Trim

[Karl G. Mueller]

Georgie,

One thing you don't want is a "completely neutral" set up. It
will be very hard on the servo gears, especially when it is too
neutral in pitch.
My last years Star had an almost neutral set up in pitch
and it started stripping the gears in the elevator servos.
It took me a little while to arrive at this conclusion since there
wasn't too much left of the plane when this happened the second 
time. My suspicions were confirmed after talking to some "Aerodynamics
Experts". Every moveable surface wants to hunt for a neutral position
and if there is no opposite force ( Trim ) to stop it from doing this
you will get a certain amount of oscillation ( flutter ). Having a minute
amount of trim offset puts a slight force from the airflow over it in one 
direction and will put a stop to any oscillation. "Completely Neutral"
is not the ideal condition.

Karl G. Mueller
kgamueller at rogers.com

  ----- Original Message ----- 
  From: george kennie 
  To: discussion at nsrca.org 
  Sent: Friday, February 13, 2004 12:50 PM
  Subject: Re: Trim


  "Completely Neutral" is the most complex descriptive condition that one can conceptualize. There are so many variables, that there is only one specific set that will approximate the required parameters to achieve the "voila" condition.Change one thing and you no longer have "completely neutral". 
  Not trying to be corrective here, just stating that in my experience completely neutral is more than elusive, but somewhat attainable under certain conditions. 
  What I'm currently searching for is the correct force arrangement that will give me a neutral airplane at the C.G. that I like to fly at. I would like to fly an airplane that adapts to me not the other way around. Elusive? Yeah! But attainable? At this point, I think maybe! 
  Georgie 
    
    
  Patternrules at aol.com wrote: 

     In a message dated 2/12/2004 11:26:21 AM US Eastern Standard Time, natpenton at centurytel.net writes: 
      For an airplane that goes to the canopy in knife-edge most trim charts say , after adjusting cg , to increase the wing incidence . My " theory " says to decrease the wing incidence. What is your theory/experience ?
     What does the plane do in the down lines, if they are good you could just mix in a little down elevator with rudder, for the knife edge.  Nat, I would have thought that a guy that designed the Voo Doo Express that was completely neutral, would have all the answers LOL.  Steve Maxwell
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.f3a.us/pipermail/nsrca-discussion/attachments/20040213/dacd7ab7/attachment.html