Extreme Speed Prop Planes Discuss the need for speed with fast prop planes (Screamin Demon, Diamond Dust, Shrikes or any REAL sound breakin'''' plane)

Tuned Pipe Question

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Old 01-16-2005, 06:39 PM
  #1  
GMPheli
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Default Tuned Pipe Question

I was wondering if some of you guys might be able to help me out. I am building kinda a speed heli. It will have a pipe timed (not sure of the actual duration, the exhaust port was raised about a mm) OS 61 SX-H (short stroke) spinning about 17k. I am looking for a good quiet pipe. I was thinking about a Bolly, but I can't find out who sells them. I guess they have been bought out. I wanted the carbon pipe so it would not make the heli too tail heavy. I like a long pipe as it keeps the heli very clean. Any help or suggestions would be appreciated!

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Alan Angus
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Old 01-16-2005, 10:04 PM
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Default RE: Tuned Pipe Question

Thats a good question. In planes you need rpm and pitch to move out usually smaller diameter prop.

In helis your kind of stuck with the main rotor blade diameter. I would think you would need a strong engine to be able to turn high pitch to get the speed. Only thing about pipes is they work at certain rpm's, to much pitch may knock you off the pipe. It would be a matter of finding a good pitch at a certain rpm'. Anything more or less wont benifit the pipe.

I am not pro at helis but going by how planes act I wouldnt think would apply to helis.
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Old 01-17-2005, 10:22 AM
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Default RE: Tuned Pipe Question

Hi Alan...

I tried something along those lines a number of years ago. We were playing with "Vertical drag racing". It was fun for a while Ate up a few too many main gears though. Used a re-worked OS 61 FSR, marine Macs pipe. Dropped two pinion sizes to get the engine up where I wanted it. Sure woke up the neighbors

Ask around in the pattern forums for carbon pipes. Although, it may be hard to find a current one that is short enough for that 17K range. Most of the modern pipes were designed for the 9000-12000 rpm range.

Also, seem to recall a couple of folks having ducted fan 15cc carbon pipes. Those might be perfect - they are set up better for the higher rpm and higher flow volume. Maybe ask in the jet forum.

Bob
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Old 01-19-2005, 04:50 PM
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Default RE: Tuned Pipe Question

Thanks guys!

Alan
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Old 01-19-2005, 04:53 PM
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Default RE: Tuned Pipe Question

Thanks guys!

Alan
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