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XyZspineZyX
01-21-2006, 12:51 AM
Why did almost all of the US fighters in WW2 carry machineguns, with the exception of the airacobra, Kingcobra & the F4UC. The rest carried 4,6 or 8 50cal 12.7mm machine guns.

Luftwaffe, Japanese, RAF & Soviet fighters generally carried a combination machinegun/cannon mount & some were purely cannon mounts.

Does anybody know why?

Gibbage1
01-21-2006, 01:12 AM
You forgot the P-38. Heh.

The USAAF was fighting a war against fighters. We had very very little bombers to shoot down. The .50 cal's I think are better suited in that way then 20MM due to its higher ROF, more weapons, more ammo, better chance of hitting.

We also had the P-61 had 4 20MM and 4 .50 cal.

FI-Aflak
01-21-2006, 01:24 AM
Originally posted by Gibbage1:
You forgot the P-38. Heh.

The USAAF was fighting a war against fighters. We had very very little bombers to shoot down. The .50 cal's I think are better suited in that way then 20MM due to its higher ROF, more weapons, more ammo, better chance of hitting.

We also had the P-61 had 4 20MM and 4 .50 cal.

The P-61 was a bomber-killer, though, totally in agreement with your theory. Yeah, I think it makes alot of sense - it didn't take much to knock a fighter down, spraying 50 cals was probably an easier way to get a kill than placing a cannon round on your target.

ImpStarDuece
01-21-2006, 02:34 AM
Infrastructure and technological inertia had a lot to do with it as well, as did a lack of indigenous weapons to supplant the .50.

The .50 worked well, and was appropriate for the job: A to A gunnery against lightly armoured targets. If the USA had gone up against 4 engined heavies, I suspect it would of been replaced by something heavier. The USNs late war fixation with fitting cannon to its fighters probably has a lot to do with its desire to stop Kamikazes as effectively as possible.


Potential replacements were the .60 cal (15.25mm) very heavy machine gun (a high velocity redesign of the German MG 151/15 15mm) and the ANM2 20mm (A US copy of the Hispano). However, these never really got off the ground during the majority of the war, due to a variety of issues, some industrial, some institutional, some political. So there was no real alternative to the multiple .50 cal installation for US fighters. Through the war period various calibres (37mm, 23mm,

US fighters were moving towards banks of HMGs as standard armament while other nations (France, Britain, Germany, Russia, and Japan to a lesser extent) went to the single/ paired 20mm. Its just a different approach to the same problem given the external constraints; putting the most amount of high velocity lead and high explosive onto the target in the shortest amount of time.

Take a look at this article for a better explanation: http://www.quarry.nildram.co.uk/US404.htm

WOLFMondo
01-21-2006, 06:21 AM
I'd say ISD's infrastructure has allot to do with it. If you start putting different guns in planes you have to re tool factories, retrain the workers, change supply chains, change shipping logistics, retrain all your pilots in how to use and fire the new gun, retrain all the ground crews in using and maintaining the guns, you have multiple stock piles of ammunition, guns and spare parts etc. It would have been a huge task to do this.

The US sticking mainly with the .50 in the European theatre meant all hit had to do was ship one type of ammunition in, supply one type of gun, spare parts for one gun only, train crews and pilots in one guns use and mainenance.

p1ngu666
01-21-2006, 07:46 AM
all the reasons above
european aircraft where bulit as interceptors too, while the american designs where too, just abit different, the european ones upgraded from mostly rifle calibre, to 20mm cannons, the americans never had a pressing need too.

think even the 190's started off with 4 mg guns or something fairly weedy

XyZspineZyX
01-21-2006, 07:57 AM
It is quite interesting why, the ME109E was cannon armed in 1939 & there was no serious bomber threat to the 3rd Reich at that stage

p1ngu666
01-21-2006, 08:31 AM
apart from the uk, france, russia http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

prewar thinking was that the bomber would always get through...

Aaron_GT
01-21-2006, 08:40 AM
US fighters were moving towards banks of HMGs as standard armament while other nations (France, Britain, Germany, Russia, and Japan to a lesser extent) went to the single/ paired 20mm.

Actually the UK went for quad 20mm cannon, if you look at the flurry of mid-1930s specifications that were issued. So in 1937 there were quad cannon Hurricane and Spitfire designs around, as well as the Whirlwind and other aircraft. In the end the Spitfire went for, typically, only 2 20mm cannon, but almost everything else had 4.


It is quite interesting why, the ME109E was cannon armed in 1939 & there was no serious bomber threat to the 3rd Reich at that stage

It was still assumed that the 109E, as well as clearing paths for German medium bombers would have to defend the forward echelons of the Wehrmacht against other medium and light day bombers.

Kocur_
01-21-2006, 10:56 AM
The reason is quite sipmle: there was no other gun in the US inventory to replace .50ANM2. The only heavier cannons were 37mm, but these were by far too heavy. The only real option was adopting 20mm cannon, but there was none such produced in US in early WW2. As the article linked in ImpStarDuece post says, US military in fact wanted 20mm and they bought licence for British Hispano. They wanted it badly enough to get blueprints and example cannons as early as january 1942! Unfortunately some idiot though he knows better than British and altered lenght of chamber. That created problems, which were not solved in time, to let "US Hispano" appear on planes which were entering MASS production in 1942/43. Later it was too late as industry inertia wouldnt permit a change. Not that US 20mm ANM2 was 'cured' entirely before WW2 ended... OTOH .50s were doing good vs. most of small planes. But that doesnt change fact, that 20mms would do better.

Before I get jumped by 'point-fifty' dedicated fans, I propose to check P-51 (without a letter) with 4 x British Hispanos: there are no bulges on the wings, i.e. Hispano was small enough to fit within P-51 wing. Also I suggest to calculate weights of armament sets, with assumption, a modest one, that single 20mm Hispano is as effective as 3 .50s.

P-51 B/C entered war with 4 x .50 with 1260 rounds total. That set weight was
4 x 39kg + 1260rds x 0,112kg = 156 + 141kg = 297 kg

Now lets replace above with two Hispanos, 50kg each. Further lets keep the weight of entire set unchanged, so
297kg - 2 x 50kg = 197kg

We are left with 197kg for ammo. One 20 x 110mm round weight is 0,240kg
197kg/0,240kg = 820/2 = 410rds

I.e. each Hispano would have 410rounds! No problem with practical realisation, since that weapon was belt fed, and there would be lots of space after one .50 gun and ammoboxes of both removal.

P-51B/C had enough .50ammo to fire for 350/13,3 = 26 seconds (although last 5s of that was fire from one pair only, as one of them had 280rds). And imaginary P-51B/C equipped with set of 2 x 20mm Hispanos would fire for 410/10 = 41 seconds! And that is with the same weight as RL plane!

Lets assume single .50 ANM2 effectiveness is 1, and single Hispano - 3:
4 x 1 = 4
2 x 3 = 6, i.e. P-51B/C armament of two 20mm Hispanos would be 1,5 times more effective that RL one with four .50s. Lets also have in mind, that ballistic properties of both weapons were similar - at least similar enough not to make difference within ranges of WW2 aerial shooting, i.e. not further than 300m.

Who would prefer to fly P-51B/C AND Mustang Mk.III with pair of Hispanos? I definately would!

That is of course for the sake of comparison, RL Mustang with Hispanos would probably get also a pair of .50s. Assuming that 21s of fire from all guns would be kept, it would be:
2 x 39kg + 2 x 280 x 0,112kg + 2 x 50kg + 2 x 210 x 0,240kg = 140 + 200 = 340kg

Only 43kg more than 4 x .50 set with:
2 x 1 + 2 x 3 = 8 / 4 = 2 - firepower twice greater than of RL P-51 B/C.

That would not create logistical problems, at least not greater than in case of P-38. All I can say is I wish 20mm cannons were used widely in primary US WW2 fighters http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif

VW-IceFire
01-21-2006, 11:53 AM
Kocur: Just to do a bit of what-if thinking on the Mustang with the 20mm cannons in the wings...while there were no bulges the cannons did stick significantly out of the wing (it looks mean that way http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif). What if they managed to fit some Hispano Mark V's in there...probably would cover all but a little bit of the barrel...imagine a Mustang with that sort of configuration.

...sort of like a Tempest I suppose http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

Kocur_
01-21-2006, 12:04 PM
Ah, we can do even more what-if thinking http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif What if replace Hispano with a 42kg 20mm cannon fed with rounds weighting only 0,205/0,183kg... http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Sergio_101
01-21-2006, 12:19 PM
In fighter vs fighter action machine guns work fine.
During the BOB the 8 .303s in the Hurricanes and Spits did well.
The reason is you only need a small leak in a
fuel line, coolant, or oil to render the
enemy ineffective and most probably destroyed.
The .303 was obsolete before WWI, but 8 of them
did rather well in 1940.

The same holds true for 4-6 or 8 .50 cals.
The "Shotgun effect".
But for the .50 at least it would make a mess
of any hard object in a 1940's fighter.
No explosives, but an engine or wing spar hit
would spell instant disabelment and the loss
of the aircraft.
Even in a "self sealing" fuel tank a .50 hit
would cause a big hole and likely a fair sized leak.

In a piston fighter based air war the .50 was
a very potent weapon.
But later in Korea the .50 was to prove marginal
at best as jet's are a much harder kill.

Range, ammunition capacity and rate of fire
are the .50's advantage.
range is not well modeled in this game
and in Oleg's defence, I don't think that can
be accurately modeled without massive
amounts of extra calculations, code and a
dramatic slowing of your computers.
The bullets vanish when "spent".
In real life your bullets can kill for many miles.
I have seen accounts of people killed by
"spent" bullets/projectiles from above.

However I do feel that the .50 cals are severly under modeled
in this flight sim.

Sergio

p1ngu666
01-21-2006, 04:11 PM
one of the advantages is longer effective range, in theory anyways

gx-warspite
01-21-2006, 04:57 PM
Originally posted by p1ngu666:
one of the advantages is longer effective range, in theory anyways
Fighters rarely fire beyond 300 yards or so. Besides, the Hispano was just as good if not better ballistically than the M2. MG151/20 would be too if the Germans ever put ballistic caps on their fuses.

The rate of fire argument is false. MG151/20s fire just as rapidly as the M2. Furthermore, you don't see Dora or Spit pilots complain that they have trouble shooting down fighters.

The US didn't use cannon because it didn't have an alternative to the M2, pure and simple. It was unwilling to switch for a variety of reasons, not least being politics, economics, and the hassle.

Gibbage1
01-21-2006, 05:08 PM
Originally posted by Kocur_:

Before I get jumped by 'point-fifty' dedicated fans, I propose to check P-51 (without a letter) with 4 x British Hispanos: (

ITs called the A-36. A P-51 with an Allison engine and 4 20MM's. It was considered a ground pounder, not a fighter. The .50 cal had plenty enough firepower to shoot down other fighters, and the US had plenty of M2's and rounds but not Hispano's.

Also, you ever consider the SIZE of the 20MM shell? Or even the weight? The shell takes up about 5x the volume of the .50 cal! All 20MM's in early war only carried 60 rounds per gun! Later on even with belt feeding it only upped to 120 rounds. Compair that to 200-250 rounds of M2 per gun. That means the .50 cal has a lot more trigger time. When shooting at small dodging fighters, its important to have trigger time and more projectines with less gap between protectiles.

Also note the F4F. It started WWII with 4 .50 cal's in the -3 model. The -4 model added 2 more .50 cal's but lowered the number of rounds for each gun. Sounds like a nice trade right? More firepower, at the cost of less trigger time? Wrong. The pilots complained a LOT about it! They wanted the longer trigger time over the greater firepower since the 4x was working fine vs fighters!!! They switched BACK to the 4x loadout on the FM2 (-5 model made by Goodyear).

Every pilot that used the .50 cal in WWII will tell you it was MORE then adiquate for taking down enemy fighters. It was not till Korea when fighting much heavily more armored jets that the .50 cal finally needed to be replaced with something more potent.

Kocur_
01-21-2006, 05:23 PM
Originally posted by Gibbage1:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kocur_:

Before I get jumped by 'point-fifty' dedicated fans, I propose to check P-51 (without a letter) with 4 x British Hispanos: (

ITs called the A-36. A P-51 with an Allison engine and 4 20MM's. It was considered a ground pounder, not a fighter. </div></BLOCKQUOTE>

A-36A (NA-97) was not armed with 20mm cannons - had six .50, four in wings, two on engine sides. Im surprised to read you saying such a thing. The only 20mm Mustang was P-51 (NA-91) - 93 of them were deliverd to RAF, where served as Mustang Mk.IA, remaining 54 entered US service modified by installing two K-24 cameras, with designation changed to F-6A.


Also, you ever consider the SIZE of the 20MM shell? Or even the weight? The shell takes up about 5x the volume of the .50 cal! All 20MM's in early war only carried 60 rounds per gun! Later on even with belt feeding it only upped to 120 rounds. Compair that to 200-250 rounds of M2 per gun. That means the .50 cal has a lot more trigger time. When shooting at small dodging fighters, its important to have trigger time and more projectines with less gap between protectiles.

You get a bit confused when it comes to technical issues, dont you http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif I cant tell anything about volumes of both rounds, but the terrible, King Kong weight of 20mm round was...about twice of .50BMG. You could have noticed in my post, that I did deal with ammo weights...
60rds was capacity of drum magazine - used before British developed their own belt mech for Hispano. 120rds is what Spitfire had, later planes, designed with Hispano in mind had 200rds.
Trigger time? Please read what I wrote above: Mustang with pair of Hispanos would have 41 seconds of 'trigger time' with set of gun+ammo weight equal to those of 4 x .50. That is considerably MORE than Mustangs had.


Also note the F4F. It started WWII with 4 .50 cal's in the -3 model. The -4 model added 2 more .50 cal's but lowered the number of rounds for each gun. Sounds like a nice trade right? More firepower, at the cost of less trigger time? Wrong. The pilots complained a LOT about it! They wanted the longer trigger time over the greater firepower since the 4x was working fine vs fighters!!! They switched BACK to the 4x loadout on the FM2 (-5 model made by Goodyear).

Rgrt. Try to note on your side, that there was difference in toughness of Japanese and European planes. You might also note opinion of Bearcat armament of 4 x .50 given by pilots from 1944 Joint Fighter Conference - were they pleased? Did they think it was suffcient and adequate? No really, in fact the only drawback of Beracat they noticed was weak armament.

Like I said: multiple .50s were good armament against WW2 fighets. Still however 20mm cannons were better.

Sergio_101
01-21-2006, 05:31 PM
Originally posted by Gibbage1:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kocur_:

Before I get jumped by 'point-fifty' dedicated fans, I propose to check P-51 (without a letter) with 4 x British Hispanos: (

ITs called the A-36. A P-51 with an Allison engine and 4 20MM's. It was considered a ground pounder, not a fighter. The .50 cal had plenty enough firepower to shoot down other fighters, and the US had plenty of M2's and rounds but not Hispano's.

Also, you ever consider the SIZE of the 20MM shell? Or even the weight? The shell takes up about 5x the volume of the .50 cal! All 20MM's in early war only carried 60 rounds per gun! Later on even with belt feeding it only upped to 120 rounds. Compair that to 200-250 rounds of M2 per gun. That means the .50 cal has a lot more trigger time. When shooting at small dodging fighters, its important to have trigger time and more projectines with less gap between protectiles.

Also note the F4F. It started WWII with 4 .50 cal's in the -3 model. The -4 model added 2 more .50 cal's but lowered the number of rounds for each gun. Sounds like a nice trade right? More firepower, at the cost of less trigger time? Wrong. The pilots complained a LOT about it! They wanted the longer trigger time over the greater firepower since the 4x was working fine vs fighters!!! They switched BACK to the 4x loadout on the FM2 (-5 model made by Goodyear).

Every pilot that used the .50 cal in WWII will tell you it was MORE then adiquate for taking down enemy fighters. It was not till Korea when fighting much heavily more armored jets that the .50 cal finally needed to be replaced with something more potent. </div></BLOCKQUOTE>



FM2 Wildcat was built by General Motors.
GOTCHA!

Sergio

ImpStarDuece
01-21-2006, 05:36 PM
The A-36A Apache never had 4 Hispanos http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif The A-36 had 6 .50 calibres, two in the nose and four in the wings. The 2 nose guns were often taken out on service machines though.

The only 4 Hispano Mustang was the Mustang Mk. IA, contractually designated P-51 under Lend Lease. They were based off the NA-91 design and 151 were made, 57 of which were retained for USAAF use.

The confusion usually arises because both the P-51 and the A-36A were known as the 'Apache' at various points in thier history. Throughout 1941 and into 1942 the USAAF officially refered to the P-51/Mustang I/IA as the 'Apache'. However, when deliveries to the RAF and USAAF began in 1942, the official name was swapped to the British moniker 'Mustang'. The NA-97 design, later designated the A-36A, then took up the 'Apache' name. In 1943 there was some effort to relable the A-36A with the name 'Invader' but it seems that both were eventually dumped for the more popular 'Mustang'.

ImpStarDuece
01-21-2006, 05:54 PM
Originally posted by Gibbage1:

Also, you ever consider the SIZE of the 20MM shell? Or even the weight? The shell takes up about 5x the volume of the .50 cal! All 20MM's in early war only carried 60 rounds per gun! Later on even with belt feeding it only upped to 120 rounds. Compair that to 200-250 rounds of M2 per gun. That means the .50 cal has a lot more trigger time. When shooting at small dodging fighters, its important to have trigger time and more projectines with less gap between protectiles.



5 times the volume? I think you'd better check your figures Gibbage

Dimensions for the .50 cal round were 12.7x99

Dimensions for the 20mm Hispano round were 20mmx110

Weight for the .50cal round was 112 grams

Weight for the 20mm Hispano round was 257 grams.

As for ammunition carried for Hispano armed fighters:


Spit Vb carried 60 rpg
Spit Vc carried 120 rpg
Spit IXe/XVIe/XIVe carried 140 rpg
Spit 21 carried 175 rpg inboard and 150 rpg outboard.
Hurricane IIc carried 91 rpg
Typhoon carried 140 rpg
Tempest V carried 150-175 rpg, with possibly 200 rpg with Mk V Hispano


FW 190As carried 250 20mm rpg inboard and 125 rpg outboard

FW 190Ds carried 200 20mm rpg

P-38 carried 150 rpg

Sergio_101
01-21-2006, 06:23 PM
Right here in front of me is a photo of a USAAC
P-51A with 4 20mm cannon.
"The American Fighter" by Angelucci&Bowers.
Page330, bottom of page.
It has 1944 style USAAF/USAAC markings.
There may have been only one built?
But Gibbage1 is NOT incorrect.

Same book, page229, paragraph5, says the
General Motors FM-2 Wildcat was the production
version of the XF4F-8.

P-51B, "Hoo Flung Dung".
http://www.wpafb.af.mil/museum/research/p51-15.jpg

Sergio

ImpStarDuece
01-21-2006, 07:08 PM
Gibbage is incorrect if he asserts that the A-36 had 4 Hispanos, which is what he did.

The P-51A was an A-36 without the divebreaks, a new V-1710-81 and a new supercharger. It retained the A-36's 6 .50 calibre armament, which was what it used in service with the RAF and USAAF. Unless it was retrofitted or a prototype, its unlikely that P-51As saw any service with 4 Hispanos. Almost all USAAF P-51As went to the CBI theatre with the 10th Air Force. Initial combat operations with the P-51A began on November 23rd, 1943 with the 23rd Fighter Group.

You can tell if its a cannon armed aircraft because of the large fairings on the wing leading edge and the cannon barrel that protrudes about a meter out of the wing. I have plenty of photos of P-51A's, but not a single one with a 4 connon installation. Google couldn't help me either

Sergio_101
01-21-2006, 08:37 PM
Originally posted by ImpStarDuece:
Gibbage is incorrect if he asserts that the A-36 had 4 Hispanos, which is what he did.

The P-51A was an A-36 without the divebreaks, a new V-1710-81 and a new supercharger. It retained the A-36's 6 .50 calibre armament, which was what it used in service with the RAF and USAAF. Unless it was retrofitted or a prototype, its unlikely that P-51As saw any service with 4 Hispanos. Almost all USAAF P-51As went to the CBI theatre with the 10th Air Force. Initial combat operations with the P-51A began on November 23rd, 1943 with the 23rd Fighter Group.

You can tell if its a cannon armed aircraft because of the large fairings on the wing leading edge and the cannon barrel that protrudes about a meter out of the wing. I have plenty of photos of P-51A's, but not a single one with a 4 connon installation. Google couldn't help me either

Ok, the P-51A officially had only the same
4 .50 cal Brownings as the P-51B.
The nose guns were deleted.

According to Angelucci&Bowers, page 334, the
engine for the A-36 was the V-1710-87 @ 1325hp
and the engine for the P-51A was the V-1710-81 @ 1200 hp.

Note the later - number and higher power ratings
for the A-36.

I have never seen a confirmed photo of a P-51A
with 6 .50 cal machine guns.

Mustang MKI seems to have been fitted with the
nose guns...
I have seen various descriptions
of the Mustang Mk1 crediting it with
8 .303's or 4 or6 .50s.

Jane's 1946 says the armament was a mix of
4 .50's and 4 .30's (US MI .30 cal also known as the .30-06).

Jane's 1946 says the P-51 with 4 20mm cannon
was the Mustang Mk1a

The British version of the P-51A was called the
Mustang MkII, also states the reduction to
four .50 cal guns.

I will tend to believe Jane's and Angelucci/Bowers.
Seems to be a popular thing to print BS before
performing any research.

Just like the P-39 supercharger myth.
bad publications have most believing that
the Allison V-1710 lacked a supercharger.
Truth is that NO V-1710 was ever installed
in an aircraft without a supercharger.
Those Allisons lacked a two stage supercharger.

Bad information so ingrained in the popular press
as to make it into the USAF museum's text
on the P-39!!!!
I sent them a letter telling them of their
mistake, maybe they will change the text during
the next 100 years.

Sergio

berg417448
01-21-2006, 08:49 PM
A couple of good photos of 20mm cannon armed Mustang MkI A in RAF use here:

http://www.clubhyper.com/eyesoftheinvasioncf_1.htm

ImpStarDuece
01-22-2006, 12:53 AM
The Allison V-1710-87 (F21R) on the A-36A was a low-altitude Allison, developing is rated output of 1,325 hp at around 3,000 feet. The supercharging ratio and propeller gearing were set for flight at very low altitudes.

The Allison V-1710-81 (F20R) mounted on the front of the P-51A was a medium altitude engine. It's rated altitude was 18,000** feet, where it was producing around 1,125 hp. It had a revised supercharger ratio which was tailored to medium altitude operations. A F20R engined Mustang II did 409 mph at 18,000 feet according to RAF testing in mid 1944.

The F20R held its power above 10,000 feet much better than the F21R did, in fact, much better than the original F3R of the Mustang I, which had a critical altitude of about 15,000 feet.

Interestingly, many of the British Mustang Is were converted from F3R to F21R engines, with higher cleared boost levels and altered supercharger ratios, giving an increase in power at low altitude but a commesurate decrease in speed above 12,000 feet. The 51" Hg cleared F21R increased speed at sea level from an already quick 320-330 mph, to a truly impressive 365 mph. However level speed at altitude fell from around 380-385 mph to around 375 mph.

** Rated altitudes drop as manifold pressure increase. The V-1710-81 originally ran at 42-44" Hg, but as boost was increased (to 56" Hg) critical altitude dropped to around 10,000 feet.

Kocur_
01-22-2006, 02:40 AM
Sergio_101! As much as I dont see canons barrels on your pic, there was one Mustang with Merlin AND four Hispanos! Two P-51s (NA-91) served as XP-51B prototypes. One of them had armament removed, but second one, 41-37421 had those four Hispanos there! I WANT THAN ONE MODELLED http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif


P.S. In the original factory project of NA-102, i.e. P-51B, blueprints of wings were drawn for Hispanos! Unfortunaltely US Hispanos were unusuable...

Aaron_GT
01-22-2006, 03:15 AM
I have seen various descriptions
of the Mustang Mk1 crediting it with
8 .303's or 4 or6 .50s.

The Mustang I was armed with 4 .50s and 4 .303s. 2 .50s in the lower nose, one each in the wing, 2 .303s in each wing.

ICDP
01-22-2006, 04:08 AM
Here is an excellent shot of a P51 with 4x 20mm cannons. Sorry about the picture size.

http://i17.photobucket.com/albums/b58/ICDP/P51.jpg

Kocur_
01-22-2006, 04:18 AM
purrrrrrhrrrrrrhrrrr http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

ImpStarDuece
01-22-2006, 04:34 AM
Now fit it with a F20R and have it do 400+ mph at 11,000 feet and 365 mph on the deck

Friendly_flyer
01-22-2006, 05:05 AM
Originally posted by ImpStarDuece:
Dimensions for the .50 cal round were 12.7x99

Dimensions for the 20mm Hispano round were 20mmx110

I'm afraid Gibbage might be right. The lengths of the rounds you list are right, but the diameter is the size of the bullet, not the cartridge, which takes up the majority of the volume.

I have a few cartridges here at home. The M2 .50 casing has a diameter of about 2 cm. I don't have a Hispano cartridge, but I have an M 103 20 mm (AA-shell). It has a cartridge diameter of ca 3 cm. The 20 mm is a millimetres longer than the .50.

Volume (a rough estimation of volume of a cylinder with the same proportions) gives 207 cubic centimetres for the .50 and 706 cubic centimetres for the 20 mm. With projectile, the volume would be even more skewed in the 20mm's direction, giving a rough 4:1 difference. Bear in mind that those calculations are not done with a Hispano round, though, so they might be a bit off.

The .50 does weigh a bit more proportionally, as a copper-cased lead bullet (the .50) weight quit a bit more than a steel encased explosive (the 20mm). Wight and volume of the two rounds do not follow the same curves.

Kocur_
01-22-2006, 05:54 AM
Ok: 12,7 x 99mm BMG rim diameter is 20,4mm, lenght is 138mm. 20 x 110mm Hispano rim diameter is 24,8mm, lenght about 175mm. We could enclose those rounds in cylinders of following volumes:
.50BMG:
3,14 x 10,1^2 x 138 = 44.202mm^3

20mm Hispano:
3,14 x 12,4^2 x 175 = 84.491mm^3

So Hispano round is about twice as large as .50BMG. Not FIVE times...
Btw: since both are of the same technology and Hispano is 240g / 112g(.50BMG) = 2,14 times heavier than .50BMG what else could one expect?


Originally posted by Friendly_flyer:
The .50 does weigh a bit more proportionally, as a copper-cased lead bullet (the .50) weight quit a bit more than a steel encased explosive (the 20mm). Wight and volume of the two rounds do not follow the same curves.

Im affraid you are incorrect on materials: cases are not made of copper! The most usually its brass, sometimes and quite rarely its brass-plated steel; there were experiments with aluminium cases.
Lead made large proportion of entire projectile weight in .50 ball projectile, others, i.e. AP and API had steel cores to penetrate armour, plus incendiary material in API; tracers were filled with burning material.

Friendly_flyer
01-22-2006, 06:20 AM
Originally posted by Kocur_:
20 x 110mm Hispano rim diameter is 24,8mm, lenght about 175mm.

I'm suprised the Hispano-cartridge is so slim.


Im affraid you are incorrect on materials: cases are not made of copper!

My fault! A should have written jacked. I was talking about the bullet, not the cartridge. The .50 BMG bullets are conventional full jacked lead bullets (some had a steel core). The Hispano bullet is a steel encased grenade. Cubic per cubic the .50 bullets are far heavier than the Hispano grenade.

Kocur_
01-22-2006, 06:54 AM
Originally posted by Friendly_flyer:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kocur_:
20 x 110mm Hispano rim diameter is 24,8mm, lenght about 175mm.

I'm suprised the Hispano-cartridge is so slim. </div></BLOCKQUOTE>

It is! Checkhere (http://www.quarry.nildram.co.uk/MCRel1.jpg).

p1ngu666
01-22-2006, 08:35 AM
that 23mm and the 15.5mm look pretty evil http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

Xiolablu3
01-22-2006, 05:37 PM
I am not sure about the US reason for using the 50cal, I just know why Britain decided NOT to use the 50cal.

After the BOB and the finding that German aircraft were coming over with heavier and heavier armour and 303 was increasily ineffective, it was decided to skip the 50cal completely and move straight on to the 20mm cannon.

Sergio_101
01-22-2006, 06:18 PM
Originally posted by Xiolablu3:
I am not sure about the US reason for using the 50cal, I just know why Britain decided NOT to use the 50cal.

After the BOB and the finding that German aircraft were coming over with heavier and heavier armour and 303 was increasily ineffective, it was decided to skip the 50cal completely and move straight on to the 20mm cannon.

But Britian did use the .50 cal in fighters, bombers and as a heahy machine gun on the ground.

True, the .303 was obsolete before WWI began, let alone WWII.
I believe in the same circumstance the US
would have folowed the same path. That is
to jump to a light cannon.

Sergio

Xiolablu3
01-22-2006, 06:22 PM
Yeah it did use it, after the US started sending them, it would be stupid not too.

But the official line in fighters was to move to 20mm cannon. I only know of the Spitfire 9e which used the 50cal in a British made fighter, there are probably others too, I dont claim to know them all.

But you will find mostly that the British made fighters had either .303 or 20mm Hispano.

LStarosta
01-22-2006, 06:47 PM
Where did Gibbage go?

Sergio_101
01-22-2006, 07:46 PM
Originally posted by Aaron_GT:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I have seen various descriptions
of the Mustang Mk1 crediting it with
8 .303's or 4 or6 .50s.

The Mustang I was armed with 4 .50s and 4 .303s. 2 .50s in the lower nose, one each in the wing, 2 .303s in each wing. </div></BLOCKQUOTE>

Jane's 1946 says the armament was a mix of
4 .50's and 4 .30's (US MI .30 cal also known as the .30-06).

Not .303's as shipped.http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Sergio

ImpStarDuece
01-22-2006, 08:20 PM
The Brits did studies in the mid to late 1930s comparing the performance of the MMGs (.30 cal apporx), HMGs (.50 cal approx) and light cannon (20mm).

Their assesment of .50 calibre weapons was that they were neither fish nor foul: they didn't have the light weight and very high rate of fire of the .30 cal class weapons nor the HE and AP damage potential of the larger 20mm class weapons. Unfortunately, the British overestimated the effectiveness of .303 fire against bombers. The upshot of this was the difficulty that British fighters had in effectively dealing with German bombers over France and southern England. Had the Hurricane and Spitfire had 4 .50cal weapons instead of 8 .303s they may of been more effective against the bombers.

The move towards .50 cals later in the war was primarily due to the increasing amount of armour that both fighters and bombers carried around with them. 2 .50 cals gave longer range and better punch against lightly armoured targets than the .303 did. Ballistically, the .50 cal round was also a better match for the 20mm Hispano.

The Germans felt similarly, upgrading the nose mounted MGs in the 109 and 190 to 13.2 mm MG 131s.


*********** ***************** **************** *********

According to its weight and loading data sheet the Mustang Mk I in British service mounted 4.50 cal weapons and 4 .30 cal weapons.

p1ngu666
01-22-2006, 10:10 PM
i think the RAF stated that they thought the 50cal would soon face the same problem as the 303, the 20mm had a longer life due to it being more powerful.

Aaron_GT
01-23-2006, 02:52 AM
Unfortunately, the British overestimated the effectiveness of .303 fire against bombers. The upshot of this was the difficulty that British fighters had in effectively dealing with German bombers over France and southern England. Had the Hurricane and Spitfire had 4 .50cal weapons instead of 8 .303s they may of been more effective against the bombers.


The specifications for 4 cannon fighters were issued in 1936 to 1937. So by the mid 1930s the RAF had decided that rifle calibre machine gun fighter armament was already obselete, but knew it wasn't at the point of being able to deploy cannon armed aircraft as the 20mm development was still going on. Since the intelligence from Germany was that war was likely to begin not until 1942 the next generation of fighters and armaments intended to replace the Spitfire and Hurricane were expected to be in production by then. As it happened the war started early and the large stocks of rifle calibre guns and ammunition had to be utilised for longer.

In the later 1930s the RAF also felt that machine gun armament for defense on heavy bombers was also pretty much obselete and specified various aircraft to be armed with 4 cannon turrets. These turrets required aircraft specifically designed for them as the turrets were quite large. Some smaller prototype 2 and 4 cannon turrets were suggested and mocked up on a Mosquito, and a 2 20mm cannon was adopted on the Lincoln at the end of the war. In the end types prototyped before the start of WW2 were the ones that stayed with the RAF throughout and that meant that the existing turret sizes were fixed which meant the easiest upgrade was to .50 calibre defensive guns. Then after the end of WW2 the whole ethos changed to a combination of Mosquito-style fast, unarmed bombers, and nuclear bombers, with just a few hang overs from WW2 designs (Brigand, Shackleton) with defensive armament.

nakamura_kenji
01-23-2006, 03:04 AM
prefer cannon fighter, main reason be fly japanese v american plane most often carrier plane. problem be much often plane be fight against are faster and much heavily armour so hit with machine gun do little compare cannon hit also because top lack speed japanese plane time where able hit enemy much low compare with american so need weapon that able kill much quick

Rattler68
01-23-2006, 11:04 AM
Xiolablu3 is correct regarding the Spit IXe. In fact, the letter designation for Spits is its "wing" type (actually the armament). The original weapons were, of course, 8x 303's. The "b" wing, introduced I believe on the Mk. V, had 4x 303's and 2x 20 mm. The "c" wing, also used first, I believe, on the Mk. V, had 4x 20 mm's. The "e" wing (2x 20 mm and 2x .50's) was used on the Mk IX, and many of the later versions of Spit.

StellarRat
01-23-2006, 12:09 PM
The reason that the US switched to 20mm after Korea wasn't as clear as you might think. During WW II nearly all planes ran on gasoline which was easy to light on fire with API rounds. After WW II jets ran on kerosene which did not catch fire easily. It therefore became necessary to dismember the plane instead of lighting it on fire (which only required a round that could penetrate the fuel tanks.) If Oleg modeled the API round correctly in our game the .50s would be far more effective even with the sync problem.

Aaron_GT
01-23-2006, 01:02 PM
The "c" wing, also used first, I believe, on the Mk. V, had 4x 20 mm's.


The C wing could take (per wing) 2 20mm or 1 20mm and 2 .303s. It was the first stab at a 'universal' wing as perfected by the E wing (which could also take 2 20mm per wing if required).

There was a version of the Hurricane that used 4 .50s. It was used by the Belgians, I think, in 1940.

Cajun76
01-23-2006, 09:50 PM
Originally posted by StellarRat:
The reason that the US switched to 20mm after Korea wasn't as clear as you might think. During WW II nearly all planes ran on gasoline which was easy to light on fire with API rounds. After WW II jets ran on kerosene which did not catch fire easily. It therefore became necessary to dismember the plane instead of lighting it on fire (which only required a round that could penetrate the fuel tanks.) If Oleg modeled the API round correctly in our game the .50s would be far more effective even with the sync problem.


A very good point many forget. This is some additional info which AlmightyTallest gleaned from various sources while researching various types of .50 cal ammo, including HE rounds....


It is interesting to note that performance figures are almost always for the BALL round, which was a few grams heavier than the Incendiary or API rounds and had a little less initial velocity, but overall the BMG rounds are all very close in weight (~45 to ~49 grams), except the M23 "jet killer" incendiary which was down around 35 grams (of even more potent IM28). The M1 incendiary round carried 2.2 grams of IM11, the M8 API round carried between 1 and 1.5 grams of IM11 depending on the year (late war M8's used moly-steel penetrators to save tungston and thus had less room for IM11).

IM11 incendiary metal alloy was and is a very nasty substance (it is still used today). When the round strikes the target, usually on the next contact after passing through typical aluminum skinning, the alloy achieves sufficient heat through compression to ignite. Because the Barium Nitrate in the alloy is a very strong oxidizer, there is no need for external oxygen and the IM will all fire up at once, creating a low-order explosion (more like confined gunpowder than high explosives). Between this low-order explosion and the force of the penetrator (or "slug") comming in behind the round, the buring incendiary metal is spewed to the sides, perpendicular to the axis of flight, mostly on the near side as it passes through the structure.

IM11 burns at over 4000 degrees F, hot enough to liquify aluminum on contact. Furthermore, this heat plus the excess O2 from the degenerating Barium Nitrate will cause the target aluminum to burn. It is not necessary for the round to completely breach the target structure though impact damage. When the round strikes the spar of a FW wing for instance, which is aluminum, it will create a .5 inch hole from impact. It will also create a considerable region around the hole which is very hot from the impact/penetration and the IM11 incendiary, and this in turn is ripe to burn, and the spar will become soft for a good radius around that. The spar can easily collapse as a result of .50 API hits.

.50 rounds were not technically "high explosive", but the incendiary metal did "burst" and imparted significant additional damage even to metal structures. The high quality of .50 ammunition was one of the reasons the USA felt it was sufficent to the task and did not focus on replacing it with a larger gun during WWII. No other country was able to mass produce such an incendiary metal alloy. Britain did manage to produce a similar alloy for their DeWilde .303 rounds, but in much smaller amounts, and the DeWilde rounds were always in short supply.

This is from a post at an ammunition forum, and not AT's words. Very nasty if ones considers the P-47 pumping out 110 rounds per second, although they're not all API of course.

Kocur_
01-23-2006, 11:22 PM
Originally posted by Cajun76:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by StellarRat:
The reason that the US switched to 20mm after Korea wasn't as clear as you might think. During WW II nearly all planes ran on gasoline which was easy to light on fire with API rounds. After WW II jets ran on kerosene which did not catch fire easily. It therefore became necessary to dismember the plane instead of lighting it on fire (which only required a round that could penetrate the fuel tanks.) If Oleg modeled the API round correctly in our game the .50s would be far more effective even with the sync problem.


A very good point many forget. This is some additional info which AlmightyTallest gleaned from various sources while researching various types of .50 cal ammo, including HE rounds....
</div></BLOCKQUOTE>

A-a! Not "the US" but USA(A)F only waited that long. US Navy did that right after WW2 and started even before it ended (late F6F-5, F7F, F8F-1B, F9F, F2H, etc.).

StellarRat
01-24-2006, 12:25 AM
Those Navy guys always causing problems! Their priorities were probably shaped by flaming Kamikazis hitting their ships. I'm sure they wanted their targets to fold up immediately. Plus they DID have to worry about enemy bombers unlike the USAF. Understandable.

Kocur_
01-24-2006, 08:41 AM
Originally posted by StellarRat:
Those Navy guys always causing problems! Their priorities were probably shaped by flaming Kamikazis hitting their ships. I'm sure they wanted their targets to fold up immediately. Plus they DID have to worry about enemy bombers unlike the USAF. Understandable.

Yeah, those problems... Like F-4 http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif
Well, isnt target folding up immediately a good thing? http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif
A bit more serious, seems to me they obseved how japanese planes growing more and more robust meant more and more problems to kill them with .50 only. Certainly late war Japanese planes used as kamikaze were dangerous, if werent, as you said folded up immedietaly. They also kept encoutering bombers till last days of war - unlike USAAF.

Philipscdrw
01-24-2006, 09:31 AM
For me, using machineguns in Il-2 is an exercise in frustration. It doesn't matter what aircraft I fly or what the target is, the machine guns take forever to cause enough damage to bring down the aircraft. Unless I'm fortunate and hit the crew or the engines, the enemy will keep flying forever!

I'm going back to first principles and flying LaGGs over Leningrad. Back to the 'Forgotten' part of FB!

Aaron_GT
01-24-2006, 11:00 AM
As an aside, one of Airspeeds late 30s/early 40s experimental bomber killers had a proposed armament of 6 20mm cannon. In each wing.

Kettenhunde
01-24-2006, 08:06 PM
Nice theory on the .50 cal API. Lets see how vunverable self sealing tanks were to catching fire from API strikes:

http://img131.imagevenue.com/img.php?loc=loc24&image=a8...190vunerability1.jpg (http://img131.imagevenue.com/img.php?loc=loc24&image=a8c37_190vunerability1.jpg)

http://img145.imagevenue.com/img.php?loc=loc24&image=dc07d_190vunerability.jpg

All the best,

Crumpp

Ratsack
01-25-2006, 04:37 AM
In support of Aaron_GT's point about the Brits' early intention to move away from the 0.303" ammo: during and after the Battle of Britain, the RAF examined a lot of wrecked German planes, and came to the conclusion that the 0.303 was only marginally effective. They found that the vast majority of the larger aircraft were brought down by critical hits to equipment or aircrew, but that gunfire did very little damage to the airframes. In these cases, the aircraft would be rendered nearly impervious to 0.303 by the addition of a modicum of quite thin armour. This evidence reinforced the Brits' earlier inclination in favour of cannon.

Regarding the U.S. fighters and the argument that the 0.50 was kept because it was good enough to kill a fighter: this is a nice argument, but it's retrospective. The U.S. may have ended up fighting relatively light aircraft, but that's not what the U.S. planes were designed for. As I've pointed out elsewhere, the P47 was designed as an interceptor, not an escort, and the P51 wasn't designed to a U.S. specification at all. We know the U.S. Navy had a preference for cannon by the end of the war, so that leaves only one modern U.S. fighter type - the P38 - and that had a cannon.

Roger Freeman suggests that the U.S.A.A.F may have been over-impressed by the success of the R.A.F.'s eight-gun fighters during the BoB, and this may have led to the acceptance of an all-machine gun armament on the P47. I don't know about that, but the P47 really does look like an anomaly.

Ratsack

Cajun76
01-25-2006, 07:52 PM
Originally posted by Kettenhunde:
Nice theory on the .50 cal API. Lets see how vunverable self sealing tanks were to catching fire from API strikes:

http://img131.imagevenue.com/img.php?loc=loc24&image=a8...190vunerability1.jpg (http://img131.imagevenue.com/img.php?loc=loc24&image=a8c37_190vunerability1.jpg)

http://img145.imagevenue.com/img.php?loc=loc24&image=dc07d_190vunerability.jpg

All the best,

Crumpp

It seems to me the docs you posted (ty, btw) have little to do with the quote I posted, and have very little relevance to how "vulnerable self sealing tanks were to catching fire from API strikes" as well, assuming you're referring to US .50 cal API, the subject of the quote in my post.

The quote has to do with US M1 and M8 ammo, with IM11 incendiary metal alloy, an almost exclusive (AFAIK) feature of US ammo, and does not mention the British Mk II incendiary mentioned in the report.

Additionally, most, if not all rounds under 20mm are assumed to be deflected by this dead six setup. In most circles, it's generally considered a waste of ammo to fire at dead six anyway, as the most vulnerable and vital parts of the a/c are generally at the other end. It would be orders of magnitude easier to hit the fuel tanks on a Focke Wulf from even a 5-10 degree deflection instead of trying for a dead six stern shot.

Using this report as a method to determine how well US M1 and M8 ammo with IM11 incendiary metal alloy lights self sealing tanks is impossible, since it uses British Mk II incendiary and virtually none are assumed to have even got to the tanks. I think if you do a modicum of research, you'll find that US API was very effective against fuel tanks. Perhaps if I worked at a museum or a restoration project of some kind I might further my knowledge in this area. I'm no expert, myself, and I€m always ready to learn.

Cajun76
01-25-2006, 08:09 PM
Originally posted by Ratsack:
<span class="ev_code_YELLOW">As I've pointed out elsewhere, the P47 was designed as an interceptor</span> , not an escort, and the P51 wasn't designed to a U.S. specification at all. We know the U.S. Navy had a preference for cannon by the end of the war, so that leaves only one modern U.S. fighter type - the P38 - and that had a cannon.

Ratsack


The original specification was for a lightweight interceptor, however, the reports from the ETO concluded that range, firepower, speed and high altitude were bigger design requirements. The "P-47" designator was still kept, even though the concept had completely changed to be designed around the R2800 and turbo-supercharging system. I've never even seen a sketch of what the P-47A was supposed to look like, but the P-47B and subsequent models were completely different spec and design, and not related at all to the P-47A.

Ratsack
01-25-2006, 11:21 PM
I am aware that it changed form, but the fact remains that the concept was for a high altitude interceptor. Thus that dirty great turbo supercharger. The P47 was most certainly not designed as an escort.

Don't misunderstand me, please. I'm not saying you've said it was designed as an escort. What I'm getting at is that the argument that goes: "Because U.S. fighters were used to fight fighters, that must've been what they were designed for" is bad history. It's teleological. It puts the cart before the horse.

Ratsack

Kocur_
01-25-2006, 11:45 PM
Originally posted by Cajun76:
I've never even seen a sketch of what the P-47A was supposed to look like, but the P-47B and subsequent models were completely different spec and design, and not related at all to the P-47A.

He, he Im just looking at pic of AP-10/XP-47 mock-up. Looks like, hmm, mix of P-39 (nose) and P-43. It was suposed to be powered with V-1710, the only difference between P-47 and P-47A was armament (2 x .50 + 4 x .30 in 47, 4 x .50 in 47A). Obviously, the plane would have nothing to do with P-47B and following. Sorry I dont have scanner http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif

Ratsack
01-26-2006, 01:58 AM
The specification did not change: it was still for an interceptor.

Ratsack

nakamura_kenji
01-26-2006, 02:17 AM
http://img.photobucket.com/albums/v492/nakamura_kenji/s-p47-xp-47-1.jpg
http://img.photobucket.com/albums/v492/nakamura_kenji/s-p47-xp-47-3.jpg

Xiolablu3
01-26-2006, 02:47 AM
A good map for perfecting machine gun use is the Ki43 vs Hurri IIb singapore map on Ukdedicated.

Very hard to bring down hurricanes with 2 Mgs on the ki43 unless you are a skilled shot.

The hurricanes whilst outmanouvred and outrun by the ki43c are lethal if they get a shot on the Oscar with their 12mgs. Burn baby burn.

guderian_ente
01-26-2006, 02:56 AM
Good discussion with many good points already made. I'll just add a few of my own:

1. There were big stoppage problems with wing-mounted cannons, at least early in the war. Almost all of the early war fighters that had cannon had them on the propeller hub (e.g. Bf 109). Wing-mounted cannon were tried on the Spitfire in 1940, and the pilots concluded that they were "great when they worked" which is pretty much the conclusion in this thread too.

If you look at the P-38 and P-39 they also fit this pattern, i.e. both of them have their cannon on the centreline and not in the wings. The P-51B and C also had problems with the wing-mounted .50 Cals, so it was a general problem even if cannons seem to have been affected more.

2. Someone mentioned logistics, and this is a huge but usually underappreciated factor. In fact I would go so far as to say it is of war-winning importance. History and aviation buffs tend to concentrate on performance, but doing so often misses the bigger point.

Yes, US procurement decisions were conservative compared to Nazi Germany. But what they gained in increased production and supply was more important than a few more pounds of high explosives here and there. Sometimes the conservative approach was wrong, like the decision to continue with the Sherman instead of the Pershing in early 1944. But on the whole the positives far outweighed the negatives.

Ratsack
01-26-2006, 03:33 AM
You're right about the logistics being important. For example, the Brits continued with the useless 2-pounder anti-tank gun for logistical reasons. This decision is even worse when you consider they had an AA gun of 92 mm (from memory: don't quote me) with very similar characteristics to the infamous FLAK 88 mm. So logistics are important, it's just that sometimes logistical concerns are the right basis for a decision, and sometimes they're not.

Running with your theme, the other thing aviation enthusiasts tend to forget is the lead-in period. The Brits were mucking around with cannon for their fighters before the war, and they only sorted out the problems sufficiently to make them combat worthy in 1941. The problems with the stoppages weren't really fixed until the introduction of the C wing with the new ammo feed.

The U.S., having designed the P47 for MGs, would've been faced with serious delays if they wanted to change over to cannon. They seem to have decided that eight MGs were enough, and they probably were. I suspect that four cannon would've been better, though.

Ratsack

Kurfurst__
01-26-2006, 05:32 AM
Originally posted by Cajun76:
IM11 burns at over 4000 degrees F, hot enough to liquify aluminum on contact. Furthermore, this heat plus the excess O2 from the degenerating Barium Nitrate will cause the target aluminum to burn. It is not necessary for the round to completely breach the target structure though impact damage. When the round strikes the spar of a FW wing for instance, which is aluminum, it will create a .5 inch hole from impact. It will also create a considerable region around the hole which is very hot from the impact/penetration and the IM11 incendiary, and this in turn is ripe to burn, and the spar will become soft for a good radius around that. The spar can easily collapse as a result of .50 API hits.

Your friend has a very vivid imagination, I can clearly see in front myself a huge main spar literally melting after being hit by, err, a 2 gram non-explosive content which burns at 4000 F. http://forums.ubi.com/groupee_common/emoticons/icon_razz.gif



No other country was able to mass produce such an incendiary metal alloy. Britain did manage to produce a similar alloy for their DeWilde .303 rounds, but in much smaller amounts, and the DeWilde rounds were always in short supply.

Uhum. Ask your friend what other countries produced during the war. He has obviously very little idea of how barium nitrate compared to the other country's choices. Barium nitrate is just one of the many incendinary materils, and not special in any way. Neither was the DeWilde rounds, which followed the same pattern as incendinary rounds at the time in general, it's just largely mythicized.

Now for starters :

4000 F, it's around 2200 Celsius. Aluminium would not melt from it, ESPECIALLY not when we are speaking of tiny SPARK from a 2 gram content round. Now in comparison, elektrothermit burns at 2-3000 celsius or about 5500 F.
The 13mm MG 131 HEI-T for example contained 0.9gram nitropenta, and 0.3gram elektrothermit. Nitropenta is a very violate explosive,it burns at 4500 Celsius (8100 F!!). Just for example of what was used also, it was a matter of choice. 2 gram of barium nitrate is nothing extraordinary that 'other countries' could not hope to produce.

Kocur_
01-26-2006, 08:13 AM
Originally posted by guderian_ente:

1. There were big stoppage problems with wing-mounted cannons, at least early in the war. Almost all of the early war fighters that had cannon had them on the propeller hub (e.g. Bf 109). Wing-mounted cannon were tried on the Spitfire in 1940, and the pilots concluded that they were "great when they worked" which is pretty much the conclusion in this thread too.

Im affraid you are wrong if mean to say that placing cannons in wings itself made problems. I do not know of any specific problems with PZL P.24F (2 x Oerlikon FF under wings), later I-16 (2 x ShVAK in wings) or MB-152C1 (2 x HS-404 in wings) or Bf-109E3 (2 x MG FF in wings), btw. the first serially produced Bf-109 with "engine cannon" was Bf-109F. The British Hispano problems were related with the cannon itself, if RAF had any fighters with nose mounted cannons those would have the same problems as those encoutered in Spitfires.

Where to mount a cannon was question of choice. Everytime low weight was primary goal and engine gave such a possibility, there would be engine cannon - strenghtening wings to mount armament there, costs weight. And so we had MS-406, Yaks or Bf-109F/G/K. Everytime heavy punch was the objective and/or engine and its installations would not permit installation of cannon there, planes had guns where many of them could be installed, i.e. in wings.


If you look at the P-38 and P-39 they also fit this pattern, i.e. both of them have their cannon on the centreline and not in the wings.

The reason is that both of those types were designed and initially produced with very big 37mm cannon, which could not be mounted in their wings. 20mm cannons appeared in those planes as soon as it was found out, that 37mm cannon is impractical.


The P-51B and C also had problems with the wing-mounted .50 Cals, so it was a general problem even if cannons seem to have been affected more.

Again, its a specific problem, not general of "guns in wings per se" - simply design of feeding was flawed.


Someone mentioned logistics, and this is a huge but usually underappreciated factor. In fact I would go so far as to say it is of war-winning importance. History and aviation buffs tend to concentrate on performance, but doing so often misses the bigger point.

As Napoleon once said: "Army marches on their bellies" - logistics wins wars. But having planes with two caliber weapons would not make any problems, well it didnt make any IRL, did it. And P-51 with 2 x 20mm + 2 x 12,7 would be armed far more powerfully that did IRL http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif
Heck! What is two calibres! You could meet US Army infantry platoons with THREE calibers of small arms ammo to deliver, not to mention each infantry battalion having four.

Cajun76
01-27-2006, 04:54 AM
Originally posted by Kurfurst__:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Cajun76:
IM11 burns at over 4000 degrees F, hot enough to liquify aluminum on contact. Furthermore, this heat plus the excess O2 from the degenerating Barium Nitrate will cause the target aluminum to burn. It is not necessary for the round to completely breach the target structure though impact damage. When the round strikes the spar of a FW wing for instance, which is aluminum, it will create a .5 inch hole from impact. It will also create a considerable region around the hole which is very hot from the impact/penetration and the IM11 incendiary, and this in turn is ripe to burn, and the spar will become soft for a good radius around that. The spar can easily collapse as a result of .50 API hits.

Your friend has a very vivid imagination, I can clearly see in front myself a huge main spar literally melting after being hit by, err, a 2 gram non-explosive content which burns at 4000 F. http://forums.ubi.com/groupee_common/emoticons/icon_razz.gif



No other country was able to mass produce such an incendiary metal alloy. Britain did manage to produce a similar alloy for their DeWilde .303 rounds, but in much smaller amounts, and the DeWilde rounds were always in short supply.

Uhum. Ask your friend what other countries produced during the war. He has obviously very little idea of how barium nitrate compared to the other country's choices. Barium nitrate is just one of the many incendinary materils, and not special in any way. Neither was the DeWilde rounds, which followed the same pattern as incendinary rounds at the time in general, it's just largely mythicized.

Now for starters :

4000 F, it's around 2200 Celsius. Aluminium would not melt from it, ESPECIALLY not when we are speaking of tiny SPARK from a 2 gram content round. Now in comparison, elektrothermit burns at 2-3000 celsius or about 5500 F.
The 13mm MG 131 HEI-T for example contained 0.9gram nitropenta, and 0.3gram elektrothermit. Nitropenta is a very violate explosive,it burns at 4500 Celsius (8100 F!!). Just for example of what was used also, it was a matter of choice. 2 gram of barium nitrate is nothing extraordinary that 'other countries' could not hope to produce. </div></BLOCKQUOTE>

<span class="ev_code_YELLOW">So your opinions are more valid than this fellow because they come from you, eh?</span> http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

<span class="ev_code_YELLOW">If you can't see a spar damaged from a .50 cal hole and simultaniously heated to 4000F as being weakened, perhaps it would be better to think of other, easier things like paint drying or grass growing. More your speed, perhaps. http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif I would expect that engineers and mechanics would be able to grasp this sort of thing, but not your typical lawyer. They generally don't have the background. Additionally, the poster never stated that one round would do the job of collapseing the spar. If you take a moment to read what he said, he states that: "The spar can easily collapse as a result of .50 API hits." </span>

<span class="ev_code_YELLOW">Aluminum (Al) melts at 660?C (1220?F) and boils at 2467?C (4472?F), but you've stated that:</span>


Kurfurst wrote:
Aluminium would not melt from it (4000?F)

<span class="ev_code_YELLOW">Just one more example that shows you live in a very different world from the rest of us, where even physics bends to fit your view.</span> http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

Kocur_
01-27-2006, 08:40 AM
Wouldnt it take a while and appropriate amount of fuel, the incendiary material in this case, to heat our spar enough to weak it...? Not to mention, that API would ignite on first surface it hit, i.e. skin - spars are deeper...

But back to XP-47 (-47A) - I scanned it http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

http://img96.imageshack.us/img96/7510/xp4747a5vy.png (http://imageshack.us)

Cajun76
01-27-2006, 10:58 AM
IM11 incendiary metal alloy was and is a very nasty substance (it is still used today). <span class="ev_code_RED">When the round strikes the target, usually on the next contact after passing through typical aluminum skinning</span>, the alloy achieves sufficient heat through compression to ignite.

IM11 burns at 4000?F
Aluminum melts at 1220?F, and boils at 4472?F

If the IM11 ignites as it hits our example spar, there's an area directly around the hole that has liqified as well. How big, I don't know. 1" seems resonable, up to 3" might feel the effects of the heat, but not actually melt. Doesn't aluminum get softer around 600-700?F or so?

In Kurfurst's world, the SR-71 didn't need to be built out of titanium because aluminum can take it.... http://forums.ubi.com/images/smilies/88.gif

Thanks for the pic! http://forums.ubi.com/images/smilies/25.gif

Kettenhunde
01-27-2006, 11:23 AM
Perhaps if I worked at a museum or a restoration project of some kind I might further my knowledge in this area. I'm no expert, myself, and I€m always ready to learn.

You are correct that off dead six is better. However it still has no chance of causing a fire. You need three things for combustion. Fuel, oxygen, and an ignition source. The design of self sealing tanks prevents the needed oxygen from reaching the fuel and the source. You would need a MUCH bigger hole in the tank than even multiple .50 caliber API rounds could produce.

That is actually covered in the report.

The conclusion of the report is very valid and was scientifically tested by a nation at war to determine the best way to destroy the intended target.

I completely understand though why some gamers would not like the results, especially those that fly US Shapes.

I believe Tony Williams has an excellent book on the subject of aircraft armament.

All the best,

Crumpp

Kurfurst__
01-27-2006, 11:44 AM
Originally posted by Cajun76:
<span class="ev_code_YELLOW">So your opinions are more valid than this fellow because they come from you, eh?</span> http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

Nope, I didn't claim that. Just about anybody's technically underlined opinion counts more than what, some fanboi quoted by another, unleashing it's imagination and picturing a several hundred kg main spar melting from a silly spark from a 2gram incendiary material, adding "nobody could come near of our stuff". Of course the guys knows nothing about the subject, he heard something about DeWilde as it's much pressed in BoB books, but quick to conclude "it was rare'.

Man if 2 gram IM in a .50 did that to a spar, 85 gram IM of 30mm rounds should have caused a heavy bomber to simply boil away! http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif



<span class="ev_code_YELLOW">Aluminum (Al) melts at 660?C (1220?F) and boils at 2467?C (4472?F), but you've stated that:</span>

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> Kurfurst wrote:
Aluminium would not melt from it (4000?F)

<span class="ev_code_YELLOW">Just one more example that shows you live in a very different world from the rest of us, where even physics bends to fit your view.</span> http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif </div></BLOCKQUOTE>

I am very proud of the fact that I live in a very different world than you. After all, there's some trouble in the head of some who think 2 grams of glorious unsupressd american .50 would melt a main spar away. It sounds like a lunatic dream.

BTW just basic physics for you. To heat up a given size of material, you need a given amount of ENERGY, not temperature. Obviously, a spark from a API round is very small and can store very little energy, and will loose a lot as it travels through the air to which it expands it's heat. It's called effiency loss. Obviously, a 0.1 gram spark heated to 4000 F won't really heat up anything, and certainly not a 200 000 gram main spar section, especially not under the 0.1 second period it burns out.

Try pouring a glass of boiling 100 celius water onto a 50 lbs ice block and see what happens.
You basically say the ice-block would boil away immidiately. US high schools, LOL. http://forums.ubi.com/images/smilies/35.gif

Xiolablu3
01-27-2006, 12:03 PM
Kurfy, you obviously have some very good knowledge and are well read on many subjects, so why do you spoil it with made up stuff?

I just cant understand it... http://forums.ubi.com/images/smilies/blink.gif

You could be a great source of info for so many things, but the lies you add just make everything you say unbelievable. http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif

telsono
01-27-2006, 12:05 PM
Kocur

I believe the major problem that the Greeks had with the 20mm Oerlikon's on the PZL P.24F was not being able to get replacement parts and ammunition even before the Germans invaded them. Most P.24F's were converted to P.24G standard (2 x .303 mg's per wing) because of these supply problems.
The P.24 was one of the first cannon armed aircraft when first offered in 1934.

There was a lot of stagnation in aircraft armament throught the 1920's and 1930's. The USAAC had a requirement for a single .30 cal and a .50 cal up armament through the P-35 and P-36.
Italian aircraft follwed a similar philosophy. This was a remnant of the biplane era. As two centerline mounted mg's was the standard for biplanes.
A fad started in the mid 1930's when countries decided to build mulit-engine bomber destroyers. The Bf 110 was a product of that fad, the Whirlwind, and several other aircraft. The need for heavy weapons for seen as well with aircraft built around certain weapons. Bell Aircraft had a fixation with the 37mm cannon using it on at least one previous design to the P-39.

Cajun76
01-27-2006, 12:44 PM
Originally posted by Kettenhunde:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Perhaps if I worked at a museum or a restoration project of some kind I might further my knowledge in this area. I'm no expert, myself, and I€m always ready to learn.

You are correct that off dead six is better. However it still has no chance of causing a fire. You need three things for combustion. Fuel, oxygen, and an ignition source. The design of self sealing tanks prevents the needed oxygen from reaching the fuel and the source. You would need a MUCH bigger hole in the tank than even multiple .50 caliber API rounds could produce.

That is actually covered in the report.

The conclusion of the report is very valid and was scientifically tested by a nation at war to determine the best way to destroy the intended target.

I completely understand though why some gamers would not like the results, especially those that fly US Shapes.

I believe Tony Williams has an excellent book on the subject of aircraft armament.

All the best,

Crumpp </div></BLOCKQUOTE>


Because the Barium Nitrate in the alloy is a very strong oxidizer, there is no need for external oxygen and the IM will all fire up at once, creating a low-order explosion (more like confined gunpowder than high explosives).

http://forums.ubi.com/images/smilies/16x16_smiley-indifferent.gif I'm no expert, but having a fire in a tank, even if it's self sealing is probably not healthy.

I'd rather have biased gamers than biased historians. I'm a fan of history myself, and the .50cal was very effective, historically.

Cajun76
01-27-2006, 01:41 PM
Originally posted by Kurfurst__:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Cajun76:
<span class="ev_code_YELLOW">So your opinions are more valid than this fellow because they come from you, eh?</span> http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

Nope, I didn't claim that. Just about anybody's technically underlined opinion counts more than what, some fanboi quoted by another, unleashing it's imagination and picturing a several hundred kg main spar melting from a silly spark from a 2gram incendiary material, adding "nobody could come near of our stuff". Of course the guys knows nothing about the subject, he heard something about DeWilde as it's much pressed in BoB books, but quick to conclude "it was rare'.

Man if 2 gram IM in a .50 did that to a spar, 85 gram IM of 30mm rounds should have caused a heavy bomber to simply boil away! http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif



<span class="ev_code_YELLOW">Aluminum (Al) melts at 660?C (1220?F) and boils at 2467?C (4472?F), but you've stated that:</span>

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> Kurfurst wrote:
Aluminium would not melt from it (4000?F)

<span class="ev_code_YELLOW">Just one more example that shows you live in a very different world from the rest of us, where even physics bends to fit your view.</span> http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif </div></BLOCKQUOTE>

I am very proud of the fact that I live in a very different world than you. After all, there's some trouble in the head of some who think 2 grams of glorious unsupressd american .50 would melt a main spar away. It sounds like a lunatic dream.

BTW just basic physics for you. To heat up a given size of material, you need a given amount of ENERGY, not temperature. Obviously, a spark from a API round is very small and can store very little energy, and will loose a lot as it travels through the air to which it expands it's heat. It's called effiency loss. Obviously, a 0.1 gram spark heated to 4000 F won't really heat up anything, and certainly not a 200 000 gram main spar section, especially not under the 0.1 second period it burns out.

Try pouring a glass of boiling 100 celius water onto a 50 lbs ice block and see what happens.
You basically say the ice-block would boil away immidiately. US high schools, LOL. http://forums.ubi.com/images/smilies/35.gif </div></BLOCKQUOTE>

<span class="ev_code_RED">Over exsageration, misrepresentation of the subject, minimalization of facts that doesn€t fit your view. Anyone with half a wit can see right through you, and it's sad.</span>

<span class="ev_code_RED">^ This stuff you wrote is about as childish and ignorant as I've seen.</span>


Man if 2 gram IM in a .50 did that to a spar, 85 gram IM of 30mm rounds should have caused a heavy bomber to simply boil away!

picturing a several hundred kg main spar melting from a silly spark from a 2gram incendiary material

<span class="ev_code_RED">

That's asinine.

Minimizing 1-2 grams of IM at 4000F as a "spark"? We'll test it. I'll drag my feet on carpet, and touch a doorknob. I'll rate the experience 1-10. Then we'll apply 1 gram of burning IM to your arm, and you tell me if it's "spark-like".

You characterize his statement on manufacturing capacity as "nobody could come near of our stuff". What he said was "No other country was able to mass produce such an incendiary metal alloy" Which is IM11 in the M1 and M8 .50cal consisting of 50% barium nitrate and 50% magnesium aluminum alloy. I'm sure other nations could produce it, but could they match US production? I don't know for sure, and niether do you, but your feeble attempts to misdirect the point he was making is seriouly lacking integrity.

Then, you put words in my mouth as an excuse to say derogatory remarks about the US. http://forums.ubi.com/images/smilies/51.gif

Lastly, please, please look up "energy" and "temperature". 4000F is 3.3 times hotter than needed to melt/liquefy aluminum, and is almost hot enough to boil it.</span>

Kocur_
01-27-2006, 01:46 PM
Originally posted by telsono:
Kocur

I believe the major problem that the Greeks had with the 20mm Oerlikon's on the PZL P.24F was not being able to get replacement parts and ammunition even before the Germans invaded them. Most P.24F's were converted to P.24G standard (2 x .303 mg's per wing) because of these supply problems.

I know http://forums.ubi.com/images/smilies/25.gif My point was that mounting cannons in wings was not troublesome per se, as guderian_ente seemed to suggest. P.24/II (prototype of P.24A with 2 x 7,92+2 x 20mm) was the heaviest armed fighter in the world in 1934 http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

Bell Aircraft had a fixation with the 37mm cannon using it on at least one previous design to the P-39.
Airacuda! Twin engined pusher with forward firing stations with 37mm and hmg placed in nose parts of engine nacelles! Also intended to be fitted with fire control system. Not so succesful idea...

Kocur_
01-27-2006, 01:53 PM
Lastly, please, please look up "energy" and "temperature". 4000F is 3.3 times hotter than needed to melt/liquefy aluminum, and is almost hot enough to boil it.

Cajun76! But it takes time to apply that temperature to object you want to heat up. Quantity of incendiary material in API projectile definately does not seem to be enough to burn long enough to heat up a spar. Like: you can put out a candle with your fingers, because contact with the flame you have is not long enough to heat up your skin to level of pain.

anarchy52
01-27-2006, 02:22 PM
Answer to the question is: no
too small incidentiary content to light up aluminium much less to heat up the spar. Elementary school physics:
Those 2g of incendiaries will burn too quickly and it's mass is too small to TRANSFER anough heat to object struck. There is no difference between incindeary rounds and FMJ when it comes to causing structural damage.

HOWEVER, if you have a leaking fueltank which fills the fuselage with fumes, incendiary round will start a fire just like a spark plug will detonate fuel-air mixture in engine cylinder.

anarchy52
01-27-2006, 02:28 PM
Originally posted by Kocur_:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Lastly, please, please look up "energy" and "temperature". 4000F is 3.3 times hotter than needed to melt/liquefy aluminum, and is almost hot enough to boil it.

Cajun76! But it takes time to apply that temperature to object you want to heat up. Quantity of incendiary material in API projectile definately does not seem to be enough to burn long enough to heat up a spar. Like: you can put out a candle with your fingers, because contact with the flame you have is not long enough to heat up your skin to level of pain. </div></BLOCKQUOTE>

Exactly the analogy I wanted to use

Kurfurst__
01-27-2006, 05:17 PM
Originally posted by anarchy52:
Answer to the question is: no
too small incidentiary content to light up aluminium much less to heat up the spar. Elementary school physics:
Those 2g of incendiaries will burn too quickly and it's mass is too small to TRANSFER anough heat to object struck. There is no difference between incindeary rounds and FMJ when it comes to causing structural damage.

HOWEVER, if you have a leaking fueltank which fills the fuselage with fumes, incendiary round will start a fire just like a spark plug will detonate fuel-air mixture in engine cylinder.


That's what I am trying to get into his head... *sigh*

WWMaxGunz
01-27-2006, 06:16 PM
Some guys must have forgotten all science after elementary school and never went back.

There is temperature and heat and your total block of material. However there is also
the rate of transfer of heat within a material object being heated and the dimensions
of the volume of that material.

Example: I can take a 1mm x 1mm x 50mm magnesium strip and hold one end in my fingers.
I then light the other end with an ordinary paper match and I can hold onto that while
it burns about halfway down before I have to drop it. Even then it is not because the
metal strip is hot but rather from the heat from the flame. At no point do I have to
heat the entire strip to ignition temperature (not heat, it takes temperature to break
down the outer oxides and initiate free combustion which may or may not continue due to
the material at that spot only maintaining temperature) to get or keep it lit.

Another Example: When welding, the metal is melted at the weld yet the entire piece is
not brought near melting which is highly undesireable.

Another Example: A very thin laser beam can cut through thick steel without not only
melting the whole steel workpiece but even metal less than a thumbnail thickness away
from the centerline of the cut. Miraculous! Well, no it just defies whatever education
someone from outside the US doesn't seem to have absorbed regardless of what he was
presented with... so I won't say the system where he lives is no good. That he can
slander the US system so easily does tell me that he either didn't learn much logic or
is up to his usual mental(case) dishonesty.

---------------

Consider that that 4000F hole is going to be a bit bigger than .50 cal. Consider that
even 2 gm of IM sprayed on an aluminum structural part or skin is going to get surface
damage, pitting, even though shallow. Consider that with parts under mechanical stress
with any sharp corners or scratches or pits the stresses will concentrate at those points
as that IS a long standing design consideration to avoid these elements, the first lesson
is to round and smooth all inside corners on structural parts. That's just good design
which I learned from a very good teacher born and trained in Germany before he left in
1939. Consider that in manuals on sabotage that adding small, shallow cuts to structural
parts set for destruction makes a large difference in how much blast is needed.

Be sure that the use of the IM does make the bullet more effective. Add the term "Rate
Of Fire" and a little common sense (supplies are short so get yours now!) and maybe it
can be clear that more is more and nobody was talking about 50 cals equalling 20+mm on a
one to one hit basis. But hey, change the claim and ridicule away right?

What we don't see anywhere here is pictures of such damage or numbers from tests so what
value has it really? It can't be modelled properly without that much.

I'd be more concerned with IM fire burning the insulation off wiring inside the wing or
weakening linkages, pivots and the like, or setting off ammo. The first of those does
constitute a major concern as the least likely is loss of some electrical subsystem after
a lot of hot sparking inside the plane.

Does self-sealing tanks stop fire when the IM has its own oxygen? How about Mk108 incendiary
with the fuse that only goes off when surrounded by liquid? Can't they rupture entire tanks?
If incendiaries go into a fuel tank and burn, will that pollute the fuel enough to screw up
the engine or clog the fuel filter depending on how many hits/how much material burned?

Thermite burns at 2500 C.

anarchy52
01-27-2006, 07:09 PM
Originally posted by WWMaxGunz:
Some guys must have forgotten all science after elementary school and never went back.

There is temperature and heat and your total block of material. However there is also
the rate of transfer of heat within a material object being heated and the dimensions
of the volume of that material.


OK Einstein, calculate the energy in Joules needed to melt 1g of aluminium.
Then calculate the energy released by burning 2g of incendiary mixture.



Another Example: When welding, the metal is melted at the weld yet the entire piece is
not brought near melting which is highly undesireable.

Welding = pumping kilowatts of electric current



Another Example: A very thin laser beam can cut through thick steel without not only
melting the whole steel workpiece but even metal less than a thumbnail thickness away
from the centerline of the cut. Miraculous! Well, no it just defies whatever education
someone from outside the US doesn't seem to have absorbed regardless of what he was
presented with... so I won't say the system where he lives is no good. That he can
slander the US system so easily does tell me that he either didn't learn much logic or
is up to his usual mental(case) dishonesty.

Again pumping kilowatts even Megawatts on a very limited area. I held my hand in front of a 2 MW pulse laser. Didn't feel a thing. That's because P = W / t while the power of the device is impressive, the pulse is short and the energy transfered to my hand was low. Contignuous beam laser is something entirely different. Same as welding or torching something.
2g flash fire won't do anything to metal as it can not transfer anough energy to wing spar to light it up.


Consider that that 4000F hole is going to be a bit bigger than .50 cal. Consider that
even 2 gm of IM sprayed on an aluminum structural part or skin is going to get surface
damage, pitting, even though shallow. Consider that with parts under mechanical stress
with any sharp corners or scratches or pits the stresses will concentrate at those points
as that IS a long standing design consideration to avoid these elements, the first lesson
is to round and smooth all inside corners on structural parts. That's just good design
which I learned from a very good teacher born and trained in Germany before he left in
1939. Consider that in manuals on sabotage that adding small, shallow cuts to structural
parts set for destruction makes a large difference in how much blast is needed.

I'd be more worried about 12.7+mm hole in my wing spar then 0.1mm dent caused by flash of incindeary mixture.


Be sure that the use of the IM does make the bullet more effective. Add the term "Rate
Of Fire" and a little common sense (supplies are short so get yours now!) and maybe it
can be clear that more is more and nobody was talking about 50 cals equalling 20+mm on a
one to one hit basis. But hey, change the claim and ridicule away right?

My god you really don't have the slightest clue what you're talking about.


I'd be more concerned with IM fire burning the insulation off wiring inside the wing or
weakening linkages, pivots and the like, or setting off ammo. The first of those does
constitute a major concern as the least likely is loss of some electrical subsystem after
a lot of hot sparking inside the plane.

Electrical wireing insulation would hardly be a reason to worry compared to risk of fuel fire or ammo detonation.


Does self-sealing tanks stop fire when the IM has its own oxygen? How about Mk108 incendiary
with the fuse that only goes off when surrounded by liquid? Can't they rupture entire tanks?

There was no such fuse.

This thing throws sparks at 3,000?C (5,500?F). Good luck trying to burn through a can of sardines with it. http://www.militarykit.com/products/military_accessorie...edish_fire_steel.htm (http://www.militarykit.com/products/military_accessories/swedish_fire_steel.htm)

Max.Power
01-28-2006, 03:38 AM
I read somewhere on a cannon ammunition site about some german shells with what they called a 'hydrodynamic fuse,' but I must confess, I did some searching just now and I found nothing.

Cajun76
01-28-2006, 05:55 AM
http://www.luft46.com/armament/mk108.html

I guess it's easier to categorically deny everything a person says rather than risk them being right about something you don't agree with, eh?

Kocur_
01-28-2006, 08:20 AM
Ehmmm... (http://www.xs4all.nl/%7Erobdebie/me163/weapons15.htm#Type%20N)

Hristo_
01-28-2006, 01:24 PM
So, did the metal plate from the original poster's video melt ? I wanted to see but fell asleep before the end http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif

Sergio_101
01-28-2006, 03:53 PM
Kurfurst__ This is amazing.
I see where you got your reputation
for favoring all things German.

Ok guys, time is a factor in the effectivness
of a incendiary round ignighting
a metal structure.
Burn temp means less than the duration
of the burn.
If a incendiary projectile passes through at 2,000 fps +
it will have little effect unless it comes in
contact with fuel. (unless it is a superior German projectile):-)

Even if your incendiary projectile is imbedded
in a heavy structure like a wing spar or engine block
the results from such a small amount of super
heated material would be neglegible.

Basicly if there is no fuel there will be no fire.
Even with the product of the Tutonic master race
the chances of a fire after hitting any aluminum
structure is un likely.

Many WWII era planes used a fair amount of magnesium
in their structures. Just a hit from a non explosive
projectile could ignite magnesium!
An incendiary round may help here.

Kurfurst__ I got a question, where do you get
the idea that the German stuff is always
that much better?
After all Germany lost despite fighting in their
home territory.
You claim sheer numbers defeated Germany?
I bet you claim Germany was simply overwhelmed by
vastly superior numbers. It's a typical NAZI cop-out.

The Allies held several technical advantages
that were very important in the 1940's.

RADAR, short wavelength RADAR vastly superior
to the German stuff.

Extremely high octane/PN avaition fuels, very important in a piston engined war.

RADAR proximity fuses for cannon and rockets

Very large piston engines and, more importantly
the bombers to mount them on.

Add to these (amongst many other) advantages
the Tutonic missfits were doomed to failure.

Note also that there was no combat over north America.....
While the US exported the war to Europe and kicked
in Hitler's door 4,000 miles away.

"Quantity has a quality all of it's own"
But the Allies had the qualitative advantage also.

When 1,200 B-17s and B-24s dropped 500lb bombs
on Berlin
I bet few worried that German explosives burned
a little hotter or faster.
I also bet more than a few were worried they could
do little against those P-51s that had flown a thousand miles
and were ready to fight over their capitol.

Sergio

Oh yes, Germany heald a clear lead in rocketry.
We got Wherner Vonbrauhn after the war ended, PRICELESS:-)

One more thing, Frank Whittle ran a gas turbine (Jet Engine)
3 years before any German did.

Ratsack
01-30-2006, 05:50 AM
In fairness to Isengrim (yes, I know, slap me) his first post in this thread was in response to a silly assertion that the U.S. alone in WWII could mass produce such high-quality ammo as the 0.50 incendiary with its barium etc etc etc.

People do get carried away, you know.

Ratsack

Kocur_
02-09-2006, 08:05 AM
I just got my copy of
"The Machine Gun Volume 1 - History, Evolution and Developement of Manual, Automatic and Airborne Repeating Weapons by George M. Chinn, Lieutenant Colonel, USMC".
What a GREAT book!

You can put on shelf with fairy tales any claims that US were totally satsfied with .50 and didnt want anythig else. As soon as 1936 USN decided to search for suitable aircraft cannon. Four types were initially considered: Danish Madsen, German Rhinemetall-Borsig and two Swiss guns: Solothurn and Oerlikon.
Develpement of Hispano was closely watched by American Navy AND Army attaches in Paris. On 27 february 1937 War Department authorised its attache to "ascetain prices and dates of delivery" of 20mm and 23mm Hispanos. On 27 july 1937 US War Department ordered a Hispano with certain amount of ammo, and that was ready for inspection on 15 december 1937. The gun and ammo arrived in US on 26 february 1938! The gun was tested by Army in Aberdeen Proving Ground, with Navy watching closely, from 21 june 1938 to april 1940 (sic!). Also 23mm Madsens were tested, even got Army designations 0.9'' T1 to T3!
Finally Hispano was chosen and contract between US Gov and Societe Francaise Hispano-Suiza was signed, by which 33 Hispanos were bought, 20 for Navy, 13 for Army plus option for buying all manufacturing rights withina a year for 425.000$ plus 100$ of royalty per gun made in US. Those 33 guns arrived Aberdeen Proving Ground on 20 february 1940.

On 11 april 1940 gen. Arnold, chief of USAAC wrote to US Army Chief of Ordnance suggesting him to take immediate steps to buy production rights to Hispano and buy 400 guns even before rights were bought. He also pointed out to standarise Hispano ASAP. Since original blueprints would not be available before buying rights to produce guns, Watervliet ****nal was ordered to prepare set of drawinigs basing of Hispanos in their disposal. Initial USAAC needs were estimated 456 guns and Navy's - 100, therefore 600 were planned for production to ensure surplus. But when it came to ordering production 1.202 guns were ordered in three companies. Finally Bendix Aviation Corp. was choosen as main US manufacturer of Hispano and order was placed there for up to 5.000 guns on 23 septeber 1940. And so something unprecedented happened: a major power, the USA, adopted a weapon of foreign origin and ordered its local production before licence to produce it was bought! I call it a serious rush, quite far from full satisfaction with .50!
Licence was finally bought on 6 november 1940. Initially 1.202 guns were ordered in Eclipse Machine Division of Bendix Aviation Corp. as M1., including 500 for US Navy. Before any were delivered, order was changed for modified version standarised as "Gun, Automatic, 20mm, AN M2 (Aircraft)". Bendix shippings begun in late 1941 and production capability of 1.300 per month was reached. Until early 1941 Army ordered production of 44.747 20mm cannons! Later on more companies joined production program including Oldsmobile (77.010 total), International Harvester (24.526 total) and... IBM (10.500 total)!
As it was said above in january 1942 British Hispano and its drawnings arrived in US. British asked to produce US Hispanos, i.e. M1 ans AN M2 with minor changes, which would make them identical to British Hispano Mk. II. Of those minor changes, one was rather major, i.e. lenght of chamber - that was shorter by 2mm in British gun. By then it was clear that US Hispanos suffered high misfire rate, which did not happen to British ones, even though both used the same ammo. But Army Ordnance enineers decided in april 1942 that British shorter chamber has no advantages over American and decided no to alter it...
But soon level of inreliability of US manufactured Hispanos forced new tests which lasted from june 1942 to january 1943. It was found that it is necessary to... shorten chamber by 1mm!! AN M2s with shorter chamber of International Harvester and Oldsmobile were tested in UK in july and august 1943, being mounted in Hurricane along with British Hispanos - reliability of all guns was found satisactory. All 35.955 US Hispanos with long chambers were declared UNSERVICEABLE!

So some conceited engineers of Army Ordnance who decided not to shorten US Hispano chamber according to British blueprints in january of 1942 so their reliability was far too low, delayed practical service of 20mm AN M2 by over a year. That forced US Hispano out of service as primary US fighters armament... And .50 AN M2 Browning was left as the only other thing in American inventory - and so legend of such a US "decision" begun...

allmenroder
02-09-2006, 08:20 AM
Originally posted by Sergio_101:


Oh yes, Germany heald a clear lead in rocketry.
We got Wherner Vonbrauhn after the war ended, PRICELESS:-)



Old Joke told by Werner von Brauhn:

It's 1965 and a Russian Cosmonaut and American Astronaut meet on the surface of the moon.

They walk up to each other and the American says "Hello Hans. Now we finally can speak German."