Brodhead Pietenpol Association

Original Posted By: "Dick Navratil"
Subject: Pietenpol-List: Washout & RiggingIn a message dated 2/18/2006 9:05:06 AM Central Standard Time,BARNSTMR(at)aol.com writes:Tim Willis and I have been discussing a few things off list and lately aboutwashout. For all of you guys with flying Piets,1) how much washout do you have?2) have you ever tried changing it any to see if handling is improved? I recently found an interesting article about the subject. (link below) It isa a NACA report done by engineers at Texas A&M in 1953 using washout tests ona Taylorcraft. (I have been trying to investigate to see if it was myTaylorcraft. It was owned by A&M at that time). Anyway - The tests looked=20attheeffects of washout and slots on lateral control near stall. The washout wasvaried from zero to 8 degrees. They used tufts all across the top surface ofthe wing to detect disturbed airflow. The idea is to have the inboard andcenter section of the wing stall first with the singtips still flying, so thattheailerons remain effective throughout the stall.I believe the NACA report conclusion was that 4 degrees washout was optimalfor the taylorcraft and thus recommended for light planes.http://naca.larc.nasa.gov/reports/1953/ ... mbnail11It might be interesting to consider tests of such on the Piet wing todetermine its optimum. Any thoughts?Terry B.Hey Terry, This is an area of aerodynamics that has always interested me. I triedprinting the pages of that naca report, because it's easier for me to relax=20inthe lazy boy chair to read, but my printer cut off the right side of the page. Here is my understanding on the subject, and what I did:A Hershey bar wing inherently stalls first at the inboard portion of thewing, and washout increases drag. Washout is much more common in Tapered Wings,because they inherently stall the tips first. Therefore, why even rig anywashout in the wing ? Because any slight discrepancies in construction, slighterrors in rigging, and in the event you don't keep the ball in the middle, Isuppose you could stall one wing before the other, albeit a rare occasion. =20Ihave Never felt one tip stall before the other...it always breaks, or actuallyjust Mushes, straight ahead, however, I haven't tried it with the ball way offcenter - at altitude of course. The Pietenpol wing has a fairly sharp leading edge, which causes asharper stall break, than say the ol' T-craft. Have you ever noticed how big theleading edge radius is on an aerobatic plane ? Those wings have a highercritical angle of attack (the angle at which the wing begins to stall), but=20payforit with an increase in drag. They have excess power to overcome the dragpenalty. Nothing is free !! The Pietenpol wing is All about Lift. It createsaLot of lift at airspeeds that the T-craft wing isn't even considering flyingyet. When I was flying in the Test Phase of my plane, I re-rigged my wingseveral times, because I had a slightly Left Wing Heavy condition. I use theplans built 'Lollipop' fittings at the upper lift strut fittings, so when Ire-rigged it was more of an adjustment in Symmetry, as opposed to changing thelength of the lift struts. I came to find that the front strap across the bottomof the fuselage was the primary cause of the left wing heavy condition. Initially I didn't have any bolts through that strap, into the ash cross member.Early on, that strap began to have a gap between it, and the bottom of thefuselage. I thought it was because of the dimension change in the wood with theseason, and couldn't imagine that slight dimension change could cause somewashout, and a wing heavy condition. Came to find the cause was hard landings.Iinstalled a #10 bolt down through the center of the ash cross piece andstrap... Presto !! Most all of the left wing heavy condition disappeared. =20Thenthedarn thing began to show a gap again, between the center, and the left side. I now have three bolts down through the ash cross piece / cross strap, spacedevenly. Hard landings in a Pietenpol are because as you roundout for landing andincrease the angle of attack, the drag increases dramatically and rapidlydecreases the airspeed...as opposed to a sharp stall break. The sharp stall breakjust isn't there in the Pietenpol wing. To conclude, I have about 1/16" to 1/8" washout in my wingtips, whichprobably is about 1=BA or so. The wing is rigged straight (no dihedral), and justslightly err towards washout. Now, instead of testing the 'Runway Hardness',I try to land as softly as a butterfly with sore feet !!Chuck G.NX770CGp.s. them ol' boys from Texas A&M probably got hold of some Federal money togo play around in the sky with the Taylorcraft, learned a Lot, shared theirfindings with us, and I'm sure they had a Lot of Fun !!________________________________________________________________________________

Original Posted By: John and Phyllis Smoyer
On the rudder horn, the GN-1 mounts the horn in a totally different location. Structurally it shouldn't be a problem although you may want to look at the locationof the hinge and keep one hinge close to the horn. On the question of the rudder bar, I currently have a rudder bar, which I reallydon't care for that much. On my new project I'm putting in J-3 pedals. Idont have any specific complaints about the bar but with the pedals, I will beable to adjust them better for distance. It's a matter of choice.Dick N. ----- Original Message -----

Original Posted By: Rcaprd(at)aol.com
Subject: Re: Pietenpol-List: Washout & Rigging > Hello Mike, > > This mail of yours is a REAL KEEPER! Everything makes lots of > sense, so has to be perfectly correct. > > Saludos > Gary Gower. > > Michael D Cuy wrote: > > I have about 2.5 degrees of dihedral, 3/8" washout at a point 3 > ribs in > from the wingtip, and ailerons in neutral are rigged 1/4" down on both > sides. > > Reason for 3/8" washout is that is what 150 years of aviation > experience > (my two 75 year old IA buddies who work on nothing but old airplanes) > told me that most Cubs, Champs, and such have in them, > > and the 1/4" droop because that is the way they used to rig old > airplanes > (including the DC-3's) because air pressures in flight on will make > the ailerons sit pretty then, exactly neutral. If they are rigged > neutral > I'm told they'll ride up a bit causing drag. > > Mike C. > > --------------------------------- ________________________________________________________________________________

Original Posted By: "LAWRENCE WILLIAMS"
Subject: Re: Pietenpol-List: Washout & RiggingIn a message dated 2/20/2006 3:14:06 PM Central Standard Time, Michael.D.Cuy(at)grc.nasa.gov writes:the 1/4" droop because that is the way they used to rig old airplanes (including the DC-3's) because air pressures in flight on will makethe ailerons sit pretty then, exactly neutral. If they are rigged neutral I'm told they'll ride up a bit causing drag.Mike et all, I have my ailerons rigged even with the wing's trailing edge, and they stay there in flight. The flight control rigging of the Pietenpol should Not have any tension to speak of...just remove all slack. When I stand out by thewing, and move one aileron 1/16", the other aileron moves exactly that much - in other words, no play. It seems to me that 1/4" is quite a lot, and if they stay 1/4" low in flight, this would negate a lot of the washout you have. Here is an old trick : If you already have your wing rigged, and you find you have a tip stall condition, rig the ailerons trailing edge a little bithigher than the trailing edge of the wing, and it causes some washout. However, if the ball is in the middle, the Pietenpol wing just doesn't have anytip stall conditions, and washout just reduces the total lift.Chuck G.NX770CG________________________________________________________________________________

Original Posted By: "Phillips, Jack"
Next time you talk to Randy Bruce ask him why he has "Captain Buck Naked" paintedon the side of his Piet!!Larry________________________________________________________________________________Subject: RE: Pietenpol-List: Washout & RiggingDate: Wed, 22 Feb 2006 07:25:04 -0500

Original Posted By: Michael D Cuy
Subject: Re: Pietenpol-List: WARNING about the Piet for sale from Ray goingto Belize I wasn't going to respond to asinine remarks by an ignoramus who through theiramateur efforts consider themselves experts on all things Pietenpol. But myEAA chapter has three A & P's, one of which is our tech counsellor and a workingFAA Inspector. They have vetted my construction on the Pietenpol all theway through. The materials are 1932 to 1949 aircraft grade materials specificationsas per original plans of Bernie and fit all FAA specs of that period. Poly fiber is probably the only modern difference? I suppose there is one stupidcrabby opinionated guy in every crowd? Insulting people you have never metand an airplane you have never seen speaks for itself. An opinion is one thing,insults and libel are another. The Mini Max, which was built in Belize has 321 hours on it and built out ofmahogany and lands fine in sugar cane field stubble, island coral sands betweenthe coconut trees and mountain tracks. Couple of times it has even landed onasphalt with no discernible difference. The only problem being one of capacity.I really need a CH 801 four place. But we are working on that down in Belizealso. At least in hanger talk so far, and trying to buy a shed next toour country airstrip for the farm to build it in. The Cessna 150 does thingsyou wouldn't believe down there in our overregulated environment up here in thestates. Carrying tourists up the gorges to see the 1600 FALLS. Now if I can just figure a way to land at 2,200 ft at the Gold Fields waaaaayback in the jungles? Trouble is the feeder streams at the gold deposits makethat valley very wet and soggy. You got any ideas on that, I'd like to hearthem?>-----Original Message----->From: Gary Gower [mailto:ggower_99(at)yahoo.com]>Sent: Wednesday, February 22, 2006 12:55 AM>To: pietenpol-list(at)matronics.com>Subject: Re: Pietenpol-List: WARNING about the Piet for sale from Ray going toBelize>>I knew he will not finish it... LESS fly it! Even if he was "Completly"convincedof his materials suaping...> > Is a diferent thing to argue to the list that "this material looks the sameas the good one", "why to pay more, just because it says Aircraft Quality" andother completly diferent thing is to sit in the flying plane and look downat 3,000 ft in turbulence > > Saludos> Gary Gower.>>Michael D Cuy wrote:>>Group--- Please read prior posts in the archive if you are even considering >asking this guy about his Piet project.>>It is basically a piece of crap built to non-aircraft grade standards and >materials and should be burned in a big>>campfire at the bast of the Alps in Belize....or wherever it sits.>>>Mike C.>>>Please Archive>>>>------------------------------------------------------------------------------This e-mail was sent using a CentralPets.com WebMail accountGet yours at: http://mail.centralpets.com________________________________________________________________________________Date: Wed, 22 Feb 2006 08:23:21 -0500

Original Posted By: Michael D Cuy