I'm always looking for odd model airplane stuff and I ran across this tuned pipe for 7.5 to 15cc engines. Has anyone used one of these adjustable pipes?

When you look inside the muffler there is alot going on inside, four smaller tubes, baffles, etc.

kewl nice and small

It sounds more like a muffler design than tuned pipe design. I made some experimental mufflers at one time, and they also utilized baffles and inner piping. They were very effective at reducing the decibel level of the exhaust without undue power loss. But increasing power they did not.

The reason for the baffles and pipes inside is to change the direction, and to expand and compress, the exhaust gases. IIRC from a book I read about 20 years ago, every time you change the direction 180° you get a reduction in sound pressure level. IIRC the expansion and compression is for keeping up the velocity of the gas.

Hi!
Must be a slight missunderstanding.
Simprop electonic is the name of the company.
What you show us just an ordinary silencer.

All the instructions are in German. The tube slides in and out and has a clamp to hold it in position. Would it not be tunable?

I just thought it a was a neat model airplane part and because I had never seen one before I figured the rest of you might want to check it out.

I haven't tried it out and don't know if it works.

Webra still make some "Vario" mufflers for some of their engines.

I think the sliding pipe is indeed for "tuning". But my guess is that it is for tuning the sound frequency and not the horsepower level.

It is still neat, and I am glad you showed it to us. Send it to me and I will give it a workout on my test stand.

PM me your address and I'll send it to you. You can horse around with it....

Hmmm, Edson mount for Simprop Electronic Tuned Pipe..........[sm=50_50.gif]