Kill radio ----> fail-safe returns throttle to idle and sets brakes

Kill Rx ----> TRS closes carb but brakes are not set (it didn't used to close the carb....hmmmmm)

do I think that the TRS adds extra stress onto the servo when the carb is open?

Of course it does, what is in question is whether it's enough to worry about. I just did a few calculations on the set-up I've got.....

With my servo (44.4oz-in.) and horn, the maximum force the servo can put out is 50.7oz = 3.17lb. The force required to overcome the TRS and bring the carb to full throttle is about 1.25lb (this is approximate, I hung a couple of water bottles from it and calculated the weight from the volume of water.....I don't have a scale :disappoin ) Anyway, what this all means is that the servo is working at about 40% of it's maximum capacity when at full throttle to overcome the TRS. Obviously, there's no problem with that, the servo will do fine opening the throttle to WOT......once

The problem, as occurs often, is with fatigue. Even though a part is stresses below it's limit, it may still fail if it is stressed repeatedly. The theory behind fatigue is pretty involved but as an approximation, the maximum repeated stress on the servo should not exceed a value equal to ~80% of it's listed capacity. If you stay under this limit, you should have a pretty long servo life.

In my case, that would be ~2.5lb so I should be okay for a while.....

did I lose everybody with my engineering ranting???