Mailing List lml@lancaironline.net Message #55225
From: Wolfgang <Wolfgang@MiCom.net>
Sender: <marv@lancaironline.net>
Subject: Re: [LML] Re: Legacy Trim Tab Servo Speed Control
Date: Fri, 28 May 2010 13:15:38 -0400
To: <lml@lancaironline.net>
How many incidents have been recorded of a shorted trim switch causing run-away servo travel ?
 
Wolfgang
 
----- Original Message -----
From: mikeeasley
Sent: Thursday, May 27, 2010 2:14 PM
Subject: Re: [LML] Re: Legacy Trim Tab Servo Speed Control

I installed the Safety Trim module primarily to handle the two trim switches on the sticks and to deal with the potential (although extremely unlikely) of runaway trim due to a stuck switch or shorted switch.  The stock ES elevator trim is uncontrollable in the full down position.  I also installed a shorter throw trim servo to eliminate unneeded down trim.  The two speed feature was more of an extra bonus in my airplane.  I flew my ES with full speed trim for 4 years, bumping the trim switch, and it wasn't that big of a deal.  With the two speeds you hold the switch for about a half second instead of tapping.
 
The Safety Trim module handles two trim switches automatically.  It has a 3 second auto-off feature to catch runaway trim.  It has a panel mounted three way momentary switch that allows the pilot to reverse the trim travel in the event of a stuck or shorted switch.  And a two speed (both adjustable) feature that can be operated by a flap microswitch or airspeed switch.
 
I removed my Ray Allen speed control module and didn't need the Ray Allen Relay Deck that has been a failure point in the past.  Although the new relay deck REL-2 is supposed to be more reliable that the old REL-1
 
The Safety Trim is just another goodie in a long list that wasn't necessary, but something that I thought added some additional safety and functionality
 
Mike Easley
Colorado Springs
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