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bmoffa
04-28-2007, 07:56 AM
This is for the air war historians....

Why is it that most American fighters of WWII were not equipted with cannon? My experience (in the game) is that the cannon are much more effective that machine guns. Nearly all the Japanese, German and British fights had both cannon and machine guns. The only cannon equiped American fighters seem to be limited to the P38 and Corsair (C model 1945). The P39, P400, P63 were cannon equipted but I believe flown mostly by Russians.

bmoffa
04-28-2007, 07:56 AM
This is for the air war historians....

Why is it that most American fighters of WWII were not equipted with cannon? My experience (in the game) is that the cannon are much more effective that machine guns. Nearly all the Japanese, German and British fights had both cannon and machine guns. The only cannon equiped American fighters seem to be limited to the P38 and Corsair (C model 1945). The P39, P400, P63 were cannon equipted but I believe flown mostly by Russians.

VW-IceFire
04-28-2007, 08:03 AM
Pretty big long story...you'll get allot of different responses here no doubt.

Basic reasons include simplification of the supply chain, the relative effectiveness of the .50cal versus the targets that were intended, the ease of hitting a target with a stream of .50cal bullets, and in some cases I believe official distrust of the cannon designs.

Case in point, the Americans bought the same Hispano 20mm design from the French that the British did. The British did it earlier and were already getting rid of the bugs in the design when the Americans did the same but the Americans had to start all over again and ignored the British efforts (maybe they were shunned too...I don't know). So the 20mm wasn't ready for combat when the 6 gunned fighters were being cooked up.

In-game the .50cal is a very effective weapon (some will argue its not but I think their aim is off) but you need to ensure that you have your gun convergence set properly, you fire at the proper range, and that you get a solid and concentrated burst of fire on the target aircraft. This is easier with a 20mm has a single 20mm can cause a critical hit whereas you need several .50cal bullets to do the same...but in theory you can do better than the 20mm by getting successive strikes on the target aircraft. If you look at most of the spectacular gun camera footage you'll see that the plane that just was torn to pieces was one that had sustained a large amount of hits in a very short period of time and all in roughly the same spot.

Online its easier to use the 20mm with all of the lag and whatnot because its harder to lead a target properly and some older aircraft in the game are more resistant to machine guns because they lack detail in their damage model. Its not perfect but you can put it to good use. I find especially against the Japanese aircraft as you're often doing deflection shots on a turning aircraft ...its easier to lead those than with a 20mm.

bmoffa
04-28-2007, 09:14 AM
Thanks...

My original thought was that the Americans did not face much of a threat from medium and heavy bombers where cannon may have been more effective. Most of our fighters were having to deal with other figthers or light bombers. The other alies (Britts and Russians) were getting hit by a lot of medium bombers. Japan and Germany were also getting hit hard by heavy bombers which reqiure a lot of firepower to bring down.

VW-IceFire
04-28-2007, 09:24 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by bmoffa:
Thanks...

My original thought was that the Americans did not face much of a threat from medium and heavy bombers where cannon may have been more effective. Most of our fighters were having to deal with other figthers or light bombers. The other alies (Britts and Russians) were getting hit by a lot of medium bombers. Japan and Germany were also getting hit hard by heavy bombers which reqiure a lot of firepower to bring down. </div></BLOCKQUOTE>
Another excellent point...it seems that any canon development in the US was in developing the 37mm cannon which I think was intended to be used against heavy bombers that would, in theory, have the range to attack the US. They were all about continental defense in the 1920s and 1930s. The P-38 I believe was originally slated to be equipped with a 37mm, then a 23mm, and then ended up at the 20mm. The P-39 we know about with its heavy armament and design decisions made around that.

Most of the rest of the designs originated in the 1930s but were developed in the early 1940s once the war was already on (i.e. the P-51, the actual production P-47, etc.) and the canons seemed less useful.

Also interesting to note that the USAAF clung to the .50cal until well into the Korean war where the weapons effectiveness was starting to decline. Incidents where entire belts of ammo were fired at Mig-15s without producing a kill were apparently a catalyst to start developing a more potent weapon.

Fox_3
04-28-2007, 10:50 AM
Found some info about actual weight of fire in pounds for several aircraft in my library.

Hurricane IIC 650lbs/min
P47 (8 Gun) 652lbs/min
Mosquito II 760lbs/min
P38F 408.9lbs/min
Hs129 430lbs/min
Me110C5 339.4lbs/min
Mustang I 594.8lbs/min
Me210 431.2lbs/min

Roblex
04-28-2007, 11:01 AM
The RAF debated it for a while as well.

Douglas Bader was strongly against the idea of switching to cannon. He was comfortable with MG and did not trust the 'new' technology. He also felt the ground crew would find it hard to re-train.
Johnny Johnson argued for using Cannon on the basis that he could empty his whole MG into a 109 at close range and see it fly away but a single shell from that 109 could cripple his plane. Johnson won the argument.

Aaron_GT
04-28-2007, 11:31 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Douglas Bader was strongly against the idea of switching to cannon. He was comfortable with MG and did not trust the 'new' technology. </div></BLOCKQUOTE>

Bader was a Johnny-come-lately to the debate, though. The decision to move to cannon had been made in the mid 1930s, specifications issued, aircraft designed to it (the initial 4 cannon Hurricane and Spitfire designs had been sumbitted in 1937).

ImpStarDuece
04-28-2007, 04:47 PM
The US never adopted cannon for a serise of reasons:

Any calibre larger than .60 was considered artillery, and manufactured by the Artillery Board, to artillery tollerances, which are different from those of a fast firing aircraft cannon.

The two major .50 cal replacement programmes, the 20mm Hispano M1 and AN-M2 and the .60 cal (derived from the MG151/15) both failed due to technical reasons. The 20mm was never fully reliable, while the .60/T12 was produced in very small numbers (~300) but was never adopted due to reliability and mass production issues.

The USAAF never encountered serious heavy bomber opposition. So larger aircraft cannon were not required. The USN, on the other hand, saw the need for 20mm cannon much earlier on.

The .50 cal was considered adequate for fighter-on-fighter combat, if mounted in large enough banks. As US aircraft were large, powerful and heavy, the resulting high weight of such large banks of machineguns.

The installed weight of a .50 cal with 300 rounds of ammunition was around 125 lbs (of which the gun itself weighed just 68 lbs). 6 or eight guns will then weigh approximately 750 lbs or 1,000 lbs.

The installed weight of a 20mm Hispano Mk II with 120 rounds was around 220 lbs. So two (roughly equavilent fire power of 6 .50s) would weigh about 440 lbs and four (roughly equavilent fire power of 12 .50s) would weigh about 880 lbs.

If your mounting those banks on a relatively lightweight turn fighter (Yak, Spitfire, Bf-109) then they are a drag on performance. However, the same guns on a 9,000-12,000 lbs long range fighter with 1500-3,200 hp on the airframe, performance isn't going to be degraded as much.

The .50 was already proven to work, was in large scale production and had tens of millions of rounds of ammunition in storage. Switching to a new weapon would of complicated supply, production and servicing. A unitary .50 soution mean that a lot less work was needed for a weapon that was almost as effective.
There is an ntresting article hereThe Hispano-Suiza HS.404 20 mm Aircraft Gun in US Service (http://www.quarry.nildram.co.uk/US404.htm) on the problems the US had getting a relaible 20mm cannon into service.

To summarise the article:

The US recieved the British designs for the Hispano in early 1942.

US engineers then redesigned the cannon slightly, particularly the chamber. The redesign lead to an unacceptably high rate of stoppages which were never fully resolved during the war.

By January 1943 Oldmobile, Bendix and International Harvester had maunfactured approximately 56,400 20mm cannon and more than 40 million rounds of ammunition.

11,600 US manufactured guns were mounted in USN planes, mostly dive bombers and scout aircraft.

US made guns were supplied to the UK, but were never considered reliable enought to be mounted in aircraft. As an aside, the RAF had real problems in mid-late 1942 over Malta, with US manufactured ammunition not firing properly and jamming more frequently than British ammunition.

VMF-214_HaVoK
04-28-2007, 04:50 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Mosquito II 760lbs/min </div></BLOCKQUOTE>

OUCH!

WilhelmSchulz.
05-04-2007, 09:29 PM
If I belive corectly the US fighters that included the 20mm or 37mm where orignaly desingned as Ground attack fighters.

ake109
05-04-2007, 10:22 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VMF-214_HaVoK:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Mosquito II 760lbs/min </div></BLOCKQUOTE>

OUCH! </div></BLOCKQUOTE>

Me262 - 1898lbs/min

Using 650rpm per MK 108 and 0.73 lbs per shell.

Kocur_
05-05-2007, 01:48 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">To summarise the article:

The US recieved the British designs for the Hispano in early 1942. </div></BLOCKQUOTE>

That certainly happened. But it must be remembered that US bough license for Hispano back in 1940.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
US engineers then redesigned the cannon slightly, particularly the chamber. The redesign lead to an unacceptably high rate of stoppages which were never fully resolved during the war. </div></BLOCKQUOTE>

That unacceptably high rate of stoppages was there already! Shortening the chamber was a British way of reducing them, but US guys shortened it less, than British subscribed.


But to answer the original poster I'll just repost what I wrote before:

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 and were seriously considered for adoption.
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 A rsenal 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...



To above let me add, that in late thirties the Army had its own fast firing aircraft cannon programme. T1, T2 and T3 were made in .9 caliber (23mm). The T1 was long recoil weapon, thus very slow. T2 and T3 closely resembled Oerlikon cannons and though had decent for that caliber) ROF of 450rpm but were very heavy, reaching 109kg.

Abbuzze
05-05-2007, 02:32 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ImpStarDuece:


The installed weight of a .50 cal with 300 rounds of ammunition was around 125 lbs (of which the gun itself weighed just 68 lbs). 6 or eight guns will then weigh approximately 750 lbs or 1,000 lbs.

The installed weight of a 20mm Hispano Mk II with 120 rounds was around 220 lbs. So two (roughly equavilent fire power of 6 .50s) would weigh about 440 lbs and four (roughly equavilent fire power of 12 .50s) would weigh about 880 lbs.
</div></BLOCKQUOTE>

You are correct, but the Hispano was a very big and heavy gun the figures would be diffent with a smaller and lighter desing like the MG151/20. Of course with less kinetical energy, but with a mine shell...

Kocur_
05-05-2007, 02:59 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">You are correct, but the Hispano was a very big and heavy gun the figures would be diffent with a smaller and lighter desing like the MG151/20. </div></BLOCKQUOTE>

Well here is the "verybigness" http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif of Hispano compared with MG 151/20 (AN M2 below...). Compare dimensions of receivers, not just first impression.
http://img407.imageshack.us/img407/6831/hs404vsmg151zk2.th.jpg (http://img407.imageshack.us/my.php?image=hs404vsmg151zk2.jpg)

Long - yes, but also very slim (plus a magazine on top or much smaller belt feed), so could protrude far from say a wing, but didnt take much space inside. MG 151 was also quite wide (belt feed trays stretching on the sides). As far as weight is concerned British Hispano Mk.II was exactly 8kg heavier than MG151/20 (50 vs. 42).

HellToupee
05-05-2007, 03:47 AM
did they ever get the plans for the hispano V?

Aaron_GT
05-05-2007, 06:29 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">If I belive corectly the US fighters that included the 20mm or 37mm where orignaly desingned as Ground attack fighters. </div></BLOCKQUOTE>

No. The P-38 and P-39 (The former designed for a 23mm cannon, the latter a 37mm cannon) were designed as bomber interceptors. Most of the other aircraft that received cannon (20mm) were designed as general purpose fighters or interceptors for Army or Navy (P-51, F4U, F6F, F8F, etc.) and only gained cannon later. There were a few US aircraft with large calibre weapons specficially designed for ground attack which were not produced, but these typically mounted 75mm weapons. The B25 mounted such a gun, and one was proposed for the A26.

P.S. Very informative post, Kocur.

jarink
05-05-2007, 05:38 PM
Just imagine.....

http://upload.wikimedia.org/wikipedia/commons/4/46/P-51A.jpg

http://forums.ubi.com/images/smilies/784.gif

polak5
05-05-2007, 06:08 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Roblex:
The RAF debated it for a while as well.

Douglas Bader was strongly against the idea of switching to cannon. He was comfortable with MG and did not trust the 'new' technology. He also felt the ground crew would find it hard to re-train.
Johnny Johnson argued for using Cannon on the basis that he could empty his whole MG into a 109 at close range and see it fly away but a single shell from that 109 could cripple his plane. Johnson won the argument. </div></BLOCKQUOTE>

was Johnson a Canuck? J/W

berg417448
05-05-2007, 08:25 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by polak5:


was Johnson a Canuck? J/W </div></BLOCKQUOTE>

No. He did command a unit of Canadians for a while though.

Manu-6S
05-06-2007, 02:56 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Roblex:
The RAF debated it for a while as well.

Douglas Bader was strongly against the idea of switching to cannon. He was comfortable with MG and did not trust the 'new' technology. He also felt the ground crew would find it hard to re-train.
Johnny Johnson argued for using Cannon on the basis that he could empty his whole MG into a 109 at close range and see it fly away but a single shell from that 109 could cripple his plane. Johnson won the argument. </div></BLOCKQUOTE>

I think that all both the armaments were effective.

IMO cannons were better for "hunters", who search their kills by ambushing and need a single and rapid fire solution; in this way even with an inferior plane you can win (look at our HurriIIc performance). And bombers destroyers too, obviously.

Instead, IMHO, MGs are more suitable to escort planes who KNOW that they will fight with advantage against planes that, in part, are not targetting them but bombers.
In that way you need a good and user-friendly armament for deflection shooting to DAMAGE enemies, allowing your bombers to do their job.

Now, speaking about ingame, yesterday on Spitsvs109s I was really surprised when the .50cal of a B25 at my far 2 literally splitted my K4 in two pieces, with one single shot.

And after I took a P51C in the next map I was witness of the power of this armament: hunting around at 6000m I found 2 bf109s who tried to evade my first attack by turning. In both cases I made 1 sec deflection shots and dewinged the first and splitted the latter (the way I was splitted by B25 fire). http://forums.ubi.com/images/smilies/blink.gif

I really can't understand the moans about ingame .50cal.

HellToupee
05-06-2007, 03:47 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
I really can't understand the moans about ingame .50cal.
</div></BLOCKQUOTE>

probly has something todo with the 190 and spitfire hater pictures in ones sig.

Manu-6S
05-06-2007, 03:54 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by HellToupee:
probly has something todo with the 190 and spitfire hater pictures in ones sig. </div></BLOCKQUOTE>

http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

I don't see the connection... Did you read my account? 2 sec of fire = 2 bf broken http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

horseback
05-06-2007, 12:45 PM
I've always suspected that bomber/attack aircraft's defensive gunners get more 'bang for the buck' in terms of the damage they can do vs similar caliber fixed armament in the flyable fighters. I can't take anything done with them seriously, period.

However, if you catch someone within 30m of your convergence with the .50, Bad Things Will Happen To Them. The problem is that this effect dissipates a little too rapidly (IMHO) the farther one's target is from convergence; it appears to me that the fact you're hitting with the bullets from one gun, then you're probably hitting with the rounds from its' one to three mates on that wing as well doesn't factor in proportionally to the damage model.

cheers

horseback