Muffler & exhaust finished.

Now I feel better. After reworking the muffler and waiting for the JBWeld to set-up, I think I have a pretty slick, scale-like exhaust system.

Basically, it’s a composite plumbing hardware (two 1/2″ 45° elbows, one 3/4″ to 1/2″ T, and a 3/4″ 90° elbow) with a bit of automotive reinforced radiator tubing to connect it all.

The copper fitting have a very tight fit into the plumbing and all joints have a coating of hi-temp automotive gasket sealant to seal it. The joint between the muffler and the larger tubing (forward of the firewall) will be the “removable” section after all is finished (just in case).

This shot is the first time I put it all together (including the spark plug ignition cap). It all fits just fine and should have plenty of clearance. Even better, I can still get the cowl off and on!

The muffler – take 2.

Wasn’t happy with a kink that developed in the tubing, so I’ve re-worked the muffler to include a 90° bend (rather than counting on the tubing to do it).

Those of you who are sharp-eyed, might remember part of this rig as the spit that turned a roasting skeleton in my Halloween deal last year. Turns out, I needed something to keep the JBWeld from dripping and this is doing the trick.

That rotisserie motor is just the ticket. Sometimes I just luck out.

Exhaust ducting.

What do you get when mix a few plumbing elbows, a t-fitting and some auto part radiator tubing?

Well, you get a way to duct the exhaust through the front part of the fuselage and exit in a very inconspicuous way.
In the full-scale, these the exhaust exits just in the rear of a cooler door and a deflector.


With this system I can put the exhaust in the same spot and it should work pretty well. I used a similar system to duct the exhaust on my Cub I competed with last year.

I’ll get it all into place and trim off the excess pipes from either side of the fuselage.

Throttle in.

Some more plywood work yields a throttle servo hookup.

Engine mounted.

Took a bit to get things worked out, but the engine is mounted. It took an extra 1″ spacer (plywood sheet) and a bit more math than I’ve used in while .

It looks like it’s swimming inside the cowl, but the time I add the exhaust ducting, fuel lines and the ignition system, it should be a nice, tight fit.