Path: utzoo!utgpu!watserv1!watmath!att!cbnews!military
From: ntaib@silver.ucs.indiana.edu (Nur Iskandar Taib)
Newsgroups: sci.military
Subject: Re: WWII fighter armaourment was Re: Us Fighter Designations
Message-ID: <1990Aug30.030129.29433@cbnews.att.com>
Date: 30 Aug 90 03:01:29 GMT
References: <1990Aug10.010748.29824@cbnews.att.com> <1990Aug15.031847.25309@cbnews.att.com> <1990Aug22.025006.15437@cbnews.att.com> <1990Aug28.030423.20866@cbnews.att.com>
Sender: military@cbnews.att.com (William B. Thacker)
Organization: Indiana University, Bloomington IN.
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Approved: military@att.att.com



From: ntaib@silver.ucs.indiana.edu (Nur Iskandar Taib)
>In terms of mass deliver rate, which is important for improving the chance
>of hitting a figther with short bursts in a dog-fight, MGs are actually better. 
>At the Battle of Britain, the Spits and Hurricanes had something 
>like 10 lb/s from their MGs. Later in the War, the rate was doubled to 20 lb/s
>with 8 MGs.

Hmm.. the early spitfires and hurricanes all had eight 
wing mounted .303 machine guns. The Mark V and IX spitfires
had four .303 machine guns and two 20mm cannon. The pilot
had the option of using all guns, machine guns only, or
cannon only. Later variants had either four 20mm cannon, 
or two 20mm cannon and two .50 caliber machine guns. 
I wonder if the early spitfires and hurricanes gave the 
pilot the option of using four or eight machine guns at a 
time. The cannon definitely had the edge over the machine 
guns as far as range was concerned. The low ballistic 
coefficient of the .303 bullets (200 grain spitzers, I
believe) caused tremendous bullet drop over the 250-400
yards that most engagements took place at. The .50 caliber
machine guns were a definite improvement over the .303. 
(700 grain projectiles, close to 3000 fps velocity as opposed
to about 2400 for the .303). The cannon had their own 
disadvantages: low rate of fire and a limited number of 
shells. The 30mm cannon on the P-39, for instance, had 
something like 12 shells - enough for one burst at most.

[mod.note:  The P-39 carried either a 37mm or 20mm cannon; in
this case, I think you're referring to the 37. - Bill ]

What really amazes me is that they could get a rimmed shell
(the .303) to work in a machine gun. The British did use the 
german 8mm Mauser cartridge in some of their terrestrial 
guns and they ought to have used it for their aerial guns
too.