REFLECTOR: Pitch Trim Alternatives

[Alex Balic]

Hi Joe-

A couple of comments on your suggestion- first, this arrangement looks
really touchy- i.e.- difficult to arrive at and maintain the correct  

trim setting, the factory screw jack system moves really slowly, and holds
position positively,  and it still is too touchy for a lot of installations,
requiring a separate braking circuit to stop the slow moving screw exactly
when the switch is released. Also, not sure if it is any sort of advantage
to have a clutch there, as it will require power to hold it on all of the
time- you might look into an acme screw design similar to the strong system-
the trim does not take too much movement to bias the elevator travel.

 

Alex

 

  _____  

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Joe Ewen
Sent: Sunday, May 13, 2007 4:13 PM
To: Velocity Aircraft Owners and Builders list
Subject: REFLECTOR: Pitch Trim Alternatives

 

I am looking into alternatives to the stock factory pitch trim.  Due to
installed instrumentation, I do not have room for the factory stock pitch
trim spring.  I was considering the Strong Pitch Trim, but due to 1 negative
report and the fact that I have electronics installed in the keel that would
interfere, I have been looking for alternatives.  One idea I am considering
is using a spring linkage driven by a servo motor.  The servo would be
autopilot grade (mechanics disengaged when power is off) and the linkage
would have enough spring travel to facilitate full elevator travel in the
event the servo was stuck in either extreme.

 

I am looking for comments and suggestions on the attached pdf as well as any
other alternatives.

 

Thanks,

Joe

 

 

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