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<< Lancair Builders' Mail List >>
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Gents: A loud "right on" to the techy engine talk. I like it--and hope
Jack, George, Gary and the rest of you engine gurus and wannabe gurus
continue the debate. I am also learning new and wonderful ways to insult
people nicely,....
And remembering that anecdote is singular for data, many anecdotes plotted
together might
yield insight. Oh--what is FMEP??<<
I was afraid that our engine "discussions" were getting a little off the
Lancair track - I for one groove on them, but others might not. One thing I
really like about this list is its civility - at least compared to others -
and I agree that we need to be careful in our comments and not say anything
that we wouldn't say in person (Try getting on the rotary engine list and
just asking about BSFC - wow.).
I'm sure someone has answered the question by now, but FMEP is "Friction
Mean Effective Pressure" usually in the units of psi and it is essentially
ft-lbs of friction per cu. in. displacement. Another one is IMEP (Indicated
Mean Effective Pressure) where "indicated" comes from the old steam engine
days where they used an indicator card to trace pressure vs. stoke.
Nowadays friction torque is usually measured by motoring the engine and
indicated torque is derived by adding friction to brake torque (here I
really should say "contrived" because engine friction is not quite the same
motoring as it is running). Indicated torque really means the torque
generated by the actual gas pressure in the cylinder. Just to complete the
trivia "Brake" torque got its name because steam engines were tested by
applying a friction brake to the output shaft and measuring the force at the
end of an arm (Called the "Prony Brake" after the French inventor, G.C.F.M.
Riche, Baron de Prony). Now top that one...
Gary Casey
Now building a dyno for my engine - an ES
LML website: http://members.olsusa.com/mkaye/maillist.html
LML Builders' Bookstore: http://www.buildersbooks.com/lancair
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Please send your photos and drawings to marvkaye@olsusa.com.
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