That
is very interesting, Yvon.
My calculation shows that if you were
turning 5000 rpm when manifold
pressure was 30.5"Hg you would have been
flowing approx 17.20 lbm of air per
minute. If the pressure drops
to 29.4" Hg (and all else the same) , you
would now have to turn 5200
rpm to get the same air flow of 17.20 lbm/min,
so there is indeed an 200
rpm difference to get the same air mass flow.
Very
interesting.
Thanks for
sharing.
Ed
All dyno runs, must be corrected to sea level standard day, so that there
will be some usable data day to day to account for temperature, humidity, and
barometric pressure. Actual HP goes up and down with changes in all of these
factors. Raw torque numbers are meaningless until corrected as above.
Like the RPM drop when you check the carb heat. And the reason you lean
the mixture as you climb.
On a Southwest 737 we landed at the old Denver, and before we pushed back
with full fuel and seats, the ticket agent got on the PA and asked for 6
people to volunteer to get off and catch the next plane, because now the plane
was too heavy to legally leave Denver. Because it was 102 degrees outside.
The wife and I held out for a round trip each to anywhere in the system.
On the way off the plane, we were handed a magnum of champagne. We went to the
ticket counter, then to the very next gate, and got on a plane that was a
nonstop to Columbus Ohio. There were 12 people on that plane. The plane we got
off of landed in Chicago and got stuck there for three hours in thunder
storms.
Life is good.
Lynn E. Hanover
Yes, apples to apples comparisons requires keeping accurate
track of all those varibles - especially if you want to determine if
changes you made actually produced and improvement or just atmosphere
conditions.
By the way, Lynn, did the Champagne help the 3 hour layover in
Chicago {:>)????
Ed