RE: Re: 40% Stab size or 20%?

From: Don DeLoach <ddeloach_at_comcast.net>
Date: Fri, 22 Oct 2010 22:13:42 -0600

What was happening in the real world is the model would fly trimmed but when
disturbed that is when the trouble started they simply did not want
to recover.

I am no "indoorist" but this sounds like too little static stability margin.
Why not just move the CG forward for SSM equal to "large stab" layout?

I think it was really due to low tail volume as the stab
was so small and as you say the wing has to go back to move the CG
forward so small tail and small moment arm = low tail volume = model
that does not like to recover when disturbed.

Small horizontal tail area and small tail moment arm does not necessarily
equal a model that's unstable in pitch. Adequate pitch stability is simply a
matter of locating C.G. far enough forward for a safe SSM.

What am I missing?

Bottom line is every wing/stab/TMA combination can be optimized for best
duration.

--Don D.
Received on Fri Oct 22 2010 - 21:13:41 CEST