If anyone is curious as to what Joe Wurts, Daryl Perkins,
et all will commonly do to "check" the CG of a plane when
you hand them the Transmitter; it's this...
They will trim straight and level at some reasonable "floaty"
speed, then roll inverted. If the plane continues happily or
climbs/descends only slighty, then it's close to where it "should" be.
If it noticably dives/speeds up then it's too far forward.
This may only work best with performance oriented designs which
have little or no decaloge, or full-flying stabs. I'm speculating because
I've never tried this test with a trainer.
None of the "best" guys that I fly with a lot pay much attention
to this or any other "test" they simply play with the CG till the
plane is "right". "Right" by the way can change from flight to
flight depending on the task. For example slope racing can benefit from
an extreme back CG because the plane is in close in where you can
see it well and needs to turn a lot. F3B distance on the other hand can
be problematic for back CG's as the plane may be a mile away while
you are trying to fly it accurately. Even worse distance wise is F3J.
However for thermal events the CG can be farther forward without making
you much less competitve, a back CG is just not as important to the task.
John Roe
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