Re: F1D longitudinal stability from Bill Gowen on 2007-11-06 ([Indoor

From: Bill Gowen <b.gowen_at_earthlink.net>
Date: Tue, 6 Nov 2007 10:17:28 -0500

Tapio
I don't want to give advice about F1D's because I don't fly F1D but in general a short heavy motor can be accommodated by using a wire spacer at one or both ends of the motor to ease the strain on the motor stick. I hope to remember this advice myself the next time I fly at Lakehurst and am having trouble with the motor causing down trim in the tailplane!

  ----- Original Message -----
  From: Tapio Linkosalo
  To: Indoor_Construction_at_yahoogroups.com
  Sent: Tuesday, November 06, 2007 3:33 AM
  Subject: [Indoor_Construction] F1D longitudinal stability

  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-



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Received on Tue Nov 06 2007 - 07:17:34 CET