Hello,
I'm building my first plane, it's an older all wood Avistar 40 ARF (not the newer Select version). I've almost got it asembled but when I go to mount an O.S. .46AX on it the muffler doesn't clear the right side of the plane if I place the engine where the manual says it should be. I've double checked the engine mount and everything seems to be as described in the instructions so I'm not sure what the problem is. Additionally, the throttle wire seems to be much too high for where the throttle lever on the .46AX is, I can make it fit without too much bend but it just doesn't look right. Is there something that I'm missing and if not, how do I fix it? Should I shim the engine up or trim the side of the airplane to make it fit?

Happy to provide more info or pictures if needed.

Much easier to just cut out a little of the cheek for the engine to fit. You don't need to be altering the thrust line of the engine anytime soon.

As for your throttle linkage, you may have to drill a new hole a bit lower. You want the throttle control to be smooth and not bind.

What warhawk said.

If you redrill the hole in the firewall, be sure to remove the fuel tank BEFORE drilling. It saves having to replace the fuel tank - found this out the "hard way".

When you cut the cheek (side of the fuselage) for the muffler, you will want about 1/4" clearance between the exhaust and the wood.

I would also suggest using a thinned epoxy OR clear dope on the firewall, any exposed wood AND fuel tank compartment to fuel proof it. If you use epoxy, use 30 minute epoxy and thin it about 10% BY VOLUME with acetone.

Thanks! It doesn't look like I'll need to trim much to make it fit but I didn't want to just go hacking at the cheek with a razor saw if I could avoid it.

Thanks for the tip about the fuel tank. I've already had to replace parts for it once as "carefully bend the aluminum tube" apparently translates into "break this piece in half and replace it with brass". I'm going to leave the throttle cable as is for right now until I get the engine mounted and see if it's binding.

Any tips for mounting the engine? The book says to place the engine such that the thrust washer is 1/4" forward of the cheek but this looks like it's much further back than any picture that I've seen. Also, I've seen posts about doing bench runin's for new engines but the book says to do the break in on the plane... Which is best and does anyone have a good link on how to do bench breakins?

Sorry to ask so many questions but I've been holding off on some of these steps for a while because the instruction manual that I have is terrible. With everything from very faded pictures to pictures and text that don't match up to steps that are out of order I've pretty much lost confidence in the book. I did request a new one from the manufacturer who kindly sent me a very nice glossy version of the book with big pictures... for the Avistar Select. That one is an RTF so the manual for it doesn't help me much with the ARF but it does have nice pictures

Thanks again for your time and efforts.

Tower has the manual for the Avistar Mark II ARF online. The link is [link=http://www.hobbico.com/manuals/hcaa2016-manual.pdf]here.[/link] This may be a little different than yours, but should be better than the manual for the RTF. As you can see, although they don't seem to mention it in the instructions, they have cut some of the cheek for the muffler. In their installation, it looks like the thrust washer is about 1/4" ahead of the cheeks. That sounds about right to me.

-Scott

Don't forget to Fuel proof the cut out with either thinned epoxy or dope. You don't want the side of the fuse to become fuels soaked

What Crashem Said !!!!!!!!!!!!!!!!!!!!!!!!!!

Thanks for all of the replies. The PDF of the manual will help a LOT. As you say, not all of it applies but just knowing how something is normally done for a similar plane I should be able to figure things out a little easier.

I won't forget to epoxy the cut... thanks for that tip.

Is it ok to do the break in on the plane as suggested in the manual or should this really be done on the bench?

Thanks again!

You can do the break in on the plane, as long as it is properly restrained.

-Scott