At 09:30 28 August 2013, Uncle Fuzzy wrote:
I have a sample size of TWO, so take this or leave it. =20
In BOTH the Speed Astir and Janus C log books, some previous owner had
made=
pen-and-ink' changes to the distance from the main wheel to the tail
wheel=
.. In BOTH cases, the factory figure was correct, and the ink changes
incor=
rect. When leveled per the POH, the factory distance figure was spot on.
Just sayin'

I am really struggling to understand your point. The distance between the
mainwheel axle and the tailwheel axle is always going to be the same
irrespective of the position of the glider. I suppose you could get minor
differences because of expansion but I would have thought that they were
not measureable.
The distance between two points on the ground, described by a line drawn
perpendicular and passing thought the axle centres will of course vary
depending on the attitude of the glider in relation to the ground.
Both measurements are needed.