wrote in message
oups.com...
I read in mag article regarding a "rule of thumb" for calculating take
off distance required when weight increased, but I cannot remember
what
is it. Does anyone know?

Also, are there any "rule of thumb" for calculating take off distance
per power loss, or increase elevation? How about power loss per 1000
ft increase in elevation?

Is there a source for all kind of flying "rules of thumb?"

Thanks.


Distance to liftoff as a function of (relative weight w/relative air
density sigma) goes as the 2.65 power. Airlines used to use 2.5 power.

For power loss with altitude, use the Gagg-Farrar relation: (sigma -
C)/(1 - C), with C about 0.12.

I used to have a small blue softbound book, I believe written by a
retired Air Force pilot, full of rules of thumb and Basic routines. But
it was so full of errors I threw it away.

John Lowry
Flight Physics