I was reading an article about an aircraft plan and it stated to allow for 3 degree right thrust when mounting the engine.
How is this done? Does it mean that I need to mount the engine 3 degrees to the left/right or does it mean that somehow I need to make the engine slant to the left/right by putting a shim behind the motor mount so that the engine points toward the right? I've never had to do any engine mounting where I had to worry about the "degree" thing. Thank you

Point the engine toward the right.

Thanks Dickj. But how is this done? Is this determined before you mount the engine or after it is on the mount and then shimmed on one side of the fire wall? I suppose what I am asking is...how do you measure the degree once you are ready to install the engine?

Hi if the firewall doesn't have the right thrust built in then place 2-3 washers between the left side of the motor mount and firewall.

But check the plans and instructions carefully first and make sure of there intent.

They might want you to move the engine left to place the prop adapter on the centerline to counter the right thrust built into the firewall.

What plane is this?

mstroth, the plane is a 1/6 scale of an L-19 Bird Dog in the RCModler magazine Apr. 95. It stated that the down thrust is already built in so all you have to allow for is 3 degrees of right thrust.

I use the washer and/or a thin piece of plastic or plywood to shim mine on the left side of the mount. I then position the fuselage on its side in a jig position by using a level on the side of the vertical fin, fuse etc. to make sure the c/l of the fuse is maintained and then use my Robart incidence meter which attaches to the prop nut to check for the 2 degrees. A simple way is put in two washers and fly it and if thats not enough adjust from there.

mstroth......ah ha! You was right on! After that last posting to you I went back and studied that tiny diagram drawing and it showed the the engine was slightly moved to the left and then stated to shim the mount and showed that the propeller adapter was in the middle of the front of the plane.
I suppose I should have studied this thing a little bit more before made postings, eh? Thank you for your help.

dickj Thanks so much for that suggestion. It certainly makes a lot of sense to me and I think I will follow your advice on doing the washer thing.

Glad to help!

with using washers though, it depends on the size of you're engine

for a size .12 engine say, the mount is small so putting in a washer will give it a few degrees of right thrust because its a small space if you get me.

With a size .90 engine, the mount is much bigger so 1 washer will not give as much right thrust as it would with 1 washer on a smaller engine.

Its like if you had a long plank of wood and a book. Rest the plank on the book and move the book furthur inwards, you'll notice the plank will slant more and more as you get to the end of the opposite side of the plank