Pietenpol-List: wing rib brads
Posted: Mon May 12, 2008 8:36 am
Original Posted By: "Ted White"
Thanks guys,I had similar thoughts, but am still bugged by the fuselage really looking longin front of the wing.My engine is supposed to weigh 315 pounds, which if it was short and close to thefirewall (like the radial in the prototype Aerial) it wouldn't be that muchof a concern, the model A wet is about 280. My wood prop is only about 15 lbs,so it isn't really far out of line.However it is pretty far forward. There is some lead in the tail and the preliminaryW&B seems okay. With the tail up in a flying position it still has a gooddeal of weight on the tail, about 50 pounds I think (need to get scales andweigh it, but it doesn't seem nose heavy on the gear.)In the air I don't think there would be an issue. The gear's camber is off andthat is what originally concerned me, however there is quite a bit of adjustmentthat can be done, so until I have the plane up off the ground where it canbe adjusted, I don't know that it has any real camber problem either.The Aerial plans have a few guidelines, essentially that if the engine is 280 lbsor more move the top wing forward a few inches, and that the distance betweenthe wings can be set to 51" without appreciable differences in the W&B to makeentry/exit easier. From measuring the plane with the wings on, those changeswere made. The plans don't have anything about relocating the landing gear,as the idea was to minimize changes from a stock plane. To get clearance fromthe gear the lower wing mounts lift the wing a couple inches above the mountpoints (which are the same mount points as the lift struts on a normal Piet orGN-1.)With the engineering math info I should be able to get an idea of whether its aconcern or a real problem, and the magnitude of what it will take to sort itout. Thought about replacing the two giant magneto's with a CDI system for instance,that could cut at least 30 lbs off the nose, and would add a small battery thatcould be moved behind the CG point. If it was just a little off that kind ofthing might help. (Probably cut more than that, was told the brass conduit forthe plug wires weighs almost 15 lbs., the mags look like starters for a bigtruck, they are huge.)But if it needs the gear forward a foot or so, its going to take some real work.To me it looked like you could slant the gear forward like a Bucker Jungmann,and gain 6-8" of forward movement of the axle pretty easily. The A&I disagreedand said it would double the landing shock load, which led to a discussionthat I didn't follow well (neither did his friend that was with him that builta Kitfox and was pretty knowledgeable.) So I will look toward a good engineerif it comes to it.The A&I is maintains a biplane museum, has 30+ yrs experience and specializes intube/rag work, and is one of our local EAA tech counselors, so I am inclinedto take his advice and investigate if I have a problem.Read this topic online here:http://forums.matronics.com/viewtopic.p ... ttachments: http://forums.matronics.com//files/dscf ... ___Subject: Pietenpol-List: wing rib brads
Thanks guys,I had similar thoughts, but am still bugged by the fuselage really looking longin front of the wing.My engine is supposed to weigh 315 pounds, which if it was short and close to thefirewall (like the radial in the prototype Aerial) it wouldn't be that muchof a concern, the model A wet is about 280. My wood prop is only about 15 lbs,so it isn't really far out of line.However it is pretty far forward. There is some lead in the tail and the preliminaryW&B seems okay. With the tail up in a flying position it still has a gooddeal of weight on the tail, about 50 pounds I think (need to get scales andweigh it, but it doesn't seem nose heavy on the gear.)In the air I don't think there would be an issue. The gear's camber is off andthat is what originally concerned me, however there is quite a bit of adjustmentthat can be done, so until I have the plane up off the ground where it canbe adjusted, I don't know that it has any real camber problem either.The Aerial plans have a few guidelines, essentially that if the engine is 280 lbsor more move the top wing forward a few inches, and that the distance betweenthe wings can be set to 51" without appreciable differences in the W&B to makeentry/exit easier. From measuring the plane with the wings on, those changeswere made. The plans don't have anything about relocating the landing gear,as the idea was to minimize changes from a stock plane. To get clearance fromthe gear the lower wing mounts lift the wing a couple inches above the mountpoints (which are the same mount points as the lift struts on a normal Piet orGN-1.)With the engineering math info I should be able to get an idea of whether its aconcern or a real problem, and the magnitude of what it will take to sort itout. Thought about replacing the two giant magneto's with a CDI system for instance,that could cut at least 30 lbs off the nose, and would add a small battery thatcould be moved behind the CG point. If it was just a little off that kind ofthing might help. (Probably cut more than that, was told the brass conduit forthe plug wires weighs almost 15 lbs., the mags look like starters for a bigtruck, they are huge.)But if it needs the gear forward a foot or so, its going to take some real work.To me it looked like you could slant the gear forward like a Bucker Jungmann,and gain 6-8" of forward movement of the axle pretty easily. The A&I disagreedand said it would double the landing shock load, which led to a discussionthat I didn't follow well (neither did his friend that was with him that builta Kitfox and was pretty knowledgeable.) So I will look toward a good engineerif it comes to it.The A&I is maintains a biplane museum, has 30+ yrs experience and specializes intube/rag work, and is one of our local EAA tech counselors, so I am inclinedto take his advice and investigate if I have a problem.Read this topic online here:http://forums.matronics.com/viewtopic.p ... ttachments: http://forums.matronics.com//files/dscf ... ___Subject: Pietenpol-List: wing rib brads