Corvair College #28 registration is open


I just got an Email from 601XL builder and information system guru Ken “Central Scrutinizer” Pavlou, sent from his secret location in CT:


“The registration form is live at:  “


You can click on that link, and it will directly take you through the on line process to sign up. Keep in mind the event is ‘free’, but we do have a per person fee that goes directly into food, beverages, space , tables and tools.  The online set up explains options on covering this expense so that Kevin and Shelley are just hosting the event, not underwriting it.

Shelley has set up a very elaborate Face book page full of information. This is an open page that you do not need to be signed up with Face Book to read:



It has a lot of basic information and will be updated as we go.


Our illustrious host 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. Symbolic of his wearing two hats in aviation is the fact he’s wearing a sock monkey knit hat while making a serious point on his introduction speech. He is cool enough to do this and never crack a smile.

About two thirds of the attendees of Corvair College #22 March 9-11, 2012, gather in front of   host Kevin Purtee’s Pietenpol. You can read the story of that event at this link:

Kneeling in the front row is Gary Boothe of California who was attending  his fifth Corvair College.  Gary’s Piet is done and his engine ran at Corvair College 18. (You can see his plane at this link: New Pietenpol, Gary Boothe, Cool, Calif. )  Yet he comes back for more because the spirit and the camaraderie of the events are contagious in a modern era of aviation where a real spirit of community is often difficult to find.

Above, Kevin Purtee and Shelley Tumino receive the Cherry Grove trophy at Corvair College #24.

ZenVair builder Ken Pavlou of Connecticut with his Corvair Conversion, in a 2007 photo I took at his “Secret location.” Ken has run the registrations for almost all of the colleges since CC#14. Today his 601XL is 99% done.


2014 Corvair Colleges and their local hosts:

CC#28 – Austin TX – Kevin Purtee/Shelley Tumino, 28 Feb. 1 Mar.

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

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

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

Corvair – Pietenpol Reference page


Here is a collection of information we have put out for Pietenpol builders. I have swept it into this single page so builders can have a single reference point on the airframe. As we have more content, I can easily add a link here and keep this current. This page is just a brief set of notes and links to stories I have written about Pietenpols. If you would like to start with a simple three page spec sheet on the engine, read this link first: Basic Corvair information

I can still recall the very first picture of a Pietenpol I ever saw, a grainy black and white image in Peter Bower’s “The 25 most practical Homebuilts.” It was love at first sight, I ordered a set of plans from Don Pietenpol the next week, and 25 years later, the design and the people who love them still hold a place in my heart.


 Above, A great afternoon at Brodhead WI, 2009. R to L, the Piets of Gary and Shad Bell , Kurt Shipman, Randy Bush, all Corvair powered.


Above, my proudest day in aviation. Grace and I with friends and my Pietenpol in front of the old Brodhead sign at the Pietenpol Reunion in 2000. We had just flown up  from Florida, and spent a great day with friends old and new, with my mother and father on hand. This single day made years of work in the hangar worthwhile.


(Click on any colored title to read the full story)


Pietenpol Aircampers:

Pietenpol review in pictures, 15 more Corvair powered Piets

Bob Lester’s Corvair/ Pietenpol nears 800 hours.

The Bell Pietenpol, 3 generations of flyers

House Call on Pat Green’s 1,000 Hour Pietenpol

Pietenpol Power: 100 hp Corvair vs 65 hp Lycoming

Steve Williamson Pietenpol at 60 hrs., SoCal.

New Pietenpol, EAA #1279, French Valley CA

New Pietenpol #3, Mike Groah, Tulare, California

New Pietenpol, Gary Boothe, Cool, Calif.

Gary Boothe’s Pietenpol, flying video

New Pietenpol, 2700 Corvair, Don Harper SC

Randy Bush’s Pietenpol hits 500 hours.

Farewell to a Good Man; Robert Caldwell departs.

Guest Writer: Pietenpol builder/flyer Kevin Purtee

Knoll Family Pietenpol

Bob Dewenter’s Pietenpol project

Pietenpol Project – Terry Hand

Pietenpol 2,775 cc Corvair; Trevor Rushton from UK


Oshkosh 2004,  Alex Sloan, holding plaque has just been presented The Tony Bingelis Award.  L ot R, Noted Pietenpol builder and pilot Mike Cuy, Pietenpol historian and newsletter editor par excellence, Doc Mosher, Grace and Myself. I have always tried to give something back to todays Piet builders, as I personally benefitted from the efforts of the builders who preceded me. I have worked with Doc on this, including developing the Weight and Balance testing and data bank. He and his wife Dee have been the single biggest factor in the design’s explosive popularity in the last 10 years.


Above, Speaking at the Brodhead forums, 2008. This gathering in July is my favorite event of the year. It is a great place to socialize, meet new friends, see planes and exchange ideas. I have only missed one year in the last 19, given forums the last 12 years. We also do practical stuff: we weighed 28 Piets on electronic scales there in a two year period. The data is in the back issues on the newsletter, available at


Installations and airframe parts.

Pietenpol Mount on airframe

Pietenpol Weight and Balance project

Pietenpol Weight and Balance article source

Current Corvair Installation in a Pietenpol, part #1

Current Corvair Installation in a Pietenpol, Part 2

Steel tube Pietenpol fuselage with landing gear and 12 x 4.8″ tires.

Great lies from discussion groups…….part #1

Pietenpol Products, Motor mounts, Gear and Instalation Components.

New die spring landing gear on a Pietenpol, 10 a.m.-4 p.m.

Pietenpol Motor Mounts, P/N 4201(C)

Pietenpol Fuel lines and Cabanes

Fuel lines and Cabanes, part 2

Pietenpol Box Spar Construction, 6/27/13

Cooling with J-3 style cowls. (Pietenpols, Cubs, Biplanes, etc)

Three Pietenpol Motor Mounts

In Search Of … The Economical Carburetor

Franklin Engine Runs at CC ##22 KGTU Spring Break 2012

Terry Hand’s 2700 cc Pietenpol engine – w/Weseman 5th bearing

 “Zen-vair” and “Piet-vair” Discussion Groups, your resource..

Pietenpol lift struts; $65, a free education, and fun with friends..

Custom Pietenpol engine mount.

Yes, Pietenpols do need 5th Bearings..

Evolution of a Pietenpol

Evolution of a Pietenpol pt. 2

Andrew Pietenpol, aviator and Grandson of BHP, right, attends Corvair College #4 with Grace and Myself in 2003. Greatest complement anyone has ever said to me in 25 years in aviation: Andrew told me that day “My Grandfather would have adopted you.”


Stories on the influence of BHP

B.H. Pietenpol, Patron Saint of Homebuilding

Don Pietenpol Passes, 1/8/14

Vi Kapler passes from this Earth, age 88.

New Pietenpol Family website

The Cherry Grove Trophy

Help Needed, Wikipedia error on Pietenpols

Cherry Grove story, “The long way home”

Cherry Grove story, Part 2.

Pietenpol first flight; Honolulu International.

Flathead Ford, 71 cid. Freedom to pursue happiness.

Guest Editorial, Pietenpol builder Terry Hand.

Bob Lester’s 48 flight hour, 3400 mile Pietenpol adventure

Pietenpol Builders and Pilots at Corvair College #31.

Ralph Carlson and Conversion Manual #1.




Above, Kevin Purtee and I speaking at Corvair College #32. Although we look very different, we have a lot of things in Common: We are both the same age; We are both Embry-Riddle graduates from the same Degree Program; we have both worked in aviation every day since we were 26; we have very similar perspectives on risk management.  Read: Thought for the Day: Two paths in managing risk.


If you would like to read a number of personal stories, some with very harsh lessons on the unforgiving nature of flight, Please look here: Risk Management reference page. If you read them with an open mind, some of my friends will be able to posthumously teach you to take care of yourself. -ww.


Updated story, B.H. Pietenpol – Thanksgiving 2013


I took a few minutes today to update a story I wrote last year on the influence of B.H. Pietenpol. It would be very hard for me to overstate how much I respect the life of this man. To me, he is on the same plateau in aviation as Armstrong and Lindbergh. He didn’t fly to the moon or even across the Atlantic, but he made an enormous contribution to the ability of working Americans to claim their rightful place in the sky. That is something to remain very thankful for.

Below the picture is an excerpt from the story. Click on this link to read the whole story:

B.H. Pietenpol, Patron Saint of Homebuilding

“10 years ago, after a particularly trying week at Oshkosh, Grace had the wisdom to understand that we had to go find something we had misplaced, something that our industry had long forgotten. The drive from Oshkosh to Cherry Grove is about 250 miles, but it takes about 60 years to get there, in the sense that you need to go back in time to get “there.”  We spent a few hours in Cherry Grove. Dave Mensink, Grace and myself were the only living people there, but it didn’t feel lonely.  We stood on the field where Bernard had 70 years before, laid claim on his right to a piece of the sky. For the next 3 or 4 decades that followed, nearly every guy in homebuilding was a working class guy, and damn proud of it. Along the way, homebuilding got careless and allowed some new people to suggest that the people who invented this were no longer what it was about. If you are a working guy, and you’re struggling to imagine how you are going to build a plane, have no worries. You have a lot in common with the Patron Saint of Homebuilding, and in this arena, that is the only currency that counts. -ww”

Planes flying on Corvair Power


 This is a single point collection of stories that have appeared individually in the last two years on this site. It is easy for me to update this as we add new stories of flying planes, I can jump back and add them to this list.

The next time anyone questions if planes have really ever flown on Corvairs ( Yes, even at places like Oshkosh, when we are standing in front of a row of Corvair powered planes, people who are actually EAA members will walk up and tell you with certainty why no one has nor will ever fly a Corvair), you can just send them a link to this collection of stories.

Above, an airborne shot of Brodhead WI, center of gravity of the Pietenpol building community. This was taken by Grace in 2006. She was in the front seat of “The Last Original“, Bernard Pietenpol’s last personal aircraft, of course Corvair powered. Beyond being the father of Corvair aircraft power and the first man to fly the engine, I hold the Bernard Pietenpol is the patron saint of working homebuilders. By all accounts a well mannered and humble man, he simply refused to accept the argument that flying was reserved for the wealthy. He was no other man’s line boy, and he was not going to settle for being a spectator. He knew his place was In the Arena, and he accepted nothing less. Neither should you.


Click on the title of any story to read it:


Films of flying planes:

Corvair planes and projects on You Tube


Stories on Faster Homebuilts:

Corvair powered Dragonfly, Charlie Johnson, aka ‘One Sky Dog’

KR-2S at 700 Hours – Joe Horton

Corvair Powered Davis DA-2, w/EFI

New 3,000 cc Cleanex, Dale Williams, SC

Panther Roll out.

Flying 2,850cc Cleanex, Clarence Dunkerly


Pietenpol Aircampers:

House Call on Pat Green’s 1,000 Hour Pietenpol

Pietenpol Power: 100 hp Corvair vs 65 hp Lycoming

Steve Williamson Pietenpol at 60 hrs., SoCal.

New Pietenpol #3, Mike Groah, Tulare, California

New Pietenpol, Gary Boothe, Cool, Calif.

New Pietenpol, 2700 Corvair, Don Harper SC

Randy Bush’s Pietenpol hits 500 hours.

Pietenpol review in pictures, 15 more Corvair powered Piets


Classics and one of a kinds:

STOL and utility planes for Corvair power

Two More Flying Planes: Merlin and VP-2

Floats on Snow, Corvair powered Merlin

Zenith 701- Corvair reference page, November 2013

Corvair powered Flybaby, Goode and Brantley, Georgia

2,700cc-Skycoupe-2002 Photos

3,100cc Corvair in Pegzair


Zenith CH-750s:

Zenith 750 Flying on Corvair Power, Gary Burdett, Illinois

first story: Gary Burdett, 2,850cc Zenith 750, now flying. (engine selection)

Flying  Zenith 750, Tom Siminski, 2700cc, PA.

Flying Zenith 750 w/3000cc Corvair, Doug Stevenson, California

New “Zenvair-750″, Jeff Cochran, 2,850cc engine, N750ZV

 Flying Zenith 750, Tom Siminski, 2700cc, PA.

Zenith 750 / Corvair reference page, October 2013


Zenith 601s and 650’s:

16 Flying Corvair powered Zenith 601/ 650s

Woody’s 2,850cc Corvair/601XL hits 400 hours.

New Zenith 601 XL(B), Conventional Gear, Jerry Baak, S.C.

Flying 2700 cc Zenith 601 XL(B), Alan Uhr

 Zenith 650-2700cc Dave Gardea

 Zenith 601XL-2,850cc, Woody Harris

Another new “Zenvair” 601XLB, Jim Ballew, 2700cc

Second “Zenvair”, the McDaniel’s 2700cc 601XLB

 Patrick Hoyt, new Zenith 601XL, now flying, N-63PZ

Guest writer: Phil Maxson, flying a 3100cc Corvair in his 601XL

 601XL-2700cc Dr. Gary Ray

 Zenith 601XL-3100cc Dr. Andy Elliott

Zenith 601/650 – Corvair reference page November 2013

Corvair powered Flybaby, Goode and Brantley, Georgia


Here is a look at a Classic Homebuilt powered by a Corvair. It has been flying for about two years. Although a lot of people have spoken about the combination for a long time, this might just be the very first one that has ever flown.

At sun n Fun this year, Glen Goode came through the booth and share these first two photos. We complemented him on the obvious craftsmanship and the persistence to see the job through. It is always a good hour when you spend it with a builder who is sharing his path to success.

Donald Brantly, the other half of the team, can be seen in the photos below.  These two have something else to be proud of: Very few teams of builders work out.  What starts with great promise, hardly ever works out that way. The completion rate for teams is certainly below that for individual builders. With these guys, I suspect that their strength as a team lies in their differences as individuals. They are quite different from each other, and they brought different skills to the project. If you are considering a team build, honest evaluation and sober thought are in order, as it rarely ends in success as it has for these men.


Above, the Flybaby in Ground run.  The design is a 1962 effort from Peter Bowers, and it was once built in great numbers in the EAA. Original specified power plant was a 65hp Continental. Construction is of wood.


Above, Glen on the left, Donald on the right, with the finished plane. A very smart looking job.


Below is a story in blue from December 2005 at our old Edgewater hangar. The story is taken directly from our main webpage  Here is a good indication of our long term support for builders. We got their engine straightened out and running eight years ago, but it took six more years of on and off work for the guys to see the project through. That’s OK, we are here for the long run.

As I look at the photos, the first thing I notice is how I look a lot younger then. More important, it was the first visit to our hangar by Woody Harris, who has not only evolved to be our “Man on the West Coast,” but also the closest of friends. The story contains some timeless stumbling blocks like ‘local experts’, but it also has good milestones like hearing your engine fire up for the first time. That moment, and the others that follow, first flight, 40 hours, and first trip to a College all belong to builders who are in it for the duration, who will get beyond the stumbling blocks.

We have a guy who drives a beat up F-150 in our town. I see his truck once a month or so, and the sticker on the tailgate always catches my eye. It says “A champion finds a way, a looser finds an excuse.” Homebuilding is a long journey of learning and effort with 1,000 excuses to quit. Some builders have a turn of events or responsibility that sidelines them, but many just are not up to the challenge, or didn’t have the resilient disposition that is common to the successful. These people who quit will often find an excuse and others to blame. They will often have a chorus of  support and understanding, as there are more people who quit than finish. But there are builders who pass through all the same tests, challenges and frustrations, but they do not give in.  Ask any one of these people if it was worth it, and every single one of them, Glenn and Donald included, will simply say “Yes.”         -ww.

If you’ve ever dreamed of building a Bowers Flybaby, take special notice of these two builders. On the left is  Donald Brantley, and at right is Glen Goode. They hail from Vidalia, Ga. In my estimation, they will very likely be  the first people to fly the Corvair/Flybaby combination. The Flybaby is an all wood, plans built, single seat, low wing  homebuilt. It is one of the all time greatest homebuilt designs. It is a natural for the Corvair. Ron Wanttaja runs  an excellent Web page on the Flybaby at Donald and Glen are jointly working on the  last stages of their Flybaby. With a running engine and an airframe needing only cover, it should fly in early Spring.  They brought down a fully jigged motor mount built from one of our Trays. I finish welded the  mount for them, and kept the jigging dimensions so we can build them for others in the future. The finished mount  weighed about 5 pounds and had exceptionally strong geometry. The Flybaby is the 27th different motor mount design  I’ve built for the Corvair.

They brought down their engine for final assembly and test run. Glen had been at CC#9. He had observed in detail, and  both men returned for the final work. It was not without problems. But concentrate on the success; the Golden Rule:  Persistance Pays. These guys dug in for three days of work at the hangar, and came away with a perfect running engine and  renewed enthusiasm.

In this photo, at right is Woody Harris. Woody is a Northern California 601 builder. He was in Orlando for the  Performance Racing Industry show. He owns MSI Motorsports in Vacaville. He has a tremendous background in the  motorsports industry which would be hard to summarize in a few sentences. After Glen and Donald’s engine was done,  Grace and I were Woody’s guests at the show. This show had 3,900 booths of pure high end technology under a square mile of  roof. We personally met with engineers from ARP, MSD, Mahle and many other companies whose products we use in Corvair  conversions. Being able to speak with these people at an industry-only show was priceless. In return, we gave Woody  our humble thanks and Gus took him up for an hour in the 601. All this, and he was good company for a few days too.

Above is a sample of the problems in the initial Flybaby engine build. I looked inside the engine and discovered that it  had weak, early model rods. Longstroke engines all originally came with heavy duty rods. In the Conversion Manual, I warn people never to use early rods. The root of all the problems in this engine was a local  machining “expert.” This person supplied the Flybaby guys with a “special set of rods,” and charged them hundreds of  dollars to prep them. I wrote the numbers on the rods, and you can see in the photo that they are not balanced, despite  the fact that the guys were charged for this. Additionally, look closely at the piston. Notice that it has drill holes  in the wristpin boss, and very crucially, on the underside of the dome. This was allegedly done to balance the pistons.  I weigh every set of pistons we put into an engine, and the forged pistons are so accurately made that I’ve not seen a  one gram difference in any set we’ve put in an engine this year. Drilling holes at random critically structurally  weakens pistons. Never drill a hole in a piston crown. Weight is removed from pistons with a mill, not a drill. If your  local machinist tries to talk you into work like this, treat him as if he’s trying to kill you because that’s what he’s  doing. Just take the pistons out of the box and use them as they are.

 Glen and Donald kept their positive attitude throughout, and were rewarded with an excellent running engine.  I’ve said it many times, but the only two places from which to get connecting rods are Jeff Ballard at SC Performance ( now out of biz. -ww) and  Clark’s Corvairs. Jeff’s rods can be considered the gold standard. Available at slightly less cost are Clark’s Part No.  C9203WW. Both have ARP rod bolts, are shotpeened and fully rebuilt. Jeff’s rods feature 12-point nuts and polished beams.  Both of these outfits work with batches of hundreds of rods. Producing matched sets from a large collection requires  very little work to balance them perfectly. Any local machine shop working with one set of rods is forced to remove a  lot of material from five of the rods to make them match the lightest one. In many cases, this will lead to seriously  weakened rods. Save yourself a lot of trouble and go to Jeff or Clark’s.

The milestone that all builders work toward: The engine comes to life. Although it was late, we ran the engine on  the Dyno for an hour. It started off with a little bit of valve train noise, but in 10 minutes  the noise was gone. By the end of the run, the engine sounded positively sweet. The guys left the following morning  full of renewed enthusiasm for their project. For our part, I’d like to say they were excellent guests who went out  of their way to fit in during a regular working week in the shop. They worked hard in the shop and they treated us to  lunch and dinner every day they were here.

The obligatory Whobiscat photo. I took this photo through a taillight hole in one of Kevin’s Corvair project cars.  The ever curious cat was sitting inside the engine compartment on the battery tray

Corvair power for Panther and Sonex reference page


I have collected in this one story a complete overview of the Corvair power option for builders considering or working on the SPA Panther kit aircraft and Sonex airframes.  These two aircraft are grouped together because both of these installations were developed by Dan Weseman, (SPA is his company) who offers airframe components that seamlessly work with our Corvair engine components.

Builders who are already working on, or flying a Corvair will be familiar with much of this material, but I bring it all together here for Panther and Sonex builders who are not yet familiar with the Corvair. If you would like to start with a simple three page spec sheet on the engine, read this link first: Basic Corvair information



Above, Oshkosh 2013: Dan Weseman selected the Corvair as the engine for his Panther prototype. He did not make the choice lightly. He has hundreds of hours of Corvair flight experience, developed the highly successful “Cleanex” (Corvair powered Sonex airframe combo), manufactures a number of Corvair flight products like 5th bearings and Billet Cranks, and is well known and respected in the Corvair movement. In 2009, we awarded him The Cherry Grove Trophy , as Corvair Aviator of the year.


The Panther:

The Panther was designed to take a very broad variety of engines from large VW’s to 160hp Lycomings. Dan has extensive flight and ownership experience with most Common light aircraft engines, but he selected the Corvair as his chosen introduction engine for the Panther for a number of good reasons. Not only is the engine powerful, smooth and reliable, it also supports Dan’s mission of keeping the plane affordable for rank and file homebuilders.

No rational man introduces a new aircraft with an engine he must make excuses for. Dan knew the Corvair would not disappoint the industry people and media who would be invited to fly the prototype. The most common thing said by highly experienced builders and designers who see the Panther perform 170 mph low passes, 1600 fpm climbs and aerobatic maneuvers is “I can’t believe that is powered by a car engine.” The Corvair in this installation has the performance to change aviators perspectives on the capabilities of auto conversion engines. Paul Dye, Editor in chief of Kitplanes, came to Florida to fly the plane. Very impressed, on the engine he commented that it functioned just like a Lycoming, just much smoother.

Above, Paul Dye, editor of Kitplanes returns from his flight in the Panther.


If you would like to see a visual example of how well the plane performs with a Corvair, get a look at this link:–ZQVI


You can read all the detailed information on the SPA website at this link:



If would like to read about how this airframe flight tested Billet Cranks Made In The USA, click on the story title.


Above, enroute to Corvair College #16, ‘Son of Cleanex’ builder/pilot Chris Smith shot this photo of Dan Weseman off his wing as they flew up from Florida in loose formation. Although it is not for everyone, the Corvair when installed correctly in the Sonex airframe provided a high performance engine that is essentially immune to overheating issues.


The Sonex:


The Sonex is an outstanding light aircraft designed by John Monnett. It, and the Y-tailed Waiex have sold hundreds of aircraft kits. For 10 years,the Sonex factory approved only three engines for the airframe: the 2,180cc VW, and the 80 hp and 120 hp Jabbirus. The factory position firmly asserted that for an aircraft to be a Sonex, it must have one of these three engines. We’re personal friends with the Monnett family, and to respect their wishes, I carefully referred to the combination as a Corvair powered Sonex airframe, or Dan’s development as a “Cleanex” (a name Dan was slow to grow fond of.) I picked the name because Dan’s plane was a very clean build, that most people were stunned to find out was plans built, not a kit.

Recently in an EAA Webinar, Jeremy Monnett announced an company policy change of sorts, and stated that they were going to adopt a much softer line on this, comparative to other experimental airframe companies. Even with this change, we still refer to any Corvair powered Sonex or Waiex airframe that is adapted to Dan’s installation and uses our engine parts as a “Cleanex.” Like 1950’s Frankenstein movie sequels, a number of builders chose names for their planes like “Son of Cleanex”, “Bride of Cleanex” and “Daughter of Cleanex.”

Dan’s plane is an outstanding performer. I flew in it with Dan, on an 85 degree day off  our 2,400′  tree-lined grass airstrip in Florida. At the time our combined weight was 430 pounds and we had 12 gallons in the tank. If anyone tells you that VW’s are as powerful as Corvairs, they simply have never seen a Corvair in action. Dan’s plane could do an honest 155 mph on 5 gallon’s an hour, and top out above 175 mph.  Dan demonstrated many times that he could run the plane flat out at top speed for more than 40 minutes without the engine running hot.

I offered an opinionated Jabaru 3300 pilot $1,000 cash if his plane could beat Dan’s over a 100 mile course.  He didn’t take me up on it for a simple reason: he was afraid if he ran his $18K engine that hard for 40 minutes he would cook it. The speed would have required running the Jabaru 500 rpm over its factory approved continuous rating. GM designed the Corvair with a 5,500 rpm redline and a 575F CHT limit. Even at top speed, Dan’s Corvair is only using a fraction of these ratings. The is the key element in the Corvair’s reputation as a very robust power plant. It is approximately 25 pounds heavier than a 3300; much of the weight difference is in the Corvair’s cylinder heads which are literally covered in deep cooling fins.

If you would like to see for 120hp Corvairs taking off in succession, check out this link. Dan’s and Chris Smiths aircraft are two of the planes leaving Corvair College #16:



Above, Dan and his Cleanex in front of my hangar at Corvair College #8. (2004) Until his airplane was done and flying, we kept Dan’s identity a mystery. At the time, a few people who saw this photo made jokes about the “Builder Protection Program” with a nod toward John Monnett’s allegededly sharp temper about people putting other engines in his designs. In reality, Dan is friends with the Monnetts.  The Cigarette was part of the ploy, Dan has never been a smoker. Today, Sonex ltd. has a much more relaxed attitude about alternative engines.

In the above photo is from sun n Fun 2012, eight years later. Building a “cleanex” has a fun side also, where builders like to keep ‘traditions.’ From our 2012 SnF coverage, a picture and a comment that pre-dates the policy change by the Monnetts: “A Sonex builder next to Dan. We are having a good laugh disguising his identity because on his shoulder is a motor mount that mates the Sonex airframe to a Corvair engine, creating a “Cleanex.” Here we are kidding around about the  man in the yellow shirt entering “The Builder Identity Protection Program” because the combination is not approved by John Monnett, the airframe’s designer. In years past, John was known for having low tolerance for people modifying his excellent airframe designs. Truthfully, I know him fairly well and he really doesn’t get that upset about it as long as builders choosing other engines do not level unfair criticism at his selected engines.  There are now about 10 Cleanexes flying, and Dan is glad to work with any builder who has chosen the combination as long as they respectfully avoid Internet comments that would raise John Monnett’s blood pressure.


Many people have seen Dan and Grace flying aerobatics in “The Wicked Cleanex” on our Corvair Flyer #1 DVD. Continuous use of this type of operation led Dan to independently develop his own simple, retrofitable fifth bearing setup to reduce flight loads on the Corvair’s crankshaft. You can read about it on his website While people just getting into aviation occasionally view Dan’s flying as daring, I want to emphasize that it is a smooth display of skill and has nothing to do with daring or risk taking. I’ve gotten to know him pretty well, and around airplanes, Dan is pretty conservative. I would easily name him the steadiest pilot and most meticulous maintenance guy in the land of Corvairs.


Above is an early (2006) view of the Cleanex engine. Our Gold Hub and Front Starter system are clearly visible in the photo. Note that all of the engines we build have Lycoming style starter ring gears on the prop end of the engine. All of Dan’s installations use our arrangement. In the past, a handful of homebuilders and here today, gone tomorrow outfits put the ring gear on the firewall end of the Corvair. On a Sonex airframe, it is a critical that no builder operate with such a location because it puts the exposed, spinning, ring gear very close to the Sonex’s plastic fuel filler neck, which could lead to a disaster in an otherwise minor accident. To fly a ‘rear starter’ in a Sonex airframe is foolish, to promote it would be amoral.


The combination of the Sonex airframe and the Corvair proved very sucessful because Dan wisely chose a mixture of our proven parts and systems, clever craftsmanship and practical hot rodding.  Once Dan showed people what the plane was capable of, it was more frequently called “The Wicked Cleanex.”  Over time the plane served as a test bed for a number of  our parts like the Gold Prop hub and the reverse gold oil filter housing. Dan used it to prove out his popular 5th bearing system. You can read more of the story of the airplane at Dan’s Web site,


Our approach to serving builders is different than typical businesses geared only to sell things to consumers. Our goal is to assist you on your path to becoming a more skilled aviator. The products we sell support this, but simply getting you to buy things is not what I am in aviation to accomplish.



This page is broken into the following sections:


1) Introduction

2) Engine and build options

3) installation components

4) Support for builders

5) Flying Panther and Cleanex info.

6) Builders in process

7) flight data and safety notes

8) who is WW?

9) Comments on dangerous trash.


At the end of each section there are links to supporting stories that have expanded information on concepts discussed in the section. Take your time and study it carefully.

I will be glad to answer further questions just email or call 904-529-0006. You can also check our two websites, , . The first is our ‘newspaper’ the second is our ‘library’ and ‘store.’ The links below are stories that already appear on these two sites, they are just arranged here to support this introduction to Corvair power for Panther and Cleanex builders. For installation components in section four, contact Dan and Rachel directly.


In the foreground above is Dan Weseman’s Wicked Cleanex. Off his wing, Chris Smith flies the Son Of Cleanex. The photo was taken over a bend in the St. Johns River in North Florida.


1) Introduction:

The Corvair has been flying 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.’  If that approach appeals to you, read on. There is a lot of material here, and it isn’t something you are going to absorb in one quick scan. Frankly, your engine selection deserves careful consideration, and it isn’t the kind of decision you should make based on a 4 page sales brochure.

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 their Zeniths 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.



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.

d) – A direct explanation of what makes my work different: 2011 Outlook & Philosophy

e) – A moving statement of philosophy: Sterling Hayden – Philosophy



Above, a 3,000 cc Corvair, The actual engine in the Panther Prototype.  The Corvair is an inherently simple engine, It’s opposed six configuration makes it the smoothest of available power plants. It has outstanding cooling because GM put a tremendous amount of cooling fins on it and  gave it a factory CHT redline of 575F. All of our engine parts are made in the United States, as are the airframe parts from SPA.


2) Engine and build options:


If you are new to Corvairs, lets quickly cover some ground: General  Motors made 1.8 million Corvairs. brand new parts, including billet cranks, forged pistons, valves bearings,  virtually every single part inside is currently made and readily available, and will remain so. Rebuildable Corvair engines are plentiful, and much easier to find that Lycomings or Continentals. We have been working with Corvairs for 25 years, and there is no shortage of core engines or parts. If you doubt this for a second, Google “Corvair engine parts.”

The Corvair makes an outstanding aircraft engine because it is a simple, compact, direct drive, horizontally opposed six cylinder, air cooled engine. It is robust, and ‘flat rated ‘ from it’s automotive output. The engine runs equally well on automotive fuel and 100LL, and it does not care about ethanol. In its 53 year flight history, more than 500 experimental aircraft have flown on Corvair power.

The engine can be built in three displacements with three respective power outputs. They are 2,700cc / 100HP, 2,850cc / 110HP and 3,000cc / 120HP. The two smaller displacements weigh 230 pounds, the larger actually weighs 8 pounds less because it uses lighter cylinders. All engines are completely rebuilt from very high quality parts before flight. They are not just removed from cars. The parts we use are specifically selected to convert the engine for the rigors of flight use. Forged pistons, Inconel valves, chrome rings, ARP rod bolts and many other components are upgraded in the rebuild.

To absorb the propeller and flight loads a “5th bearing” is added. It is a billet housing with a very large bearing from a V-8, bolted on the end of the case. The ignition is redundant and utilizes two 40,000 volt systems, one driven by digital electronics the size of a match book, the other by a traditional set of points. The engine is direct drive, it has no complex reduction unit. It makes good thrust because it has more than twice the cubic inches of a Rotax 912. All of the systems on the engine are intentionally patterned after those on Lycomings and Continentals, because they are the  model of success in proven aircraft power plants. People who do not acknowledge certified engines as excellent models of success are often just zealots.  To succeed in experimental aviation you need dispassionate information not emotional opinion.

One of the unique features of the Corvair is that it can be built at home, from our information and parts and a locally acquired rebuildable engine, or it can be purchased from us, test run with logs. 90% of current builders are building their own engine at home. Only 10% of the builders opt to have us build their engine. We have happy to serve both builders. In either case, Corvairs are the best match for builders who want to understand and be the master of their engine.

Because of the plans built vs production engine nature of the Corvair, there are large variations in how much builders budgets run. Below is a quick look at the differences. Keep in mind, these budgets are for first class, completely overhauled, zero timed engines with 5th bearings, starting, ignition and charging systems. We have clever builders who have built and flown engines for less than $3,000, but this not representative of main line builders. The numbers below are much better for Zenith builders to budget on.


2,700cc / 100HP typical homebuilders budget: $6,500- Same engine assembled and run from us $9,750

2,850cc / 110HP typical homebuilders budget: $7,500- Same engine assembled and run from us $10,750

3,000cc / 120HP typical homebuilders budget: $8,500- Same engine assembled and run from us $11,750


If you are attracted to the concept of building your own engine, but have not built motors before, Good.  About half of our builders have never built any kind of an engine before. Our main work is teaching people what we know and providing the parts to work with. Our system does not require anyone to be a machinist nor to have previous engine experience.

The procedure of building an engine in your shop follows this format:

1) Get a conversion manual and DVD’s from us, use them to find a rebuild able core engine locally. Disassemble this engine following the steps in the DVD.

2) Send the crank and heads to our approved facilities for rebuilding and modification. They come back ready to ‘bolt on.’ Other parts of the engine are cleaned and inspected. The parts to convert the engine are ordered from us, many of the standard rebuild parts like lifters and gaskets are available from local auto parts stores. We do not ‘middle man’ anything you can directly buy.

3) Assemble these parts according to the manual and DVDs. There is no machine work required, only basic tools are needed, and a few specialty tools like a torque wrench. Many builders attend our free Corvair Colleges and directly learn hands on skills. You can even bring your parts and assemble them under our supervision, and test run your engine on our equipment. College attendance is a plus, but not required. Our methods work without direct training; a good number of engines are built and flown each year by builders who have never met me in person.

4) The test run serves several purposes. We teach people to build one of  three specific models, and we teach them to use specific parts. Not only are these proven, but it also allows me to verify from a remote location that the engine was assembled correctly. A builder can report his static rpm, CHT, oil temp during the test run with his Warp Drive prop at the specified setting, and I can confirm the output and assembly of the engine without seeing it personally.

If you would like a sample of the information on working your way through the above four steps, get a look at this: Getting Started in 2013, part #1, Crankshaft process options.

We also have all of the ‘getting started’ series on a single page, at this link: Getting Started Reference page.

I have broken down building a Corvair and installing it on your airframe into 42 “groups”. Part #1 is about  ’Group 1000′ the crankshaft. If you would like to look at every part that goes into a Corvair, along with the conversion parts we sell, look at Groups 1000 -3300 at this link to our catalog:

If you would like to read above the value of proven engines, read: Why Not the Panther engine?

All builders get started with a conversion manual. The first part of the above link is about manuals and DVD’s.  The direct link to the manual is: almost all builders looking for a rebuild able engine also order the Disassembly  DVD, which covers core engine selection visually. The direct link to it is: We encourage everyone to get started with information, even if you are pretty sure you would like to purchase a production engine from us. If you eventually buy an engine from us, we directly reduce the price to rebate all the money you spent on manuals and DVD’s.



a) – Corvair Weight story: Corvair vs O-200…. weight comparison

b) –  Samples of our production engines:  2012 Corvair Engines For Sale: 100, 110 and 120 HP

c) – For an explanation of ‘flat rating’ and an engine build : Shop perspective: Mastery or ?

d) – A story about engines running on our hangar Dyno:

e) Engine of “Cleanex” builder: World’s Strongest 3,000cc Corvair, built by Greg Crouchley

f) A story about the evolution on 120HP Corvairs: 3,000 vs 3,100 cc Corvair engines.




Above, a 2009 photo from our workshop. I kneel in the workshop next to motor mount Number 100 for the 601 XL.  Most experimental aircraft companies, both large and small, fail because for two simple reasons; First, the ownership cannot physically make the product the sell, and second, their financial backers are unwilling to go several years before seeing the payoff.  Neither of these conditions are true about our business nor SPA/Panther. We are craftsman and homebuilders first, and neither of us has partners nor investors. Few people new to experimental aviation understand that this is key to company stability and longevity, not big size nor flashy promotion.


3) Installation Components for the Panther & “Cleanex”:


Normally we provide every part it takes to install a Corvair in your airframe.  The Panther and the Cleanex are different because Dan developed these specific installations himself.   It is important to understand that these installations work seamlessly with our engine components, and they are custom adaptations of systems that have long been proven to work very well.  In the case of the Sonex airframe, there have been a handful of other people who tried, with poor results, to put a Corvair on that airframe. If you have heard a poor report on a Corvair powered Sonex, it is important to understand not all Corvairs in these airframes are people following Dan’s proven path.

Here’s a 2004 view of the underside of the Cleanex’s motor mount. Dan designed this mount combining the basic geometry of the Sonex airframe’s landing gear attach points and our traditional Corvair bed mount. The structure is well thought out and perfectly triangulated. Although it looks heavy, it is not. It weighs 13.8 pounds, only four pounds heavier than the factory Jabbiru 3,300 mount. Dan’s mount has flown hundreds of aerobatic maneuvers. Dan’s motor mount page is here:


  Being air cooled and carbureted, The Corvair is one of the easiest engines to install. Many companies that are good at selling things are poor at teaching things, like how to install their products. Teaching is the very cornerstone of my work, I am a skilled writer, we run Corvair Colleges, and we have a simple engine. All this adds up to a comparatively easy engine to install. There is no need to rush it, but I can do it working in one long day.

 Installation part numbers are Groups 3400 through 4300 in the second half of our numbering system. Get a look at this link: It contains installation component lists for other Corvair powered airframes, but the list is very similar to the required items for Dan’s installations. The detail items on electrical and fuel systems are identical, and you can review the SPA website for the specific details on the Panther and Cleanex installation components. There are many good photos here:

For the Cleanex, Dan and Rachel offer their own Nose bowls, Cowls, Mounts, baffle kits, Exhausts and intake manifolds. While you are there, get a look at his 5th bearings, rear alternators and Billet Cranks. A sample of their parts page is here:

Dan and Rachel are just in the process of organizing the Panther/Corvair components like the mount, cowl, intake, exhaust and baffling.  You can check the Panther website for up to date information on these parts. If you would like to see the Panther engine runninga prop test, click on this link: Panther
Engine propeller test

Although the Panther is new, the systems are fully tested and well proven. It is important for builders to understand the engine test program went flawlessly because it used custom variations on proven systems. For example, the Panthers exhaust is made from the same materials and processes and uses similar design to the stainless systems we have made for other airframes for more than 10 years. The carburation, intake, cooling and spinner are also variations on long proven themes.

Many people new to building initially think that very economical engines like the Corvair must also be inexpensive to install. In reality, the cost of items like motor mounts and cowls are not affected by the cost of the engine they mount and house.  A mount for a $30K UL-350 and a $7K Corvair have about the same amount to tubing and welding time in them, and thus cost about the same. Most engines have installation kits with exhaust, cowl prop spinner etc, run from $3,000 to $6,000. The Corvair is near the bottom of this range, but the savings of using the Corvair is mostly in the engine, not the cost of installing it.

Above, Chris Smiths plan’e uncowled with Dan’s in the background. A ground run cooling shroud sits atop Chris’s engine. Dan stand on the edge of this 2007 photo I took in his hangar.


a) – For an example of 74 years of aircraft welding talent: Zenith 601/650 Motor mounts, P/N 4201(A) Both Vern and I are friends with Dan and assisted him with some of the welded parts that went into the Panther prototype. Dan is a skilled craftsman and a welder on par with us.

b) – To learn about the Stainless exhausts we make: Stainless Steel Exhaust Systems . These are identical in material and construction to the Panther and Cleanex stainless systems.

c) – Louis Kantor’s 601XL running for the first time in our front yard: The plane is one of more than a hundred  Corvair powered planes that utilize Dan’s 5th bearing. Dan used his Cleanex as the chase plane on this planes first flight.



Above, 2004 at Oshkosh: Next to our personal Corvair powered Zenith N-1777W, I explain our dual ignition arrangement two executives from Falcon insurance, The EAA’s provider. To offer real support, an alternative engine provider must be an effective advocate for his builders on many fronts, including meeting the requirements of underwriters. Just being an engine guru is not nearly enough. Corvair engines that follow our design,  including to ones assembled by builders, are fully insurable at the lowest rates, right from the first flight, because they have an outstanding safety record. Having good effective hands on support is a critical element in this outstanding record.


4) Support for Builders:


Builders selecting a Corvair for their Panther or Cleanex project have an advantage that is hard to overstate; Because Dan and I have been friends for more than 10 years, I am very familiar with both of his installations. I followed his Panther development from the first sketch through the flight test program. While the design can and will be flown on a broad variety of engines, it will be a long time before any other alternative engine provider understands the design and program as well I do.

Many new builders mistakenly believe that they can marry any engine they like to their chosen airframe. In reality, compatibility goes far beyond horsepower ratings and weights. To be successful, it is critical that the engine match the designers perspectives on reliability, risk management and ethics. Differences on these subjects create issues builders can rarely resolve themselves; conversely, having both support teams share the same perspective gives builders strong allies. In 25 years of working with homebuilts I have met many designers and innovators I respect, but my personal perspectives share more common ground with Dan’s than any other person I know in this industry. Please take a moment to read: Panther Roll out.


Beyond the basic engine and installation components, we offer many forms of support to Corvair builders. :


a) We have a flight operations manual with specific test flight plans and procedures: Dan wrote one of the chapters in this manual to share his experience with Corvair builders.


 b) We hold 4 free hands on technical seminars called “Corvair Colleges” every year.  For an introduction to Colleges, read this link:  An overview of upcoming colleges is at this link:  Upcoming events, Airshows and Colleges #26-28. If you would like to see video of a College, here is a link to Corvair College #17 Dan and Rachel attend many of the colleges and were our Co-hosts at Corvair College #23.


c) Woody Harris, subject of this story:  Zenith 601XL-2,850cc, Woody Harris Is our West Coast representative. Although we have held 5 Corvair Colleges in California,  we only make one trip to the west per year. Woody covers all the shows and events from Arlington to Copper State when we can’t be there.


e) I am the last guy in aviation who still makes free house calls. Over the years I have made more than 400 in person visits builders projects. I travel extensively, and go out of my way to include builders workshops on these trips.  These stops and the colleges allow me to really understand the needs, strengths and dreams of rank and file builders that no one can read in email or at an airshow. for a sample, read this story: Corvair House Call, Range: 335 miles.


f)  By my continued advocacy and industry relations, Corvairs have full insurance, at the lowest rates, available from a number of sources. If you would like to find out more Contact Bob Mackey, VP of Falcon insurance, The EAA’s designated provider, seen on the left in the photo above.


g) Over the years, we have built a very tight knit community of like minded builders. If you read this story about fools at our county airport: A visit to the insane asylum, and it sounds like your airport, and if your local EAA chapter is devoid of homebuilders and filled with negative people, you will find the Corvair movement to be a powerful antidote. Many Corvair builders catch several colleges a year, there they find positive, outgoing, energetic builders, effectively making the Colleges their “local EAA chapter” We have worked very hard to attract outstanding people interested in accomplishing their goals. I  go out of my way to encourage new builders but I am intolerant of people who are compulsively negative. I am willing to be a cheerleader, but not a therapist.



Above, Chris Smith’s Cleanex after painting. Chris was building a Sonex airframe from a kit and met Dan as Dan’s airplane neared completion. Chris opted to build a close copy of Dan’s aircraft. Although Chris had many years of flying experience, he had never built an aircraft before. Because of this, he wisely chose to follow Dan’s proven format closely. When Chris’ aircraft was done, it earned the nickname “Son of Cleanex.” It first flew at the end of 2006, and it served Chris through several hundred hours flying over the southeastern United States. Today the aircraft is owned by Ron Monson, who has put a great number of flying videos of it on You-tube.


5) Examples of flying Corvair powered Sonexes:



Above, The Cleanex of Dale Williams taxis out at Corvair Colle #27. Read more on the man and the plane here: New 3,000 cc Cleanex, Dale Williams, SC

Above, Cleanex by Chuck Custer, after flying to Corvair College #25. This aircraft is one of approximately 12 that have flown utilizing Dan’s installation.



Above, Clarence Dunkerley beside his 2850 cc Weseman bearing equipped powerplant destined for his Cleanex project. Sharp eyes will  notice that this is equipped with the Reverse Gold Oil Filter Housing which we developed specifically  for Corvairs going into Sonex airframes. Photo taken at Corvair College#21.


6) Examples of Builders working on this Combination:


Many experimental aircraft companies like to tout how many of their product has sold as a measure of  success. Sales numbers on only a measure of their success, not that of builders. The only number that counts are how many builders that make it all the way to flying and enjoying their creation. It is a fact of marketing that it is far easier to keep finding new buyers to spend money than it is to support the ones that already spent the money, all the way through flight.  This is why many aircraft companies have planned lifespans of only 48 months, so they make all the sales and fold up the tent before they have to do the real work of supporting builders.

We are very different.  I have been working with Corvair builders since 1989. I am in this for the long haul, and my measure of success is getting people flying. Likewise, Dan has been working with Corvairs since 2003, and has been offering parts like his 5th bearing design since 2006.  If you select a Corvair engine, we will be your allies in completing your plane, just as I have been for many others before you.

If your goal is to merely buy something, you need only find a salesman with an engine to sell. If your goal is to learn about, understand, build and fly your plane, you need an instructor-guide-mentor, an aviator not a salesman. Think it over: If your goal was to climb mount Everest, there would be plenty of people you could buy equipment from, but that isn’t the same thing as finding a Sherpa who has been to the top to act as your instructor and guide.  A big part of why experimental aircraft have a 20% completion rate is that most people purchasing a kit or an engine have not spent 3 minutes learning how to differentiate between a salesman and a guide.

Below are a sample of our builders, each of whom I am going to see all the way through their aircraft finished and flying:

Above, Cliff Rose, Cleanex builder from Florida, with his 2700 cc, Weseman bearing, Falcon head engine with Reverse Gold Oil System. Cliff  spared no expense to acquire all the parts of his engine. Still, he spent less than one third the cost of an imported engine. More importantly, he has the well earned  pride of creating his own engine. Photo taken at Corvair College #19.

Above, Aerospace engineer Paul Salter stands beside the Panther prototype. Paul is close friends with Dan and Rachel and has played a significant supporting role in the Panther introduction. He is building Panther beta airframe #2 for himself, and he is already collected most of the parts to assemble his own 3,000cc /120hp Corvair, which will be a direct clone of the Corvair in Dan’s prototype.

Above, Phil Maxson (Left) gets his airworthiness certificate for his 2700cc Corvair powered 601XL from legendary DAR Johnny Murphy, in our old Edgewater hangar in 2006. Today, Phil still flies and enjoys it, but is also well at work on Panther Production kit #1, which will be powered by a 3,000cc Corvair. We awarded Phil The Cherry Grove Trophy for 2013, as Corvair aviator of the year.


Above, Waiex builder Greg Crouchley stands beside me after the test run of his Corvair at our hangar in 2012. Although headed into a Waiex, Greg’s engine is essentially a clone of the Panther’s, including a Weseman billet crank. Read about the man and the engine at this link:World’s Strongest 3,000cc Corvair, built by Greg Crouchley 

If you would like to read a story about and see the film on a running 3,000cc Corvair for a Sonex built at a College, Click on this link: Corvair College #27 run on film. It is the engine of Amit Ganjoo, who is also the builder with the yellow bag over his head in the photo at the beginning of this story.




7) Operational Data for this combination:

Dan and Rachel’s website will be the primary source of performance data for Panther and Cleanex builders. Our website have a continuous flow of discussion on Corvair operations for all types of airframes. If you would like to read a story about detailed flight data collection on a 2,850cc 750, check out this link: CHT part #5, flight data from Zenith 750 . It is an example of the type of information exchanged between our builders.  If you are drawn to aviator’s groups made of intelligent thinking people, you will fit right in with Corvair builders.

Here is a visual example of testing: Panther Engine propeller test

And you can also read a story on operations here: Starting
procedures on Corvairs, 2,000 words of experience.
 Our .net website has more than 375 different stories on it, about 225 of them are purely technical posts with expanded operational information and experience.

I have long stated that I can teach a 12 year old how to assemble an engine, but what we are really trying to share with people is a knowledge base that will effectively allow them to master the engine and use it with good judgment, something a 12 year old (and some adults)  cannot do. If some of the articles that I write don’t initially sound like a set of instructions, consider for a moment that the message of the artice may be about the critical element of Judgment.

If you would like a single example to effectively demonstrate that I am an aviator not a salesman, it is the type of data that I discuss with builders. No salesmen will acknowledge accidents nor difficulties that involved their products, even circumstantially.

Conversely, I am here to teach people what they need to know. I have a long history of writing about subjects that salesmen wouldn’t touch with a 10 foot pole. I write about accidents and friends I have lost, honest mistakes people made and things you can learn from them.  Just about everything know in aviation cost someone dearly to learn. If you are unwilling to talk about these things in plain language, people are doomed to repeat them.


Risk Management, Judgement Error, money in the wrong place. is the story of our only fatal accident in a Corvair powered Zenith. (There is another below, but it was a different company) The NTSB pointed to an incorrectly assembled carb, but read the story and decide if judgment isn’t the root cause.

“If only someone had told him……” is a story about people who don’t listen. Guy A and Guy B were both Zenith 601 builders. Guy B was the passenger in the First 650 accident (AMD airframe- O-200 engine, ruled pilot error). Guy A was a well known and liked Zenith builder and flyer, who quit aviation after this incident.

Risk Management, Factor #1, Judgement. Covers how developing and exercising judgment is paramount to managing your own personal risk.

Risk Management, Experience vs Judgement. Ken Terry was a friend of mine and a huge influence on Grace’s flying, and her development as a pilot. The story is about how experience, even 40,000 hours of it is not a defense compared to exercising good judgment.


Dan Weseman and Dave Dollarhide having a good time at Sun n Fun 2013. They both are in the last story “Friday night” in the link “Three aviation stories”.


 Three Aviation Stories  covers my personal perspective on risk, and what level is worth managing, and how aviators come do deal with this. It speaks of meeting Al Haynes at two points in my life, 14 years and a world of experience apart. It also covers how several members of our EAA chapter each looked at loosing two friends.



Above, A photo taken at Sun n Fun 2006. My wife Grace Ellen and myself, in front of the first Corvair powered Zenith, our own N-1777W. The plane was the first XL model with conventional gear.  Grace is a skilled pilot in her own right. She has been a pilot longer than I have, holds more advanced ratings and owns two aircraft. As a point of ethics, we do not promote, advocate nor sell things we have not personally flown behind.


8) Who is William Wynne?

Modern consumer sales logic dictates that that business should ‘de-personalize’ themselves so consumers find nothing objectionable about the provider while they are spending money.  That model may work elsewhere, and even have advocates experimental aviation, but I don’t buy it.  I contend that Aviation is a different arena, and who you are dealing with, and their ethics, experience and perspective matters.

Building a plane or an engine is a marriage of sorts between the builder and his airframe or engine company. I believe that it is best if everyone goes into it well informed with their eyes wide open. I am always surprised how few people even Google the name of a person they are thinking of working with. You don’t need to see eye to eye with them on every point nor even love them, but the relationship must absolutely have trust and respect operating in both directions. In 25 years I have seen many builders try to justify buying a product from a provider they didn’t really trust. It never works out. It doesn’t matter how good it looks, what it costs or how great it is supposed to work, if it is from a bad guy, it isn’t worth buying.

I could write a quick paragraph about how I am a pilot, a 22 year A&P mechanic, and that I hold both an AS degree in Maintenance and a BS in Professional Aeronautics (accident investigation) From the worlds #1 aeronautical university, Embry-Riddle , but I don’t think that any of that explains my commitment to builders nearly as well as the flying planes of our builders and things we have accomplished. Henry Ford said “A man can not base his reputation on what he says he will do; only what he has done.”

I am plain spoken. to understand why, read the ‘Effective Risk Management’ story below. I have many friends who are experienced aviators who value plain talk. This type of speech also tends to offend people who dabble in aviation and would rather read polite things that align with their pet opinions. I am in aviation to share experience builders need to know, not say things people want to hear. Below are a selection of stories, some humorous, but all with a point, that give people a better understanding of who I am. From there you can decide if you choose to work with me as your engine mentor.


a) Fixing America is going to cost each of us $1.69

b) Greatest Book on Flying Ever Written, (Is your life worth $16?)

c) In defense of plain speaking……

d) Turtles and Cell Phones, 6/24/13.

e) A thought on Easter….

f) Happy Father’s Day William E. Wynne Sr.

g) Effective Risk Management – 2,903 words




9) Notes on trash:

Not all things called a Corvair represent my work or designs. Over the years, our success and willingness to share information has brought out a number of short lived companies that were run by rip off artists, and mentally ill people. Particularly, there have been four businesses that made poor copies of our parts or untested garbage. All of these are bankrupt today. Today, I have just heard that another is coming back with a new name. The story will never end as long as people don’t do their home work or believe that they are getting a bargain. You can read about one of these companies at this link: Cloudn’t have happened to a nicer guy……

I warn people all the time not to buy things from these people, or to buy this stuff at the flymart. For examples of things no one should have bought, look at this story: Built by William Wynne? Built according to The Manual?

Let me be absolutely clear, that I will be polite to people, but I will not work on, offer advice on, or help with products made by bankrupt people that I considered vermin.  Nor will I allow these people to attend any of the Colleges. This isn’t out of spite, it is to protect these builders lives. They all want to put a band aid on their bad purchase and make it “good enough to fly.” A band aid isn’t going to do it, an amputation is in order. People who blew $12K on junk don’t want to hear this, they are still looking for a cheap out that doesn’t exist.  I will not assist them in the delusion that they have found one.

On line discussion groups and websites have a small number of old posts from people who bought trash like this for their projects. If you look closely, these people offered great testimonials, but later abandoned their builds. Look at the dates on many of these posts and then compare them to FAA aircraft registrations on  From looking at our sites you can see photos of dozens and dozens real builders with real names and flying planes. I encourage builders to do their home work; our track record will speak for itself. -ww.


One hour, four years ago.


Four years ago today I wrote a story about a single hour that had passed the day before at our airport. Most hours go by in your life with little or no memory, others stay with you vividly. I would remember this hour well, even if I had not written it down in the story.

It was widely read at the time. I initially wrote it on Mark Langford’s discussion list, just as a set of notes in the middle of a long night of insomnia, but it was eventually circulated in email and printed in a magazine. It has an element in it that moves some aviators. At places like Oshkosh people will mention it to me, even years later. People ask sometimes if the characters in the story were ‘real’. I tell them they were not characters, they are people. I share stories, but I don’t write fiction. When you are immersed in aviation, you don’t need to, just recording observations on reality is enough.

Today, 4 years later, a handful of photos of the people from the story.  I consider myself lucky to know them.  I am 50 now, and have spent 25 years in aviation, literally half my life. It is enough experience to say that the humans you meet at airports can be a lot more alive than the people you meet on the street.

All my life I have been plagued by the feeling that time passes too quickly. Although we have done a lot in the last four years, it isn’t enough, and the thought that the hours and days got away bothers me. Yet, one hour, four years ago, will never slip from my grasp. I get to keep it, and herein lies the secret of my happiness: fill the hours with quality and they will not get away. I can not remember what I ate for breakfast yesterday, but I can remember that the tug boat captains shirt was blue and he waved a white hat as we passed 100 feet above the Tennessee river in our Pietenpol on the way to Oshkosh 2000.

The full story “Friday night” is reprinted below. It’s subject is somber on the surface , but the story in it really isn’t.  It is just about being alive and how you can really feel it some hours more than others. -ww


Above, Dan Weseman and Dave Dollarhide at Sun n Fun 2013. They are both in the story “Friday Night.” Dave is fairly well known in Naval Aviation circles because of a short film clip of a young pilot escaping from an A-4 in the USS Forrestal inferno. In one of those stories that only happens in aviation, Dave is now flying one of the very few remaining airworthy A-4’s… 45 years later.


Above is Dave’s RV-4. I shot this photo from the RV-7 of Pat Lee, another person in “Friday Night”  when we departed St. Augustine airport. Off our other wing was the RV-4 of Bob Woolley (who is now building Panther #2). In the story he is “Bob from the north end.”

The buildings in the photo are Northrup-Grumman; the road is U.S. 1. St. Augustine is on the coast, about 20 miles east of our grass airstrip.


Above, Dan Weseman flying “The Wicked Cleanex” in the foreground. This is the aircraft that Dan is flying in the story. Off his wing is Chris Smith in “The Son of Cleanex.” The location is a bend in the St John’s river a few miles from our airstrip. The site of the Glassair accident was on the far bank of the river, visible in the upper right as a peninsula. This photo was taken in 2007, a year before the accident.


Friday Night, November 20, 2009

Just as I am getting used to Daylight Savings stealing an hour of the  evening, the days are getting noticeably shorter here. During the week, our  clock revolves around 4 p.m. This is last call to drive the ten miles into town to  the Post Office with the days mailings. In the summer there are hours after this  to eat dinner, mess around in the shop, and casually pre-flight the Taylorcraft  before going aloft for the last hour of light. But now the casual hours are  gone. I drove back to the airport with an eye on the low angle of the sun, maybe  only 50 minutes until it sank.

I pushed the plane out to the edge of the runway. I stood there for a  minute, not a single person was in sight. Just the sound of a circular saw from  somewhere up on the North end of the field. The visibility was poor, there would  be little to see, but I had been out the past 6 days in a row and today would  make a week. Kind of a pointless exercise, going up for 20 minutes to round out  a week, frivolous really.  These are the things you think of on the ground,  by the time I am running through the mag check the pros and cons of going  aloft are forgotten. I orbit the airport in big slow circles at 70  mph, engine at 1700 rpm, just licking over. It all looks gray and  colorless. Was it noticeably greener a week ago or is it just the  haze setting the mood?

When I touch down, the landing gives me the  same feeling as finishing a chapter in a captivating book: Looking up  from the last page with the powerful feeling that you have just been  somewhere else. Taxing up to the house and shutting off the engine I  have the same sensation.

Three or four minutes later, our EAA chapter president returns from being away all afternoon. A 180 mph pass at 10 feet  signals the arrival of his RV-7. As he flies the landing pattern, I walk  the 400 feet up to his hangar. We arrive at the same time. He has an unexpected  passenger, Dave, our airpark president. Dave has his own RV-4, and I have never  seen him as a passenger in any plane. In his youth he flew an A-4 from the  USS Forestal into the most fiercely defended airspace on the planet. The black and  white photos of him in his hangar are of a much younger man in a flightsuit  with a helmet under his arm. He has the same grin today, but you get the  impression that big chunk of Dave’s youth, and a good number of his friends, only  exist in his memory after 1967. Either way, he looks really out of place in the  right seat, or in any side by side aircraft for that matter.

The moment fits the gray haze: Pat and Dave have just returned after  delivering the RV-9 of a fellow EAA member.  This man has also taken up  residence in Dave’s memory. He was killed this summer, along with another friend,  in an unexplained Glasair crash. One moment they were flying a low pass over our  airport, a little dog leg to say hello on their way home. The next day  Pat found the wreckage in the woods a few miles away. They delivered  the RV-9 to the man’s widow, who was very thankful. The plane was just  finished, and it is magnificent. She is keeping it in storage until next Oshkosh.  The man was an EAA member for 30 years, known in some circles. She would like it  judged posthumously. She had said some moving things to Pat and Dave, but at the  moment we were standing out on their ramp with the sun fading, neither of them  felt up to relating her exact words.

Dave started a sentence twice, but after  a pause he didn’t finish.  Pat spoke about a guy he knew in flight school,  lived 3 doors down, a Marine. Pat heard about his crash on the news, and walked  out his front door in disbelief. Seeing the black cars gathered down the block  took away the doubt and hope at the same time.

An engine starts at the far south end of the runway. It is Dan Weseman and  the Cleanex. After a minute of run up, he roars past us, 50 feet at midfield.  Dave looks at Pat and says “Let’s get him.” The RV-7 turned around and back on  the grass in seconds. Dave pushes out his RV-4. Their take off alerts the  airport, and several people drift out of their hangars to sit on the grass and  watch.

 If flying at most airports is an elegant ballet, flying at our airport is  Mixed Martial Arts. The furball is formed, broken and formed again over our  heads at 1500′. Between the sounds of wide open engines, the radio  chatter barks out from the base station in Alan’s hangar. In minutes they  are joined by Bob in an RV-4 from the North end, and then another  RV-7. In the sky they turn impossibly tight. You can’t always make out who is on  top, or even who is who, until a glint of the sunset differentiates a painted  wing from a polished one. It is hard to believe that the same airport was dead  silent 20 minutes ago.

One by one, they drop out and land. Pat is first, and has most of a beer  finished as Dave rolls up. Bob is the last to break off, leaving it where it  started, with Dan alone in the sky doing a few last slow rolls. The mood is transformed. It was 10 minutes of really being alive. Dan landed, rolled  out in front of us, turned a smooth 180 and taxied back towards his hangar, his  home, his family. He was close enough for us to see his expression, but he didn’t look  over. In the air, he had been far closer to the other pilots. The light is gone  now, and the day is over.

A few more words, and the hangar doors are shut, and people drift away.  Walking back to my place, I pause in the dark to watch Dave walk out to his  pickup. He had been the one to say “Let’s get him.”  This had been Dave’s  doing, perhaps his ritual. A little farewell to a man whose memory had just been  carefully and lovingly wrapped up for safe keeping. It was now stored beside the  others. A resident, final age 58, joining a group of younger men, some  of whom arrived 42 years ago. Although I’m sure he cherishes them all,  he probably doesn’t visit with them often. Dave is too full of life for much of  that. Besides, one day he will have all the time in the world to spend with  them.

William  Wynne, 2009

Getting Started Reference page


Below are links you can click on in sequence that follow through a detailed series I wrote on Getting Started in Corvair building. They are detailed and long, but successful builders tend to spend the time to learn and make better choices. I wonder about people who decide to buy an engine or a plane of any kind after reading a 4 page sales brochure with less than 200 words on it. Hardly due diligence in a ‘flyer beware’ marketplace. If you would like to start with a simple three page spec sheet on the engine, read this link first: Basic Corvair information

Conversely, we offer a very detailed picture of exactly what Corvairs are about, what you can learn and achieve by building one, and the infinite ways you can build one that will conform to you needs, goals, skills, timeline and budget. The Corvair can be made to fit your project, you don’t have to rearrange your plans and budget to serve the company that is selling you an engine. Sounds funny when you put it that way, but that is just what most people do.

I could drive myself to madness by concerning myself with what the masses will or might do. In experimental aviation you don’t have to be concerned with what ‘most’ people are buying or doing (unless your goal is to be like everyone else rather that being yourself), you need only find the right path for you. Corvairs are not for everyone. The strongest appeal are to homebuilders with traditional goals of Learning, building and flying. Many people interested in experimental aviation today have short attention spans and shallow goals. They want to posses skills but are unwilling to learn; They want to have things but are unwilling to make them; they are unable to differentiate between going for a ride in a plane and being an Aviator.

If you want to learn, I have long proven I have things to teach; if you wish to build and be the master of your engine, we have a proven path; If you long to find your place among real aviators, we have a home for you. You do not need any prior experience, just a willingness to learn and a positive attitude. In 24 years we have shared our experience with hundreds of builders. If your goals match our strengths, we will be glad to work with you. -ww.

Getting Started in 2013, part #1, Crankshaft process options.

Getting Started in 2013, Part #2, Group numbering system

Getting Started in 2013, Part #3, The Camshaft Group (1100)

Getting Started in 2013, Part #4, Case Group (1200)

Getting Started in 2013, Part #5, ‘Allan Able’ short block.

Getting Started in 2013, Part #6, ‘Bob Baker’ short block

Getting Started in 2013, Part #7, ‘Chas. Charlie’ Short Block

Getting Started in 2013, Part #8, ‘Davie Dog’ Short Block

Getting Started in 2013, Part #9, ‘Eddie Easy’ short block.

Getting Started in 2013, Part #10, Piston and Cylinder options.

Getting started in 2013, Part #11, Comment of the day

Getting Started in 2013, Part #12, Piston Choices

Getting Started in 2013, Part #13, Basic piston/rod/cylinder combo.

Getting Started in 2013, Part #14, 2,850 cc piston/rod/cyl. Kits

Getting Started in 2013, Part #15, 2,775cc, (imaginary piston)

Getting Started in 2013, Part #16, 3,000 cc Piston/cylinder kits

Getting Started in 2013, Part #17, Short block cost chart.

Getting Started in 2013, Part #18, A look ahead

Getting Started in 2013, Part #19, Cylinder Heads

New Numbering System, Final, please print.

Corvair College #27 run on film


“Cleanex” (Corvair-Sonex) builder Amit Ganjoo sent us a you tube link of his 3,000cc/ Dan bearing engine running on our stand at CC#27:

Amit started his assembly at CC#24, also in Barnwell, one year before. He went home and finished the assembly, and later returned to CC#25 in Florida to observe/socialize (popular with completed engine guys and flyers). For CC#27, Amit decided that he would rather do his break in run on the stand than his airframe. His aircraft is complete except some small wiring, but it was a simple matter to pull the engine in an hour and pack it up for the 400 mile ride to CC#27.

The engine ran beautifully. The film shows the actual first start. Even after a few decades of doing this and several hundred engines, I still like watching a number of cold metal parts in close formation that have never run together start and run smoothly in 2 seconds of cranking.

Note that the engine is not primed other than the accelerator pump in the carb, and it is starting on the points side of the distributor. So much for the arm chair engineers still speculating that long intake tracts somehow don’t work.  They will still be speaking about that when Amit is out flying the plane and engine he made with his own hands.

Amit is many things, from skilled IT guy through devoted family man, but a year ago “Motorhead” was not on his résumé.  Often, when you learn a lot of information, but it comes in sequential bite sized chunks, as building a Corvair does, you loose perspective of how much you have learned. Often builders are given a new overview of their learning and achievement at the moment of first run. A moment well spent in the company of other ‘traditional homebuilders’ at a Corvair College. -ww

On the Way to Corvair College #27


We are in the last 12 hours of prep before we head to CC#27. We will be driving away on Thursday, arriving at Barnwell in the evening for the College start on Friday morning.  Our plan is to work through Sunday at the College and return by way of a short visit to my sister’s place in Charleston. We should be back and working in the shop on Wednesday the 13th.  We will be very busy and I doubt we will have a chance to cover anything in email, and I can not pick up the phone messages until our return.

After Barnwell, the work season slows a lot with people getting focused on Family and Holidays. We have many more hours for longer calls and more detailed email communication from November 15 through Feb 15. It just works out this way every year. If you have an email or a phone call into us, I will be glad to cover it upon our return.-ww.


Above, how colleges make you feel: Delton Perry at the first run of his engine at Barnwell, CC#21.