Original Posted By: "Steve Eldredge"
Pietenpol-List: FW: Pietenpol News
Pietenpol News
Original Posted By: "Kirk Huizenga"
Re: Pietenpol-List: Axle Dissertation
Original Posted By: "Kirk Huizenga"
Kirk,First, let me recommend to you and everybody else we fly balance ships. Whocares what the FAA says about 180 lb people. You are flying the plane andit should balance with you in it.Second, I recommend using something other than the wing leading edge as thedatum. It does not make any sense to do so. If you are moving the wingaround, then you are moving around the datum . The whole IDEA of the datumis that it is a PLACE THAT DOES NOT MOVE. It is by definition, a fixedreference point. I was at a loss as to what to use until some othersmentioned using the bolt on the left side were the front cabane attaches tothe fuselage. It seems that people will stretch and shorten the fuselage,shift the wing forward and aft but this point seems to not get tamperedwith. So let us use it going forth. If people give me good numbers, I willcalculate W and Balance for them if they think they can't do it. I agreeethat the Leading edge of the wing eventually becomes important because weneed to make sure the CG is within the fore and aft limits of the airfoilbut we can work that into the calculations later.I suggest that you look in the archives under the discussions on axleplacement where one puts the axle at some angle forward from the vetical ofabout 12-16 degrees with the angle measured at the longitudinal and verticalCG point on the side of the fuselage. I forget what the number is and Iloaned the book out on it last night so I can't look it up. You will needto compute the exact point on the aircraft where the CG is when looking atit from the side. This means longitudinal (how far back from the bolt) andvertical or up from the floor (Of course the aircraft is levellongitudinally and laterally). You are familiar with the longitudinal CGbut the vertical CG is new for most and this can be computed through amethod Hank Jarrett posted last week and I posted through Jim Markle wherehe put it up at:http://www.mykitplane.com/Planes/photoG ... umID=185In short, yes, if you move the wing back, the axle needs to be moved backtoo.Chris----- Original Message -----
Kirk,First, let me recommend to you and everybody else we fly balance ships. Whocares what the FAA says about 180 lb people. You are flying the plane andit should balance with you in it.Second, I recommend using something other than the wing leading edge as thedatum. It does not make any sense to do so. If you are moving the wingaround, then you are moving around the datum . The whole IDEA of the datumis that it is a PLACE THAT DOES NOT MOVE. It is by definition, a fixedreference point. I was at a loss as to what to use until some othersmentioned using the bolt on the left side were the front cabane attaches tothe fuselage. It seems that people will stretch and shorten the fuselage,shift the wing forward and aft but this point seems to not get tamperedwith. So let us use it going forth. If people give me good numbers, I willcalculate W and Balance for them if they think they can't do it. I agreeethat the Leading edge of the wing eventually becomes important because weneed to make sure the CG is within the fore and aft limits of the airfoilbut we can work that into the calculations later.I suggest that you look in the archives under the discussions on axleplacement where one puts the axle at some angle forward from the vetical ofabout 12-16 degrees with the angle measured at the longitudinal and verticalCG point on the side of the fuselage. I forget what the number is and Iloaned the book out on it last night so I can't look it up. You will needto compute the exact point on the aircraft where the CG is when looking atit from the side. This means longitudinal (how far back from the bolt) andvertical or up from the floor (Of course the aircraft is levellongitudinally and laterally). You are familiar with the longitudinal CGbut the vertical CG is new for most and this can be computed through amethod Hank Jarrett posted last week and I posted through Jim Markle wherehe put it up at:http://www.mykitplane.com/Planes/photoG ... umID=185In short, yes, if you move the wing back, the axle needs to be moved backtoo.Chris----- Original Message -----