Original Posted By: jmcnarry(at)techplus.com (John McNarry)
>Hey Greg:After two years flying behind an A engine I converted to a C-100. Theinitial installation was without offset. The first flight,don't ask. I waslucky to get the airplane on the ground. I had to use fwd right stick,( alot of fwd right stick) just to keep the airplane somewhere near straight &level. I then put in a down & right offset. I did that by insertingaluminum washers between the engine & mount.If I can remember,two 1/4 in onthe left & one on the right. Believe this-in calm air the airplane flys hands off. Of course a C-100 is not an A - 65, but the idea is the same.There areguys flying with A-65's, perhaps they have a differnt idea. One thing more, a bigger problem will be your CG with the light engine. Mike B (N687MB)________________________________________________________________________________
Pietenpol-List: engine offset
Pietenpol-List: Re: engine offset
Original Posted By: Peter P Frantz
Subject: Pietenpol-List: Re: engine offset>Greg- The bigger issue with a Piet is are your wings and tail surfaces>true ? My Piet drifted left hands off and just a few turns on the rear>fork end made a huge difference. Engine offset and downthrust are>important though...not to slight that issue. Pietenpol himself wrote in>on of the Flying and Glider articles something like " a twisted horizontal>stabilizer can be a most vexing problem.">>Wing setback for a 200 lb. pilot, short fuse Cont. 65 Piet ? Set mine>back 4.0 " aft of vertical and most rear CG came out at 19.68" which>is fine. I think 21 or 22" is rear limit. (ps, I've got a 6" solidrubber>tailwheel and two leaf spring deal back there)>>Mike C.>________________________________________________________________________________
Subject: Pietenpol-List: Re: engine offset>Greg- The bigger issue with a Piet is are your wings and tail surfaces>true ? My Piet drifted left hands off and just a few turns on the rear>fork end made a huge difference. Engine offset and downthrust are>important though...not to slight that issue. Pietenpol himself wrote in>on of the Flying and Glider articles something like " a twisted horizontal>stabilizer can be a most vexing problem.">>Wing setback for a 200 lb. pilot, short fuse Cont. 65 Piet ? Set mine>back 4.0 " aft of vertical and most rear CG came out at 19.68" which>is fine. I think 21 or 22" is rear limit. (ps, I've got a 6" solidrubber>tailwheel and two leaf spring deal back there)>>Mike C.>________________________________________________________________________________
Pietenpol-List: Re: engine offset
Original Posted By: Michael D Cuy
Greg- The bigger issue with a Piet is are your wings and tail surfacestrue ? My Piet drifted left hands off and just a few turns on the rearfork end made a huge difference. Engine offset and downthrust areimportant though...not to slight that issue. Pietenpol himself wrote inon of the Flying and Glider articles something like " a twisted horizontalstabilizer can be a most vexing problem."Wing setback for a 200 lb. pilot, short fuse Cont. 65 Piet ? Set mineback 4.0 " aft of vertical and most rear CG came out at 19.68" whichis fine. I think 21 or 22" is rear limit. (ps, I've got a 6" solid rubbertailwheel and two leaf spring deal back there)Mike C. ________________________________________________________________________________
Greg- The bigger issue with a Piet is are your wings and tail surfacestrue ? My Piet drifted left hands off and just a few turns on the rearfork end made a huge difference. Engine offset and downthrust areimportant though...not to slight that issue. Pietenpol himself wrote inon of the Flying and Glider articles something like " a twisted horizontalstabilizer can be a most vexing problem."Wing setback for a 200 lb. pilot, short fuse Cont. 65 Piet ? Set mineback 4.0 " aft of vertical and most rear CG came out at 19.68" whichis fine. I think 21 or 22" is rear limit. (ps, I've got a 6" solid rubbertailwheel and two leaf spring deal back there)Mike C. ________________________________________________________________________________
Pietenpol-List: Re: engine offset
Original Posted By: Michael D Cuy
Conventional wisdom for an A piet is 1" down and 1/2" right. I spent sometime talking with the builder of a well -known Piet who is also a retiredMcDonnel Douglas engineer about this. He indicated he thought the theorywas good but the draggy, low-powered Piet just wasn't very sensitive toanything. He put his motor on straight ahead and, I think, 1" downthrust.Said it flew fine.I set out to get 1" downthrust, but ended up with about 1/2" due toinadequate jigging. Otherwise my motor is straight ahead. Hopefully, anydifficulties can be overcome with a small trim tab on the rudder.The same builder also mounted his vertical fin straight, no offset. The finwould be easier to change on a finished airplane than the motor mount andcowling.John-----Original Message-----
Conventional wisdom for an A piet is 1" down and 1/2" right. I spent sometime talking with the builder of a well -known Piet who is also a retiredMcDonnel Douglas engineer about this. He indicated he thought the theorywas good but the draggy, low-powered Piet just wasn't very sensitive toanything. He put his motor on straight ahead and, I think, 1" downthrust.Said it flew fine.I set out to get 1" downthrust, but ended up with about 1/2" due toinadequate jigging. Otherwise my motor is straight ahead. Hopefully, anydifficulties can be overcome with a small trim tab on the rudder.The same builder also mounted his vertical fin straight, no offset. The finwould be easier to change on a finished airplane than the motor mount andcowling.John-----Original Message-----
Pietenpol-List: Re: engine offset
Original Posted By:> John Greenlee
I guess you could think of your Piet as a really big model plane -- myfreeflight models usually have some down thrust to tame the initial powerburst of the rubber motor (not the usual problem in a Piet!) & some rightthrust to keep it in a turn.(Yes, Mike, that is how my peanut-sized Piet isset-up!) Our plans for our big Piet will start with 1" downthrust & noside thrust at the start of testing and we'll see how that works out. Has any thing more been heard about the "Iron Duke" engine in the "PopularPiet"? "the other" Mike C.Pretty Prairie, KS
I guess you could think of your Piet as a really big model plane -- myfreeflight models usually have some down thrust to tame the initial powerburst of the rubber motor (not the usual problem in a Piet!) & some rightthrust to keep it in a turn.(Yes, Mike, that is how my peanut-sized Piet isset-up!) Our plans for our big Piet will start with 1" downthrust & noside thrust at the start of testing and we'll see how that works out. Has any thing more been heard about the "Iron Duke" engine in the "PopularPiet"? "the other" Mike C.Pretty Prairie, KS
> Re: engine offset
Original Posted By:> Michael D Cuy
> > Conventional wisdom for an A piet is 1" down and 1/2" right. I spentsome> time talking with the builder of a well -known Piet who is also a retired> McDonnel Douglas engineer about this. He indicated he thought the theory> was good but the draggy, low-powered Piet just wasn't very sensitive to> anything. He put his motor on straight ahead and, I think, 1"downthrust.> Said it flew fine.> > I set out to get 1" downthrust, but ended up with about 1/2" due to> inadequate jigging. Otherwise my motor is straight ahead. Hopefully,any> difficulties can be overcome with a small trim tab on the rudder.> > The same builder also mounted his vertical fin straight, no offset. Thefin> would be easier to change on a finished airplane than the motor mount and> cowling.> > John> > -----Original Message-----
> > Conventional wisdom for an A piet is 1" down and 1/2" right. I spentsome> time talking with the builder of a well -known Piet who is also a retired> McDonnel Douglas engineer about this. He indicated he thought the theory> was good but the draggy, low-powered Piet just wasn't very sensitive to> anything. He put his motor on straight ahead and, I think, 1"downthrust.> Said it flew fine.> > I set out to get 1" downthrust, but ended up with about 1/2" due to> inadequate jigging. Otherwise my motor is straight ahead. Hopefully,any> difficulties can be overcome with a small trim tab on the rudder.> > The same builder also mounted his vertical fin straight, no offset. Thefin> would be easier to change on a finished airplane than the motor mount and> cowling.> > John> > -----Original Message-----
> Re: engine offset
Original Posted By: jmcnarry(at)techplus.com (John McNarry)
> Subject: Re: engine offset> > > >Greg- The bigger issue with a Piet is are your wings and tail surfaces> >true ? My Piet drifted left hands off and just a few turns on the rear> >fork end made a huge difference. Engine offset and downthrust are> >important though...not to slight that issue. Pietenpol himself wrotein> >on of the Flying and Glider articles something like " a twistedhorizontal> >stabilizer can be a most vexing problem."> >> >Wing setback for a 200 lb. pilot, short fuse Cont. 65 Piet ? Set mine> >back 4.0 " aft of vertical and most rear CG came out at 19.68" which> >is fine. I think 21 or 22" is rear limit. (ps, I've got a 6" solid> rubber> >tailwheel and two leaf spring deal back there)> >> >Mike C.> >________________________________________________________________________________
> Subject: Re: engine offset> > > >Greg- The bigger issue with a Piet is are your wings and tail surfaces> >true ? My Piet drifted left hands off and just a few turns on the rear> >fork end made a huge difference. Engine offset and downthrust are> >important though...not to slight that issue. Pietenpol himself wrotein> >on of the Flying and Glider articles something like " a twistedhorizontal> >stabilizer can be a most vexing problem."> >> >Wing setback for a 200 lb. pilot, short fuse Cont. 65 Piet ? Set mine> >back 4.0 " aft of vertical and most rear CG came out at 19.68" which> >is fine. I think 21 or 22" is rear limit. (ps, I've got a 6" solid> rubber> >tailwheel and two leaf spring deal back there)> >> >Mike C.> >________________________________________________________________________________