Mailing List lml@lancaironline.net Message #55169
From: Chris Zavatson <chris_zavatson@yahoo.com>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Legacy Trim Tab Servo Speed Control
Date: Mon, 24 May 2010 13:09:42 -0400
To: <lml@lancaironline.net>
Valin,
The 360 MKII tail is the same as the Legacy so this may be useful. 
I regulate trim servo speed by switching between bus voltage and a 5V regulator for low vs high air speed trim.  I found 5V to the best compromise between low speed and having enough torque to operate the trim.  High rate is used in the pattern, low rate everywhere else. This set-up has woked great for the last 12 years.
I would avoid anything that simply puts another resistance in line with the trim circuit for speed control as the voltage across the servo will vary with load.  A variable voltage regulator is another option and is in fact what I used originally.  I found that dual rates were plenty for this system.
Chris
 
 
Chris Zavatson
N91CZ
360std


From: Valin & Allyson Thorn <thorn@starflight.aero>
To: lml@lancaironline.net
Sent: Sun, May 23, 2010 8:52:58 PM
Subject: [LML] Legacy Trim Tab Servo Speed Control

Hey Legacy gang,

 

Could I get recommendations on the best way to set up the Ray Allen trim tab servos in the Legacy so that they have the right sensitivity throughout the range of flight speeds?  I know from 99L that at cruise speeds without a speed control rheostat to slow the tabs down that they’re too sensitive – slightest tap on the switch causes a “bump”.

 

Ttcwtech.com has a $49 speed switch that they sell that can be used to set a speed where the sensitivity changes – up to 145 kts.  Is it good enough to have a speed control rheostat cut in to slow the tabs down once the gear and flaps are up?  Or, has anyone found a rheostat that’s directly driven by the airspeed so that the sensitivity is always in proportion to flight speed?  Other ideas?

 

Thanks,

 

Valin Thorn

Eternal Legacy project

Houston, Texas USA

 

 


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