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”

About William Wynne
I have been continuously building, testing and flying Corvair engines since 1989. Information, parts and components that we developed and tested are now flying on several hundred Corvair powered aircraft. I earned a Bachelor of Science in Professional Aeronautics and an A&P license from Embry-Riddle Aeronautical University, and have a proven 20 year track record of effectively teaching homebuilders how to create and fly their own Corvair powered planes. Much of this is chronicled at and in more than 50 magazine articles.

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