On Thursday, March 9, 2017 at 9:52:34 PM UTC-5, David R Brooks wrote:
Yes, I know this isn't strictly metalworking, but there are plenty of
gun people here.
A howitzer fires, with elevation 45 degs. So the shell exits, pointing
upward at 45 degs., spinning. When it hits the target, it is (to 1st
approximation) falling at 45 degs., but the spin should have kept it
pointing upward. This means it would be flying sideways-on.
This sounds wrong to me, but where is the error?

I don't know if this is a really accurate description of the dynamics, but this is the way it was explained to me, and it makes sense. It starts with the idea that aerodynamic force overcomes the gyroscopic effect, and the pitch of the shell is a response to greater aerodynamic force being applied *behind* the center of gravity:

http://www.4point2.org/ballistics.htm


Maybe someone will have a more precise explanation.

--
Ed Huntress