Mail Sack, 2/15/13 Various topics


Here is a lot of mail on a number of different topics. Putting this together takes a few hours, and for a computer troglodyte like myself, they have to be quality hours of actually being awake, lest I hit the wrong key and evaporate an hour’s work. Builder mail is very important because it is a big part of giving my work feedback and focus. I have experience and perspectives, but many of the builders we work with have far greater accounts on both fronts. They are well worth listening to. I read all the mail carefully, and it fine tunes my picture of the Corvair movement. I spend a lot of the Colleges, Oshkosh and fly ins listening to builder’s perspectives because I, like everyone else, learned most of what I know by listening to, or reading the work of others. Even if I don’t initially see things the same way as a writer, I put real effort into following their line of thought. At Oshkosh every year I speak with a number of people who are very attached to an old wives’ tale or a piece of experience that doesn’t apply to Corvairs. I can tell that these people are not actually listening, they are just hearing enough to develop their next reply, a superficial debate move, not learning. I am not fond of this, and I put a lot of effort into not being “that guy” myself when I hear from people who see things differently.-ww


On the subject of cold weather operations,

Click on: Thoughts on cold weather operation, minimum oil temps, etc.

601XL builder/flyer Dr. Gary Ray writes:

“William, When we installed my remote 4 line Oil Filter with the Sandwich for the Oil Cooler, we removed the original oil by-pass spring and valve from beneath the top block off top cover. Is this still the preferred set up? What is the effect on the oil circulation pattern (cold, hot)?
After reading this, I will definitely pre-heat every time.”

Dr. Ray,

Any time you have the sandwich adaptor in our system, you need to remove the stock cooler bypass. Its function is replaced by the bypass in the gold sandwich itself. With a flat block off plate on the side of the case where the stock cooler was mounted, the circulation pattern through the engine is retained with the sandwich. -ww

Merlin on Floats builder/flyer in Newfoundland Jeff Moores writes:

“Hi William, Thank you, thank you, thank you for your post on cold weather operation. Excellent information. As you know I have been operating my Corvair this winter and have been preheating before every start. It usually takes an hour minimum and I see it as a necessary part of winter flying. I usually spend the time inspecting the airplane, using the snowblower to clear the hangar doors or just having a lunch and a cup of tea. I’m in no rush….this is all for fun!!! The flight afterwards is well worth it. Before I start the engine I’ll also rotate the prop several times to help prevent a dry start. I don’t know where you find the time to write these posts but keep them coming!!!, Jeff ”

Note: More photos of Jeff flying Lotus floats directly off his snow covered lake in Newfoundland coming in an update in the next day or two. -ww

On the subject of Cylinder heads,

Pietenpol builder/pilot Kevin Purtee  writes:

“Good points about the cost of heads, WW. When I originally built my motor (1999), many of the parts and processes you recommend were not yet available. With the rebuild, we included the basic upgrades that you’ve researched and developed to make a better motor: 2nd generation Dan bearing, gold oil system, MP heads. I’ve followed your work since 1999 and have flown behind your motor for over 300 hours, I’d remind folks to not save on the wrong end. Kevin.”


On the subject of “Calling all Zenvairs”,

Click on: Calling All “Zenvair” Flyers……601 / 650 / 750

601XL builder/flyer Lynn Dingfelder writes:

“William, I’m interested in your offer regarding flying in to Sun-N-Fun in my ZenVair 601, though perhaps I’m responding too late. I have uncertainty about being able to depart my home field in early April, due to potentially soft turf. Only the coming of spring here in snow country will answer that concern. I’ve done some initial flight planning, and am excited about the possibility of making this journey. Please let me know if your display openings are all spoken for.
Thanks, Lynn Dingfelder”

Lynn, we still have space in the Zenith booth, we will be glad to have you on hand at Sun ‘N Fun-ww


On the subject of Oil Systems,

Land based Corvair guru Bob Helt writes:

“Hi William, You said the following in a recent posting: ‘If you would like to read the whole report, it is on, search “2003 oil system test” in the search block on the bottom of the main page.’ I can’t seem to be able to locate the original test report. I keep getting the summary where I found the statement. Could you please point me to a copy of the original report. Thanks, Regards, Bob.”

Bob, read all the way down at this link:


On the subject of numbering systems,

601XL builder Oscar Zuniga writes:

“William: Please stop the world so I can catch up! I’ve been away from the site for a few weeks since I’m buried with academic work, and I come back to see what’s up only to find a rich treasure of posts about building, choices, and costs, with a numbering system to track it all. Please tell me that this will be organized and published as its own book, manual, or supplement on It’s worth what a builder will save in mis-spent money… and that can be a lot! Please consider publishing it as a separate resource for manual owners and builders.-Oscar”

Oscar, I Chose the title “Getting started in 2013” because that is the goal, to have the people who have hesitated to get started understand that this is the year, there is nothing to be gained by daydreaming another season away. The notes are to give these people a clearer picture of their personal path to success. I have a lot of the stuff written in great detail, but for right now I want to give builders a large overview; we will come back and look at every detail later.-ww

On Part #11, 3,000 cc Waiex builder Greg Crouchley writes:

“Amen. And thanks for continually striving to point this out. The life you save next might be mine.Best regards, Greg”

Builder Henry Vickers writes:

“In looking over your Web page, I note that you have put some supplies in a group – in particular 2775 and 2850. Are those prices firm or just proposed prices? Thank you”

Henry, the 2,850 price is our regular retail on that kit. We have sold about 30 of them. The 2,775 is just proposed, but since it is made of parts from the same suppliers, the estimated price is accurate, but the pistons are yet to be made.-ww

On “Part #14”, Builder “Jacksno” writes:

“CH-750 + 2850 is my main plan. I’m interested in hearing from others who may have used floats and 2 up (about 350# worth of meat). Plenty of fun on wheels to be had and I could drop this romantic notion without much fuss. Or if the notion remains stubbornly in place, elect to go the extra expense of the 3000 if that would make the difference in torque I imagine would be necessary to water operations. Are there others out there with float experience with 2850, 2 up? Or take the big step up to 3000 or fogeddaboudit? Thanks!”

We don’t have anyone who has flown a 750 on floats yet. From land based performance reports of the 2,850s and 3,000 cc on the 750 I have little doubt that either one would pull two people off the water in a 750-ww

Builder Douglas Cooke writes:

“Hello William, I have a 1964 engine/heads that has been disassembled and cleaned and a standard grind nitrided crank. I have the new piston/rod assemblies, rings, and the .060 Clark’s full fin cylinders to make it into a “sixty over” engine. I do plan to use mogas as much as possible (my home airport has 93 oct mogas). I don’t see the engine getting built this year, so going with your “2775″ engine seems to make sense as it would give better quench for more reliable detonation resistance and possibly a couple more horses than my current parts would. Might you offer a trade-in of my “brand new” (but about 5 years old) Sealed Power and Hastings “Sixty over” parts for the “2775″ parts, or maybe I should get my cylinders bored another .045 and go with a 2850? (I don’t quite know what airframe the engine will be going into). I am on a tight budget, but would be willing to spend a couple hundred or so more for a little more power, and most definitely I’d spend it for better detonation resistance/reliability. Thanks, Douglas Cooke”

Douglas, your motivation to build the best engine you can sounds like common sense to me. Since you already have the full fin cylinders, it would make the most sense to go for a 2,850 cc upgrade when the time is right. Your .060″ pistons will find a buyer with little trouble, they are still popular.-ww

On “Part #15”, Piet Builder/ATP/USMC Terry Hand writes:

“William, Count me in on the 2,775 cc pistons. I am still building my Pietenpol, so I am not in a rush necessarily to build my engine. Aviation is a lot like Medicine. For example, if you can hold off having a medical procedure done, the medical technology advances makes it better. The neck surgery I had done a year ago was a 1 and 1/2 hour outpatient procedure. 15 years ago it involved a week stay in the hospital with part of the time in ICU. Aviation advances in much the same way. I can’t wait to see the technology improvement in these pistons! Thanks to you and Mark for your work on these pistons.”

Terry, I consider the Corvair to be fully developed, with only detail improvements and small parts like the 2775 stuff as “mopping up” projects. The largest part of my efforts in the next two years will be improving the accessibility to the engine for first time builders. The new numbering system is the root of this. Having good stuff comes first, and we have that down, and proven with years of service. Now the focus is on motivating people to become builders and use the parts and information we painstakingly developed in the past 20 years.-ww 

On Part #15 Builder Bruce Culver writes:

“This is a terrific idea, because if the folks working with the stock cylinders can get the detonation-resistant cylinder-head design, that makes operating these engines safer and improves reliability. Such a deal. You don’t see this sort of thing in most of aviation, or most other activities for that matter. Congratulations on working for us, no matter how we plan to build our engines. Of course, that beautiful billet crank from Dan is still calling my name – maybe for a 2850……William, I forgot to mention my choice of the Corvair….. Although I am thinking of the 2850cc engine, I originally looked at the Corvair as an affordable alternative to certified engines, as in, I can afford a Corvair if I build it and then I can fly. I can’t afford a new or even refurbished certified engine, so that way I can’t fly. I was a loggie (logistics analyst) for 25 years in the defense industry. Our watch word was “life cycle cost” – the total cost of acquiring, operating and maintaining an item. As you are well aware, with the Corvair, we could completely rebuild an engine with all new parts for little more than the cost of the valves in a certified engine. I have never considered any other engine than the Corvair ever since I attended your presentations at Sun ‘N Fun a number of years ago. To me, knowing the engine – its guts, and what makes it work – is more valuable than any engine I could buy, even if I had the budget. That’s why I’m here.”

On Part #17 Buttercup Builder Daniel Kelley writes:

“William, Clark’s Corvair OT-10 and ordering assembled they seem to want to use a single part number. Clark’s ( sells the stock cam gear or the Failsafe gear as separate parts or you can have them mount the gear you choose on your choice of OT-10 cam (new or regrind) with a new key and thrust washer function=goto&catalog=SPECIALTY&section=OTTO&page=OTTO-8

On the subject of “Getting Started Pt.#19”, 750 builder Charlie Redditt writes:

“Reminds me of saying ‘There is hardly anything in the world that someone cannot make a little worse and sell a little cheaper, and the people who consider price alone are that person’s lawful prey.’ Of course, most of your posts remind me of that saying, but this one particularly so. The irony is, of course, that Corvairs ARE the best deal for the money. It just requires a bit of self-education to realize this.”

Builder and International Man of Adventure Tom Graziano writes:

“William, Having flown in some of the most remote and inhospitable places on earth and having seen the consequences of various failures, there is no question that reliability should secure the #1 spot on the list for us aviators. (Interesting how safety and reliability so often go hand-in-hand.) Fortunately, we homebuilders and our experimentation and quest for a better mousetrap have led to much innovation and advancement. Unfortunately, there are those of our clan who have their minds made up and don’t want to be confused with the facts nor schooled about that which has already been thoroughly tried and discarded such as carbs, 5th bearings, fuel hoses/fittings, crash resistant fuel tanks, and such. The results are too often bad publicity from the ensuing accident or incident. I really wish homebuilders would put more thought and money into safety of flight vs. convenience of flight or the coolness factor.
I am really enjoying these Getting Started articles! Keep ’em coming! Tom”

601XL builder/flyer Dr. Gary Ray writes:

“Hi William, I am enjoying the new ultra-organized presentation of options for building the Corvair engines. I think this simplifies and clarifies the thought process for builders. Matching their engine requirements for a best fit to the projects is easier and provides a comparison of price/performance. This also lists all of the required parts, services, and timelines that need to be considered for the build. I am becoming inspired to start a new engine build just so I can have some of the fun. This is a really good idea and possibly should include all of the FWF item choices that you offer. Most kits do not include help forward of the firewall. As an earlier builder, one of the reasons that I chose the Corvair was the fact that you were building the same aircraft and I would benefit from going to school on your expertise on FWF systems design. Thanks to your efforts, I know a lot more now and I have avoided countless mistakes, possibly some that saved my life. I am sure this applies equally well to others building in the void between airports.
Thanks, Gary Ray”


On the subject of 150,000 page reads,

Click on: breaks 150,000 page reads, 2/6/13.

601XL builder/flyer Phil Maxson writes:

“Your readership may be even higher. I read this blog on email frequently and don’t hit the site directly. My “hits” may not be included in your numbers.”

 601XL builder Becky Shipman writes:

“Congrats on your 150,000 page reads. FYI, I generally notice your e-mails on my work computer, which feels that is a dangerous site and won’t let me go there. So I read the e-mail but don’t go to the site. So it’s probably a little higher than 150,000 – I may not be the only one. Take care, Becky Shipman”

On the subject of  “The JAG-2 Twin Corvair”,

Click on: JAG-2, Corvair Powered Twin, Jim Tomaszewski, N.Y.

Builder Allen Oliver writes:

“My interest was piqued by your first mention of the JAG-2, so I went over to the Web site before you posted the details of his project. I was frankly impressed at the scope of the work and the thoughtfulness behind his design. I tend to think of it as an 80% Piper Apache.”

Piet builder Bob Dewenter writes:

“Cooler than cool!”

601XL builder/flyer Rodger Pritchard writes:

“William, Thank you for keeping us posted on what people are doing. I had a smile almost the size of the one I get flying my ac just reading about Jim’s design and build. I hope to see it at Oshkosh someday.
Roger Pritchard, N20RB Zenith/Corvair, 106 hours on engine 97 on airframe”

Builder Dan Branstrom writes:

“This is neat, and obviously a labor of love.”

750 builder Charlie Redditt writes:

“Über kewl! A real-live Corvair twin!

I’ve also come across this on the web:
but it doesn’t seem to exist quite yet. Spec’d for 80hp jaibaru, but I assume anything that would take a jaibaru could also take a Corvair.”

Charlie, the Gemini is an old project, it flew for many years, it is still out in Mexico MO. Chris Heintz was interested in an updated version based on XL stuff in 2004 when we first had our XL flying. I mentioned to him that Corvairs can be built in both L and R rotation, and were comparatively very cheap compared to Rotaxes or Jabarus. He was interested, but he was already looking forward to retirement in France.-ww

On the subject of “The case of the Murphy Rebel”,

Click on: The case of the Murphy Rebel, “eyeball vs. testing”

Builder and International Man of Adventure Tom Graziano writes:

“William, Good post. I take it ‘common sense’ is naysayer code for ‘insufficient research’? Whoever stated that about the Corvair and smaller props is misinformed and definitely doesn’t ‘get it.’ (For a few bucks the guy could get a copy of Jack Norris’ book on propellers and, if he read it, maybe he’d get it then, but I don’t hold out much hope in that regard.) Then again, most naysayers don’t want to ‘get it’ and they’re content rolling around in the muck of old wives’ tales and ‘don’t-confuse-me-with-the-facts’ tradition. All the best, Tom

P.S – anyone interested in what a well-designed prop looks like should take a look at the laminated prop example on the web page.”

Builder “Jacksno” writes:

“Thanks for the intro to prop theory/practice! Especially interesting was thinking about too much pitch, the excess angle of attack leading to the blades stalling out – maybe they are still pushing wind back over flight surfaces, but no lift component when stalled, reducing forward energy. None of us can be surprised when we discover that people’s opinions are more precious to them than truth – a function of false pride and ego. Out here in the country, it’s called ‘ignorant.’ The meaning thereof is that the individual in question refuses to seek the true facts on purpose. Just my .02, I suggest you ignore them, but please keep on educating us!”

601XL builder and PhD engineer Becky Shipman writes:

“Almost everything we use that is manufactured is made by trying to optimize multiple factors. The one described here is relatively simple – props have performance that depends on things like length, RPM, pitch, shape, etc. Engines have torque and HP curves, and other factors that affect reliability. I think if you look at historical development of engines and props, much of the relevant info has been understood for at least 50 years. Thank you for elevating the debate by pitting 1960′s engineering versus ‘black magic’ and winning. Almost every design that works was done with some forethought by folks who knew what they were doing. Before changing it, it’s vital to take the time to understand why they did what they did, and then what might be different in the current situation. If you take a tractor transmission, driving big wheels with a diesel engine, and put it on a car with a 4-cylinder turbocharged engine and 14″ wheels, would you expect the optimum rear end ratio to be the same? Apparently our Murphy Rebel commentator would. (Probably not exactly the right analogy, but I bet someone who knows more about cars and airplanes could come up with a funny and relevant variation on this.) Sadly this happens in many fields other than aeronautics. For example, I carry around dimensionless heat transfer graphs from Carlsaw and Jaeger which were developed in 1906. I can settle arguments more than 100 years later by referring to these graphs and taking a few simple measurements with a thermocouple and a stopwatch.Thanks for a thoughtful post.”


On the topic of “2,500 words on aircraft Finishes”

(2,500 words about levels of aircraft finsh……)

Builder Steve Dawson writes:

“Hi William, I was employed in EAA’s shops & knew Jack Cox. I also volunteered as an antique judge after my employment there. Finding your article quite interesting and tending to agree, I must say, ‘if’ Jack Cox was naive, he also edited the magazine which did build the movement for many years. This alone made him one of grassroots aviation’s greatest advocates. I flew a Vag., which had Colt wings, tanks, & struts for many years. It would carry anything, passenger, full tanks and all up to the Rockies. Yours is giving me nostalgia, etc…………………”

Steve, I spent little time with Jack Cox, but I read virtually ever article he wrote for the EAA. To me the best thing that Jack did was his own personal magazine, “The Sportsman Pilot.” It was a pretty good demonstration of his personal work aside from the EAA’s agenda.-ww

Builder Dan Branstrom writes:

“Hi Grace Ellen & William, The EAA sent out a request for feedback. I answered all of the multiple choice questions, but, at the end, after thinking it over for some days, this is what I put in the comments section:
The articles in Sport Aviation on hints to homebuilders, building techniques, and theory are too short. They need to cover those topics in more depth. I’m sorry, but while it is good to strive for professional writers and people with experience, too much of the orientation is becoming tilted towards general aviation, as well as flashy builds. Unfortunately, there isn’t enough orientation on the part of Sport Aviation that emphasizes form following function in the articles. Burt Rutan’s original homebuilts were built for performance, not beauty. He built them for lightness, efficiency, and speedy construction, not beauty. Those qualities need to be emphasized more.

Flashy paint jobs with airbrushed graphics are OK occasionally, but none of that helps an airplane fly any better, but often adds weight and work to a homebuilt aircraft. It also discourages people who are building, because they end up spending time on flash instead of flying because they think that is the standard they must build towards. If Burt Rutan built his designs that way, he probably would have had only about 1/2 or less of his designs fly. Another item that threatens the whole experimental aviation movement is the hired guns that turn out award-winning experimental airplanes. We all know they’re out there, and when, not if they are exposed, it will damage the EAA, as well as all of the homebuilders that hew to the rules. The recent rule changes only put them into a more stealthy mode. While I can appreciate J. Mac McClellen’s expertise in instrument flying was great in Flying magazine, but this is NOT Flying. I hope that he starts to change his orientation to more grassroots aviation.

I also object to having Jack Pelton heading up the EAA, particularly since he made the decision to construct the Cessna Skycatcher in China. The issues of technology transfer and lack of Chinese respect for copyright and patent protection obviously weren’t a consideration in the decision. I do not state that lightly, because, as the son of missionaries to China, I love and respect the Chinese people, but do not respect the mendacity of their government nor the way in which it operates. The Chinese government was, I surmise, a large party in the negotiations.”


On the subject of Expert witnesses:

 Click on: Expert Witnesses in civil Aviation trials.

Note: After I wrote the story above, my friend Tom Graziano wrote me a letter defending the work of Harry Riblett. Tom said he had known Riblett and he feels the man’s goals were to inform and educate people about airfoils, and that Riblett had little control over what lawyers did with his data. He said Riblett was probably extreme in his statements for shock value to try to get the complacent to awaken and he didn’t think Riblett should be painted with the same brush.-ww


Jon Ross writes:

“Dear William:  I salute your courage in stating these facts, and let me just say that I have had dealings with all three men which has led me to the same conclusions that you have arrived at. There are a few out there in aviation that ‘fly under false colors’ just as these three have.Very warm regards, JR”

Builder Dan Branstrom writes:

“I remember Burt Rutan in a seminar, holding up a dime and saying, ‘This is 10 cents more than any attorney will ever get out of me in a lawsuit.’ They never did. He probably spent far more money, and a lot of his valuable time, fighting lawsuits than it would have cost to settle, but he never lost, and I’d guess that he probably had some sleepless nights worrying about them.”

Builder Sonny Webster writes:

“Following the money trail and the hidden agendas which motivate actions always leads to the place in which truth is rooted. Your stories provide three additional reasons that rational minded, independent thinkers become cynical.”

Sonny, 98% of the people we have met in aviation have been really good people, not infallible, just regular people working hard to do something very extraordinary with their lives. Don’t let anything I say make you cynical of the big picture of building and flying. -ww

Builder Ned Lowerre writes:

“William I couldn’t agree more with your disdain for the tort legal system. Recently I was involved in an auto accident that totalled the car, deployed three air bags, and left me with a concussion and a sore body. I was not allowed drive or fly for several weeks, my primary methods of commuting, and therefore was not allowed to go to work. It cost me a couple of weeks work and pay as well as the cost of a new automobile. The fellow that hit me was in his mid 70s going to visit his wife’s grave site. He rolled a stop sign and accelerated across a posted 65MPH roadway which I happened to be on. After the accident I had attorneys contact me about suing the driver, suing the auto manufacturer, even suing my employer since I was legally on duty.

The reality was a person made a mistake. We will all make mistakes in our lives and some of them may hurt others. If our first response is how do I make money off this at someone else’s expense, than something is very wrong with our society. The eventual outcome will be a society where no activity with a risk of mental or physical injury will be allowed. Once we are painted into that little box the only flying someone in my income category will be allowed to do will be on a computer screen. What a shame!
Ned Lowerre”


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