4.13 development update discussion and feedback

[Pursuivant]

Originally Posted by ElAurens

The Merlin had an aluminum engine block with steel cylinder liners.

I stand corrected then, and I feel stupid because I looked at that very page and somehow missed the aluminum reference. It also appears that cast aluminum block engines date to WW1 (Hispano-Suiza produced the first one).

Anyhow, that would explain why some inline engines are so vulnerable. Bullets will generally go right through aluminum, although some grades of aluminum make decent armor (the M113 APC had 3/4" of aluminum armor which prevented penetration by most small arms fire).

So, it's not so simple as figuring joules of energy vs. mm of homogenous rolled armor and dividing by some factor to get penetration of cast iron!