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Old Feb 08, 2009, 05:37 PM
Nitro Buster
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OS .46 SF, OS .46 FX, or OS.55 AX with Tuned Pipe

I have these three engines and was wondering what engine would give the best rpms based on experience with testing and knowledge. I use an 11x7 APC, the header from the pipe is 4.5 inches. Any opinions?
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Last edited by Nikolizer1; Feb 08, 2009 at 06:25 PM.
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Old Feb 12, 2009, 10:58 AM
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Everett Wa.
Joined Jun 2001
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Since this has fallen off the front page with no response, I thought I'd give it a shot.

From experience most pipe lengths are measured from the piston face to the high point of the diverging cone. So you are looking for number like 12 to 18 inches. The actual header length means nothing in tuning a pipe.

I'm not sure what you want to do with this engine, prop and pipe. A pipe can be thought of as a super charger like that used in FAI F3D Pylon racing or as a gearbox moving the torque curve like in FAI F3A pattern. As you seem to want to use a rather large prop for a piped 7.5 cc to 8.5 cc engine, it looks to me like you want the pipe to act like a gearbox

From experience the OS engine will not hold up well to the elevated power levels that I use. So I can't offer much specific to the engines in question. I have posted some sites that should help you in understanding how a pipe works and how to adjust one. Also do a search under my name and pipe in this form to learn more about pipes.

http://www.jettengineering.com/tech/pipetune.html
http://www.mh-aerotools.de/airfoils/javapipe_de.htm

Friends don't let friends fly nickel,
Konrad
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Last edited by Konrad; Feb 12, 2009 at 11:06 AM.
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