I'll have a crack at two.
JDK wrote:
1. What was the most common calibre of gun in W.W.II?
I'm going to go with the US .50 cal round as used in the Browning .50 cal MG. I started to collate info by aircraft type, but it got way too difficult. I'll go with the .50 cal as the sheer number of bombers with 10+ of these weapons as defensive armament, along with the number of fighters with six or eight of these guns surely puts it in front. I've ruled out the .303 as it wasn't the only British/Commonwealth weapon, being supplanted with heavier calibre weapons later. Also the defensive .50s on 20000+ US bombers outnumber the smaller number of British/Commonwealth-produced bombers, which had fewer MGs per aircraft.
The spread of weapons among aircraft of Russian, German and Japanese manufacture would appear (famous ast word, appear) to rule them out also.
So with ten-odd .50 cal machine guns on upwards of fifty thousand bombers, I'll give it to the Yanks with the .50 cal.
JDK wrote:
5. How many types can you name that were in production on opposing sides in W.W.II?
Douglas DC-2/Nakajima Ki34
Douglas DC-3 (C-47 etc)/Lisunov Li-2/Showa L2D
NAA T-6 Texan/Harvard. This is a shakey one as the CAC Wirraway and Kyushu K10W1 were developments of early variants of the type but weren't the same. Related, yes, the same, no.
To stretch it further, the Douglas DC4E was sold to Japan and became the basis of the Nakajima G5n. Neither were successful.
Cheers,
Matt
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Matt Austin - playing with warbirds since the early 80s.
See my Lee-Enfield videos at -
http://www.youtube.com/user/Jollygreenslugg