I'm converting my small AD Rafale to P-80 power, and have installed a Tam's Bifurcated SS Jet Pipe. How far inset should the rear end of the SS pipe be inside the scale exhaust nozzles. The way I have mine set now the end of the SS pipe is about 30-40mm in from the rear edge of the glass nozzle. I briefly ran the engine for the first time at idle the other day, and afterwards noticed that the glass nozzles were a little warm. Should I move the pipe rearwards a little to reduce the risk of burning the glass nozzles.

Thanks

Paul

Page 18 in the Jetcat manual shows a diagram of a P-80 install. If you don't have the manual you can download it from the Jet cat website.

http://jetcatusa.sitewavesonline.net/p80.html

Paul,
It's important to get the gap between the engine and the pipe correct (roughly 3/4"), this will basically define how far out your pipe sits....
As Kenny said, refer to page 18 for correct install tolerances.
Todd

The engine end isn't the problem, it's the rear end. I can move the whole engine and pipe forwards and back within reason, but I don't know how far the rear end of the pipe sould be inside the scale exhaust cone. I've got the engine, to pipe inlet spacing about right.

I'm at work at the moment, otherwise I'd post a picture, as that's worth a thousand words.

Thanks

Paul

The outer pipe (SS one) should be sticking out past the glass portion or it will cook the glass. At least in a dual wall pipe anyway. The inner pipe should be inside anywhere from 3/16" to 3/4" from what I've been told, but if you have any fiberglass exposed it will get cooked.

It's my understanding that what makes a dual wall pipe work so well, is the fact that the inner pipe is shorter at the back than the outer pipe. This helps draw air between the 2 pipes. The same is true of the fuselage. The outer tailpipe should be a little short of coming out of the fuse, to help draw air out of the fuse. Is this correct?

"Bald jet guy" lol

Good answer Gary.
Don't worry about little warm on the nozzle. I haven't experience any burn nozzle on normal engine running condition.
My Y/A F-18 single nozzle even smaller than Rafale. I got 35 flight plus. The paint on the nozzle doesn't show any blister.
Brg,
Tam