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B,
Yep, I agree. It would be much better to actually
know the hp generated at every RPM. Seems to me, some of the guys have a
motor mount setup and can swing a prop. How about combining
resources...?
Then again, it would give an indication of requirements
even if there were no load.
Jack Beale
----- Original Message -----
Sent: Monday, November 08, 2004 4:32 PM
Subject: [FlyRotary] Re: EWP Info- Lynn?
Jack, your experiment below would be interesting but there is one
caveat you must remember: The engine has to be under load for that to be a good
test. The engine can produce next to no horsepower and be revving 2000 rpm in
neutral. It won't be producing rated horsepower. On a piston engine, the way to
measure the load is the BMEP (brake mean effective pressure). See http://www.tsrsoftware.com/bmep.htm
for an explanation. I don't know exactly what the equivalent formula for a
rotary.
Think of it this way: Without a load, all that the engine needs
to put out to hit 2000 (or 3000) RPM is enough HP to revolve that rotating mass
of the rotors a little faster. That will be really nominal HP and a nominal
cooling load.
That's why engine dynos have to be harnessed to water
brakes to get valid data.
Barry Gardner
Wheaton, IL
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