Try the method described in this webpage. I think it does what you want,
plus more. http://www.avweb.com/news/airman/182410-1.html
tom pettit


"Michael Horowitz" wrote in message
...
I'm flying a BC12-D behind an A-65 engine.
The Service manual says 500fpm at gross
There are no charts (in the manual) which describe the effect of
density altitude on this performance.
Other than thru experimentation, can I calculate the Rate of Climb at
various density altitudes? How? - Mike