[NSRCA-discussion] 2C Pipe vs Muffler

[Rcmaster199 at aol.com]

I have used the OS160 as a test bed for such comparison, in the air. Ground  
running doesn't show much of a difference; just a couple hundred.  Eventhough 
it is very mildly timed for tuned pipe use, the device definitely  adds HP. Of 
course it can be set too long to have a useful boost in output and I  had it 
set there initially. As it was shortened to a more typical setting for  large 
2C engines, not only was the output improved (again, in the air), the  engine 
became sweeter running with improved response.
 
Don't ask for RPM's, I couldn't care less. It improved the capability  of the 
airplane and that's about all that counts.
 
MattK
 
In a message dated 3/6/2006 9:01:40 PM Eastern Standard Time,  
jeffghughes at comcast.net writes:

So you are saying you have tried a comparison of a tuned pipe vs a  muffler 
back to back? Any data?
 

--------------  Original message -------------- 
From: Rcmaster199 at aol.com 

In a message dated 3/6/2006 6:57:30 PM Eastern Standard Time,  
jeffghughes at comcast.net writes:

was  going through the data on Ed Hartley's 2 stroke page and noted that 
there  is virtually no difference between a piped OS1.40 and a muffled OS1.40 for  
the prop sizes being used.  I assume that is because to get a nice  linear 
throttle curve on a pipe, the pipe is deliberately set too long for  peak 
horsepower. My question is why run a tuned pipe at all if you are  going to set it 
too long for peak power?. Has anyone run back to back  tests with same engine 
and plane with a pipe vs a muffler to see if  there is truly a difference in 
power or feel?

 
Yes and there is
 
MattK




 
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