F1D longitudinal stability

From: Tapio Linkosalo <tapio.linkosalo_at_helsinki.fi>
Date: Tue, 6 Nov 2007 10:33:11 +0200 (EET)

Re-built the collapsed fuselage form my overweight F1D model, with
excellent balsa that I got from Mr. Benns. This one seems to take the load
of overly-thick motors without problems, so I can look forward to wind the
motor to full torque. With the new fuselage it looks like I'm back to the
old stability problem that I had with my old model, in turbulent air the
model pitches up until, in severe turbulence, the tail stalls and the
model tailslides to regain stable flight. In lighter turbulence it only
stops for a while until prop pulls it out of the trouble.

For the old fuselage the cure was to move wing 10mm backwards. I could do
that, but I though whether a slightly larger tailplane would be a better
solution? Also, the problem seems to be worst in the initial moments of
the flight, so maybe adding little boron to the wing to reduce warping
under load, and maybe a little more downthrust or loosening the motor tube
rigging wire would help the initial flight?

The model still seems to need awful lot of energy to fly, with a fat
one-third motor I managed to climb only about 10 meters, and the flight
ended dead-sticking when the motor ran out of turns. So I need to go to a
thinner motor (this was about 1.7mm wide), but I would have expected a
rocket climb to high altitude with such a short motor...


-Tapio-
Received on Tue Nov 06 2007 - 00:33:16 CET