Mail Sack, 5/30/13, Cowls, Balsa Planes , Stick and Rudder


Here is a sample of the mail:


On the story about Cooling with J-3 style cowls. (Pietenpols, Cubs, Biplanes, etc)

Jeff Moores Corvair/Merlin builder/flyer from Newfoundland writes:

“Hi William, While flying over The Avalon Wilderness Reserve this evening and listening to the strong steady  beat of my Corvair I realized that I will soon have a year of flying with my engine. In spite of our poor weather most of the time and my full time job, I have almost 100 hours on it now. I have flown it in every month since last June. I’d like to make the point here for any current or would be builder that since the initial timing setup with a timing light and idle mixture adjustment of the Stromberg, I HAVE NOT HAD TO CHANGE OR ADJUST ANYTHING !!!! My engine is built exactly to the instructions and procedures in the manual. I’m using a Dan 5th bearing that was extremly easy to install with excellent instructions. (thank you Dan for designing and selling this.)

Aircraft carburetor, 100LL fuel, 5th bearing, manual and parts from the Corvair Authority, Williams’ help and advice, you can’t go wrong!! Jeff Moores Corvair/Merlin”

Piet builder Harlod Bickford writes:

“Hello William, The attached cooling article re: Garidner’s engine left me with two conclusions.for the side by side Piet our project has developed into. Namely use a cowl along the lines of the Wagabond and Zenith or the cooling fan as used on the stock Corvair, albeit about 25 lbs heavier. With one less thing to break and less weight the pressure cowl makes more sense. With a firewall height at about 30″ high and 38″ width there is lots of room to work with. Harold”

Pietenpol builder Mark Chouinard writes:

“William: The write up on Gardiner Mason’s engine issues was very informative.  I have printed it, as I have with many other writings in order to keep it in my “Corvair” binder for review at a later time.  That part that discusses detonation, the spring effect of the head studs and the type of damage this causes to the heads went a long way in describing the damage that I found when disassembling my core.  Once my heads were off, I found a quarter sized hole in the top of the #2 piston.  It was not completely punched out, but a hole none the less that was probably 3/4 punched.  Later in the conversion process, Joe at Moldex informed me that my crank had a crack at the #2 journal… what a bummer, but I’m sure glad they found it!  I had a local shop perform a magnaflux inspection on my crank just to see if it was worth sending to Moldex… they said it looked good.  Never again will I trust  the locals for anything other than degreasing dirty crap… they just don’t understand or don’t have the skills or don’t care or are dishonest or all of the above.  Not sure which and don’t care.  Once I found another crank I sent it directly to Joe… no need for any further waste of time.  Finally, when I received my heads back from Mark at Falcon, he had stamped one with “use .042” and the other with “use .052”… my assumption would be that he had to remove more material from one of the heads in order to resurface the gasket seats properly… likely the one that experienced detonation.  He did explain to me that the different thicknesses would balance the compression ratio between the cylinder banks.  This stuff is so much fun.  Like Gardiner, I am not a real motor head, but with all the lessons that have been learned by others I feel confident that I can do this properly and safely.  Thanks for your continuing support and education… looking forward to Austin in 2014!- Mark Chouinard Owasso, Oklahoma “

Pietenpol pilot and 601 Builder Oscar Zuniga writes:

“Yes, I read the 16-page writeup on PietVair engine cooling and it was worth every moment it took to read it.  There is no need to wait for next month’s “Hints for Homebuilders”, there are a month’s worth of them in this article.  Some are subtle, but most are as plain as a “remove before flight” streamer is on a preflight inspection.  There is no need to wait for next month’s “I Learned From That”… it’s here.  “Tech Tips”?  It’s here.  “From The Cockpit”?  Yes.  “Parting Shot”?  Got it.  Color photos?  Illustrations?  Yes.  So this article is a full aviation magazine in one spot ;o)  All for the price of a full year’s subscription… same price as what I’ve paid William for every bit of advice, information, counsel, opinion, conversation, and honesty since I registered the Corvair conversion manual that I bought from Joa Harrison about twenty years ago.  Zero.  I think I’ll renew my subscription to”

601XL Builder/flyer Andy Eliott (Phd aero engineer) Writes:

“OK, I read the article on Gardiner Mason’s Piet problems.  You will have to agree I know the theoretical part of aero.  Multiple times in the article, you state that mass flow rates scale with the square of the airspeed.  Unfortunately, this is not true.  If you look at a stream tube you can see (even from dimensional analysis) that m_dot units are mass/time.  rho is mass/length3.  A is length2. V is length/time. Surface cooling rates are a different story, but effectively are a nonlinear function of m_dot and delta_T, the time in which the air is in contact with the surface.  With equivalently good inlet, plenum and exit designs, two planes would comparatively cool simply as a function on m_dot.A small editing pass might be in order. -Andy”

Andy, you are the only guy to write in about this, and of course you are correct, mass flow is only doubled, it is dynamic pressure that is squared. I saw that when I put the story together, but couldn’t correct is as the original story is from our old website which is written in a computer language that only Grace and two guys a DARPA understand. The point I wanted everyone to take away was that small changes in forward airspeed make a big difference in cooling. Everyone who has flown enough with good CHT’s knows the effect of lowering the nose, picking up 10 mph and increasing the cooling at the same power setting. -ww  (Andy’s letter has an equation with it that may not show up on your computer.)


On the story about Fixing America is going to cost each of us $1.69

builder Doug Wright sends:

“William, This is one of the funniest things I have read in a while:

I told them that there were many reasons to use planes, but the best one of them all is just to have fun. When one of the kids asked if this was OK, I told him it was not just ok, I did it for a job. There was a lightbulb that went off in his mind, this was the first time he had heard you could evade becoming a grown up.

Just thought you might like to know it was appreciated.-Doug”

Doug, the story was popular, it had 1,000 page reads in the first 24 hours. Part of this was several people putting a link to it on face book. The tracking on our site also showed that It was picked up as far away as “GTT”, a web discussion group for people who appreciate and restore small tractors. I am glad it appealed to a wide variety of people.-ww

Dragonfly builder Guy Bowen writes:

“Fixing America is going to cost $1.69 is dead on. I was a huge fan of the Guillows products that were, at the time of my childhood, available at the local 7-eleven. Now a trip to the Hobby Lobby, Micheals, or the local RC shop is necessary to find these gems. I would add to that list my personal favorite: Model Rockets (although they were relatively more expensive). I preferred them over plastic models because they were dynamic…they did things that you could show your friends. I never realized that I was learning anything playing with these things until I ran into the kid down the block who was just amazed at the fact something that I built not only flew but I could explain how it worked! My youth was filled with kites, chemistry sets, telescopes, microscopes, electronic sets, rockets, planes, bikes and lawnmower engines. There is an unnamed layer that exists between the youth of today from the mechanisms that we use and it is growing more obfuscated as we become a more consumer-centric society. Black box engineering has become a more prevalent tool in production since processes and products have become more complex. Black box consumerism on the other hand, promotes apathy and laziness of the underlying nature of things so much to the point of disconnection. Just as I did not realize I was learning playing with balsa wood gliders and rockets…the inverse is true: consumers experience a loss of physical connection or fascination with the machines inner workings. The “wow” factor becomes focused on what machines do…not how they accomplish it. My 3 yr. old loves to work on machines with his old man while my 12 yr. stepson keeps his face buried in a video game and is more worried about fashion brand names that some girls his age…sad really, I wish I had more of his childhood back to show him the fascination of machines instead.”

Builder “Jacksno” writes:

” Your most fun post yet re Cub Scouts and Guillow planes.  Here you were preaching to the choir:  I was 19 in 1962, had been making model planes for 11 years.  First one I made was from 1 x 6′s in the garage.  Wanted to make a swept wing rocket/jet thingy.  No tools.  No dad.  But I had passion.  And a hammer.  And glue. I would not be refused:  I  beat on the boards full chat until I had an assortment of aerodynamic looking pieces.  glued that all up and painted it silver.  Put a stout cord on it and whirled it around my head like crazy.  Cord broke when the craft reached escape velocity – it did not land anywhere in our yard!  I had no idea there was an EAA, but I was on it in miniature from then on.  Oh, I did hack something together earlier out of balsa pieces with scimitar wings.  Talked my mother and grandmother into sending it to President Truman so he could kick some commie butt.  They did it and I got a nice letter from somebody up there, official white house stationery. No, I don’t know where it is.  Not my longhorn bull embossed ‘pearl’ handled colt .45s in matching holsters, either.  A little later I developed a modicum of craftsmanship and built hand launch gliders of solid balsa that would eventually get an stc for jetex 50s.  Fun days. Built every Monogram kit, some 2 or 3 times, had awesome Jim Walker folding wing rubber launched gliders, and the ‘P80′ type that cost .10 – all well modified and over powered.  Lookin’ to have some more (still flying gas and electric models) real time full size action before it’s all over! {;^) OK, OK, I know…I will calm down, be safe, build carefully and reliably under the expert and qualified eye of you and other real aviators, never ‘have’ to get there, never run scud…and I’ve read S & R often and will continue to.”

Kr2 builder/flyer Steve Makish writes:

“Hi William, read your post on balsa planes etc. Great stuff. My go cart when I  was a kid had a 2 hp Briggs and Stratton from my grandmothers washing machine,  yes it was a gas powered washing machine (outdoors of course) It actually had a  kick start ratchet device and was at about a 45% angle. It was the first motor I  ever souped up. took the head off and made a head gasket out of newspaper to  raise the compression (wow) I thought it doubled the hp because it ran so great. Regards Your friend Steve”


On the story about Greatest Book on Flying Ever Written, (Is your life worth $16?)

Pietenpol builder/flyer Kevin Purtee writes:

“You just can’t beat Rod Machado…”

Builders: One of the things I ‘like’ about Kevin is that you can never tell when he is kidding. He is a tough guy so you never really want to offend him on the chance he isn’t kidding. He also wrote me to say that he is a Celine Dion fan…..-ww.

Parting Shot, on the topic of   Built by William Wynne? Built according to The Manual?  from 601XLB builder/flyer Dr. Gary Ray,

“An advantage of the Corvair Engine that builders don’t easily have with any other engine is the ease, short turn around time, and low expense to do a complete disassembly and rebuild.  For this reason, it would make sense that all purchased engines (not directly built by the end-user) be taken down for inspection and rebuilt before flight.  This is the only way to know if any variation exists with accepted practices stated in your manual.  The new owners knowledge is now at the hands-on level of understanding.  This is a small price to pay for safer operation and it deals with a major portion of any future liability issue.  If I ever sell my aircraft, this will be part of the contract.”

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