Electric elevator trim
Moderator: drseti
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owenstrawn
- Posts: 20
- Joined: Sun Jul 02, 2006 10:44 am
MAC was an older brand of servo. I think the Allen is the same thing.
One thing to watch is if a airframe manufacturer lists the electric trim servo as an option and it is installed in the elevator did they check for flutter and / or rebalance the controls.
The servo adds a lot of weight to an elevator or aileron if installed in the control. Better would be install in the stabilizer and run a pushrod.
Also is the airplane controllable if the trim runs to full deflection due to some kind of malfunction.
Manual trims are not perfect either. The Cessna 185 in a shallow dive with a worn elevator trim ratchet will all of a sudden run to full up trim. Just makes kind of a tick tick then zip noise and you start pitching up real fast.
Makes you pay attention to wear in the little trim clicker after that.
One thing to watch is if a airframe manufacturer lists the electric trim servo as an option and it is installed in the elevator did they check for flutter and / or rebalance the controls.
The servo adds a lot of weight to an elevator or aileron if installed in the control. Better would be install in the stabilizer and run a pushrod.
Also is the airplane controllable if the trim runs to full deflection due to some kind of malfunction.
Manual trims are not perfect either. The Cessna 185 in a shallow dive with a worn elevator trim ratchet will all of a sudden run to full up trim. Just makes kind of a tick tick then zip noise and you start pitching up real fast.
Makes you pay attention to wear in the little trim clicker after that.
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Mostlyflying.blogger.com
- Posts: 1
- Joined: Tue Apr 01, 2008 7:50 pm
- Location: Florida Keys
My AMD-made 601XL has the trim buttons on the top of the stick and they can be a pain. Honestly, I think the aileron trim is more dangerous than the elevator trim. I immediately feel a change in pitch... particularly with a good breeze blowing up my shorts.. but it might take a second to properly interpret grossly out of trim elevator and figure out what happened.
At my 50 hour check, I had the folks at AMD crank back the sensitivity potentiometer a quarter turn. It made all the difference in hitting the right trim setting quickly.
If I'm going solo cross country, where I will be wrestling with airport diagrams, charts, the A/FD, etc and there is an excellent chance that I will bump a rim button, I will pull the trim breaker. On my panel that breaker is set off by itself and easy to find.
At my 50 hour check, I had the folks at AMD crank back the sensitivity potentiometer a quarter turn. It made all the difference in hitting the right trim setting quickly.
If I'm going solo cross country, where I will be wrestling with airport diagrams, charts, the A/FD, etc and there is an excellent chance that I will bump a rim button, I will pull the trim breaker. On my panel that breaker is set off by itself and easy to find.