Author: William Wynne

I have been continuously building, testing and flying Corvair engines since 1989. Information, parts and components that we developed and tested are now flying on several hundred Corvair powered aircraft. I earned a Bachelor of Science in Professional Aeronautics and an A&P license from Embry-Riddle Aeronautical University, and have a proven 30 year track record of effectively teaching homebuilders how to create and fly their own Corvair powered planes. Much of this is chronicled at www.FlyCorvair.com and in more than 50 magazine articles.
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2,850 kit “Request List”

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Builders:

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My traditional method of selling 2,850 piston, rod and cylinder kits has been to build up 10 sets, then put them in stock on my webstore. I did this in hopes of fulfilling all the pent up demand in a few rounds.  This has not happened, and has been frustration for some builders who don’t watch the webstore.  Thus a change in tactics  in order. 

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Above,  18 sets of 2,850 pistons in my machine shop. I continuously order more, to replenish the ones going to builders. 

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Above, a complete set on the bench before packaging. This set sells for $2,200 + shipping, which is typically $60 in the US.  Builder do not need to send cores in advance, I just ask them to within 30 days of receiving the kit. 

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The New Procedure: 

Builders who would like to purchase a set should text me their Name, Address and Email  to my 904-806-8143 number.  I’m going to keep a “Request list” in order, and as sets are finished, I will call builders and alert them I and emailing them and invoice. When they pay the invoice, I will ship the set. 

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My normal production rate is 3 sets a week. They are time consuming, and I obviously can not just work on one product.  I have no ability to predict how many people with text me,  but I will fill them in order. 

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Important: 

DO NOT send me a check in advance.  I have a strict business policy of not taking peoples money in advance of having the product ready to deliver. 

This is a “Request List” , it isn’t an order form.  Orders have deposits, and I don’t take deposits.  If 60 days from now I see anyone on line saying “I’ve had a set on order for 2 months”,  I will remove their name from the list. This may sound trivial to some people,  but it isn’t to me.  I have built my reputation not taking orders with deposits.  Other businesses have different policies, that’s their choice.  There is a type of person who loves publicly complaining about waiting on an ‘order’.  No one is placing and order here, they are just sending a request, and I’m working to meet those requests in sequence, without the builder having to check my webstore for availability. 

“Scalping” – If I catch anyone,  putting in a Request and taking delivery to try to resell them for a profit  to someone unwilling to wait in line,  I will excommunicate both the seller and the buyer.   I work very hard and having an actual supportive community of builders who  look out for each others safety and applaud fellow builders achievements.  We have all been the recipients of scores of my builders  supporting this with act both great and detailed, putting back as much as they found in Corvair building.  Anyone who wants enjoy the benefits of this, but also take an opportunity to make a personal profit, or cut the line, will find themselves with zero product support from me.  A casual review of my demeanor will show I wouldn’t hesitate to  publicly name such people.  Because every single Ross piston has an individual serial number, it would be especially easy to track such resales. 

Hopefully I will never have to bring up the the three paragraphs again. 

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Thank you,  

William 

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Zenith 2026 Homecoming Sept, 18 & 19.

Builders;

The Zenith Aircraft Company is holding their 35th annual Homecoming, at the factory in Mexico Missouri September 18th and 19th.  I will be attending, it is a great event, this will be my 25th consecutive  year attending. I highly encourage all homebuilders to attend. The Heintz family welcomes all homebuilders, particularly individuals who are just formulating their own plan in our branch of aviation.  It is a free event, including the camping, and you do not need to make reservations.  To be a part of the event, there is only one thing required: You have to show up.  Decide you are going now, its much better than looking at the pictures and videos three weeks from now and  wishing you had been there.  

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Above, The Eiberger’s and their 2,850 Corvair powered Cruiser, flying since 2022. I took the picture at last Years Homecoming, and they are planning to be at this year’s event also.  You can get a good look at the wide variety of their creative mechanical adventures on their YouTube channel, “Ozark Garage”. 

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As Always, I will be speaking about Corvairs, but Zenith is a great setting for “Parking Lot Tours”,  where we go from vehicle to vehicle inspecting core parts which builders bring. Its very educational, and fun in a small group setting. If you have core parts you would like inspected, good, bring them. If you are looking for a core to work with, several builders have mentioned bring a spare for sale. Additionally, I will be able to bring back core part to my shop, and save you shipping. I will have limited items on hand for sale, like manuals. 

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I’m looking forward to seeing many of you in person at the homecoming.  Safe travels, be prepared to have a very productive and memorable time. 

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WEWjr. 

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Safety Alert: Imported Bronze Distributor Gears.

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This is a Safety Alert. For more information on Safety Alerts for Corvairs, read that  section on the main page of this website. 

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Date and Revision : This is dated August 8th, 2026.  It reiterates previous warnings from 2019-2022. The information is the same, but being presented here to alert anyone who ignored or missed previous warnings. 

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Subject:  Corvairs drive the ignition and oil pump through a bronze gear mounted on the crankshaft.  The part is assigned #1008 in my conversion manual.  The original GM gear has a perfect track record, but aftermarket imported gears have a very high failure rate, and should not be flown under any circumstances. 

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Applicability:  This applies to 100% of all engines which have, or are suspected to have, an aftermarket bronze gear. Be advised, no matter where they are distributed from, all replacement gears available in the last 20 years are imported.  and covered by this safety alert. 

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Exclusion:  This alert does not apply to engines equipped with original GM bronze gears.   !00% of the engines I built, and kits I built used GM gears.  However, a very high percentage of engines resold fraudulently claim they were built in my shop. The word of a previous owner is not acceptable proof of having a GM gear.  Please note the origins of our understanding of the issue came from aftermarket gears installed on new cranks made and sold by Sport Performance Aviation.  When the problem was identified 8 years ago, the purchasers where notified.  However, no records were kept on which owners elected to comply with replacing the gears with an original GM gear.  Additionally, I had no control over decisions made by builders who attended my training events with their own equipment.  No assumption should be made without specific proof.  GM and aftermarket gears can not be told apart in typical photographs. .

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Discussion:  This subject has previously been discussed at length with builders in several venues. It is being presented again here because we have recently has another builder have an un eventful off airport landing caused by the degradation of an imported bronze gear.  He is the original builder of the engine, and he missed the previous warnings.  Additionally, he was not utilizing our oil sample analysis program, which has the proven ability to spot the degradation of an imported gear before it stops the engine. 

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If an imported gear is installed in an engine, it will operate and give the appearance of normal operation.  However, they do not have the correct complex tooth shape, and will wear in operation against the steel distributor gear.   The wear particles from this action can not be visually seen in the oil, but the advanced oil analysis system we use can spot it in as little as 5 hours of running time.  It has previously caught six engines with a degrading imported gear before any operational discrepancy was detected by the pilot. 

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If the issue is not addressed or detected,  between 75 and 120 hours the imported gear will wear the buttress style tooth design into a continuous knife edge,  This misshapen gear will cause very harsh vibrations to travel up the distributor shaft mounting the steel meshing gear. These vibrations will eventually crack the rotor or dislodge the metal tab on the rotor, either will stop the engine.  I have only 4 known occurrences of this. The first was an uneventful off airport landing in a stol aircraft, and the origin of the discovery of the gear issue. The second was a partial rotor failure, and the aircraft flew back to the airport. The original warnings date from this time. The third event was a builder who was aware of the warning, but chose not to change the gear. The rotor failure he experienced at 110 hours resulted in a very serious accident and the total loss of the aircraft.   The rotor from the most recent event is pictured below. There was no damage to the aircraft, it was towed back to the airport with the wings on. All four of the aircraft were not utilizing oil analysis. 

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All engines which showed a degrading imported gear on  oil analysis, and replaced the gear with an original GM unit have never shown a recurrence of the issue. The high time aircraft has subsequently logged more than  550 hours on a GM gear without issue. 

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Suggested Action:  If the gear is imported, or suspected to be imported, replace it with a GM gear before continued flight.  It is highly reccomended that all Corvair operators utilize the oil analysis program offered by Larry Nelson at LNCLabs.com 

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Thank you for addressing this matter. 

W.W.Jr. 

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Above, a worn, sharpened imported gear on the left. On the right, a cleaned original GM gear. 

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Above, a GM gear. Although it has 100,000 miles of automotive use, it retains the correct flat topped tooth of a buttress thread, correct for these gears. 

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Above, a worn imported gear. Note how the tops of the gear teeth have become sharpened to a knife edge. This causes the extreme vibrations to be transmitted directly into the meshing steel gear on the distributor shaft.  That vibration attacks the rotor on the top of the distributor shaft. 

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Above, an ignition rotor with the dislodged metal contact. This is done by the vibration. In my 37 years of working with Corvairs, I have never seen this happen, except in the case of the imported gears. 

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Thank you.

 

 

 

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2026 Oshkosh and Brodhead

I will be at Brodhead WI for the Pietenpol gathering on Saturday the 18th

I will be at Oshkosh the 20th -27th, in my same spot, 614 North Aircraft Display, adjacent to Zenith Aircraft.

My forum is in the Homebuilders Hangar, Thursday 10am.

Looking forward to seeing many of you there,

William .

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A belated goodbye to Terry Bailey

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Builders, 

Today I spoke with the wife of one of my earliest and most illustrious supporters,  Terry Bailey.  I had not spoken with him in a decade,  as medical issues made him drift away from flying, a passion he couldn’t resign himself to being a spectator in.  His wife called to say that he had passed at age 72, four years ago. 

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We spent an hour on the phone remembering good times, and a man who was a wholly unique character,   a 6’5′ charming hell raiser, and craftsman of boundless energy and ideas.  His life had only two throttle positions,  sleeping and take off power, and the man didn’t sleep much.  He was a nationally known member to the tandem wing  community,  and when he discovered my work with Corvairs, he instantly became a builder and supporter. He was a phenomenally good welder and fabricator, and a very free thinker, socially fearless.  He was a first class story teller who could  make you laugh  long and hard enough asphyxiation and urination  were eminent threats. 

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He wasn’t yet 60 when serious cardiac problems  ended his flying. I drove him to Emory in Texas where he was told his flying was over and his time was short.  This would have overwhelmed most people, but Terry wasted no time moving into classic hot rods, all centered around early Hemis, 331s, 354s , and 392s.  He invested the same energy as he had put into building and flying.  We spoke less, but it was the kind of friendship which required no maintenance.   When a gap of time went by, I  guessed the diagnosis had caught up to him.  Speaking with his wife today, it assuaged to the loss somewhat to know he got nearly 15  more years, and had a lot of good times, right up to the last week. 

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A belated farewell and blue skies  Terry, my life is far richer for having the great fortune of knowing you  as a friend. 

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ww.

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Picture from the late 1990s, me on the left, Terry on the right, behind my Pietenpol.  All four people I gave thanks for on the tail are now gone from this world, but their invaluable influence will  live as long as I do. 

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Here for the long run.

Builders, 

I was visiting EAA chapter 534 in central Florida yesterday, looking at Zenith airframes which they acquired.  In the paperwork was the logs and photos of the late Bill McManus, he was one of my earliest Zenith builders. 

The photos brought back memories of him;  On the surface he was a gruff chain smoking curmudgeon with a salty vocabulary,  but if you spent the afternoon with him, and were secure enough to not let the cover tell the whole story inside the book,  he was a real character,  He was enough of a craftsman and motivated enough to build a 601XL in a carport next to his mobile home in just 16 months,  

Back then, Gus Warren was our test/demo pilot, and he gave more than 100 people a demo flight in my 601XL.  Gus’s father was a legendary CFI, and schooled his son rigorously in the art and science of being a good aviator, with a sharp focus on fundamental flying skills ……. It surprised Gus, when he turned over the controls of the 601XL in the demo flight, virtually every single ‘pilot’ tried to fly the plane without the slightest input on the rudder.  I clearly remember that McManus was the exception, and when we later asked him about it, it turned out that almost everything he knew about planes came from a lifetime of flying Radio Controlled planes.  I found it ironic that 1/3 the people who went on the demo flights wanted to tell you about their intention to fly IFR or discuss the stability as if they were Kelly Johnson, but none of them were capable of basic stick and rudder flying like the gruff guy huffing on Marlboros and dropping and occasional F-bomb.  Go figure. 

By the time we bought our Zenith Kit, I had already been working with Corvair flight engines for 13 years, but the decision to build the first Corvair powered Zenith brought us a flood of new builders, Bill Mcmanus  in the first wave.  He is long gone now,  But looking at the 19 year old picture of me running his engine on my test stand, its a reminder that I’m here for the long run. 

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Bills engine doing a break in run on my test stand 19 years ago.  Yes, I looked like that once. 

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Bills 601XL nearing completion. notice he  painted it outside with the neighbors 25′ away.  The guy was determined.  The black lines were to his BRS chute. 

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His airworthiness card was in the papers.   Bill was a new pilot when he was building, and was unaware that weasels in the FAA aeromedical department  had just argued to gain access to VA medical records without the permission nor  notification of the individual veteran.  Bill was a Vietnam vet and found out the FAA wanted to question things he and most Veterans believed were doctor-patient confidential.   If you are new to flying and you encounter a pilot with a particularly low opinion of the Aeromedical  FAA, understand it might have been formed by the FAA  pulling stunts like accessing VA records without notification. 

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The man himself, with his creation.  Blue skies and tailwinds, RIP Bill, you were a real individual, and quite a character. 

 

WWjr. 

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Duc Propellers, now entering Corvair testing.

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Builders, 

 

Pictured is a two blade, hollow carbon fiber ground adjustable propeller, tailored for the Corvair my the French company Duc .(Pronounced “Duke”)  This prop in my shop is the result of extended conversations with the staff of Duc. This is just the first combination to be evaluated, and the results form this will refine future tests, including the possibility of an inflight controllable model.  Projects like this are part of the reason why I got our own in house test Zenith 601. 

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As we gather flight information, I will share it with builders here.  For now, special thanks goes out to two members of the Duc team, Gaetan Fouozing, who runs the US sales office out of Sebring Florida, and Michael Derderian, who was our engineering rep from the Factory.  Both of these men have put a sustained, serious effort to advance this project.  Many old guard Corvair builders  know that I have been a dealer for or an employee off many well known propeller companies.  They all have particular strengths and unique  designs which excel in particular applications, but most people are yet to understand how the individuals in the companies make the difference on if the capabilities of the companies are accessible.  There two men really know their companies products, and have done an outstanding job advancing this project.  More news as it develops. 

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Hollow carbon blade with an Inconel leading edge. 

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The two piece hub, it is made from solid Carbon fiber. 

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Above, the two blades. 

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Above, the other side of the hub. 

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Above, the gold blade shank is aluminum. 

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WWjr.

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Flycorvair 2,850/601XL Demo plane. part #1

Builders, 

Here is post #1 on our project plane.  Just some brief notes about cleaning up the existing firewall. 

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Above, a short video, as we received the plane. 

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Above, Gary drills off the skin between the instrument panel and the firewall. This only takes a few minutes, does no damage,, provides great access,  easily replaced. 

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This is a fuel pressure regulator. It was on the plane because the builder used a non-standard carb.  I highly discourage anyone from using one of these in a plane, they have a very poor track record, and are never needed with the correct carb. 

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This is an electric primer solenoid.  My Zenith manual tells how these are used, as old Ellison carbs needed these.  Those carbs are out of production, and neither an MA3-SPA nor a Rotec TBI need this. 

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Above, this is an ACS gascolater, they come with Zenith kits. They work, but I only use gascolators with a screw on bowl, like an Andair or a Smith. The blue Vans one is very gig and heavy, I never use it. 

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My finger is pointing at the ground strap lug on the motor mount. In the photo, the builder ran the ground strap from the firewall, which worked, but I would rather have a short jumper from the mount to the head. 

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Above, the view inside. The work is very good and tidy, it just needs a bit of cleaning. 

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Above, Motor mount removed, I sold it to the builder 14 years ago. Its in perfect condition, I going to send it out and have it powder coated our standard gray color. 

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I’m leaving for the Zenith Homecoming on Tuesday the 17th. , Next update will be after I get back. 

WW.

 

 

 

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Our ‘New’ Zenith demonstrator , 601XL-B

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Builders, 

6 weeks ago I put out the word I was looking for a flying 601/650 which I could use as a demo aircraft for the 2025 season,  and to have for R&D and development projects.  There were a number of good offers, but the one that best suited the mission was Jim Ballew’s 601XL-B in Tulsa.  We made arrangements to buy it without the engine and trailer it back to my place in Florida. 

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Jim finished and flew the plane in 2012.  It is actually only one of his 3 Corvair powered planes. A very skilled and experienced builder, he has been an EAA member nearly 60 years.  The plane  is simple, no frills, and well built.  Just what I was looking for. 

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The plane has some dated systems, and some unique installation elements that we are going to update and replace with a 100% standard 2,850cc Corvair installation, up to date all the way down to the wiring harness matching the diagrams on my website. 

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Along the way, I will share the step by step process., in pictures and short videos.  So the work begins.  When you see this plane in person at Sun-n -Fun 2025, keep in mind that all good outcomes can be traced to a single day, the day you decided to begin. 

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Above, Myself, Jim Ballew and my compadre, ‘Uncle” Gary Coppen. 

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Above, adventure on the way home. Its a long story,  People who follow my Face Book Page “WW Flycorvair” got to read it blow by blow. 

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The aircraft getting unloaded at my hangar in Florida. 

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WW. 

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Corvair / Zenith of the week: Ken Pavlou’s 601XL-B

Builders, 

Continuing the series, here is one of the best known Corvair/Zeniths, from a very friendly and extremely talented builder-flyer, Ken Pavlou. 

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Ken’s first flight was 10 years ago in 2014, but he started building in 2007.  A family man with a challenging career in health care and a side line of residential property renovations, the project had to fit into the remaining hours.  After a big push in early 2014, he completed the plane and flew it to Oshkosh, where it was autographed by the master himself, Chris Heintz. 

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In the 900 hours since, the plane has made several return trips to Oshkosh and many trips up and down the east coast.  People who thought of the 601 as a fun sport plane had there understanding of the planes capabilities expended when Ken shared videos  like directly overflying JFK airport at night. 

Corvair College 31 Barnwell, SC

2002 Mile Round Trip to Florida

Ken could select any engine he wanted for his plane, budget was not a factor. The appeal of the Corvair for him was the chance to build it himself, and the basic simplicity of the engine and systems.  He built and flew a standard 100hp Corvair for the first 503 hours, and then he upgraded to a cost is no object 3.3L 125+hp engine with a stroked billet crankshaft.  Ken is one of a handful of builders who have flown both ends of the Corvair power spectrum in the same airframe.  He points out they each serve particular goals well. 

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Ken is an accomplished pilot with more than three decades of flying and more than 6,000 hours in GA aircraft.  He has nothing but praise for the 601/650 design and Zeniths support for it.  When you select an aircraft to build,  you are also getting ‘married’ to the company which provides it.  Thousand of builders, Ken among they, will attest  the Zenith factory and community of builders  was a very good match  for homebuilding ambitions. 

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Above,   Ken at one of my Corvair Colleges, where he was awarded the Cherry Grove Trophy for his long standing contributions to our Corvair community

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Ken’s 601XL, one of two in my front yard in Florida that day. 

 

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Ken’s plane in New Hampshire, with two other Corvair Powered 601XL’s 

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Ken, with his plane, on the flight line at Oshkosh. 

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wewjr. 

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