This is the C.E. Andersen Equation for semi-infinite penetration. Two home-brewed modifications were added for scaling and back-surface effects. I think Paul had indicated that there were several folks involved with the two home-brewed modifications.

Yes (with a DU modifier as the basic equation is for Tungsten penetrators). So it basically gives a ballpark estimate against "semi-infinite" RHA based on the basic physical properties of the penetrator.

Of coarse, MBT armor is not all RHA but their protection esimates are also estimated as RHAe. And we all know that different penetrator vs different armor will in reality produce results different that their respective RHAe. If we ever are able to get more than just ballpark estimated figures, then doing a separate calculation for each & every combination would be worth doing, but for now, ballpark figures for penetration & protection normalized to RHAe at least gives us values to work with.

Your numbers are presumably for 0-degree obliquity? What sort of numbers would you estimate for say 68-degrees to 70-degrees? A common attack angle for alot of glacis configurations.

Yes, 0-degree obliquity (straight on).

For oblique non-zero degree (straight on) hits I personally just simplify it by multiplying by the cos of the angle. It is obviously more complicated than that but we are only really able to "estimate" ballpark figures anyway.

common angles (ones I know the values of "off the top of my head")

30 degrees = 0.866

45 degrees = 0.707

60 degrees = 0.500

For glacis specifically, the RHAe estimates for the protection they provide already takes the angle into account.

**Edited by pfcem, 24 May 2006 - 1523 PM.**