Re: Rudder size effect on control

From: Tapio Linkosalo <tapio.linkosalo_at_helsinki.fi>
Date: Tue, 25 Sep 2007 09:28:58 +0300 (EEST)

On Sat, 22 Sep 2007, Bill Gowen wrote:

> I've been told that not enough rudder area will cause a Dutch roll which
> is a rolling oscillation from side to side. A commercial SO design of a
> few years back had very small twin rudders and was prone to this
> problem.

I had a FW Stieglitz No-Cal, that - I think - suffered from too little
rudder area. It flew OK on moderate torque, but the launch was worse: the
torque from the prop dropped the left wing, but the model started to
sideslip to the left, keeping banked and nose slightly up attitude, and
flying straight (to the wall). Once the torque dropped the model started
turning nicely. The initial flight looked like a bit more of rudder area
would have turned the model into the slip direction and would have
restored normal flight. I think some pennyplanes that I used to have also
showed same kind of behaviour.



-Tapio-
Received on Mon Sep 24 2007 - 23:30:17 CEST