Why 37?
Joe Drees
on a tank at the start of WWII. My question is why 37mm? Why not 35 or 39?
Also did medium WWII AAA have a time fuse or was it an explode on
contact load. Specificly German 20mm and 37mm..........TIA..Joe
EGMcCann
"on impact" fused. Wouldn't get the nice, puffly, deadly black clouds
otherwise...
"Joe Drees" <dr...@charter.net> wrote in message
news:urotvr3...@corp.supernews.com...
Ruediger LANDMANN
: Seems almost every country had a 37mm anti-tank gun or mounted as main gun
: on a tank at the start of WWII. My question is why 37mm? Why not 35 or 39?
: Also did medium WWII AAA have a time fuse or was it an explode on
: contact load. Specificly German 20mm and 37mm..........TIA..Joe
Probably an imperial -> metric thing. 1.5" = 37.5mm.
DHopper8
rate of fire, weight and bulk of the delivery platform, etc.) In an armoured
vehicle, they also had to consider the size of the weapon and the recoil.
It seems that pretty well everyone zeroed in on 20mm and below for infantry,
37mm to 95 mm for WW2 tanks, 75mm - 110 mm for light field artillery, 150-155
for medium and the rest (200 mm and up) is heavy.
It is interesting that for field artillery, it seems that everyone came to the
same conclusion that something about 105 mm would be optimal.
For AA systems, 20 and 37 mm would be classified as light (as would the 40mm
Bofors) and would have had (in WW2) impact (Contact) fuzes, sometimes with a
self-destruct after 'x' seconds of flight. They were really just big machine
guns at that time.
Heavy AA guns were (roughly) 75mm to 120 mm. These are the ones that would have
had the time fuzes and (on the Allied side) proximity fuzaes.
Times have changed.
Cheers,
Doc H
dke...@mindspring.com
Yeah, I think you're right, but 38mm is even closer to 1.5" -->
1.496 vs 1.46
whatever
Dk
On 28 Oct 2002 01:54:25 GMT, Ruediger LANDMANN
Kurt Laughlin
"Joe Drees" <dr...@charter.net> wrote
> Seems almost every country had a 37mm anti-tank gun or mounted as main gun
> on a tank at the start of WWII. My question is why 37mm? Why not 35 or 39?
Left over from the days of sizing guns by the weight of shell. A 37mm was a
1-pounder. Once people got to supplying ammo and guns in that caliber, it
just kept rolling because it was too expensive to change tooling and scrap
ammo. International sales would spread a particular caliber world-wide.
I wouldn't say that 37mm was dominant, but in that range was common. The US
and Germany used 37mm, the British 2-pounders or 40mm, the Soviets 45mm, the
French, Japanese, and I think Italians used 25mm and 47mm. Many used both
37mm and 40mm one for AAA and one for ground use.
BTW, the American 4.5-inch rocket artillery was that size because the person
developing it used fire extinguishers as motor cases during development.
KL
Tony H
"Benjamin Berkley Hotchkiss, born in Watertown, Conn, in 1826...{snip}..
Hotchkiss had earned his first reputation in ordnance by designing artillery
projectiles and systems of firing. From this background he proceeded to
formulate what he considered the best calibre to produce maximum devastation
on personnel while the arm remained light enough to be fired with great
rapidity.
It is interesting to note that the Saint Petersburg Convention in 1868 had
specified 450 grams as the minimum weight of a projectile carrying
explosives intened for antipersonnel use. This total included the
projectile and the bursting charge. To be on the safe side, Hotchkiss
allowed himself 455 grams minimum. When he arrived at the proper calibre
with bursting charge cavity of correct dimensions and a balanced fuzed nose,
he had a 37mm projectile. So accurate were his calculations that, though
Hotchkiss originated this dimension, it is still considered absolutely the
largest projectile that can be fired with any semblance of machine-gun
rapidity"
On the AA question, I think 20mm flak is too small to have a time fuse
fitted, although most AA shels had some sort of self destruct fuse, ....what
goes up, must come down.... :)
Hope this helps
Tony H
London UK
Kurt Laughlin
"Tony H" <hoplo...@despammed.com> wrote
> So accurate were his calculations that, though
> Hotchkiss originated this dimension, it is still considered absolutely the
> largest projectile that can be fired with any semblance of machine-gun
> rapidity"
Obviously written before the development of the Mk. 19 40mm machine gun.
KL
Vance Henize
;->
"Kurt Laughlin" <fle...@sgi.net> wrote in message
news:us0u95k...@corp.supernews.com...
Kurt Laughlin
"Vance Henize" <vhe...@houston.rr.com> wrote
> wow, they squeezed out another 3mm?!?
Well, the statement "absolutely the largest", means it's impossible to
"squeeze out" even 1mm more. Yet somebody managed three. Doing the
impossible does warrant a "wow", don't you think?
Besides, "any semblance of machine-gun rapidity" is undefined. Hotchkiss'
original gun was quite slow as I recall, perhaps 100-150 rpm. Much larger
guns have been able to match that cyclic rate.
KL
chris
street".
Someone got the idea to make a 37mm, and everyone else just had to have one
because they did.
If you'll look at history, you can see why this might be the case. Many
tank guns are up to 120mm now. Much of the world has a standardized
military rifle and pistol round. I believe prior to WW2 there wasn't really
much cause for heavy armament. As I recall the bore diameter and power of
tank cannon increased not to do more damage, but to compete with enemy armor
thickness. With so many lighter tanks in the era, 37mm wasn't so bad.
As to why, exactly 37mm, it's anyone's guess. It could have easily been
35mm, 40mm, 39mm, etc.., so it's really hard to say. But likely one nation
developed the 37mm, and others copied, as is today's fashion with military
technology.
Matt Bacon
'cos it's 1.5" would be my guess...
best,
M.
Kurt Laughlin
"Matt Bacon" <matt....@ananova.com> wrote
> > As to why, exactly 37mm, it's anyone's guess.
>
> 'cos it's 1.5" would be my guess...
Well, any guesses on
1.1-inch
47mm
57mm
77mm
90mm
105mm
4.2-inch
155mm
7.2-inch?
KL
William H. Shuey
Kurt Laughlin wrote:
>
> Well, any guesses on
>
> 1.1-inch
This was the U.S. Navy's 1 pounder anti aircraft gun of the late
1930's. Water cooled, 4 guns on a powered mount, found very
unsatisfactory due to short range, low hitting power and "reliability
issues". Was ultimately replaced by the 40 mm Bofors.
> 47mm
This is the traditional bore of a 3 pounder gun.
> 57mm
Likewise for a 6 pounder gun.
> 77mm
Essentially a German size, like 88 mm, maybe someone from across the
water could address this one. Can't comment on the rest below.
> 90mm
> 105mm
> 4.2-inch
> 155mm
> 7.2-inch?
>
> KL
Bill Shuey
Kurt Laughlin
reasoning that it was because 37mm was 1.5 inches. If it was that obvious
to him I thought he could point out the rationale behind some others.
"William H. Shuey" <whs...@starpower.net> wrote
> > 1.1-inch
> This was the U.S. Navy's 1 pounder anti aircraft gun of the late
> 1930's.
It was also a British caliber, and in the Army, the 1-pounder was 37mm.
> > 47mm
> This is the traditional bore of a 3 pounder gun.
> > 57mm
> Likewise for a 6 pounder gun.
> > 77mm
> Essentially a German size, like 88 mm, maybe someone from across the
> water could address this one. Can't comment on the rest below.
Right. Obviously not just an Imperial conversion. If you wanted to go
deeper, you could ask why a 6-pounder and not a five? The British used 77mm
for a tank gun in WW II, but for the same reason that we had a 76mm gun and
American recoilless rifles used 106mm: To avoid confusion with existing
weapons with identical bores.
Mark Schynert
"Kurt Laughlin" <fle...@sgi.net> wrote:
> "Matt Bacon" <matt....@ananova.com> wrote
>
> > > As to why, exactly 37mm, it's anyone's guess.
> >
> > 'cos it's 1.5" would be my guess...
>
> Well, any guesses on
>
> 1.1-inch
47mm--naval QF 3 pdr
57mm--naval QF 6 pdr
77mm--approximately 3 in.; also naval QF 14 pdr
90mm--approximately 3.5 in.
> 105mm
> 4.2-inch
155mm--approximately 6 in.
> 7.2-inch?
>
> KL
>
Likewise, 65mm was naval QF 9 pdr, 66mm = naval QF 8 pdr, 40mm= 2 pdr,
75mm= 12 pdr (or Russian 11 pdr), 50mm = 4 pdr, 88mm = 15 pdr or 22.5
pdr. These ratings by shell or projectile weight (I don't know which)
were probably more nominal than literal as gun designs evolved, but once
a barrel dimension was established, it probably made design sense to
stay with it and change other characteristics of the piece instead.
Mark Schynert
Kurt Laughlin
"Mark Schynert" <mas...@earthlink.net> wrote
> 47mm--naval QF 3 pdr
> 57mm--naval QF 6 pdr
> 77mm--approximately 3 in.; also naval QF 14 pdr
That's true, more or less. The British used it to designate their shortened
17-pounder (3-inch or 76.2mm) so as to avoid ammo mix-up problems, and the
Germans used it for their version of the 75mm medium gun. The three "pound"
difference is noteworthy.
> 90mm--approximately 3.5 in.
Nah. This was mainly an American caliber. Why not exactly 3.5-inch? (Like
the Super Bazooka which, if you do the math, is closer to 88 than 90.)
> 155mm--approximately 6 in.
Again, why not exactly 6-inch, or exactly 150mm? At least the Russians used
152mm. (Amazing how much Soviet equipment was still dimensioned in Imperial
units, e.g., actually .375 inches rather than .394 / 10mm when measured with
a micrometer.)
> Likewise, 65mm was naval QF 9 pdr, 66mm = naval QF 8 pdr, 40mm= 2 pdr,
> 75mm= 12 pdr (or Russian 11 pdr), 50mm = 4 pdr, 88mm = 15 pdr or 22.5
> pdr.
US 15-pounder was 3-inch. I question the link between any pound rating and
a metric measurement, given that the two countries that used them were
exclusive users of Imperial units prior to 1918 and predominant in that
system until 1945. My suspicion is that pound-based weapons were originally
dimensioned in Imperial units but through modernization they were rounded to
something convenient, and that was later rounded or changed to something
metric.
KL
Mark Schynert
"Kurt Laughlin" <fle...@sgi.net> wrote:
The notion of pdr ratings is complicated by the fact that these were
reporting names in Janes, and consequently there was an English-measures
influence not necessarily corresponded to by France, Austria, etc. The
reliance on 90 as opposed to 88, or 155 as opposed to 150 in US guns
might be something as simple as a specification for a gun of not less
than 6" shell diameter, with a particular projectile weight. The
engineering then happens to lead to 155. Speculation, I'll admit. It is
interesting that you get clusters around certain measurements (75,
76.2,77; 100, 102, 105; 120, 127, 128; 150, 152, 155).
I also suspect that original shell-weight ratings were at best nominal,
and as shell architecture and compostion changed, so must the weight.
But some of these historic calibers, once established were less likely
to be abandoned. The US Navy managed to employ 3 different 5" calibers,
/25, /38, and /54, each with different weights; in fact, while the first
two used a one-piece shell, the 5"/54 was separate projectile and bagged
charge.
Mark Schynert
Larry Curtis
hotchkiss's day. The standard back then was recoil or gas operated, where
the bolt did all of the work in extracting, stripping, and chambering a
fresh cartridge. Modern mechanisms do not generally involve a full linear
stroke of sufficient length to chamber a loaded round using only the
boltface as the means of driving the cartridge into the chamber. The weapons
of hotchkiss's day were stictly powered by the impulse provided by the
firing itself, excepting human powered weapons such as the gatling. Modern
weapons of greater than 37mm that fire in machinegun fashion are nearly
always electrically or hydraulically actuated.
As for some fixation on the use of the word "absolute" there is the fact
Chinn's books were written in the 60's if memory serves. And very few laws
remain static over such a period of time in our modern world of
technological innovation. Remember that the U.S. Patent office has closed
twice because everything that could be invented had been invented.
Larry
"Kurt Laughlin" <fle...@sgi.net> wrote in message
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Kurt Laughlin
"Larry Curtis" <LarryD...@worldnet.att.net> wrote
> As for some fixation on the use of the word "absolute" there is the fact
> Chinn's books were written in the 60's if memory serves. And very few laws
> remain static over such a period of time in our modern world of
> technological innovation. Remember that the U.S. Patent office has closed
> twice because everything that could be invented had been invented.
Yeah, which is why I originally said: "Obviously written before the