I am installing a DLE 20 engine in a Great Planes Revolver. The throttle servo can either be mounted on top of the engine box or aft of the wing tube. CG won't be an issue in either case.

If I mount the servo aft of the wing tube I will have a fairly long pushrod to go from servo to throttle. I would prefer the shorter pushrod setup if the servo is mounted on top of the engine box.

However, I'm concerned that engine heat may effect the servo if mounted that close to the engine The servo would be about 4 inches behind the engine head and within the engine cowling.

Do you think the servo would be okay within the engine cowling or should I mount it aft the wing tube.

Thanks
Indiomike

Heat isn't an issue if the cowl is vented for engine cooling properly, I've mounted a few in the cowl, I'd focus on where it allow the plane to CG out easier.

good luck

naw you're good either way with heat....go for the engine box and the shorter pushrod....Oh I always take the return spring off the throttle....no need to have the extra drag on the servo

Thanks guys. I appreciate the feedback. I will mount it behind the engine with ball links on each end.

Mike

Leave the spring on.

Mounting the servos as far away from a gas engine is a good habit to get into. Running a long nyrod throttle isn't hard to do and it's a good idea to always use completely non conductive rods that attach to the engine like the throttle. With the 2.4 radios we have today RF is not as hard to remove or keep away from but it can still happen. I lost my last summers build to RF so I know first hand it is still waiting to bite you in the butt! Keep all servos as far away from the engine as you can. Read about it in the gas engine forum.
The spring under the throttle arm can be dis-connected but leave it in place, leaving it attached is also a good idea. Remove the idle stop screw so you can use your radio trim as a way to kill the engine.

+1


Bob

I;d be worried about vibratin so close to the motor but maybe thats not an issue.

I remove the springs on my gasser throttles and keep the throttle servo at least 10" away from the magneto or sparkplug.  That spring isn't going to defeat a servo that has lost power, and the failsafe should be set to lower the throttle to idle or lower if signal is lost.  If too close to the ignition circuits the windings on the servo motor coil will transfer the spark impulse to the receiver through induction (aka "EMI").  Less a factor with 2.4GHz, but still a factor.

At least that's the way I was coached on gas ignitions and servos.  Has worked for me so far.

True,, the spring will only help if the throttle linkage comes disconnected. Which has been known to happen. But even so that is why you run a remote kill of some sort,, optikill preferably

I guess we who have been spoiled by 2.4 fail to consider the OP may be on 72,, that would change my post above for sure