RCU Forums - View Single Post - header length for pattern - max RPM or not
Old 05-27-2013, 11:18 AM
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rmh
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Default RE: header length for pattern - max RPM or not

A couple of points-
a slightly smaller prop may resolve a problem of "peaky power
a larger diameter header may do the same thing .
Books on tuned pipes are relatively worthless because they look at max power tuning
A good setup for pattern works a lot like a control line stunt setup - the power ONLY reaches max when he plane is loading the engine - a vertical climb for example.
adding more nitro also may help - adding another head gasket may help
the point of all this is to broaden or slightly DE tune the engine.
there is no magic right length

start with running the engine with NO exhaust system - and adjust needle for max - power but only for a few seconds!!
now richen the needle a bit - install your exhaust setup -
ideally power will increase a little and the needle will easily adjust to full power or if backed off - easily reduce power .
If power drops -you are way off on length
If power surges violently as you try to adjust needle - too short .
Never do these tests for more than a few seconds at full tilt - you will just overheat things and likely wreck the engine.
It is a learning curve.