Pietenpol-List: Re: raising the seat, extending the vertical stab, and

[matronics]

Original Posted By: "tmbrant1(at)netzero.com"
I saw Pat Green's 1977 Piet this weekend at Corvair College. It has a fewmods to it, including a 34 foot wing and an extended vertical stabilizer.Pat told me the reason for the higher vertical tail was after a couple ofincidents where he held the tail up as it slowed on the landing roll. Therewas no wind, yet it suddenly shot off to the right of the runway and intothe weeds. No damage was done, but he tried it again and this time it didthe same thing, except that it went off to the left. after a while theyrealized that the problem was that the elevator was capable of holding thetail (and the tailwheel) up down to a lower speed than the point where therudder lost effectiveness. Another time, a pilot took it up for spintesting. He started at 4000 feet, got a good spin going (was hard to getinto the spin) and then couldn't get out of it until he got down to 800feet, he got it out by modulating the power. Pat went up and had littletrouble with spins. The first pilot was a really tall guy, while Pat was abit shorter. He believed that the spin problem was due in large part with atall pilot blanking out the vertical stabilizer, which would also be afactor in the landing experience (though the quick solution to the landingthing was simply to not hold the tail up too long.) He installed a tallerstabilizer of the same basic shape, I think he said it was 10 inches taller.and now he says that it's very authoritative. I didn't see his arrival toWilliam Wynne's place but there was about a 20-knot direct crosswind oversome trees, and he said that it was no problem at all.So it sounds like raising the seat might even affect control by blanking outthe rudder in some situations.After looking at Pat's plane, I think I really like the idea of making ataller rudder. It was the kind of thing where sub-consciously, you saw theplane and felt like something was different, but it didn't really stand outuntil he said something. I think it might even look nice to re-shape theupper part of the stab and get a little more of a classic rounded look (Ican hear the gasps of the purists from here... hehehe) If you were to raisethe stab and make the top into a nice curve, starting roughly at the ribwhere the brace wires attach, would there be any reason to think you'dcreate any bad flight characteristics in doing so? I'll be building awidened, long-fuse Piet, I'm 6' 1" with long legs so I might end up blankingthe rudder no matter where the seat is!This is the second Piet that I've seen with added wing length. Pat said thathe visited BHP, and was told that it didn't need a longer wing. Pat feltthat he did need it, so he could clear the 50 foot pine trees we have hereinstead of the 6-foot Minnesota corn stalks.) Apparently it adds somestability and makes the aileron response a bit slower. The plane has ahand-start BHP Corvair conversion with a blower on top, hadn't seen one ofthose before and it looks a bit different than the Wynne conversions. Idon't know if Pat and his starter/partner in crime Jack are on the listhere, if they are they could correct anything I remembered wrong. Super niceguys.Corvair College was great, as usual. Lots of fun, saw neat planes and meteven neater people. I'm sure they'll have a report posted soon. There was 1Pietenpol, 1 Cleanex (basically a Corvair Sonex), 1 flying CH-601XL and onebeing built, one KR-2S, one KR-2, a Mustang I, a Wagabond, and a turboCorvair Stits Sky Coupe. Also several Corvair cars and a van were there.Cool stuff.-MikeMike Whaley merlin@ov-10bronco.netWebmaster, OV-10 Bronco Associationhttp://www.ov-10bronco.net/___________________ ... __________

[matronics]

Original Posted By: "Oscar Zuniga"
Can't find an email for him, but the N-number is registered to this address:14281 Urn RdJacksonville, FL 32218-MikeMike Whaley merlin@ov-10bronco.netWebmaster, OV-10 Bronco Associationhttp://www.ov-10bronco.net/ Good info Mike, does Pat Green have an email address that you know of? Wouldlike to ask him some increasing wingspan questions.________________________________________________________________________________