Boomerang 40, engine mounting question

[JayJay-2008]

Good afternoon ladies and gents

I've stumbled upon the forum after searching for an answer to a question that I have and have had no lucj, so perhaps you can help?

I have a Seagull Boomerang 40 Trainer that I am building as a first plane and am currently stuck on mounting the engine.

I was recommended an SC52 2-Stroke engine for the model but when trying to mount the engine it seems that it is too big for the mount. The rails line up nicely but the crankcase is preventing it from sitting snug and if I place enough pressure on it to get it to sit flush, the arms on the mount spread.

Is it possible to remove material from the mount to allow the crank case to sit inside the mount? Or do I need to source another mount?

Thanks in advance

Jay

[Richard]

It depends... If you remove some material will you still have room for the bolts and will it still be strong enough?

Sometimes, its easier to take the engine to the model shop with the mount you got, then have a chat about what is available and get a more suitable if it exists.

A photo would really help us

[David]

Its quite common to file the insides of a mount to allow the engine to fit. If its the supplied mount it was more the likely to fit a smaller 40 size motor. A 46 would have been a step up and more then likely fitted without issue but you have gone one bigger

Its also important that its a snug fit without spreading the legs as this can and will "kick" the motor to one side at the spinner. It also brings the other point that if you do file you should take equal amounts both sides, so measure the engine width and the gap width and score a line on both legs to get it even.

As Richard said you need to make sure you have enough material left for the bolts to fix through.

You could get another larger mount, but they almost never fit the bulkhead fixings and often bugger up the cowl alignment. Again as Richard said its an idea to take it to a model shop and try a few.

[JayJay-2008]

Thanks for the advice guys

I tried filing the mount last night but the legs are kicking out as you suggested they would and so a larger mount is the way to go.

It seems that the mount is an Irvine type and so I'm going to grab the 60 size mount today and try that in, it's a P.I.A to be honest but I have to deal with what I've got.

One other question that I have is that the kit has supplied 4 self tapping screws with which to fit the engine, would it be better to fit it with a machine screw and nut?

Thanks again

Jay