeller. In this photo you’ll clearly see that this is not a rebuilt engine. We used the engine as is to confirm the initial sizing of the turbo. At this point, we did not have it heavily instrumented. Without an accurate EGT gauge, it’s quite easy to harm a test motor when initially developing a turbo installation. However, I had no worries here. This particular engine, nicknamed “Old Greasy,” was purchased running for $200, putting a very low cap on my potential loss. Notably, the engine ran through all the tests with flying colors, and never broke anything.

Above, Dave is holding the digital optical tach and the pressure gauge. If you look closely, you’ll see the engine is turning a wood prop, the thrust output here is about 360 pounds. This is an appropriate prop for a 180mph aircraft. When this propeller was replaced with the 72″ Warp Drive, a prop appropriate for a plane with an 85-100mph cruise speed, the thrust shot up to 470 pounds. This is roughly equivalent to the static thrust available from an O-320 powered Cessna 172. The main difference between the two props is primarily the pitch, not the diameter. Lower pitched props appropriate for aircraft with lower cruise speeds produce significantly more static thrust than props with higher pitch. The 72″ prop and the turbo is a combination we’re looking into for STOL airplanes. My line of thought: The 20 pound turbo setup is lighter than any gearbox or belt reduction, comparitively immune to torsional vibration, and a whole lot less expensive. More testing to follow, but the few runs we made here already exceeded my expectations.

Above is a line of airplanes outside our hangar. The Cessna 120 belongs to Gus,  The Taylorcraft is Grace’s BC12D (C-85 powered). The Corvair powered KR2 belongs to Steve Makish. Of interest here is the StolGlas in the foreground. This is a factory built aircraft from South America. It is imported by CR Aviation in Miami. It is a popular aircraft in South America, and is now being brought to the U.S. as a kit/LSA. Steve Critelli of CR Aviation brought the aircraft to our hangar to explore the possibility of re-engining the aircraft with a Corvair. When we tested it for a baseline, it had its factory installed Rotax 912S 100hp powerplant and a 3-blade, 72″ diameter, in-flight adjustable Ivoprop. The engine and propeller were in first class condition with 140 hours on them.

The results of the test were surprising to say the least. Let me start by acknowledging that the Rotax is a good engine, it’s known to make its rated power, and it is something of an industry standard for experimental engines in its class. Although it’s a small motor, barely more than 1,300cc, it’s heavily geared, 2.58 to 1. Common consensus holds that a combination like this should be capable of producing a lot of thrust. We carefully rigged the airplane for thrust testing to make allowances for the thrust line of the aircraft, and also to protect the airframe.

After several full power runs, carefully checking the propeller’s low pitch setting, and confirming WOT, the engine pulled 340-345 pounds of thrust. The propeller rpm was about 2,200. With the gearbox, the engine rpm was near 5,700. This amount of thrust was far less than expected if old wives’ tales of low rpm propeller efficiency are to be believed. Compare this with direct drive Corvair powerplants we have built turning 68″ props at 2,800rpm. The Corvair powerplant easily produces 10-15% more thrust. This is contrary to what most people have been led to expect. I’ve been teaching people for many years that higher rpm props are better right up to the point where the tip goes supersonic, and that low rpm props with low tip speeds are actually a disadvantage. The time to climb capabilities of aircraft like Pushy Galore are graphic presentations of my point. So why did Rotax gear this engine down this far? The most plausible explanation is for noise abatement. Although not yet a design consideration in the United States, European engines are required by very strict laws to meet extremely stringent noise restrictions. It is illegal to operate engines which don’t meet these standards throughout much of Europe. The Rotax engine is a European product designed to meet these standards. While the Corvair engine is not particularly loud by American standards, it would be hardpressed to match the Rotax. Having worked for the German firm MT-Propeller, I can attest to the great efforts European manufacturers go to in order to meet their noise standards. There’s nothing wrong with the Rotax, but there’s certainly no magic in its gear reduction when it comes to thrust output. Of course a 1,300cc powerplant needs some type of a reduction to be a viable 100hp aircraft engine. But this testing has shown just as obviously that a 2,700cc engine does not need a reduction to more than match the smaller engine’s thrust output. While theories have their place, testing in the real world has far greater value for people who want to build and fly airplanes, not just talk about them.

Thank you.

William Wynne.