Brodhead Pietenpol Association

Original Posted By: Alan Swanson
I just wanted to put in another comment about some folks having theimpression that the model A engine is an "insane" choice for ourPiets--anyone that goes to Brodhead each year would know that the model Apowered Piets not only fly well, but quite a number of them are thereregularly. That is, they haven't fallen out of the sky during the previousyear, or during their trip to Brodhead, etc. Bernie figured out a verysimple system that still works today.Cordially, Mac in Oregon-----Original Message-----

Original Posted By: "Ignitor"
Subject: RE: Pietenpol-List: 65 Cont. vs. others ?>>>>From some of the comments that have been posted, it might sound likeputting>a Model A on a Piet is insane. My Dad has questioned my sanity. But I>would second Mike's comments below about using experts to rebuild the>engine. I am using an old guy here in Minnesota who has been rebuilding>Model A's for 60 years, along with other engines of the era. I got his name>from Vi Kapler, who also has an engine in this guy's shop. He has pickedout>others who specialize in some of the work, such as pouring new babbit>bearings, who he has confidence in. What has given me some confidence in>him is he has made several recommendations. For example, he insists on new>pistons, slightly undersize so if there is an oiling failure there will be>extra time before the engine seizes. And we will be putting a temporary>Plexiglas cover over the valves to watch the oiling system during theground>break-in period to be sure the bearings are getting sufficient oil. He had>the engine magnafluxed and determined there were no cracks in the water>jacket. And he also swapped the crank that came with my engine withanother>that was a heavier casting.>>I guess what I am saying is that flying behind any engine is a risk, and a>poor rebuild job on an aircraft engine is always a problem. But if you do>careful research, and farm out the parts of the project that you are not>competent to do (in my case the engine), the risks can be minimized. The>Model A is an inherently strong engine, and is simple. Many are still in>daily use in out of the way places for irrigation pumps.>>I have this strange burning desire to build this as original as I can>consistent with modern building practices, and fly it to Brodhead.>>Call me crazy, but don't call me late for dinner.>>Al Swanson>>>-----Original Message----->From: owner-pietenpol-list-server(at)matronics.com>[mailto:owner-pietenpol-list-server(at)matronics.com]On Behalf Of Michael D>Cuy>Sent: Tuesday, September 18, 2001 10:11 AM>To: pietenpol-list(at)matronics.com>Subject: Pietenpol-List: 65 Cont. vs. others ?>>>>>Group---I happened to stumble onto an A-65 with everything>but the log books. Fortunately it was re-buildable--but still ended>up costing nearly $4,500. I would go with an auto engine only if>you did it by the guru's knowledge. For Fords I would pick the brains>of Lowell Frank or Wil Graff who have flown countless hours behind>those engines because they knew there stuff. (I'm sure there are>others, but those I know.) Pick a Corvair authority>like Virl Deal or W. W....when he's back up to speed. Unless you are>an avid engine head, I'd closely follow those who've rebuilt and>successfully flown>behind auto engines to the tee. A 65 Cont. can be rebuilt wrong>too......or>the carb or mags done improperly.....but they still are the most reasonable>engine for the money out there as far as A/C engines go. I could not>imagine>paying the money for a 150 hp engine for an RV when compared to our little>Pietenpols.>>Mike C.>>________________________________________________________________________________Date: Sat, 22 Sep 2001 11:39:24 -0700

Original Posted By: Isablcorky(at)aol.com
Am building new engine mount (A-65) and altering it 2 inches forward forW &B considerations. Questions: Top mount arms are, according to plans,9/16forward of lower arms. What degree of down incidence does this provide?Also,there are no dimensions of the plans that provide for any rightdeflection ofcenterline thrust. What should I do in this case?Corky,I do not have the plans in front of me but I do know that the mounts onthe crankcase are exactly perpendicular to the crankshaft bothvertically and horizontally. If what you say above is true, then itwould give quite a bit of downthrust. If we knew the coefficient oflift of the airfoil and the airspeed we could figure the angle of attackat cruise and then adjust the downthrust so that the crankshaft isparallel to the direction of flight. But I have never seen any numbersfor C sub L for Bernard's home brewed airfoil although one of these dayswe will make a full scale section and have Kip Gardner get some studentsto work up the numbers where he works. Side thrust is determined by the degree of sidelip of the aircraft inlevel flight. The P-factor is such that the right side of the disc ispulling more than the left, assuming not enough downthrust or withenough downthrust but with the spiral of the propwash impinging on theleft side of the fuselage and vertical stab aft of the CG (point ofrotation). This would be just like being in a climb where you have tohold right rudder to keep the ball in the middle except that you wouldnot be climbing but still having to hold the ball centered with rightrudder. Add some right thrust and you take your right foot off of therudder. Of course, this is for cruising speed in straight and levelflight only. All other regimes would theoretically require some rudderinput either left or right to keep the ball centered. Another fix forthis, usually in combination with the right thrust would be to offsetthe vertical stabilizer's leading edge to the left. Old Travelairbiplanes have an adjustment on the stab for just such a purpose.I believe Mike Cuy said that if you set the ship so that the fuselage islevel fore and aft (firewall at right angles to the floor) andlaterally, and prop up the motor in position so that the crank isexactly in line with the fuselage when looking at it from the top andthe side, then hang a nail from the cieling with the point right infront of the center of the prop hub, then move the motor so that thecenter of the prop hub is one inch to the right of the nail tip and oneinch below it. That is the downthrust and right thrust needed. anyone else?chris bobkaMinneapolisl ----- Original Message -----