ron ward

iknow the general rule for a taildragger is to place the axle in line with the leading edge and maybe a bit more forward, but am a bit puzzled with certain ambiguousdetails of this rule. given the general rule above, should the axle be aligned with the plane at normal flying attitude and a line projected verticle or should they be aligned with the plane at 3-point rest on the ground with the line projected verticaly or should the line be projected at right angles to the plane'sdatum?. all threeset-ups result in the gear being in slightly different locations.
i have also read that they should be placed 15% +/- of the wing's chord ahead of the GG. i can only assume that this rule is with the plane at normal flight attitude and the line projected verticaly becauseas the plane sits on the ground, the CG means very little, but it means everything once the plane is moving and flying.

maybe i'm being a bit anal about this, but after 30 years of reading blueprints and building specs, my mind catches these little ambiguities automaticly and sets thered lights flashinglike a house a-fire!
thanx in advance... what do you think?........
ron ward

All Day Dan

My Feedback: (5)

Install the landing gear with the axle of the wheels at the leading edge of the wing with the chord line of the wing parallel to the ground. Dan.

BMatthews

It's actually supposed to be forward from the true three dimensional center of gravity at about a 20 degree angle when the model is level.  But the reality of grass field flying results in a lot of models having this angle more like 30 degrees.  All of this happens to put the wheels below the wing leading edge more often than not.  Or if the gear is really long then the wheels may be even a bit forward of the leading edge. 

For this same reason on a low wing model the wheels will end up a little behind the leading edge because the low wing location moves the true CG to a lower point.

If the gear is TOO far forward ground handling becomes a bit twitchy as the model will tend to ground loop more easily.

ron ward

once again, thanks for the answers!..

BMathews,
again you've come through with an answer and some reasoningbehind it and even some expansion, i really appreciate the effort and time you've given me to more fully understand things at more than just a beginners level. i used the "20 degree" rule when i drew the gear onto my print. it's good tosee some assurance.
presently my axles sit about an eighth inch infront of the leading edge with the plane level, so i should be good to go.
i just finished putting in the radio and everything is working great........i'm stoked! now, on to the finishing and covering.