Pietenpol-List: Landing Gear location
Posted: Mon Feb 16, 2004 11:03 am
Original Posted By: "Ted Tuckerman"
Pieters,I have been recently reading the e-mails about landing gear location again andit's location relative to the firewall or other parts of the plane such as wingleading edge etc. I think using any reference other that the mass CG locationof the plane is wrong, especially because the wing is movable on a Piet. EachPiet is different, but the CG of the wing must be within the same limits forthem to fly well, and therefore the mass CG of the entire plane will be close,relative to the wing, beween various Pietenpols.On January 13th I wrote and suggested:"The CG of the entire plane is a combination of the horizontal and vertical centersof gravity. From this point a line may be drawn to the ground contact pointof the landing gear. The angle of this line is usually 16.5 degrees forwardfrom the vertical if the plane is equiped with brakes, somewhat less if theplane has no brakes. It might be neccessary to increase this angle if the thrustline is high, so as to prevent nose over during run up and rough field operation.However, the heavier the tail load is, the more of a tendency for groundlooping upon landing. On "Mountain Piet" this angle is about 12 degrees and this seems to work out OK,both for rough fields and no ground looping tendencies."Chris Bobka also pointed out that the plane should be leveled up when determiningthe CG of the plane. And additionally, Chris wrote a good explanation of thesame subject in another e-mail on about January 24. Look it up in the archives.Then, as I remember, there was also some discussion about how to figure the CGof the entire mass of the plane by weighing the plane both in a three point positionand level position from Hank Jarrett.Hope that this is helpful.John________________________________________________________________________________
Pieters,I have been recently reading the e-mails about landing gear location again andit's location relative to the firewall or other parts of the plane such as wingleading edge etc. I think using any reference other that the mass CG locationof the plane is wrong, especially because the wing is movable on a Piet. EachPiet is different, but the CG of the wing must be within the same limits forthem to fly well, and therefore the mass CG of the entire plane will be close,relative to the wing, beween various Pietenpols.On January 13th I wrote and suggested:"The CG of the entire plane is a combination of the horizontal and vertical centersof gravity. From this point a line may be drawn to the ground contact pointof the landing gear. The angle of this line is usually 16.5 degrees forwardfrom the vertical if the plane is equiped with brakes, somewhat less if theplane has no brakes. It might be neccessary to increase this angle if the thrustline is high, so as to prevent nose over during run up and rough field operation.However, the heavier the tail load is, the more of a tendency for groundlooping upon landing. On "Mountain Piet" this angle is about 12 degrees and this seems to work out OK,both for rough fields and no ground looping tendencies."Chris Bobka also pointed out that the plane should be leveled up when determiningthe CG of the plane. And additionally, Chris wrote a good explanation of thesame subject in another e-mail on about January 24. Look it up in the archives.Then, as I remember, there was also some discussion about how to figure the CGof the entire mass of the plane by weighing the plane both in a three point positionand level position from Hank Jarrett.Hope that this is helpful.John________________________________________________________________________________