Re: Pietenpol-List: Graham-- are your cabanes slanted at all or vertical
Posted: Thu Feb 05, 2004 1:58 pm
Original Posted By: Gnwac(at)cs.com
Mike C.,Yes, my cabanes are slanted back. They are aligned approximately with theslant of the fuselage side truss members directly beneath them. This iswhere I arbitrarily set them and have had no need to change them since.Weight and Balance figures were within reason. Motto: "If it ain't broke,don't fix it".Regarding directional instability with the longer forward fuselage, the fourdifferent Pietenpols I have flown (all Continental- powered) exhibited someinstability in yaw. One of the four had the standard fuselage (1933 plans)with a really long engine mount. When I flew it in 1963, I didn't think ithad a yaw stability problem. It was the first Pietenpol I ever flew and myonly negative impression was that it had sluggish aileron response. (Thebuilder had altered the stick-to-aileron ratios and, I think, he didn't havegap seals. The other three a/c have sealed aileron gaps and conform to theplans. Their aileron response is fine.) He obviously thought it needed morekeel surface aft and installed a larger vertical fin and rudder, but I neverflew it with these mods and don't know how effective they were.Compared to production lightplanes in the same power/size range, thePietenpol seems to be less stable and needs to be flown all thetime---except in still air. But that is part of its appeal: When you fly aPietenpol, you are really flying; you don't just trim it and sit back. Thecontrols are highly responsive and their input forces are light, so a tad ofinstability is of no concern, in my humble opinion.Graham Hansen (Pietenpol CF-AUN)________________________________________________________________________________
Mike C.,Yes, my cabanes are slanted back. They are aligned approximately with theslant of the fuselage side truss members directly beneath them. This iswhere I arbitrarily set them and have had no need to change them since.Weight and Balance figures were within reason. Motto: "If it ain't broke,don't fix it".Regarding directional instability with the longer forward fuselage, the fourdifferent Pietenpols I have flown (all Continental- powered) exhibited someinstability in yaw. One of the four had the standard fuselage (1933 plans)with a really long engine mount. When I flew it in 1963, I didn't think ithad a yaw stability problem. It was the first Pietenpol I ever flew and myonly negative impression was that it had sluggish aileron response. (Thebuilder had altered the stick-to-aileron ratios and, I think, he didn't havegap seals. The other three a/c have sealed aileron gaps and conform to theplans. Their aileron response is fine.) He obviously thought it needed morekeel surface aft and installed a larger vertical fin and rudder, but I neverflew it with these mods and don't know how effective they were.Compared to production lightplanes in the same power/size range, thePietenpol seems to be less stable and needs to be flown all thetime---except in still air. But that is part of its appeal: When you fly aPietenpol, you are really flying; you don't just trim it and sit back. Thecontrols are highly responsive and their input forces are light, so a tad ofinstability is of no concern, in my humble opinion.Graham Hansen (Pietenpol CF-AUN)________________________________________________________________________________