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From: CHRISTOPHER_ZAVATSON@udlp.com
Date: Mon, 5 Apr 1999 17:58:43 -0500
Message-ID: <002A965F.C21254@udlp.com>
Subject: Horiz. Stabilizer and Elevators
To: Lancair.list@olsusa.com
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          <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>>
          <<  Lancair Builders' Mail List  >>
          <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> 
>>
     <<Doug assured me that there was plenty of authority at that 
     dimension.  Don't forget, you're probably going to want to put a 
     potentiometer or resistor inline with the trim tab switch to give you 
     variable speed operation of the tab... normal tab speed at cruise is 
     reported to be pretty twitchy, that's another part of the reason the
     tab is a bit smaller.>>
     
     Marv,
     I have a high and low rate switch for the trim servo.  High rate feeds 
     bus voltage to the servo which produces a good travel rate for pattern 
     work.  Low rate supplies a regulated 5V to the servo.  Any less 
     voltage and you run the risk of stalling the motor in the servo.  The 
     much slower servo speed takes the 'twitch' out of trimming in cruise.  
     I like having the option of switching back and forth.
     Also, if you make the trim tab too small you may run out of authority 
     in the slow end of the flight envelope with full flaps and a forward 
     CG. 
     
     Chris Zavatson
     N91CZ

[Thanks, Chris, I guess it was unclear when I suggested that providing
"variable speed" to the trim tab implied a switchable voltage supply.
Your setup is exactly what I was trying to describe.  Obviously a
regulated voltage supply is far superior to simply installing a pot
or resistor onto a SPDT switch to provide lo/hi speed switching.  Your
clarification is appreciated.    <Marv>   ]
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