Re: [MV] Mosquito vs. B-17G

From: islander (islander@midmaine.com)
Date: Thu May 10 2001 - 09:14:26 PDT


Hello Renaud,

>On Wednesday 09 May 2001 17:49, I was honoured by a missive from Richard
>Notton that said :

>> Molins gun:
>> Weight of shell 7.1lb
>> Recoil action
>> Cyclic rate 60 rpm
>> Weight 1800 lb
>> MV 2,600ft/sec
>> Capacity 22/27 rounds
>> Recoil on airframe 8,000 lb
>> Made by the Molins Machine Co. of Peterborough

Ahh.... a "cyclic rate" of 60rpm is a lot different than the "practical
rate". For those of you who might not know, the "cyclic rate" is the
theoretical max rate of fire if everything goes off without a hitch in a
lab and assumes there is a feed system (or an "at the ready" supply for
manually loaded weapons) that can supply one minute's worth of ammo
during sustained firing. For example, the cyclic rate of a German MG42
is 1200 rounds per minute. The practical rate of fire is generally
thought to be around 600-800 rpm for about 30 seconds of sustained fire
(i.e. 200-300 rounds expended before cooling and reloading) for an
experienced team.

Looking at the ammo load of this plane shows that even if the gun *could*
realistically do 60 rpm outside of laboratory conditions (which I very
much doubt), having only 27 rounds max means less than 30 seconds worth
of ammo :-) Meaning, no pilot would ever pull and hold down the trigger
in actual combat. 2 shots per target would probably be all that was
needed/practical. So I'd peg the practical rate of fire at somewhere
around 3-5 rounds per minute in ideal circumstances. Just a guess!

Why am I bothering with all this? Just to underscore that "cyclic rates"
are like many figures for MV/planes/ships -> they sound more impressive
than they really were in action.

>This is getting more and more interesting; was the Molins a multi-barrel
>effort, or a single barrel piece ?

The weight of the barrel, breech, feed mechanism, power supply (electric
or mechanical), etc. would really dissuade experimentation with multi
barrel setups. Plus, it really wasn't necessary.

BTW, the Germans had a knack of always fielding something bigger than the
other guy ;-) In 1944 they introduced the Henschel Hs 129B-2/R4. They
built 25 of this model, sporting a modified 75mm Pak 40 anti-tank gun.
That's right, the inverse of 57 :-) Maximum speed was 253 mph (407 km/h)
at 12,565 ft (3830 m); service ceiling 29,525 ft (9000 m). Unfortunately
for the pilots, the heavy weapon + thick armor plating made this plane
rather difficult to fly. It was easy pickings for enemy fighters, which
of course were common in 1944/45. The Hs 129 family of planes only flew
on the Eastern Front (spitballs would have worked fine for the Western
Front, so this was overkill <g>), most notably during the large scale
1943 summer offensive around Kursk.

Oh... and getting back to heavy bombers. The Germans did have an
operational 4 engine heavy bomber, the HE 177, but the fuel supply wasn't
there. They had 270 of these planes by summer of 1944. However if all
of them went on one medium range mission, they would have consumed a
day's worth of Germany's ENTIRE fuel production. So even though the
Germans had a bomber fleet of about 1/30th the size of the Allies at the
time, they couldn't afford the fuel to use even this paltry number.
Again, a lack of fuel is why the "New York Bomber" never went on a
mission.

Steve



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