Mail Sack, various topics, 12 /5/12.


Below is a lot of mail on many different subjects. It is a mixture of technical notes and social stuff. Both are welcome. A number of people write in each week to say that a balanced mixture makes the best reading. I encourage anyone to write in with news of their project or any type of comment about their perspective on building and flying. When you do, include a note about what your building or thinking about getting started on. If you include your geographic location we can often connect you with another builder in your area.-ww

On the topic of machines vs appliances, builder Brandon Gerard writes:

“Not only do posts like these make me want to get out in the garage and work on my core, but they also make me want to sell my Camry and go hunt down another old-n-busted pickup truck to drive like I used to.”

Builder Patrick writes:

“This is a great statement ..”

On the topic of inexpensive panels, 601XL builder Becky Shipman writes:

“William, Thank you for publishing this info – though I found bits and pieces of a lot of it in the manuals and on the site. I have pretty much the same philosophy – I fly to look out the window, not look at a panel, and fly by looking out the window, not at the panel. The one concession to modernity (and my computer savvy son) is to put in a small Dynon D-6 EFIS in place of the turn and bank indicator. It’s light, and I get the turn and bank plus attitude capability without needing vacuum or heavy gyros. I’ve already got the SW tach and the autometer fuel gauge. Looking at Wentworth – local parts recycler – for the gauges. I’m under the Minneapolis Mode C veil, so I need a transponder, and it’s busy enough at my home base that I want a radio, too. I have a hand-held GPS I can use. Oh, and I have decided that welding is definitely not a Troglodyte level skill. I’ve been working on making a simple work stand out of angle and tubular aluminum, and it is definitely a challenge for me. I think after I finish the plane I’ll set myself up in a shop, put in enough power for the Lincoln Precision 225 Tig, and put in some serious practice time. Some of my welds look nice, some not so nice. I have new found appreciation for some of the pretty welds on my Zenith fuel tanks, and on my Corvair intake and exhaust manifolds. Take care, Becky”

Builder Harrold Bickford writes:

“William, I like the instrument panel article approach; simple, economical, reliable and readable. The analog gauges convey needed information at a glance while allowing a continual scan of the flight area. It fits the Pietenpol utility very well. Drawing things out on vellum-an evening project perhaps-still works well prior to transferring and cutting. The items we make also seem to bring the best intangible rewards. What could be better? Thanks too for referencing the MP gauge from the P2V. I used to watch them flying in the vicinity of Brunswick, Maine growing up. As a USAF cold warrior from 1967-75 I had the opportunity to serve five of those years in Berlin. Needles to say, a different world. Harold”

Builder Tom Griesemer writes:

“I always look forward to your articles. I’m right with you on mechanical gauges. The last paragraph is well said. I have a similar alarm system that’s probably as loud as yours. My code is (4-0). One less number to remember…”

Sprint Builder Joe Goldman writes:

“William, Assuming you have a switch for the CHT, which cylinders do you monitor. What do you look at when you lean. Joe”

Joe, Yes, I have a hole for a DPDT switch under the CHT also. The Corvair has a pad under each head that is where GM took the temp. It is threaded 3/8″-16. Given a choice, I run a 10mm washer type spark plug type senders clamped to the stock pad by a 3/8″ bolt and washer. I want to warn every Corvair builder never to lean a Corvair until it runs rough. When you do this with a 7:1 compression O-200 with 15K volt mags on it, the roughness you feel is harmless lean misfire. The same technique on a 9:1 Corvair with 40K volt coils stands a very good chance of detonating. Don’t risk it to save 1/2 gal./hr. of fuel. Note this: I know of almost no aircraft mechanics who will operate their own engines “Lean of peak egt”, because they understand the potential for expensive damage. Mechanics know gas is the cheapest and easiest thing that you can install in your engine. GAMI and EPI have made a fortune selling things to get pilots to lean out their engines. It’s an easy sell because lots of pilots are cheap, particularly penny wise and pound foolish. If you want to lean a Corvair, creep up on it very slowly, find peak egt, and run 100 degrees rich of it. This is something you do after you know the plane and get all the other issues worked out in the first 40 hours. If anyone wants to talk you into leaning aggressively, you can shorten lecture by just asking them if they are speaking of personal experience in a plane that they personally owned, paid for, and did the maintenance on.-ww

On the topic of “My favorite Tach”, builder Brad Boon writes:

“That’s funny you mention that I just bought that tach last week, along with the magnetic pickup summit part # SWW-82646. I searched for a couple hours for a tach that didn’t not connect to the ignition and finally gave up and just got Stewart Warner. Also funny is that when I got the tach, I looked at it and thought that it looked very familiar. Then I went and looked inside our Ford L8000 grain truck and sure enough it has the exact same tach. I think It has a 3306 caterpillar diesel. Well, I look forward to seeing the new panel on the Wagabond. Brad Boon
Greenwood, WI”,

On the topic of steel tube fuselages, Builder Ron Condon writes:

“Did the Big Piet boys in Atlanta have plans for their steel fuselages?”

Ron, the ‘Big Piet’ fuselages are 28″ wide and very heavy duty. I don’t know if those guys went ahead and made the drawings available. You can contact them through the Carrolton GA EAA chapter, Speak with Barry Davis.-ww

On prop construction, Builder Pete Chmura writes:

“Check out the latest postings on for one builders recent prop construction.”

On Oscar Zuniga’s Guest Perspective, Builder Tom Griesemer writes:

“Like minded people…”

On issues of getting an MGL tach to work with a Corvair, 2,850cc 750 builder Gary Burdett writes:

“After working for a couple days , Matt of MGL finally told me that the RV-3 tachometer will not work with the GT 1 gear tooth sensor on the135 tooth gear on the corvair because when I told him that at 3000 rpm there would be 6750 pulses per second, he said, “Oh, that’s too many pulses”. He then looked up some data on other users and offered that it could be connected to the coil. I told him I knew that but I wanted to use the gear tooth as in the brochure. It would get to 2000 rpm then start reversing 1900, 1800, and so on.
Despite the fact that these devices are sold together at Spruce, they are pulse limited, a fact it would have been good to know 300 dollars ago.”

 500 hour 601XL builder/pilot Andy Elliott writes:

“Ref. connection of the ignition to an MGL EFIS – I have been flying this kind of set-up for more than 500 hours now with no problem. The key thing to note is that the tach channel in the RDAC (remote data acquisition) unit is sufficiently sensitive to run off the *ground* side of the coils, picking up on the small potential ripple each time the coil dumps. So there is, at least as far as I can tell, no danger of the tach faulting the ignition or vice versa. There is only one tach channel on the RDAC, so I put in a simple diode bridge which prevents the RDAC tach channel from being completely grounded to the non-operating ignition ground. Andy Elliott, Z601XLb, 512 hours since Nov. 2008”

Gary and Andy, This is the kind of issue I was speaking of. MGL stuff has been flying with Corvairs for years, but it is the builders who have done the R&D, and the factory doesn’t know anything about it. They are selling $300 tachs and making a pile of money. Sure they answer email quick, but service is about correct answers not quick wrong ones.The people they picked as their reps and dealers were just chosen at random, who ever had a website that they thought could move product. It had nothing to do with who might know something about a particular community of builders or a unique engine like the Corvair. They are computer people from South Africa, I am sure they don’t know what a Corvair is, and they seem to have no understanding of why its a bad idea to directly hook a tach to a distributor ignition. Andy, while your system works, I would like people to understand the one Dan Weseman made for an MGL. It has nothing to do with the ignition.

When Dynon first got started, they had an absolute “No dealers, no discounts” Policy. The owner said to my face “When it works, you don’t have to pay people to by it, pay them to endorse it, or pay them to sell it. We are focused on making a good product.” When it was introduced, builders raved about Dynon stuff. Here is what went wrong: Kit plane companies had no way of making money off Dynon. Once companies like MGL started offering 20% for doing nothing to every kitplane company, Joe Average Builder started hearing great testimonials from people he perceived as independent. Want to see this in action? Go to Oshkosh, walk into most companies booths, and tell them your best friend owns one of their kits, and he is just about ready for a panel, but can’t decide between Dynon and MGL. What you are very likely to hear is a salesman going after his 20%, saying anything to get it. That is not homebuilding, its consumerism. If you liked the EAA of the 1970s more, recognize that letting salesmen take the podium from testers, real journalists, engineers and builders was the single biggest factor in things going off track. Sadly, Dynon was forced to concede that they couldn’t compete without paid people also. Today they have a small number of dealers, so the cycle is complete and salesmanship won over quality. For one more joke, go look at MGLs website, the testimonial picture of Kirby Chambliss shows his cockpit to have traditional gauges in it. Also note that MGL actually sells traditional gauges like airspeeds as “backups.” If their product is alleged to be reliable, how could it be backed up by something as cave man as a mechanical gauge?-ww

On the topic of Bruce Culvers Fokker Project, Builder Dan Branstrom writes:

“In the Continuation War of 1941-45, again fighting against the Soviets, and loosely aligned with the Nazis (more out of a desire to get out of Soviet clutches than any kinship with Nazis), the Finns flew a de-navalized version of the Brewster Buffalo, producing 36 aces. The US Navy considered their version a pig. The Finns did quite well with theirs.”

“I’m Swedish, and while Swedes tell jokes about the Finns, in a milder vein than we have in the past about the Poles, there’s a lot of kinship between them. (The Norwegians and Danes tell Swedish jokes). The Finns are known as TOUGH. There is not a lot of love towards Russia from the Finns or the other members of the Baltic states.-Dan”

Corvair Cooling, Three 2007 examples from our hangar.


Here are a few more observations on cooling. One of the central themes here is what we have proven to work over years of building and testing -vs- what some people perceive to be factual. First, because of the expanding nature of the Corvair movement, we will always have a steady stream of new arrivals who need to read up on what has already been accomplished and long proven. Most new builders are eager to do this, and our main page is the primary resource for this study. There is a minority of new arrivals that will find out about the corvair on Monday, skim the first page on our site, and commence to send me 6 or 8 text messages a day from their black berry or ipad, questions that could be answered with a few minutes of reading. Often, if I don’t answer them by Wednesday, they ask other people on net discussion groups, Thursday they send out messages asking if I am still in business and Friday they post a long story to the web about how rotten I am and how they just sent a big check…to a Unicorn breeder.

Those people are hard to help, but people willing to learn mostly invest the time to see what has been done, and this continuous learning cycle is part of my job, and I am glad to do it with any builders willing to learn. This is part of the normal path to successful building. These people can read about planes like the three examples we built below, and learn why their cooling systems work great. However, there is also a second type of perspective. This is a guy who has a specific view in his head, like “Corvairs have unsolved heat problems,” and he is going to try to find data to support it, all the while ignoring all the examples we built and flew and the builder clones of these examples that are out flying today. Changing the perspective of a guy who looks at the world in such a prejudiced way is very difficult.

People like this have an attachment to their perspective that is not softened by facts nor data. I will try once or twice, but beyond that, my work is confined to presenting data that shows these people are wrong, and prevents them from derailing the building process of other people who are making progress. One of the things I have learned about people in the last two decades is that the people who perceive these types of problems and ignore proven data to the contrary are very unlikely to ever finish a plane. That is their problem. If you are a regular builder and your working to build and fly your plane, your only concern is to learn to detect and avoid this type of person and not let their problem become yours.  Below are three examples of aircraft that were built or finished by my “Hangar Gang” at our old hangar in Edgewater FL in 2007.  All three used our standard cowlings and cooling methods. This is information that is more than five years old, and plenty of people have seen these aircraft from Coast to coast in the US. This is what is known as physical proof.

In the above photo, Gordon Alexander’s 3,100cc Pegzair complete and running has just passed its FAA Airworthiness Inspection.  Gordon brought the project down on a trailer from Minnesota to the main hangar in Edgewater, where he commenced a savage 14-hours a day for 100 days to finish it. Inspired by his commitment, Gus, Kevin and I each worked to assist him. This is a very large corvair powered plane, it is a true STOL type with automatic leading edge slats, and it will fly below 40 mph. It is very draggy, and it had no problem cooling. I flew the plane, and it worked well after only a few small tweaks. It has an MA3 carb and a very quiet exhaust. It did not use inlet rings and it has a front alternator. The person who told me on the phone that he thought slow planes “had heat issues” knew about this plane but chose to ignore it’s sucess because it didn’t fit his pre-conceived model of reality. Thats ok because reality works weither or not every armchair expert agrees with it or not.

Above is a shot of Rick Lindstrom’s 601XL with its complete paintjob outside our hangar in 2007. The prop is a Sensenich 64×41. The carb is a MA3. This aircraft has flown all over the US. It has been in FL, Southern California and to Washington state. It has been seen by builders at the Sun n Fun, Arlington and Copper State (AZ) airshows. It even won the best engine trophy. A number of pilots have flown it long distances Like Rick, Amy Choi, Woody Harris and Michael Heintz. It flew across the US in the middle of a heat wave that showed outside air temps above 105F at 9,500 feet. The plane was flying at a special gross of 1425 pounds for the flight. It was climbed under these conditions at wide open throttle for over 50 minutes without pause after a number of fuel stops. This climb was flown at airspeeds near 65 mph. Yet it never over heated nor detonated, period. It has the exact same cooling system that we teach builders to install on their Zeniths. Physics doesn’t play favorites. It works here, and if you build a copy of this, it will work on your plane. Let anyone who thinks we don’t know how to cool a Corvair explain the history of this aircraft….they can’t.

A look at our 701 testbed in the Zenith booth at Sun ‘N Fun.2010. The plane was finished in the old hangar in 2007.  In 2010, Dan Weseman and I worked to upgrade the aircraft with one of his 5th bearings. This aircraft is capable of very slow climbs at high power. It is a cooling challenge. When we first finished the plane it had an aerocarb on it. This was later changed to an Ellison. We tuff tested the cowl and made a number of small tweaks. The only serious issue we had with the plane running hot was caused by the owner resetting the ignition timing without a light. This corrected, the plane worked fine, and a number of well-known Corvair pilots like Gus Warren, Arnold Holmes and Dan Weseman flew the plane. This aircraft had the first Gold Oil Fliter housing flown.

A negative person could claim we had to work some to make this plane fly cool, but reality says that is why there are 40 hour test periods, that is why we build and test things ourselves instead of using builders as guinea pigs, and lets not forget, this is why we use timing lights to set timing. This aircraft worked and cooled itself, and any 701 builder who made a clone of the configuration of this aircraft would have it work for him also. If you are new to Corvairs, and going through the learning cycle, keep in mind that you may hear of examples that didn’t work (that didn’t use our data or meathods) or you may hear from people who are willfully ignoring aircraft we have built and publicly demonstrated to work. If you let them deter you, you are allowing them to rob you of a chance to finish and fly your plane. What will you get as a consolation prize? you get to be nothing more than a supporter of a person who’s claims can be shown to be false just by looking at the above three photos. Some of these people will pose as experts just trying to “help” you with your plane. You need only ask them to show you the Corvair powered planes that were finished and flown out of their hangar. They will have nothing to show.-ww

There is a quote that comes to mind when dealing with people who will not openly observe things that we show to work, nor even acknowledge the existence of these planes, in the dogged need to keep their pet belief:

“If a man, holding a belief which he was taught in childhood or persuaded of afterwards, keeps down and pushes away any doubts which arise about it in his mind, purposely avoids the reading of books and the company of men that call into question or discuss it, and regards as impious those questions which cannot easily be asked without disturbing it–the life of that man is one long sin against mankind.” -William Clifford

Mail Sack, 10-25-12 , Kevin Purtee and Colleges.


A sampling of letters on Kevin Purtee’s story;

Builder and CC#22 grad Vic Delgado writes:

“Great Writing Kevin! I had no idea you had an accident either. Glad you were able to recover and still at it! I look forward to hopefully catching up with you and Shelly and rest of the awesome Corvair group at one of the future Colleges.-Vic.”

Michelle Gilbert,United States Army, writes;

“Inspiring… I am so proud to call you all my friends! :D You’re both so special to me.”

Corvair/601XL builder, Host CC#3,  and Pietenpol pilot Oscar Zuniga writes:

“Roger, experimental niner-niner-kilo-pop. You’ve got it SOOOO right!-Experimental four-one-charlie-charlie”

Zenith 750 builder and 7 time College grad. Dan Glaze writes;

“what a fantastic love story”


On the value of Corvair Colleges, 750/2850cc builder Gary Burdett writes:

“My Cray comment (in the last mail sack)was meant as humor of course, but to be serious for a moment, I have had two individuals in the last several months email me on the zenith site because they see that I am a 750 corvair builder. I tell them to get more info about a corvair in airplanes, go to a college if you can, buy manuals at least if you can’t , and go to both websites anyway and read as they both give as good a flavor about the corvair as you can get short of the two options above. And do it now, not later. There , that’s it for the seriousness, back to humor.”

Builder Bruce Culver writes:

“William, I missed CC#22 in Georgetown and was wondering if you are planning any other Corvair Colleges roughly in the Texas area in the near future. If not, I used to drive 1100 miles from Dallas to Jax to visit my brother…..Wow. (Of course I was a LOT younger in those days…..)”

Bruce, We have spoken to a number of builders in favor of a Texas or a Oklahoma College in 2013.  Arnold Holmes, host of #17, would like to do another in Central Florida, the weekend before sun n fun in April. We are pretty sure we are going to Chino CA in the spring and with PF Beck and Crew’s blessing back to Barnwell every November.-ww

Best of Mail Sack……’Albus D. Onis’


I read email in between doing all the other tasks here. Many things require daylight or one’s immediate and full attention. Combing through email requires neither, which is why I often get to it in the middle of the night.

Intermixed with questions, notes and a photo or two are a few gems. when it’s 3:30 am and I have turned myself into a sleepless zombie by absent-mindedly drinking a gallon of coffee after dinner, I will sit a the computer and run through a number of short emails to be productive. In the middle of a long list, I will actually get 10 sentences into an email like the one below before I understand what I am reading:

“Mr. Wynne, I’m so happy and stimulated that I’ve come across your wonderful website. I’ve been struggling with an engine choice for my latest project and I feel the corvair will be the perfect choice after I apply a few modifications.”

I am currently scratch building a 1/6 scale H-4 Hercules from scratch. I designed it to be LSA legal. I’m hoping you can help me with a few questions. Even though I’ve read your website thoroughly and now know as much as you about corvair, the copied copy of your conversion manual that I’m using is faded in spots and the text is illegible. I’m sorry I didn’t buy one from you but I am on a very tight, low fat budget. Anyhow, here are my questions:

Being that I’ll be installing eight engines, how do you propose I synchronize all the props?

Is it possible to share one ignition for all engines to save weight and money?

Will one alternator (i’m planning on using a motor out of an old battery drill i’m not using anymore) feed the ignition, lights, dual 10″ dynon skyviews, dual navcoms, and dual gps’s?

How feasible is to hand-prop the corvair to start it? I can only afford starters for 2 of the engines.

In your opinion, is 1/2″ black pipe strong enough to use for motor mounts?

Would a 1/2 HP sump pump provide adequate pressure for the shared fuel injection system?

Thank you so much in advance for what I am positive will be a most prompt response to my questions.

Finally, I look forward to attending your next college of corvairs edition 24. I stimulatingly dream of meating you, your brother Roy, and your pet falcon, Mark who likes the petunia flowers. If i only come for a few hours during dinner to eat and talk with you at the college of corvairs, do I still have to pay the $79.00?

Fondly, Albus D. Onis”

Albus D. Onis sounds like “Adonis” which is the popular moniker of Corvair 601 builder Ken Pavlou, in reference to his Greek heritage. (I once said ‘Ken you’re as brilliant as Plato!’ to which he responded dead pan “And I have the body of Adonis.”) I was half way into this email before I understood it was a joke. This should tell you both how tired I was and that over the years we have received a number of emails that were nearly this bad that were actually ‘serious’ questions. -ww

Above, I introduce our local host Ken Pavlou at Corvair College #14. In addition to an impressive job at CC#14, Ken has organized many Corvair Cookouts, run the on-line registration for the Colleges, and he set up the format that I use for this blog. On line he likes to be called “The Central Scrutinizer”, a character who is a omnicient narrator in the Zappa opera “Joe’s Garage.”  Outside of the Corvair movement, Ken has a long list of accomplishments: emigrating from Greece at age 8, he has gone on to earn an electrical engineering degree, become a registered nurse and skilled pilot. Happily married and the father of two, he’s also the State Ballroom Dancing Champion of Connecticut (no kidding), and he could earn a living doing stand up comedy. Not bad for a guy who’s barely in his 40s.

Mail Sack 10-3-12


I write a lot about motivation and philosophy, and most of the stuff rarely generates email, but if I write a piece that sounds cranky, people write in response.  Below, a few thoughts from builders. keeping in mind that independent, intelligent people often see things from a different angle, I rarely expect builders to see eye to eye on perspectives, and it worth including that I am often more entertained by people I disagree with than people who see a subject the same way. I am open-minded, notice that “Guy A” gets the last word on the subject with his own letter.I wrote a long detail piece on plugs a few months ago, to read it type the words “Spark Plug Woody Harris” in the search block on the above right.

At the very bottom is a very thoughtful letter from Harold Bickford on the article Mastery or ?. Well worth reading -ww 


From builder Matt Lockwood:

Good points (pardon the pun). Speaking for myself, I have learned tremendously from you, WW, thanks for being a pioneer.


From 601 Builder/pilot and DVM Gary Ray:

“You are not alone.
I have seen similar behavior in my profession. If West Nile virus is reported in the press then all animals that die in the next year were one of the unlucky ones that got it. Or if the Chinese contaminate dog and cat food with sawdust, then all animals that die of kidney failure must have been poisoned even though no toxic agent has been found, no animal gets sick when deliberately fed the suspected food, millions of animals that have eaten it have perfectly normal health and blood work, and none of the tissue damage found on necropsy of animals that die is related to other cases. Or, when a client states that they think their cat is responding poorly to a vaccine that he got two months ago and it is making him sick, they are not convinced by me when I tell them that the tire imprint on the white-haired abdomen probably has more to do with his current problem. “


From west Coast Pietenpol builder Pete Kozachik:

“Hi William, I’m having a Dickens of a time with your tale of two spark plugs; seems I used the wrong gap on my test run some time ago. The last line in your piece calls for .016″, but I used the 1965 Corvair Shop Manual’s spec, .030″. I used AC-R44F plugs, and ran the test using high octane no-lead gas as prescribed. What gap should I have used under those conditions? Same as for 100LL? One thing I noted after the run was some wet(?) soot on one plug, which I figured was due to any number of things, but not the wrong gap. What’s your diagnosis? Best wishes, Pete”

Pete, I included your note here in case anyone else read the story and got a detail wrong: .016″ is a gap that is correct for a magneto ignition, as on the Franklin in part “B”. Corvair should have a gap of .035″ and use ACR44F plugs.  Other ones work, but if anyone wants old reliable, this is the best set, especially if you are trying to track down any kind of issue of experimenting with some other variable. We soot on a plug on a first run is often assembly oil from the engine’s build up.-ww


From Builder Mr. Jaksno:

“Sorry to hear this. Aviation does not suffer fools. The rant was well deserved, AND instructional. Thank you for being a ‘Lifeguard’. And thanks for being the Godfather of Corv-air!”

If you read the letter from Guy A you will see he is a pretty good cat, just missed it on the plug issue. A lifeguard will rescue people, (I tried it once, worked, but I promised Grace that I would let professionals and those clad in asbestos extract trapped people next time.) Just think of me as a guy standing on the beach pointing out where the rip tide you can’t see is. -ww


From Builder Bruce Culver:

“Don’t that make your brown eyes blue…..?”


And a response from the ever mysterious “Guy A” Himself, with whom I had a very pleasant 25 minute phone call today. If I ever sound cranky in email, it’s probably an attempt at humor gone bad. There is little between friends that can’t be fixed with a phone call……Guy A is obviously a thoughtful guy who considers risk management seriously, he just missed a basic important point on his engine.

I (Guy “A”) had night of introspection, and not much sleep, after reading this over a few times. I know that I’m *not* a taker of unmitigated risks, as you might infer. Instead, like nearly all long-time pilots, I recognize that flying, especially flying an airplane I built-in the garage with an engine not originally designed for a plane, is an inherently risky activity. And I believe that the risk can be reasonably managed through precise construction and maintenance, well thought-out testing, careful operation, and learning from the experience (and mistakes) of others.
I retorque my wooden prop at every oil change, and I do those at short intervals recognizing that Rotella-T and a $6 oil filter are not expensive compared to the engine. I have two batteries and an alternator in my electrically dependent airplane, and every year at annual, I put in a fresh battery in the #1 spot and move the #1 battery to the #2 spot, so that I always have at least one battery that less than year old. The manufacturer says the batteries should last 6 years, but what’s a battery worth when you’re in the clouds, an hour from the closest airport, and the alternator belt breaks?
I change my tires before they’re bald. I use flight following whenever I can and file flight plans when I can’t. I check the weather before I fly, every time, and I talk to Flight Watch a lot when it doesn’t look good. I use carb heat at low power whenever it’s below 75 degrees, even if I know the relative humidity is 20%. I attend FAA safety meetings regularly, because that one minute reminder of something I’m supposed to know might make the difference, making the two-hour presentation worth the time.
When I had a certified plane, I only used the specified plugs, and I cleaned, gapped and rotated them on a regular basis. So how did it happen that I flat-out “missed” the *requirement* to use the right plug with the proper gap in my engine?
I could try to explain that the plugs I used *are* listed in the spark plug cross references, and that I ground tested a range of supposedly acceptable heat plugs, found no apparent differences and stuck with the middle of the range. I could note that I’ve flown probably 400 of the 500 hours on my plane with those plugs. I could mention that modern cars with computerized adaptive ignitions are much less sensitive to particular plug heat and gap, so it wasn’t on my mind.
But all that would just be underlining the remarkable strength and robustness of the Corvair design. During all those hours, I was probably getting less-than-optimal performance and building up lead deposits on the valves. And a choice to use conservative timing (about 28 degrees max advance), in case I had to run on auto fuel, probably kept me from seriously damaging the engine.
So I’m just going to say, “I missed it, and messed up.” My bad. Experimental aviation is supposed to be a long journey of learning, and now I’ve learned this one,Luckily, no metal got bent and no one got hurt. ACDelco R44F plugs, gapped .035-.040. Got it.
Final note – If you also cannot find these plugs in your local auto parts store, try Rock Auto on-line ( for the best price.


On the subject of Mastery or ?  Builder Harold Bickford wrote:


It seems to me that when you build something from components or better yet from basic materials you have to learn about craftsmanship, patience, accuracy and so forth. By it’s very nature homebuilding is not instant gratification and that is a good thing in a society that seems to want things right now for little or no cost. It is better to invest yourself and learn than to simply have someone else say “this is the airplane you want”.

Certainly part of the building adventure has been to visit and work with a fellow Piet builder. He ultimately chose an O-200 which he rebuilt. The Corvair engine mount he had is now in my shop along with a Corvair engine on an engine stand that will be torn down when it gets colder Meanwhile the wood for the fuselage is ready for cutting and framing up while we still have nice temperate days. True it is labor intensive (and we are on a budget) but the point is that when done the Piet will be a known quantity and at virtually every point Edi and I will be able to say “we built that”.




A Tale of Two Spark Plugs……


“They were the best of plugs and they were the worst of plugs; It depended solely on which engine you screwed them in. Applications be damned, to hell with gaps! We’ll run what we like and blame the results on GM and William Wynne”

……The following story is true, the names have been changed to protect the guilty…………

Guy “A”, Sends several notes, calls etc. Reports his engine is running poorly after a number of hours. He is a technical kind of guy, interested in concepts like lean of peak operation, analysing performance, fuel additives, etc. We run through a pile of different possibilities. Thinking that it must be something that troglodyte ww did, he gets inside his distributor and starts changing stuff to see if he can cure an intermittent hard miss on climb out. It doesn’t do anything. (but mess up the distributor)

Along the way, It is discovered that one cylinder is blowing 50/80 on a compression test. This is now the new suspect for Guy “A.” He is sure of it. I carefully explain that a leaking exhaust valve will not produce an intermittent miss. I go in to explain that even if the engine had 40 over 80 on a differential compression test, this in no way is indicative that cylinder is producing 1/2 power.  Even if a cylinder indicates this low, I seriously doubt that any more than 2% of the flammable air fuel charge escapes past the leak in operation. Just think about how short a period of time the compression stroke is on an engine turning 3,000 rpm.

After all kinds of communication and tests, some how we stumble over spark plug gaps and Guy “A” casually says he gapped the plugs correctly at .025″. I ask why on earth he would do this? Guy “A” feels that this is the correct gap for reasons he cannot explain. A moment later he reveals that he has NGK spark plugs in the engine! He thinks they are great plugs. I agree, pointing out that I always liked them in two-stroke dirt bikes, but that has nothing to do with Corvair engines in aircraft. I ask how he decided which NGK to use, he tells me he tried several, and it ran best’ on the one he picked out. (I wonder to myself how badly it detonated when he found the plug that was too hot.)

Guy “A”  Complains that they don’t sell AC-R44F plugs in his local auto parts store. He goes on-line and finds out that the correct plug we tell people to use cost a whopping $1.44 a plug, far less than the incorrect ones he is using. He goes back and regaps his plugs while waiting for the correct ones, and Volia! intermittent miss gone (at least on the side of the ignition he didn’t mess with.) Today he sends me a picture of the incorrect plugs, he has 83 hours on them. The includes the opinion that they “look pretty good.” I point out that they are the worst looking plugs I have seen in a while. His return question is what is wrong with his motor that it makes the plugs dirty? HOW ABOUT THIS: ITS THE WRONG PLUG FOR THE ENGINE, AND IT HAD A GAP THAT WAS CORRECT FOR A LAWN MOWER.

Trick question: A guy tells you that he has been driving Corvairs for 25 years, he knows engines real well and he has had great results with NGK plugs in his Corvair. They are great to use right? WRONG. Don’t take advice from car guys. Show me the car guy who runs is car on 100LL all the time and cruises at 75 HP. A 1965-69 Corvair will break 100 mph on 75 applied HP. It is not valid data, it doesn’t apply. You can’t show me a land based corvair that only fills up at airports and always drives at 100 mph. 

Here is my major problem, at Guy “A”‘s airport, a lot guys have watched his engine do this intermittent miss on many, many take offs while Guy “A” has been ‘testing.’  Do you think that each and every one of them will now be made to understand that the root of all of Guy “A”‘s issues is caused because he willfully ignored the correct plug for his engine, and then made up a new gap? No way, I am sure that the lesson that each of these people learned is “Car engines suck, Corvairs are bad, they are promoted by a fool, Since guy “A” has a PhD in engineering, if he couldn’t figure it out, no regular builder could.”

My second major problem is with anyone who has an issue with their engine, and the very first thing they decide is “It must be something William did or sold to me.” Statistically speaking, the last 50 times some one jumped to this conclusion, it was something they were doing 49 times. I don’t mind questions, but I do mind the assumption that I don’t know what I am doing, especially when it comes from a person who isn’t even willing to follow my spark plug recommendations. Think it over, Civility is a two-way street. Would you like me if I went to your place of work and always started communications with the assumption that suggestions you made are not worth following and the work you produce is the root of all my issues. How long are you going to be civil with me?

I like teaching people what we have painstakingly learned. Mistakes are ok, we can correct them, but let me point out that this entire wild goose chase was avoidable. It was caused by an attitude problem, a perspective that asking some people on the net and guessing was technically just as valid as all the reasearch, testing and operational data that I have gathered since 1989. -ww

PS: Lest anyone think I am just picking on Guy “A”, let me share a story of Guy “B”. Guy  “B” is an old friend, and he owns a certified aircraft with a 150 hp Franklin, (Which has magneto ignition.) He is not an a&P , but does some Pilot preventive maintenance on it. When it is cool, it runs fine, but after a while, it runs poorly. Winter weather leads him to understand that he must have carb ice. This goes on for several flights, some of which almost end up as forced landings. Everything is considered the culprit, even the basic Franklin design. Steve Upson, old member of the ‘hangar gang’, and very stubborn mechanical detective makes it his personal mission to figure it out. After a long day, he asks the operator about the kind of work he did. He goes into how he cleaned the plugs and gapped them at .035″ Steve points out that this is more than two times the limit allowable. Owner chimes in that it works on all his cars. Steve asks how long he has had Bendix mags on all of his cars. Plug gaps corrected to .016″ plane flies perfectly.



EAA Webinar notes…..


EAA headquarters sent me a followup spread sheet with all of the data from last night’s webinar. It included about 120 questions that builders watching wrote in with. When we were doing the session, only the people at headquarters can see the questions, they didn’t come to my computer, so we relied on Charlie Becker picking out 20 questions that time allowed us to answer. Many of the questions were covered in the talk, but I wanted anyone who didn’t get an answer to send me the question directly, I will be glad to answer it for you. The EAA ia good about protecting the privacy of members, and the data we got was not tied to anyones email address, so it isn’t possible for me to answer the questions for people without them resending them directly.

One other note, several people mentioned that the program started 4 minutes late and had some audio difficulties. One or two comments suggested that we should have check the system earlier. Actually Charlie Becker is a stickler about doing just that. He gave us a long tutorial the day before, and insisted we run wire in the house and go out and buy the exact headset model he wanted. We did all these things. At 3pm, Charlie had us do a full dress rehearsal, including every element of the log in, it worked perfectly. We didn’t touch anything. We checked it 25 minutes before broadcast, and suddenly nothing worked in the audio. Grace and Charlie worked to reboot the system several times, and tried everything we could think of without avail. As we got to the last-minute, Charlie quickly hooked up a telephone connection through the EAA switchboard, and then through his office. Instead of everything going through the computer, all of the things I said in the entire interview went through the phone line, where we had little chance to control even rudimentary things like volume. Thanks to Charlie’s quick thinking, the show went on, with little noticeable issue. I asked Charlie if it had ever happened before, and he said that they had not had this issue ever. Hats off to Charlie for saving the day.-ww