I originally posted this in the electric forum but only received one reply, so I thought I would try my luck here:

[link=http://www.rcuniverse.com/forum/m_8268707/tm.htm]Original post[/link]

Your suggestions would be greatly appreciated, and I wish you all a Merry Christmas.

First off, how much is the finished plane going to weigh approximately? Are you sure that motor will do the job? The mount you have is for a stick-mount application.

What I would do is cut the existing glow engine mount flush with the firewall. Then select the appropriate outrunner based on the expected finished weight of the airplane. since this is a Cub, you don't need to overpower it. I'd say 100 Watts per pound would be plenty. Then you can determine what you need to do to mount the motor on the firewall and space it out as needed.

Chuck,

The plane is very light. Without the electrical gear it weighs under 12 ounces, so I will have more than 100 Watts per pound with this motor - assuming I can trust the specs at 200W.

Wow, that is light. I'd toss the stick mount and try to bolt the motor directly to a flat firewall.

I think ChuckW has got it. Simplicity is beauty.

Bill

I don't think bolting the motor to the firewall will get you past the cowl.

I wouldn't use the plastic GWS mount.

I would make a fixture consisting of a 1/8 ply firewall large enough to mount the motor to plus some extra, and another piece of 1/8 ply at a right angle on the back and in the center, with gussets to the motor mounting plate for extra strength. Make this horizontal piece the same width as the mount you already have and deep enough to cover about 3/4 of it when the vertical part is slid back against the front of the rails. This whole assembly could then be slid fore and aft on the existing mounting rails till you have the correct clearance for the cowl, and then screwed directly to the OEM mounting rails. This will also preserve the designers thrust lines for you.

In other words, take advantage of what you already have to make it easy to set up the motor. And you could always mount a larger motor to the same rig in the future.

Thanks for the responses everyone, much appreciated.

ram - great advice, I think I'll do it exactly as you said.

Alright, this is what I ended up doing: I shortened the existing mount and made this "adapter" which simply slides over it. All I have to do now is reinforce it using a few pieces of triangle stock and I should be good to do.

I now have a new problem: When trying to install the servos, I was surprised to see that there was only a very thing strip of plywood available to screw in the servos. This problem became somewhat worse as I had to make a "notch" to allow the servo wire to clear the opening. If I tried to screw in the servos as is, I would likely split the strip of plywood or at best have a very weak installation which would eventually let go. Interestingly enough however, there is plenty of room on the sides of the servo. Only if the mounting wholes were there... To make it easier to follow what I am saying, I have drawn lines to illustrate where the plywood is under the covering.

Any suggestions on the best way of properly securing the servos in the wing?

Looks like that will work fine.

For the servo mounts....CA some balsa stock under where the screws will be. Pilot the holes with a 1/32 drill bit, run the screws in then back out, then drop thin CA in the holes. After it is dry, the threads are hard and strong. No worries.