First Flight Resources to review


I got a short note from a Pietenpol builder, saying he just got the FAA sign off, and will be taking his first flight after a few details are taken care of. It brings up a few things everyone should have in mind at that point. While a general review of this page is in order:  Engine Operations reference page, and everyone needs to have read the flight test plan in the ops manual: , I have listed several things below that builders need to have at the forefront of their actions.


The number one rule of first flights in anything, but particularly any alternative engine, is the “Two Minute Test.”

Understanding Flying Corvairs Pt. #5, Two Minute Test


It should be an indication of how important setting the timing is by the number of stories I have written about it. 20% of the people doing a first flight have never set the timing on their engine. Do not be one of them, the results are not pretty.


When to check your timing, Lessons learned Pt#2

Ignition Timing on Corvairs

Ignition timing on Corvairs, Part 2





Above, a 2007 picture of the homebuilt of Ken Lien of WA state. The following year, he was killed on the very first flight. You can read the story I wrote a long time later here: Risk Management, Judgement Error, money in the wrong place.  THIS ACCIDENT WOULD NEVER HAVE HAPPENED IF HE RAN A TWO MINUTE TEST. This is not a one of a kind accident, we had two planes wrecked on their first flight in 2015 by pilots who didn’t bother to run a two minute test.


By an absolute coincidence, a life long best friend of Ken’s, named Denny Jackson became my neighbor at our airport in FL just after the accident. Denny was deeply hurt by his friend’s death, and finding out that I was the ‘Corvair guy’ lead to him angrily confronting me at our EAA chapter. He was 6’5″ and 325 pounds and not to be trifled with. Because I was part of the investigation, I already knew what Denny did not: It was caused by his friend putting his carb together incorrectly, it had nothing to do with Corvair engines, yet I could not say this to him, I could only ask that he withhold judgment. Months later, Denny understood the report, came and explained that he was just hurt at the loss of his friend. I told him I might have done the same thing.

Read more here: Comments on aircraft accidents.




Thought for the day: Choosing to be alive ““If the goal of the captain was to preserve the ship, he would never leave port. Most people never do. The goal of the captain is to seek adventure, to meet all the challenges and still achieve the goals, to be In The Arena, not rusting at the pier in the safe harbor.”-ww.



Air / Fuel ratios on Corvair carbs.


Here are some short notes on the topic of carbs.  It is my hope that builders will read and think about them, consider the logic before jumping up to debate. The Comments are based on 25 years as a working aircraft mechanic and working with Corvairs since 1989. These comments are not based on a single planes experience, but take into account all types of testing, education, and practical experience.


How Rich is right?  Recently, a builder has told people that correctly running aircraft carbs on Corvairs need to have black sooty tail pipes.  I can flatly state that this is way too rich, and there are a number of very good reasons why you should not fly a carb running that rich.


As a logical base line for what exhausts should look like, perhaps we can all agree that an Exhaust of Certified plane, running 100LL fuel, with a correctly running engine, with by the book performance, a Certified aircraft carb running without adjustment for more than 20 years. is a standard we should use. This engine has never fouled a plug in 17 years, has never harmed the engine in any way. Notice that the inside of the exhaust pipe has a dusty light gray color, and that new paper towel was vigorously wiped on the inside of the pipe, and only produced that light stain between my thumb and the exhaust pipe. This is the correct color and soot content for any Corvair running an aircraft carb.  I know this from working with countless flying Corvair powered planes over the years.


Why not black and sooty? A correctly running aircraft carb on an air cooled engine will have an air/fuel ratio of about 12:1 in normal cruise. This will automatically go richer, to some thing like 10.5:1 at wide open throttle, and in low power cruise at altitude, it can be leaned to 14:1 for maximum efficiency.  Any engine that is making black soot in the exhaust and can be seen to visibly smoke at 1,000 rpm is running an air/fuel ratio of 9:1 or so. I know this not just from books, and working on certified planes, but from directly reading a laboratory grade A/F meter while running an EFI Corvair on my dyno in 2007:


Above, An exhaust evaluation as part of an Electronic Fuel injection test on a 2,700cc Corvair in 2007. It is shown running at power on my dyno. With this arrangement, a simple twist of a knob on the computer produced any A/F ratio you wanted to test. This is how I can say what A/F ratio produces visible smoke on a Corvair, and it is part of how I can speak about it’s relationship with power output.


At any airport with a density altitude less than 3,000 feet, your Corvair should run perfectly smoothly and make good power with the mixture set full rich, just like any Cessna 150 with the same carb will do.  One of the reasons why I use MA3-SPA carbs is so they have the exact same ‘normal’ operation as any certified plane I have flown, and if the carb doesn’t work like it does on a Cessna or a piper, don’t fly it, period.




A builder with an MA3-SPA carb reciently said his engine only ran correctly with the mixture pulled half way out. He was considering actually doing his first flight in that condition. His home airport elevation is only 516 feet. If I went to his airport, and got in a Cessna 150 and it took pulling the mixture out half way to run correctly, You could only make me fly that plane with a gun to my head. Something is wrong with it, and sane people do not fly planes with things wrong with them. It doesn’t suddenly become “O.K.” because the carb is now on an experimental. Wrong is wrong, time to correct the issue, not to find some condition where it kind of works for the first flight.


Any guy who would consider flying a plane in that condition, has missed the point of this story: Risk Management, Judgement Error, money in the wrong place. Where Ken Lien was killed on the very first flight of his plane because he didn’t bother to correctly assemble the mixture control on his plane and it moved to idle cut off on its own. If you are in a plane, getting ready for the first flight, and the mixture has to be pulled half way out to run, please explain to me how you know that this isn’t the first sign that the mixture is assembled incorrectly.  You wouldn’t, and there is a significant chance the engine will quit.  People who want to die should step in front of busses, not fly planes that are not set correctly, as using a plane and poor judgment to end ones life only unfairly punishes those of us who practice intelligent flying.




If the mixture was half way out on the first flight, and the new pilot had to do a go around on the first approach, most pilots would instinctively push the throttle, carb heat and mixture to the firewall.  This works, and it is the correct procedure. However if the pilot is tolerating a plane that must have the mixture half way out, when he does this, the engine will quit, he will overshoot the runway, and smash up the plane on the over run. All the local experts will then say “The Corvair quit, I told him not to use a car engine, he should have used an O-200” Neatly ignoring the fact that it is the same carb as the O-200, and it would have done the exact same thing.  If instead, the same pilot stepped in front of a bus, preferably while holding the hand of the ‘Expert’ who tells everyone not to use car engines, aviation would benefit, and the rest of us would come out ahead. Cold, but you know it is true.




Engines running black soot are wasting fuel, prone to fowling plugs, can damage the cylinder walls, and will have excessive carbon build up. On the other hand……..wait, there is no upside.




Anyone who says that an MA3-SPA needs to be jetted differently for different displacement Corvair engines is wrong. Think of how many different engines have run on my test stand, all with the same, untouched in 15 years, MA3-SPA. Note that I have the mixture set full rich on the stand, and it runs cleanly on all engines. And yes, my stand has both EGT and O2 sensors. Beyond this, Dan Weseman and I recently took his 3,000 cc and 3,300 cc Corvairs to one of Florida’s most respected dyno shops and ran them both is a day long session.  What carb did we use? Why the same one off my run stand. It ran perfectly on both motors and the shops very elaborate instrumentation showed that the air/fuel ratio stayed correct through out the power range on both engines, without any kind of adjustment. Aircraft carbs work like that.




Would you like to know how aircraft carbs are supposed to be operated? Read this story: Cylinder Head Temperature measurement and learn what a Lycoming Operations Manual is.  Down load it, print it, read it and know it. This is what successful people will do.


Conversely, You could get advice from a guy who is neither an pilot nor an A&P, who has never owned nor flown a plane with a mixture control, teamed up with a guy who has never seen a Corvair turn a prop in person, and another guy who damaged his engine by using a carb no one ever head of so he could save some bucks. Take your pick, but if someone doesn’t like the concept of listening to the professionals and people with experience, again, I am going to suggest that bus thing again, I know it sounds mean spirited, but people willfully doing dumb things shouldn’t even be called ‘accidents’ because they are not really. an accident is someone trying to do the right thing. Willfully choosing not to do the right thing is not an accident.



This ends the technical part of this story.  No valid technical information follows.



I am not listening to William Wynne because:


One: He sounds arrogant, and although I have never met him, and he wrote stories about people he loved: Risk Management reference page in hopes that others could avoid being hurt, I still say he is a jerk because I found two sentences in the 855 stories that are on this site that offended me, and I refuse to learn anything from him since.


Two: I own a Prius, and he is always mocking people who own Priuses, and I can tell he isn’t kidding, and he feels superior about this, which is stupid because as a Prius owner I alone have a right to feel superior to all other car owners because I know the best way to protest the use of fossil fuels is to buy a car that you can feel superior about.


Three: When I was in his tent at Oshkosh pontificating about how America has been ruined because no one follows the Ten Commandments anymore, he asked me to name them, and I couldn’t. The year before I said the problem with America was no one followed the Constitution, and he asked me how many articles it had and I said 10, and he said “guess again, you are off by three” , and I guessed 13.  I don’t get the connection that I should read more before being sure I am right.  I never listen to people with long hair, even though William has essentially the haircut as Jesus and everyone at the Constitutional Convention of 1787.


Four: I don’t listen to people who sell things, because they are trying to make money off me. I only listen to people on the net who’s opinion about how to do things can’t get them a job doing it, nor is it apparently worth money to anyone. Those are the people I trust.  Yes, I know that I should trust William because he has a vested interest in my success even if he actually likes me or not, But I would rather trust people I have never met, who write in nicer tones, who I have a simplistic childish belief are motivated to tell me the truth, unstained by their limited experience, personal bias, and ego.




If anyone read the above for points and didn’t find them funny, you probably have good taste, and I remind you I am a mechanic, not a comedian. I have a small but consistent group of people, most who have never met me, who remain quite sure that I have a “Condescending tone” and a “Giant ego”.  Before anyone is temped to say those things, I ask that they read the two paragraphs below, which appear both on my website and in every manual we print, and please share with me how this isn’t adequately honest and frank:


“If you have never met me, but read this and think that I am charmed with myself, you got it all wrong. I know countless humans who are better people than I. They are kinder, smarter, and harder working. I can’t sing nor dance, I learn slowly, and I can’t stand to hear my recorded voice nor see my image on film. If I was once handsome, all trace of it is gone along with my uncorrected eyesight. I can be a conversational bore, and I deeply wish I had given my parents more moments to be proud of me. At 50 I look back on my life with a very critical eye and stand on the far side of a very wide gulf from the heroes of my youth. Even our dog, impeccably honest and loyal as canines are, Loves Grace and only tolerates me.

Honest evaluation leads to harsh thoughts like this. I spend a lot of time alone and have long bouts of insomnia, which can lead to thinking about things excessively. But the secret I would like to share with anyone who at times feels the same way, is that I have a sanctuary where I am insulated from much of my self-criticism, and a have a front, where at 50, I am much better on than I thought possible in my youth. When I am building things with my hands in my shop, I rarely feel poor. Although I now need glasses to do any close work, and my hands have lost a lot of dexterity, I am a far better craftsman than I ever was in my youth. I am not a great craftsman, but over a very long time I have worked to develop these elements in my life, and I compete with no one except who I was last year. While all else fades, these things flourish. It is a gift I am most thankful for.”




Ignition timing on Corvairs, Part 2


Eighteen months ago I wrote a comprehensive story on ignition advance and timing on Corvair flight engines. I consider the story one of the most important and fundamental elements of mastering your Corvair. If you have not seen it in a while, or you have joined up since then, I suggest making 15 minutes in your schedule to read this and give it your full attention. The story is here: Ignition Timing on Corvairs.


I use the term “suggest” above because I am my brother’s keeper, but not his jailer. I care about people, but I can only appeal to their willingness to learn and do a good job, their ethical responsibility as an airman to take risk management seriously. I can not force anyone to do anything with their own property. If you would like a real world example of this, we have this story from last year: Understanding Flying Corvairs Pt. #6, 98% DNA not enough. In it you can read about a person who destroyed his plane on it’s first ‘flight’,  severely injuring himself and a passenger, simply because he didn’t care to understand timing, long refused to buy a timing light, and refused to stop what he was doing when I warned him.


For Part 2 , a slight update: On the internet, there is a suggestion being made by a non-pilot, that fliers using Corvairs should only use 24 degrees total of ignition advance on their planes, because this will allegedly make the same power as using the full advance we recommend. After 25 years of doing this, building several hundred Corvair flight engines, countless tests and having spent 5 years of my life at Embry-Riddle, I an assure builders that they should simply follow my timing recommendations for best results. To offer some further ‘why’ to expand the understanding.


Ignition advance isn’t magic, it is Chemistry in action, particularly a branch of study in it called ‘rate of reaction.’ While I am not a Chemical Engineer, I was fortunate enough to have a number of classes with Dr. D. Cameron at Embry-Riddle, and he was an outstanding professor who really understood and could teach the physical properties of this branch, and he also knew internal combustion engines very well. This doesn’t make me an expert, but compared to a guy who slept through 9th grade Chem class, I am Alfred Nobel on the topic.


How long it takes to burn the air and fuel in the cylinder, and thus how much ignition advance the engine needs, is a rate of reaction problem. Combustion dynamics in a real running engine are very complex, driven by the fact that once the combustion starts, the reaction itself is changing the dynamics of remaining unburned fuel and air. This acknowledged, the principles still apply, and they can be seen in action and tested easily for their proportion and effect.


I could list 10 factors playing a role, but let’s look at just two of the ones that make using too little ignition advance an issue:


The lower the pressure in the cylinder, the more advance it will need to make full power: Rate of combustion is greatly affected by the pressure in the cylinder when the spark happens. Three factors on this are the compression ratio, how wide the throttle is open, and what is the atmospheric pressure outside. While a max power test on a high compression engine, at sea level with the throttle wide open, may show OK results with less advance, That isn’t how planes go flying. Lower the compression to what most builders are using, understand that much of flying is cruising at part throttle, and the critical item a car mechanic never sees, the reduction of atmospheric pressure as the plane climbs, all call for more ignition advance for the engine to make best power and run efficiently.

The lower the starting temperature (given the same density)  the more advance it will need to make full power: While cold dense air burns fairly quick, cold thin air does not, and it needs more ignition advance to run efficiently. Again, this is a common factor to planes that few car mechanics consider. As a plane climbs it will do much better with even a slight increase in timing. Many people know that Klaus Savier’s Vari-eze is one of the most efficient homebuilts ever made, particularly in any contest where he can get some time at altitude, and he primarily credits his ignition that has far greater total timing than the magneto it replaces.


There are plenty of myths about aircraft timing. I have people tell me every year that “aircraft engines all have 25 degrees advance” Really? evidently this people missed all the manufactures data working A&P mechanics use. Look at this Mandatory Service Bulletin from Continental:  Notice how the A-65’s all use 30 degrees of advance on both mags. People tell hangar stories about ‘the big bore of aircraft engines needing two plugs’ ignoring the idea that an O-200 continental’s piston is just 5/16″ larger in diameter than the one in a 3,000cc Corvair. The internet theories are endless, but mostly based on things easily disproven on inspection.


Limited timing does appear on some other engines, like Jabarus and some VW’s, but this is driven by the mechanical design of those ignitions. Such engine are not noted for easy starting nor high altitude efficiency. Some people tout that Continental reduced the timing on O-200’s years ago, but his was actually driven by pilots using auto fuel that didn’t meet the STC requirements, and doing damage to the cylinder mounting studs on certain models. Car mechanics don’t know this, but ask anyone who flew a 150 before and after the timing reduction, and they will tell you the 4 degrees Continental ‘dumbed down’ the engine made a power difference.


On it’s face, saying the Corvair makes full power at 24 degrees doesn’t make sense. What would GM, the original manufacturer use far more advance than this if that was all it took to make full power? Even the most torque oriented Corvair engine, the 95hp model, which had a peak torque at just 2,400 rpm and made it’s full rated power at 3,600, arguably closest to the flight engines we build, used 32 degrees of total advance (with the vacuum advance disconnected). If the engine made full power with 24 degrees, GM would have made them that way.


The only possible motivation for a car mechanic to recommend using less ignition advance is if he is concerned about an engine having been assembled with substandard parts, like Chinese valves, and he is trying to convince people to lower the power output to protect the cheap parts. This also applies to telling people the engine can not fly with cht’s that touch the 400’s like this: CHT info taken from test flight of 601XL  Many of the issues where builders have been told they hurt their engine by running it to hot and be re-evaluated. There have been plenty of builders who made poor cowling choices who damaged engines, but we have positive evidence and factual data that shows the Corvair can run the CHT at my recommendations, provided of course, it doesn’t have sub standard valves in it.



Above, a closer look at an E/P distributor in my distributor machine ( circa 2008). The machine has a large electric motor inside that spins the distributor. I have made hundred’s of Corvair ignition systems over the years.


From  Ignition Timing on Corvairs :

“If a builder reads and follows the directions, he has mastered level 1). If he reads, considers and understand this story, he has moved his understanding up to level 2). Does he need to know more than this to effectively use the engine? No, but if he would like to know far more, it is one of the things I have a good understanding of in engines. This did not come from years of being a mechanic. The further understanding came from a number of years in Engineering classes at Embry-Riddle, Particularly the Chemistry classes. While the subjects we studied were academic examples for almost all of my younger classmates, I was 26-28 years old then, and the information was enlightening when I had a sudden understanding of combustion dynamics that I had observed for years in automotive racing, but didn’t have a detailed view of how the factors worked together, far less that you could make calculated and predictable changes.”



Above, as you see it, this is a non-running model, but it has a serious purpose. The red parts you see are plastic, and were made for us by Corvair/Panther builder Paul Salter. Read the story here: Ignition system, experimental “E/E-T”


“Local Expert” convinces builder to use cast pistons


When we were at Oshkosh this year, a man walked into the booth on a slow afternoon. After 20 years of doing presentations at airshows, I can say that it is very hard to predict who the serious builders are when they walk in for a look, but I can always tell in 10 seconds who is there with an “issue.”  None of these people are actual builders, they are all “Local experts” who want to tell me that they know more about Corvair flight engines than I do. Mostly, they are harmless blowhards there to complain that none of our builders respect their “advice.” But the particular guy who walked into my booth was a dangerous idiot because he had actually convinced a Corvair builder at his local airport to use cast pistons in his engine, completely against advice I have been giving for 25 years. He came to the booth to gloat over his success. In reality he had just seriously endangered the builder, and every one of the man’s future passengers, all for the sake of his own ego.


Above, BHP’s Corvair powered plane The Last Original. This plane has 800 hours on it today. It lives at Brodhead and belongs to our friend Bill Knight. Contrary to what some people think, this plane has forged pistons in it.


The builder in question is a guy I have known for years; He is a very nice guy, his Pietenpol is almost done and it is outstanding in appearance. At any grass strip, this man and his plane  would inspire confidence to allow many people to let their child take a flight in his plane. Externally, this engine would even look like one “built to WW’s specs.” But with Chinese cast pistons in it, this plane contains a very dangerous hidden flaw with a very high probability of a disaster awaiting.


Most planes that are the aviation equivalent of an IED look the part, and are presented by people who are easily recognizable as mentally ill. People understand to stay away. What makes the plane described to me at Oshkosh so dangerous is that the finish and demeanor of the builder will be very disarming. I don’t have to warn people about what to do if they meet a guy with a wild look, speaking about the afterlife and holding a grenade with no pin. This warning is about recognizing that sometimes the same grenade is wrapped in a very nice gift box, and the pleasant guy offering to let your kid look inside doesn’t himself understand the contents. All he knows is that his “local expert” (who will not be flying in the plane) assured him that he and his passengers were in no danger at all.


The dangerous idiot local expert stood in my booth and offered these reasons why he told the Pietenpol builder not to use forged pistons: 1) the cast pistons were made in the U.S., and our forged ones were made in China, 2) Bernard Pietenpol’s own plane The Last Original has cast pistons, 3) The engine only makes 70 HP so it doesn’t need the extra $80 expense (per set) that forged pistons cost. Everything this man said is a vile lie, but dangerous idiots never restrict themselves to the truth nor reality when dispensing “advice.”


Lets look at the lies one by one: 1) In reality, it is the “High Tech” cast pistons the idiot advocated putting in the engine that are made by the Chinese. Every forged piston we have ever sold was made in California, so the idiot had it 100% backwards. Every cast piston for the Corvair that I have seen for sale is a product of China. They may say “ISO-9001” on the box, but that is just printed words from a culture of corruption.


2) BHP’s own plane, The Last Original, does not have cast pistons in it. A number of years ago, Bill Knight, the owner, contacted us about upgrading the engine to my spec’s internally. The only visible external change is that the engine has our black prop hub, but internally, it is all modern stuff out of our Conversion Manual, including forged pistons. I have one of the original GM pistons in my shop, and it is in poor shape. Bill Knight made a very good call on standing the plane down until it was updated. The actual engine assembly on the update was done by Mark Petz, who was standing in the booth when the idiot was saying his lie. When I asked the idiot if he would like to personally meet the man who put the forged pistons in The Last Original, the idiot was dumbfounded.


3) Everyone who came to our booth at Oshkosh this year saw both the display engine I built and Roy’s water brake dyno.  After Oshkosh, we went to Roy’s in Michigan for a day and did a complete break in run on the display engine before delivering it to a Canadian Zenith 650 builder. Because the engine was brand new, I didn’t lean on it very hard, but the engine pulled 76.5 HP at 2,675 rpm, which is below the static take off rpm of a Pietenpol. If the idiot was counting on a modern Corvair to only make 70 HP he is very wrong. I owned a dyno for years that we ran countless engines on in public, Roy has a better one, and Mark owns an even more sophisticated one. I am sure that the idiot based his guess on nothing, because that is what idiots do.


Even if the engine was to produce only 70 HP, it should still have forged pistons. In reality, all the original GM pistons were cast, but they were vast better quality that the Chinese junk sold today. The GM pistons were all U.S. made and had a steel belt cast inside to control expansion and strengthen them. Because people flew them in the 1970s means nothing about Chinese parts today.


The great danger in using cast pistons is that undoubtably the builder is going to use our CHT limits, ignition advance curves, carb jetting. cam, rpm, spark plug and prop recommendations, which are all based on the engine having forged pistons, a requirement I have held for 25 years. It is my prediction that the builder will blow a hole in one of his Chinese pistons in the first 25 hours of operation. When he does this, he may not get back to the airport, and he may wreck the plane and get hurt. Does anyone think that the idiot will then show up and build him a new plane and pay his medical bills? And then people will say, “See Corvair engines don’t work,” neatly ignoring that Continentals with the wrong pistons in them don’t work either.


I have not included the name of the builder here, because I want people to focus on not listening to local idiots. I have said this countless times, and I have no idea why the builder couldn’t just say, “Sorry, no offense, but I am going to just follow WW’s recommendations.” After I publish this I am going to go on the Matronics Pietenpol list and state the builder’s name, and say that I do like the guy, but his engine is unairworthy.  I will do this in hopes that he will change them, but if he doesn’t, and his Chinese cast pistons fail, it will be public record that I warned him, and maybe the next guy will learn not to listen to idiots.


Above, Tom Brown’s Pietenpol, flying since 1982. It has more than 1,500 hours on it. It is often said that this plane has cast pistons in it, but we are very good friends with Tom, and he has told me that he and his dad rebuilt the engine after briefly flying it in 1982. It may have forged pistons, but if it does have cast ones, they are U.S. made ones from GM, and they are vastly better quality than any cast piston from China. This plane does not use the full ignition advance, cam nor carb jetting we use today.



It is not possible for me to express how much I detest people who will not fly in planes, but give advice to others contrary to what our testing has shown. Words like “Vermin” hardly cover it. I suggest that people read my story about how fools in aviation have an ironic way of hurting others and walking away without a scratch, at this link: Effective Risk Management – 2,903 words.


The link contains the story of a great aviator, Phil Schact, a man hugely influential on Grace’s flying, who burned to death as the direct result of an idiot’s actions. In the year that followed that accident, I spent a number of long quiet nights sitting on the front porch thinking, and came to the conclusion that I will never be a good Christian, because I was not willing to even contemplate forgiving that idiot. I understand the power of forgiveness, in my life I have been both the recipient and the grantor, but we know the real measure is can you forgive the unforgivable? By this measure, I will always fail to forgive dangerous idiots in aviation. No matter how long I live, I will go to my grave with this black mark on my heart. -ww.

When to check your timing, Lessons learned Pt#2


Here is a story about when to set and check your timing.  Over the years, I have written many stories about timing Corvair engines. Many of these stories point out that 1/5th of the flying Corvairs have never had their timing set. I suspect that builders think I am exaggerating. I am not. Here we will examine the case of a Corvair powered plane that has been flying for several years, and has never had the timing set or checked, in spite of having many annuals, being destroyed and rebuilt, wasting the engine on a poor installation and rebuilding it, and flying the airplane to two colleges. There are several lessons here please read carefully. My point is not to condemn the owner, it is to get people to take airplane operation, maintenance and ownership more seriously.

Above is Gardiner Mason’s plane, the focus of this story.  Just to be clear, I like the guy, but I really need builders to do better on timing, and I am going to use Gardiner’s case as a specific example in hope that more builders take this issue seriously.

Above is a n early 2007 photo of Gardiner’s engine running on our test stand at the old Edgewater hangar. It was started at CC#10. That was eight years ago. Anyone who comes to a college understands that I set the timing statically to get the engine to start, and teach builders how to set the timing and check it when the put the engine in the plane. I do not set it for them because in the transportation, storage and installation, it might get bumped and altered, and I want them to check it. Besides, the College and the building process are aimed at teaching builders, not doing things for them.

Gardiner flew his plane to CC#27 in Barnwell 2 months ago.  He came a day early. he later told me he was cold and fatigued and off his game on arrival. His landing was hard enough to break an axle off the plane. By luck, it wasn’t severely damaged, and the local crew provided the assistance to fix the plane in one day. I only briefly got a look at the plane. On the way back to Georgia, Gardiner had the oil pressure drop off to 10 pounds….twice. After the first time, he landed and found the engine 2 quarts low; he refilled and noted an improvement, but not the restoration of normal pressure. He elected to take off, and the next leg brought a repeat of the same. He called me when he got home and told me that the plane now had no compression in several cylinders. He removed the engine and drove it to my shop. While he was here, he said to me that he had never set the timing on the engine. Not once that he could recall.

Let’s cover some basics:

1) The timing needed to have been set on installation and checked at least at each annual.

2) The oil pressure in an engine never drops until it runs out of oil and sucks air. A Corvair with 3 quarts in it will have the same exact pressure as one with 5. Low oil pressure is the sign of internal damage, and it has nothing to do with the number of quarts in the crankcase.

3) NEVER take off in an engine that has just given signs of failure, like dropping oil pressure. There is no excuse. In Gardiner’s case, “get home itus” was a factor.

4) an inspection of his engine showed that it had been detonated to death from having the timing too far advanced. The low oil pressure is bearings that were beaten by the pounding, the low compression is having the head gaskets blown out. When it was landed the first time, rotating the prop by hand, which I tell people to do on every preflight, would have confirmed the lack of compression on several cylinders.

Here is a vital point I want to make clearly: Gardiner has flown more than 20,000 hours. He has had some issues with his plane and engine. Many new guys seeing this ask themselves “if that guy has problems, why can I, a rank amateur expect to do better?” Here is why: Because a guy with 100 hours of experience who exercised good judgment is going to have better results than a 20,000 hour guy who thinks “it will be alright.” If you are a new guy, read this story:

Risk Management, Experience vs Judgement.


How often should I set or check the timing on my Corvair?

On installation, at every annual, after any unusual operational event, after any engine removal and reinstallation. If I add these up on Gardiner’s plane, he missed about 10 points where he needed to check the timing. There is some validity to checking it at oil changes. If you change the oil, you are going to do a run up test to make sure you have no leaks. I can combine this with a timing check, and I will literally be adding less than 4 minutes to the oil change.

Above is a famous photo from Sun n Fun 2011. It is three Pietenpols smashed by the tornado. It is hard to see, but Gardiner’s plane is at the bottom of the pile. I admire the fact he aggressively went to putting it back together, but he has recently told me that he never checked the timing on the distributor after salvaging the motor out of this wreck. Common sense says that any of the airframe part could have smashed into the distributor body, or the salvage crews that moved the planes with front end loaders could have altered it, or it just could have gotten bumped putting the engine in and out of the plane. Gardiner flew the plane about 30 hours since rebuilding it, but did not verify the timing.

The tornado was not the only issue Gardiner had in the last 8 years. This link is to a long story about how I worked with him to fix his engine after he damaged it with cooling issues: . Below, in color, is an excerpt from the story, written almost 4 years ago:

“This is severe detonation. Many times, people ask me if high oil temp can cause a loss of power, etc. Here is the absolute bottom line: If you lose more than 50 rpm,  immediately suspect detonation, and take action. I have actually had a builder try a take off when his engine was down 500 rpm from normal on a take off roll. (He had an “expert”  set the timing for 55 degrees of advance.) If I see 75 rpm low on a plane on take off, I abort the take off. Any noticeable reduction in power on a Corvair is detonation.  You can run the engine with the oil at 300 degrees, and it will actually make slightly more power on the dyno; likewise, a high CHT that isn’t detonating will have little  effect on power. Running on five cylinders, the engine will lose only about 250 rpm on take off. I point this out so that people can understand just how much violent force the engine  is absorbing when it is detonating bad enough to lose 700 or 800 rpm.”

After the issue, in May of 2010, I helped Gardiner put his engine back together and we ran it. Last month, Gardiner said he assumed I set the timing then, and never bothered to check it, not at any of the annuals, not after the tornado, not after the reinstallation.


How hard is it to check the timing?

Here is a link to the set of instructions that come with every distributor we make, which are also on our webpage, which I also use as a guide to teach builders at Colleges:

Below is a photo from the instruction sheet, the process isn’t just described, it is fully illustrated.


Developing your own inspection Checklist:

Below is the FAA’s basic check list for engine inspections during a 100 hour or annual inspection. They are the very minimum. Engine manufacturers can, and do make further specifications. In short, you can ask any A&P or IA, and they will tell you that the timing, differential compression, spark plugs and the inside of the oil filter are checked at every single annual.  If you meet any A&P who disagrees with this, have him put it in a one paragraph email with his name and license number, and I will forward it to the FAA, and we will see who is right. Use the notes below and develop your own detailed list.

Each person performing an annual or 100 hour inspection  shall inspect (where applicable) components of the engine and nacelle group as  follows:

(1) Engine section – for visual evidence of excessive  oil, fuel, or hydraulic leaks, and sources of such leaks.

(2) Studs and nuts – for improper torquing and obvious  defects.

(3) Internal engine – for cylinder compression and for  metal particles or foreign matter on screens and sump drain plugs. If there is  weak cylinder compression, for improper internal condition and improper internal  tolerances.

(4) Engine mount – for cracks, looseness of mounting, and  looseness of engine to mount.

(5) Flexible vibration dampeners – for poor condition and  deterioration.

(6) Engine controls – for defects, improper travel, and  improper safetying.

(7) Lines, hoses, and clamps – for leaks, improper  condition and looseness.

(8) Exhaust stacks – for cracks, defects, and improper  attachment.

(9) Accessories – for apparent defects in security of  mounting.

(10) All systems – for improper installation, poor  general condition, defects, and insecure attachment.

(11) Cowling – for cracks, and defects.


Thoughts on reasonable responsibility:

Last year, I had a guy who called me up and said he was having some issues with the ground runs on a Corvair he had put on his plane. I asked him if he had set the timing or checked it. Answer “No.” He went on to explain that The engine was one that I had built in 2005 for a former owner, it had been shipped around the country, resold, etc. His comment was that he assumed that the timing was correct because I “would have set it.”  OK, let me put this in simple terms. If you bought a gun from a guy who told you he bought it from me eight years earlier, would it be safe to assume it was unloaded now? Maybe a prudent plan would be to simply check to make sure.  If you learn only one thing about flying this year make it this : Maybe 1/3 of the people killed in aviation were done in by something that they just assumed someone else checked for them.  Want a foolproof way to avoid that? Get out of the mentality that says you count on anyone to have done something that you can easily check for yourself. You are building a plane to be in Command of every aspect of it you can.  This means that you do not trust the line boy to have filled the tanks when you can just look, you do not trust another pilots opinion of the weather when you can walk over and look at the computer, and you do not trust that your timing has never changed because you don’t want to buy a $39 timing light.

Above, one last look at Gardiner’s plane after the tornado. Can you see a single part that you wouldn’t carefully inspect and verify before flying? The conservative approach would be to assume that every part was 100% garbage until proven otherwise by detailed inspection. That would be exercising good judgment. -ww.

Zenith 601/650 – Corvair reference page


Here is a single location page that has a great number of links to information specific to the Zenith 601/650 / William Wynne-Corvair Combination.  It is a particularly good match, we have a number of different ways to approach it that serve the needs of many different builders, and it is a success story that builds on our 10 year history of working with Zenith builders, starting with our own personal 601XL in 2003. Since then we have assisted more than 80 builders to complete and fly their Corvair powered Zeniths.

If you already are working on your Corvair, this page will have information you have seen already on our websites, but I have included it so that this page can function as a ‘stand alone’ guide for 601/650 builders who have just heard about our work with the Corvair. 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. If you would like to start with a simple three page spec sheet on the engine, read this link first: Basic Corvair information

This page is broken into the following sections:


1) Introduction

2) Engine and build options

3) installation components

4) Support for builders

5) Flying 601/650s

6) Builders in process

7) 601/650 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 601/650 builders.

Above, Phil’s Maxson’s 601XL airborne over the Florida coast at Ponce Inlet, 2006. Phil finished the plane in our Edgewater hangar and has been flying the plane ever since. It has proven to be economical and reliable over the long run. Phil is a skilled manager from the Fortune 500 world of business and could have purchased any engine on the market, yet he selected the Corvair as the best match to his personal goals of Learn Build and Fly.-ww


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 for the Zenith 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) – An example of our ling standing working relationship with Zenith: Friday out of shop until 4pm.

e) – A direct explanation of what makes my work different than typical LLC’s : 2011 Outlook & Philosophy

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


Above, the 3,000 cc Corvair, configured for a Zenith 601/650. 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.


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 dispacements 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.

I have broken down building a Corvair and installing it on your airframe into 42 “groups”. The previous link 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:

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 a Zenith engine build : Shop perspective: Mastery or ?

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

e) Engine of builder now working on Zenith airframe: World’s Strongest 3,000cc Corvair, built by Greg Crouchley

f)  2.700cc engine we built for Becky Shipman’s 650: Shipman Engine at CC#22

g) 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. This sounds like a lot, but I made the first one in 2003 for our own 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.  We succeeded because I am a craftsman first, and can make all the parts in the catalog, and we have never had, and would not accept having any partners nor investors. The Blue fixture is the one we use for the 601/650.


3) Installation Components for the 601/650:


We provide every single part it takes to install a Corvair in your 601/650.  You can buy them one at a time, or all at once. Our Zenith 601/650 installation, which has been successfully flying for a decade, is a long proven system that has only seen a few very minor detail evolutions. Our Zenith installation manual detail how and why each of the installation components are installed on your airframe.

The installation does not require any modification to the airframe fuel system like most EFI engines do.  Being air cooled and carbureted, it 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 comparitively 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: From that list, you can see that the major installation parts for a 601/650 are: #3601(S) intake manifold, #3901(A) Stainless exhaust, #4002 spinner bulkhead, #4003 Warp Drive prop, #4101 baffle kit, #4102 nose bowl, #4103 cowl kit and a #4201(A) mount. The other smaller items listed are detail in our Zenith installation manual. All of the above parts have links to stories through the products page.

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 for Zeniths have installation kits that run from $4,000 to $6,000. The Corvair is near the bottom of this range, but the savings of using the Corvair is in the engine, not the cost of installing it. Builders can save a significant amount of money by fabricating many of the parts like #4103, but most people are near the finish line at that point and opt to buy it and save the time. Exact cost on the installation parts varies a bit, I will be glad to review it with builders after they study the installation manual.


a) – For an example of 74 years of aircraft welding talent: Zenith 601/650 Motor mounts, P/N 4201(A)

b) – To learn about the Stainless exhausts we make: Stainless Steel Exhaust Systems

c) – Louis Kantor’s 601XL running for the first time in our front yard:

d) – The same aircraft on its first take off, from our airport. July 2009.


Above, 2004 at Oshkosh: Next to our personal 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:


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


a) We have a very detailed Installation manual for all Zeniths: We also have a flight operations manual with specific test flight plans and procedures:


 b) we hold 4 free hands on technical seminars called “Corvair Colleges” every year. This includes an annual College held in Mexico MO at the Zenith Factory timed to coincide with the factory open house in September. 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


c) The “Zenvair” group is a separate on-line peer-to-peer discussion group just for Corvair/Zenith flyers to directly and freely share information and data with each other in a civilized productive format. The link is : ‘Zenvair’ Information board formed  This is very effectively moderated by Zenith/Corvair builder and flyer Phil Maxson who’s 601 is pictured at the top of this page.


d) 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, including 2 at Zeniths west coast facility Quality sport planes,  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 is Rich Whittington’s fabulous looking 601 HDS at Corvair College #21. Our Conversion Parts work with all models of the 601 and  the 650. One of the things I respect about Rich is his outspoken honesty. He started out with a criminally poor 2,700 made by a rip off artist in GA. To prevent other builders from making a similar mistake, he wrote a number of comments on this on Zenith Builders and flyers page. His second engine was a standard installation matched with a 3,000cc engine his is very pleased with.


5) Examples of flying Corvair Powered Zenith 601s and 650s:


In 2011, I wrote up a quick list of flying Zeniths, Since then a number have been added, but this list is a good beginning point, it has date of first flight and the N-number of these aircraft. Click on this link:  List of Corvair Powered Zeniths

If you would like to get a look at pictures and short notes on a number of 601/650’s, click on this story link:

16 Flying Corvair powered Zenith 601/ 650s

Below are a number of stories about flying planes.  We get a steady flow of new flyers Like Jerry Baak and Pat Hoyt, whos names are not on the first list:

 A really nice 2700cc tail wheel XL:  New Zenith 601 XL(B), Conventional Gear, Jerry Baak, S.C.

Good looking 2,700cc plane in FL, story is about a house call: Flying 2700 cc Zenith 601 XL(B), Alan Uhr

Very nice looking 650, links to movies of plane: Zenith 650-2700cc Dave Gardea

Our west Coast rep, Woody’s plane: Zenith 601XL-2,850cc, Woody Harris also read the story: Woody’s 2,850cc Corvair/601XL hits 400 hours.

A plane seen at Brodhead, Oshkosh and the Zenith open house in 2013: Patrick Hoyt, new Zenith 601XL, now flying, N-63PZ

Story from the moderator of our “Zenvair” discussion group: Guest writer: Phil Maxson, flying a 3100cc Corvair in his 601XL

Story on a long time member of the Corvair Community: 601XL-2700cc Dr. Gary Ray

Story on a 500 hour 601 Tail Wheel aircraft: Zenith 601XL-3100cc Dr. Andy Elliott


Above, Making a house call in California to Larry Winger’s. His engine ran at Corvair College #18. Larry’s aircraft is a magnificent 650, built from plans, not a kit. The aircraft has since been completed and has been moved to the Chino airport. Larry exemplifies many of the finest qualities in homebuilding. When he started the project, he had never built an engine, a plane and was not yet a pilot. He has since accomplished all three.


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 LLC’s 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 supporting Zenith builders for a decade, but 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. We have many people working on Corvair powered 601s and 650s. In the first 10 years, we build and sold about 160 motor mounts for the combination. I didn’t make them just to have something to sell, I made them so that each builder would have a good shot at completing and flying his plane. I will be here long enough to support each of those builders in completing their plane. If you select a Corvair engine, I will be your ally 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:


Nice guy who has been to many Corvair Colleges: Jim Waters 601XL-B project, “In The Arena,” Memorial Day 2013.

Our oldest builder in action :Dick Otto in California, S.R.B. (Senior Ranking Builder)

A letter from the same builder: Mail Sack – Letter of the month – Dick Otto, 601XL Calif.

A 2,700cc break in run on a 90% complete airframe: Weekend Double Header, 2nd engine of the year, Rick Koch



7) Operational Data for this combination:

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 on our ‘Zenvair’ group.  If you are attracted to a builders group that is made of intelligent thinking people, you will fit right in with Corvair builders.

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 from Bankrupt LLC’s:

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 LLC’s 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. Because they were LLC’s they could take peoples money without any liability to repay it. 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. If you have one of the engines from these LLC’s you are out of luck. I will not allow you to join our ‘Zenvair’ group nor will I allow you 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.

The Zenith Builders and flyers website has 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. On the same sites, I have builders like Larry Winger and Rich Whittington sharing that the same people took their money and delivered trash. Some people still don’t do their home work.

Bear-Vair First To Roar To Life In 2013


Below are some photos of the test run on Dave Vargesko’s 2700 cc Corvair in front of our hangar on Saturday night. I wrote about this engine in the first post of the year, “What is your 2013 reality?”. Dave worked on it last weekend and returned Saturday afternoon for finishing touches and a test run. It got a 30 minute run in, and we had it all packed up in the back of Dave’s truck by 9 PM. Dave lives about 3 hours South of us, so he had a long ride home to think about the next airframe he is going to build for his engine.


Above, Dave, who detests being photographed, monitors the test run of his engine. He originally built it in 2004-05 out of basic stuff we had around our old shop in Edgewater. The heads on this engine are actually the ones from my Pietenpol engine of 1999. The engine flew for several years without any issue in the Hangar Gang Wagabond.  Last summer we picked the airframe back up from Dave, but he kept his engine for his next project. We are in the final process of going through the whole airframe and re-engineing it with our own 3,000 cc engine. We are going to utilize the Wagabond as a general purpose work horse in 2013, for testing, demo flights and general fun.

The Center piece of Dave’s Upgrade was installing a retrofit (I call this a generation #1) Dan bearing. He also upgraded to an E/P distributor, and slightly refreshed the valve job. We also installed valve rotators on the exhausts. We took the engine down to the removing the pistons and cylinders, but did not open the case. It showed no detectable wear on the inside. We replaced a few gaskets, but there was no call to change any rod bearings or the rings. the engine was reassembled with the same parts and it worked great. A compression check after the test run revealed that it was sealing up perfectly.


Grace wanted a photo of Dave the bear in the prop blast, so out of respect to Dave’s belief that photos steal your soul, we called for the “Stunt Bear” as a stand in, just like they do in Hollywood.

The main theme I would like builders to take away from this is that we have always gone to great lengths to make sure improvements to the Corvair are economically and easily retrofitable to existing engines in the fleet. This is evolutionary progress in our movement.

There are plenty of other “alternative engines” brought to the market in a rush that later required a series of expensive ‘upgrades’ (translation: customer funded R&D and Builder test piloting) The modifications Dave put into his engine were not costly nor mandatory. You can look at the photos in the story of the 15 Pietenpols and see that there are many of them flying for many years on very modest engines. It is all about personal choice.

For anyone who is a fan of certified engines to critique our system, let me say that very few AD’s on certified engines are as inexpensive as buying a 5th bearing. Lots of ‘experts’ who have never had a DAR inspection on a plane tell people the half-truth that you don’t need to follow AD’s on a certified engine on an experimental airframe. Yes, that is true, in theory, but I know very few DAR’s that will knowingly sign off a new homebuilt with an engine of certified origin that does not have it’s AD’s complied with.

People argue this without even thinking about the concept that if the primary reason they wanted a certified type engine was “reliability” and the first thing they want to do is see if they can get out of the Manufactures required up grades. I don’t see the logic in claiming that you respect Lycoming and Continental’s engineering, but putting great effort into ignoring their advice on operation and upgrades.  An 0-320 on the front of an RV-4 doesn’t magically know it isn’t on a Cessna 172 anymore. If Lycoming said the engine they built needs a different oil pump, it doesn’t really matter if the engine is on an RV or a Cessna. Often people will pick and choose which AD they want to comply with as if they were qualified and had all the data to make such a choice. Such rationalizations are usually thinly veiled excuses for being cheap while the person deludes themself they have “safety” because their engine once had a data plate. There are good reasons to have a certified engine in some homebuilts, and I support the choice, but often people making it are immediately undermining the logic with secondary choices.

In the land of Corvairs, we do not have these issues. Our system of ‘safety’ is based on a rock solid foundation of getting people to understand that they are in charge of making intelligent decisions about their own risk management; Our testing is to provided them with good information upon which to make these decisions; The up grades that are available are options that builders can choose based on operational data, not revenue generation or correction of half-baked products; Our recommendations are based solely on what makes sense, not what the accounting or legal departments say.

The above paragraph doesn’t make everyone comfortable. Plenty of people approach aviation with the consumer society driven attitude “Just tell me how much money I have to spend to be 100% Safe and not have to think about it.” For people who bring this attitude to the unforgiving world of flight, there are, and have always been Unicorn salesmen with brochures that claim ‘the worlds most reliable” engine and a dollar number to spend. In Corvairs I have gone to great lengths to teach builders that you can’t spend your way to safety, but you can educate yourself to a very effective management of your own risk.-ww

Numbering System update…….Real Goals in Aviation.


Below is a sample of the 1100 group of the new numbering system. We saw this earlier, in the ‘Getting Started in 2013’ series I wrote last month. I am going to slightly change the system of numbering to make engine building easier to organize. It is a subtile change, but an important one. I pick this simple group to show the before and after, and to explain why. Very shortly I am going to come back with the final revised numbering system, and print it all out here.  We are going to change our own parts numbering system on our catalog page on our main website to match the new system, and we will have a vastly better organized system for builders to work with that will provide a very orderly path to a running engine.

Below is the original numbering system from last month. Note how the group is 1100 and also the camshaft itself is part number 1100.


Cam group (1100)

1100- Cam

1101- Thrust washer

1102- Key

1103- Cam gear

1104- Hydraulic lifter set -12 total-

1105- Cam lubricant

1106- ZDDP oil additive


Ok, here is the change: Notice the group stays the same, 1100, but everything moves down one number. below this I will explain the why of it.



Cam group (1100)

1101- Cam

1102- Thrust washer

1103- Key

1104- Cam gear

1105- Hydraulic lifter set -12 total-

1106- Cam lubricant

1107- ZDDP oil additive


Now, picture yourself building an engine with the new numbering system. As I will show everyone shortly, there are 40 different groups, each with their sub component numbers. We are going to have a checklist for builders with the 40 groups on it, so a guy heading to a college to close his case will know that he needs to have all the sub components so he can ‘check off’ groups 1000, 1100 and 1200 from his list.

The new change eliminates confusion between a builders speaking of ‘having part 1100’ which was just the cam, and ‘having group 1100’ which are all the items listed above. The simple number change above fixes this.

Second, we are moving toward a system where we will be able to offer an entire group in one box, instead of just some parts of the group. for example, Lets look at the Oil Pan Group (2200).


Oil Pan Group (2200)

2201- Oil pan

2202- Oil pickup

2203- 1/4″-20 hardware -19-

2204- Drainplug

2205- Oil pan gasket

2206- Dipstick

2207- Dipstick bracket


Traditionally, a builder bought a pan and an install kit from us, and ended up with all the things listed except for 2205, 2206, 2207. respectively, his gasket was from a gasket set like the clarks 120ww set, but we are moving toward getting builders to look at the gasket as a part of the group, because big sets often have things like front seals that 5th bearing builders don’t use. In this case I want builders to just have a clarks c-199 gasket. We have long told builders to get the Ford 302 dipstick and cut it down. This hasnt been a problem, but I could just get a giant stack of them and cut them all down to the correct length in 30 minutes. The tab is a small bracket the stabilize the top of the dipstick to one of the 5/16″ top cover bolts. Easily hand-made if the builder wishes, but I want to have laser cut ones available because they are cheap enough and I want builders to focus on the big things, not a detail like fabricating this small part, especially at settings like Colleges.

Thus, we are shortly going to revise our catalog page to have something called a “Complete 2200 group”, which will have all of the parts of this group in one box. We will have clearly explained letter code suffixes, so a builder can directly order a 2200B, which will be the whole group with a Gold Billet pan, and we will also have a 2200W, which is the whole group with one of our welded pans. Of course, we will still have the Gold Billet pan by itself, and it will have part number 2201B.

You don’t have to memorize any of this, we will spell it all out in detail, but I just wanted to give builders a look ahead and a specific sample so that we can understand the system and where we are headed with it.  I personally think that it will make a big difference on the accessibility of engine building.

Now, follow this next part closely, because it is the whole reason why I have spent a year developing this new system. I want more builders to get more focused on developing their fundamental understanding of the Corvair engine, and become much better operators and mechanics on them. Right now, we are doing good, the average Corvair builder is a Motorhead/genius when his engine is done, if we compare him to the average guy that just bought a buy-it-in-a-box imported engine. But I am setting my educational standards higher than that. I want every guy to get the most out of building his engine in terms of a learning opportunity.

Here is how the new system serves this: right now, too many builders view the engine building task as collecting the parts, assembling them, and getting it done. Thats fine, but I am not after improving builders shopping/scrounging skills, nor am I interested in having builders focus much thought on making a dip stick tube bracket.  I want builders to really know things like how to install and time distributors, how to set valves once, how to use a differential compression tester, how to do a valid 100 hour inspection, when to preheat in cold weather and why. These things are the type of things that really good A&P mechanics all know about the types of engines they master, and there is no reason why any person in homebuilding for the right reason should accept knowing less. Having the parts system better organized and group parts more accessible gets more people away from the parts perspective, and get them to a mindset where they are focused on improving their real skills at being the true master of the engine they fly.

That may not be the goal of 90% of the people wandering around in experimental aviation, but let me tell you this with 25 years of hindsight of doing this stuff every day: The people who get something out of experimental aviation, really know it’s rewards, are the people who came here to learn. To really learn, not just know the answers on the quiz, or to sound smart in hangar BS sessions, but to be able to walk out to their airplane to preflight it and know that they are not taking a random chance, nor hoping some one else knew what they were doing. To walk out to your own plane with confidence because you are the master of it, and you are the only person you will be counting on today, and you are calm because you know that you invested the time and effort to really learn something, and you have made your plane right with this knowledge. That is getting something out of experimental aviation that is worth all the time in your shop, all the money you spent, all the things you sacrificed to do it.

And the other 90%? I hope God looks after them, or at least their families. Sound harsh? Try this: go to your airport today, find the oldest aviator there, a guy so old he flew radials commercially, the guy who is likely to have seen just about everything in flying, and ask him just one thing. Ask him if he ever saw a single person hurt in aviation because they knew too much about the machine they were operating, that their mastery was too high for their own good, that a person with less skills would not have been hurt. I don’t care who you speak to, no one has ever seen this. Today, somewhere in print, some moron will say that buying a new Lycoming or Rotax is the path to safety. What a joke; there have certainly been ignorant users, thinking they could buy their way to ‘safety’, who were shortly thereafter harmed by their allegedly ‘safe’ item. Anyone with a brain and a speck of honesty will tell you that the only path to safety is Understanding, Skill ,Knowledge and the Judgment to apply them. Anyone who says that you can buy some product and not have to be so concerned about U-S-K-J is a dangerous fool.

Ernest Gann may have been aviations greatest writer. In “Fate is The Hunter,” preface states that flying is a kind of war story, where “the designated adversary always remains inhuman, frequently marches in mystery, and rarely takes prisoners.” He wasn’t kidding or stretching the analogy. The book has several pages of abbreviations in small print, which you only understand later are a list of all the people he knew who were killed flying. Gann and his contemporaries where doing far more dangerous flying than we are, but it is fair to say that they were also professionals who were vastly more talented that average pilots today.  I can tell people the risk typical GA pilots face today is a small fraction of what Air Transport pilots faced then. What is your response? 90% of EAA pilots take this to mean that they can get by aspiring to a lot less than those early aviators knew. If you are part of the 10% that understands that your risk will only be far lower than theirs if you work to develop the same Understanding, Skill ,Knowledge those men had, then welcome, I have things I can share with you. You will not need God to look after you, you can do it with the brain you received.

I think Gann’s analogy holds. You are headed to a combat of sorts. My goal is to really teach you how your weapon works. To take it all apart, be able to clean and maintain it, spot trouble before it happens, put it back together, and how to fine tune it and operate it with great skill that only comes with intimate knowledge of a machine.  Even though the task ahead is serious, you will be prepared, and harm will not come to you because you didn’t know your weapon in the conflict. Contrast this with the prevalent mentality of 90% of the people in the EAA.  Just like everyone else, they are headed to a conflict, but they don’t like thinking about it, “it will be all right” is their common motto. They think they can buy a new weapon, and this will make it reliable, even if they don’t know how to clean it, far less understand it. They think high-tech is some sort of magic armor, a replacement for understanding. They are not the master of their arm, they are just the person holding it. Deep inside they know this, and they suppress that thought every time they meet a well prepared master by blurting out “mine is new, I don’t have to know what you do.” Who do you think is more at risk? In the hours before conflict who do you think will be frightened and who will be confident?

They will never feel what you do when they walk out to preflight their plane. You will be confidently checking your workmanship. A preflight to them a some sort of ritualistic pagan dance they were taught the moves of, by an equally ignorant ‘instructor’, a dance that they desperately hope will appease the gods of luck and chance and keep evil at bay by a method that is unknowable. The real gods of flight, Physics, Chemistry and Gravity, look down from above, unmoved by the little dance.  They only respect people who follow their rule book. To Aviators, the book is on the shelf and written in plain language.  Dancers who never took the time to learn to read view bad events that happen to the dancers in their troupe as running afoul of luck and chance, fake gods they themselves made. Each of these events looks very different to any aviator who knows who the real gods of flight are, and understand that these gods are just, but never understanding nor merciful.

Are you a person who spends money and hopes for the best, or are you a person who actually likes knowing that your fate is in your own hands, and no one elses’s?  This answer matters more than any other in your experimental aircraft experience. Any commentary on risk management, be it in print, in person, or broadcast isn’t worth paying any attention to unless the focal point of it is developing the Understanding, Skill ,Knowledge of the Aviator. -ww