Looking at P40 Speed Performance Numbers...

[ElAurens]

Originally Posted by IceFire

What does the "Rammed" indication mean at Sea Level?

Interesting that the K seems to have the greatest power? What's the story there?

They are taking into account the effect of the air being rammed into the carb intake because of aircraft speed, unlike when an engine is running on the ground attached to a dynamometer.

[secretone]

So there was not a huge increase in performance in the F model because the blower was only single stage. Apparently Packard was not yet producing the 2 stage version of the motor at the time the F model was in production.

Here is a discussion thread for anyone who wants to explore this further:

http://www.ww2aircraft.net/forum/avi...40s-30910.html

[ElAurens]

Interesting discussion there, thanks for the link.