bj229r:
Hmm, I have the D-40's listed as using the R-2800-59 while the N's using the R-2800-57,-73,-77's.
The -59's have a different power output than the -57's,73's,& 77's. For WEP it's 2600 hp (-59) vs. 2800 hp (-57,73,77).
2ndly you have to keep in mind that the power curves for each engine can also vary with altitude.
Tango, XO
412th FS Braunco Mustangs