Colyn, Thanks for the questions.
In the system you described the Safety Trim actually goes between the manual trim switches and the trutrak auto trim module. Otherwise it would in fact interfere with auto trim operation as you described. So in theory, the trutrak could still command a run-away trim. However, I've never heard of that. Also, in talking directly with Trutrak I believe there design is solid in that regard. The safety trim system is protecting you from inadvertent runaway conditions caused by issues with the trim switches and or pilot's accidental input. The safety trim system is all electronic and it does eliminate the need for any relay decks. (Which have been the key issue in the field). Regarding mtbf, this calculated life expectancy can be so skewed by the input variables used in the math I find it to be not useful. Instead, we use design rules for our component selection/derating factors to ensure operating lifetimes of more than 50000 hrs. For general aviation operation therefore, beyond the useful life of the aircraft. Additionally, for Safety-trim we have had zero design related returns or field issues.
Hope this helps,
Bob Newman
Sent via BlackBerry by AT&T
Date: Wed, 19 Jan 2011 11:33:27 -0500
Subject: ***SPAM*** safety-trim vs. auto-trim
Hi,
I have a Lancair IVP with a tru-trak sorcerer and auto-trim.
I'm interested in your safety-trim product and had a few questions.
First of all, the way the tru-trak auto-trim unit works is to intercept =
the manual trim lines and take them over.
To get protection from runaway trim, you would want to have the =
safety-trim unit between the auto-trim box and the servos. My question =
then is what happens if the auto-trim box commands a trim change that =
exceeds the 3 second limit of the safety-trim?
I can imagine this situation if you were in a steep climb and then hit =
the alt hold button on the auto-pilot.
My guess is that the safety-trim will stop the trim but the auto-trim =
box will keep commanding it so the two will never reach resolution. Do =
you have any installations that include a tru-trak auto-trim box?
Other questions:
Looks like your box eliminates the ray allen relay deck, is this =
correct? =20
Do you use solid state relays? What's the MTBF on those?
thanks,
Colyn Case
Hyde Park, Vt.