Hi Charon,
>Seeker, it is hard to belive that an engine can just run on and on with virtually no oil, except thare are more than a few accounts along those lines.
I guess the large oil reservoir of the P-47 could have been responsible for this reputation - the engine kept running while losing oil all the time. A complete failure of lubrication would probably kill the R-2800 just as quick as any engine of the period, but with an oil cooler pierced, the engine might have lived long enough for a retreat to friendly lines and a landing with a smoking engine, and founded the P-47's reputation.
>Looking back at all the accounts and guncamera film I've come across, the usual "kill" was, from my impession, an engine kill (big jump from inline to radial), fire or likely dead/wounded pilot.
Let me guess - these were American gun camera films? ;-)
The main kill mechanism of 12.7 mm fire was damage to critical components of the aircraft. Since the projectiles would mostly hole the skin, structural failure could only be achieved by a comparably large number of hits. German cannon on the other hands were designed to destroy the enemy aircraft by achieving extensive structural damage. Their kill main mechanism was the destruction of the load-bearing skin, which resulted in the remaining structural members to be overstressed and fail. While the critical components of an aircraft usually were concentrated in a small fraction of the target area, mine-shell type cannon projectiles could attack most parts of the aircraft with good chances of achieving the desired destruction.
Monocoque structures like most modern aircraft employed were most vulnerable to the German cannon. Steel-tube framing like that of the Hurricane withstood cannon fire much better - the light (fabric!) skin would tear away harmlessly, and the naked steel tubing would carry the entire load just like it did when they were still covered in fabric. For once, myth matches reality :-)
To support your assumption that engine kills (or, as I'd add, critical component kills) were a major factor for killing Luftwaffe planes, I could rely on Albert Speer, who mentioned that at least 50% of the Luftwaffe pilots downed above the Reich survived unhurt (from memory, I don't have the book ready to look up the exact quote).
Since parachuting was a contributor to pilot injuries as well, I'd say that pilot kills and structural failures (which made bail-outs much more difficult) were indeed only responsible for a minority of the kills.
The value of stronger structure might have been that it kept the number of structural failures down, increasing pilot suvivability. I guess that would also apply if the attack's wouldn't have been predominantly 12.7 mm attacks, but 20 mm cannon attacks, though very likely not to the same degree.
(By the way, we should not forget both sides used Flak guns that were more potent than aircraft guns, but could only fire short bursts at passing aircraft. When hit by these guns, structural strength might make a big difference.)
Regards,
Henning (HoHun)
