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chunkydora
06-30-2008, 08:56 PM
Why the heck did they USN change the corsair back to 50 cals in the D version after having 20mms on the C? 20mms seem like the perfect blend of rate of fire and destructive power against the manueverable and lightly armored Japanese planes.

In the European theatre, the 50 cals feel real good attacking german planes, but against the Japanese I'd rather have a real quick kill with the more destructive gun.

Sirrith
06-30-2008, 09:58 PM
I dont think I understand your post... you seem to be saying 20mm cannons would be better against jap planes while .50cal would be better against the german planes? Weren't the german planes better armoured than the japs?

And if this game is anything to go by, Id say the ROF from the .50cals and the amount of guns compared to the 20mm cannons were much more effective against the jap planes...

ImpStarDuece
06-30-2008, 10:05 PM
Originally posted by chunkydora:
Why the heck did they USN change the corsair back to 50 cals in the D version after having 20mms on the C? 20mms seem like the perfect blend of rate of fire and destructive power against the manueverable and lightly armored Japanese planes.

In the European theatre, the 50 cals feel real good attacking german planes, but against the Japanese I'd rather have a real quick kill with the more destructive gun.

The US had significant reliability problems with its version of the Hispano 20 mm cannon. The AN-M2 averaged approximately one stoppage for every fourty rounds fired (compared with the British Hispano Mk II, which averaged one stoppage for every 275 rounds fired). As a result, it was reluctant to install it in anything more than a minority of aircraft.

It should be noted that the SB-2C and the SB-W also carried the weapon into combat for the USN, as did some night fighter versions of the F6F.

chunkydora
06-30-2008, 10:37 PM
Originally posted by Sirrith:
I dont think I understand your post... you seem to be saying 20mm cannons would be better against jap planes while .50cal would be better against the german planes? Weren't the german planes better armoured than the japs?


Late war German planes were well armored but not very manuverable. So it is easy to keep hitting them with sustained 50 cal fire. But the Jap planes never even fly level at all in a fight if they can help it, which means I want to be able to destroy them with only a couple bullets from a longer range, not have to worry about sustained firing even for a second.

ImpStarDuece
06-30-2008, 11:40 PM
Originally posted by chunkydora:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Sirrith:
I dont think I understand your post... you seem to be saying 20mm cannons would be better against jap planes while .50cal would be better against the german planes? Weren't the german planes better armoured than the japs?


Late war German planes were well armored but not very manuverable. So it is easy to keep hitting them with sustained 50 cal fire. But the Jap planes never even fly level at all in a fight if they can help it, which means I want to be able to destroy them with only a couple bullets from a longer range, not have to worry about sustained firing even for a second. </div></BLOCKQUOTE>

The problem here is you are thinking like a WW1 pilot, not like a WW2 USAAF/USN aviator.

All the maneuverability in the world doesn't mean anything if your opponent can engage and disengage at will, due to superior speed and/or altitude performance.

Against fighters like the Ki-43/61/100 and the Zero, pilots in a Corsair or P-51/47/38 have the speed and rate of climb advantage (at speed) to dominate the fight completely. All the Japanese pilot can do is use his superior rate of turn to avoid attacks, without much hope of returning fire.

The German aircraft, while not as nimble in the horizontal as their Japanese counterparts, are generally the equal o(r better) of the US ETO aircraft in terms of speed, climb and performance at altitude (although the FW 190A series suffers above 24,000 ft). Similar conditions exist for the later Japanese aircraft, like the N1K2-J, Ki-84 and J2M, which have the speed and power to stick with the US fighters.

Personally, I'd rather the revers of your preferance: multiple, lighter, more rapid firing machine guns against the lighter, more nimble, more flammable Japanese aircraft and the heavier, slower firing, more destructive cannon against the German aircraft.

WTE_Galway
07-01-2008, 12:15 AM
When looking at real world equipment decisions remember its not a game and real world military rarely have the luxury of always having the best weapon for the job.

Why was the early war Panzer III fitted with a 37mm cannon when the much more effective 50mm was available? Because the ordinance people said we already have 37mm anti-tank guns and we want to use the same ammo in the new tanks. Similarly why wasnt teh p38 upgraded to Packard Merlins once they were available ? (Would have made an awesome p38)Because every P38 made would mean losing 2 x p51D's .. the engines were in short supply.

In the case of USAAF Marine Corp and USN aircraft, the US made 20 mm cannon was unreliable as mentioned above ... but in addition it would need special separate ammo.

Almost nothing else used 20mm guns. On the other hand the 0.50 cal Browning was fitted to aircraft, tanks, jeeps, half tracks, armored trains, personnel carriers, ships and even lugged by hand with numerous rifleman squads all over Europe and the Pacific. The 0.50 cal BMG was ubiquitous.

The decision process was probably something like "The 20mm cannon are probably 10-20%(made the figure up) better but at least 30% of the time they will be low on ammo whereas crates of 0.50 cal are everywhere"

Sirrith
07-01-2008, 12:24 AM
Originally posted by chunkydora:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Sirrith:
I dont think I understand your post... you seem to be saying 20mm cannons would be better against jap planes while .50cal would be better against the german planes? Weren't the german planes better armoured than the japs?


Late war German planes were well armored but not very manuverable. So it is easy to keep hitting them with sustained 50 cal fire. But the Jap planes never even fly level at all in a fight if they can help it, which means I want to be able to destroy them with only a couple bullets from a longer range, not have to worry about sustained firing even for a second. </div></BLOCKQUOTE>

but going by that logic, wouldn't it be much easier to bring down the less manoeuverable german planes with cannon rounds which have a lower ROF but more power? and for the jap planes, more manoeuverable would mean harder to hit, which means if you use the .50cal, you have a much higher chance of hitting them than with the slow firing cannons (and besides, since their armour is so light anyway, a few rounds of .50cal would be enough to bring them down)

chunkydora
07-01-2008, 02:24 AM
Originally posted by Sirrith:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by chunkydora:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Sirrith:
I dont think I understand your post... you seem to be saying 20mm cannons would be better against jap planes while .50cal would be better against the german planes? Weren't the german planes better armoured than the japs?


Late war German planes were well armored but not very manuverable. So it is easy to keep hitting them with sustained 50 cal fire. But the Jap planes never even fly level at all in a fight if they can help it, which means I want to be able to destroy them with only a couple bullets from a longer range, not have to worry about sustained firing even for a second. </div></BLOCKQUOTE>

but going by that logic, wouldn't it be much easier to bring down the less manoeuverable german planes with cannon rounds which have a lower ROF but more power? and for the jap planes, more manoeuverable would mean harder to hit, which means if you use the .50cal, you have a much higher chance of hitting them than with the slow firing cannons (and besides, since their armour is so light anyway, a few rounds of .50cal would be enough to bring them down) </div></BLOCKQUOTE>

Yes, obviously it would be easier to bring down the less manuverable Gerry planes with cannons than with 50 cals, but it's not hard with 50 cals if you come from above with speed. With the Japs, those little bastards can always break away and manuver around the instant they see a 50 cal tracer wiz by their cockpit. Only a couple 20mm shells (1 if in fuel tank) will destroy a zero or zeke or even ki-84 from 300m. So, if I could have the 20mm in the european theatre, that would be awesome, but I don't need it. Whereas in the pacific it makes my job much easier.

I know this does sound backwards, but don't worry if it is at least I am having fun in my mixed up fairy tale world. And it does work that way for me anyway.

BTW, thanks guys who provided info on unreliability of hispano cannon and lack of rounds lying around.

Erkki_M
07-01-2008, 07:04 AM
50 cals are easier to hit with, and carry more ammo (and more firing time). Against vertically superior but slow and weak planes(you have all the time in the world) its better have a reliable but less effective gun than an effective but highly unreliable. Against German planes you might get only that one guns solution. Better hit hard while you still can...

TinyTim
07-01-2008, 07:42 AM
Originally posted by chunkydora:
20mms seem like the perfect blend of rate of fire and destructive power against the manueverable and lightly armored Japanese planes.

...in IL2 1946 simulation that is.

But USN used .50cals instead of 20mm in real world.

Blutarski2004
07-01-2008, 09:04 AM
Originally posted by WTE_Galway:
When looking at real world equipment decisions remember its not a game and real world military rarely have the luxury of always having the best weapon for the job.

Why was the early war Panzer III fitted with a 37mm cannon when the much more effective 50mm was available? Because the ordinance people said we already have 37mm anti-tank guns and we want to use the same ammo in the new tanks. Similarly why wasnt teh p38 upgraded to Packard Merlins once they were available ? (Would have made an awesome p38)Because every P38 made would mean losing 2 x p51D's .. the engines were in short supply.

In the case of USAAF Marine Corp and USN aircraft, the US made 20 mm cannon was unreliable as mentioned above ... but in addition it would need special separate ammo.

Almost nothing else used 20mm guns. On the other hand the 0.50 cal Browning was fitted to aircraft, tanks, jeeps, half tracks, armored trains, personnel carriers, ships and even lugged by hand with numerous rifleman squads all over Europe and the Pacific. The 0.50 cal BMG was ubiquitous.

The decision process was probably something like "The 20mm cannon are probably 10-20%(made the figure up) better but at least 30% of the time they will be low on ammo whereas crates of 0.50 cal are everywhere"


..... A well reasoned, logically presented post is indeed a thing of beauty.

PanzerAce
07-02-2008, 03:11 AM
In the case of USAAF Marine Corp and USN aircraft, the US made 20 mm cannon was unreliable as mentioned above ... but in addition it would need special separate ammo.

Almost nothing else used 20mm guns. On the other hand the 0.50 cal Browning was fitted to aircraft, tanks, jeeps, half tracks, armored trains, personnel carriers, ships and even lugged by hand with numerous rifleman squads all over Europe and the Pacific. The 0.50 cal BMG was ubiquitous.


That isn't entirely true. ALL of the close in AA weaponry on ships larger than say an LCT were 20mm, which means that in all likelyhood, in the USN, there were MORE cases of 20mm available than there were cases of .50.


Why was the early war Panzer III fitted with a 37mm cannon when the much more effective 50mm was available? Because the ordinance people said we already have 37mm anti-tank guns and we want to use the same ammo in the new tanks.

I'm also going to question this. Based on what I know and have read about, it seems that it would have more been a case of "37mm is enough for all the tanks that we are planning to fight, so lets go with that which also allows us to carry more ammo".

berg417448
07-02-2008, 07:23 AM
Originally posted by PanzerAce:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
In the case of USAAF Marine Corp and USN aircraft, the US made 20 mm cannon was unreliable as mentioned above ... but in addition it would need special separate ammo.

Almost nothing else used 20mm guns. On the other hand the 0.50 cal Browning was fitted to aircraft, tanks, jeeps, half tracks, armored trains, personnel carriers, ships and even lugged by hand with numerous rifleman squads all over Europe and the Pacific. The 0.50 cal BMG was ubiquitous.


That isn't entirely true. ALL of the close in AA weaponry on ships larger than say an LCT were 20mm, which means that in all likelyhood, in the USN, there were MORE cases of 20mm available than there were cases of .50.

</div></BLOCKQUOTE>

But was it the same type 20mm gun and ammo as the aircraft used?

luftluuver
07-02-2008, 08:29 AM
Wasn't the 20mm Oelikons used on ships? Would the ammo be the same?

Skoshi Tiger
07-02-2008, 09:07 AM
Originally posted by luftluuver:
Wasn't the 20mm Oelikons used on ships? Would the ammo be the same?
I'm fairly sure the answer to the first questions is YES and the second definately NO!

I remember reading somewhere that the reliability problem with the US Hispanos was caused by an oversized chamber. The British found out that the problem could be solved by smearing the cases of the cannon rounds with grease (To take up the extra space in the chamber), but the US forces weren't allowed to to use the grease.

Xiolablu3
07-02-2008, 09:10 AM
Thats a good question, I dont know.

I doubt it, as the Hispano shells were seen to be more powerful and have a better trajectory.

I THINK the Hispano shells were bigger.

Xiolablu3
07-02-2008, 09:15 AM
http://www.quarry.nildram.co.uk/MCRel2.jpg

Left to Right :-

First 5 :- Not sure of the first one, can anyone help? , 15mm MG 151 (15x96), 20mm MG 151/20 (20x82), 20mm Ho-5 (20x94), 20mm Hispano (20x110)

2nd Group of four :- 60" T17 (15.2x114), .50/60 (12.7x114), 20mm M39/61 (20x102), 20mm Mk 11/12 (20x110 USN)

3rd Group of two :- 20mm FM-K 38 drill round (20x139), 20mm HS 820/Oerlikon KAD (20x139)

4th group of two :- 20mm and 23mm Madsen (20x120 and 23x106)


COmpare to Oerlikon family...

http://www.quarry.nildram.co.uk/Oe1b.jpg

Maybe if the Oerlikons on the Ships fired the Oerlikon 'S' round that is shown above, they may be compatible? They look identical to the Hispano round. What exactly were the Oerlikon guns on the US ships?

jimbolina-1
07-02-2008, 10:00 AM
hi all! my grandfather flew p39s and p40s early in the war and later did debreifings. hes still alive but last year got really sick. he had nothing good to say about the US decision makers higher up. i feel he always told the truth. he said almost all decisions were due to politics and fighting with each other. he said stuf like pilots of the p39 always got in and out the right side door as stuff on the left side caught on the parachute. he thought the original p39 was the greatest. the British had asked for it very early for the BOB but we wouldnt give it to them. then later we gave them and the Russians a really bad one. He said the original p39 did not spin any more than any of the other planes and the allison engine was meant to be flown as an interceptor for only a short time ane never left waiting inline to take off. you never read about all the P39s lost in the pacific because they ran out of gas. he said there were lots. he said losses were lied about both europe and pcific.

you never read about the pilots got out of their planes and threw up or **** their pants or asked and asked for a 20mm cannon in europe or pilots who broke their back or neck and died from a bouncing landing. dont read about all the US planes shot down by their own pilots. My grandfather said they shot at anything and couldnt tell the planes apart so he finally got the higher ups to take the paint off the planes. he said it had notheing to do with flying faster.

US pilots also asked for the 20mm cannon. My grandfather new the US and British cannons were bad so he let some US pilots put german cannons on which worked great. he got in lots of trouble he said and was told "US pilots fight with US made equipment" and at that time he said they had never decideed on what shell to use. He recommmened that they copy the german gun but was told that was against US policy.

At one time he said the US was going to fly the Spitfire as its main plane but pilots complained of no combat flaps so my grandfather recommended to change it. He was told it wouldnt hapen anyway as it would be "unAmerican" for us to fly Spitfires.

My granfathers normal saying: remember the ronson lighter (referring to the Sherman tank)

ImMoreBetter
07-02-2008, 10:11 AM
Read this. (http://www.quarry.nildram.co.uk/US404.htm)

Or at the very least the purple paragraph on top.

Ronbo3
07-02-2008, 11:44 AM
What was your grandfathers name and what unit did he fly with?

We did fly with Spitfires in the ETO/MTO...

Interesting comments from a veteran. Tell us more if you can.

jimbolina-1
07-02-2008, 05:42 PM
My grandfather told me not to tell his name or unit. He gets really mad when we ask him questions about the war. My uncle calls him a staff weenie which i guess isnt very nice. He did teach me how to fly the IL2 game a couple years ago. My idiot brother is Zebra.

My grandfather would not let me play on line until i could land on a carrier. He told me to get my brothers football helmet and put it on to be more like a real pilot. I crashed a lot of times but finally the first time i landed i bounce really high but stopped without crashing. I was real happy but my granfather said I was dead. i said no way. He hit me on the helmet with a frypan and said i had just broken my neck as my head would have hit the top of the canopy and killed me. He said the game isnt real and told me to remember that.

WTE_Galway
07-02-2008, 06:05 PM
"My granfathers normal saying: remember the ronson lighter (referring to the Sherman tank)"

Overall the sherman was an OK medium tank, the upgunned firefly sherman was on par with other mediums like the PZkpfw IV or T34 and in the desert it was better than the PZkpfw III. It was deadmeat compared to a heavy tank like the Tiger or Panther but you expect that.

Your grandfather has a point though ... you do have to wonder about what sort of idiots approved petrol engines in a tank instead of diesel.

Then Germans did the same thing in the Panther, presumably thinking the better armor would make petrol safe to use but they were just as wrong, panthers cooked as easy as Sherman's http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Skoshi Tiger
07-02-2008, 08:45 PM
Originally posted by Xiolablu3:
http://www.quarry.nildram.co.uk/MCRel2.jpg

Left to Right :-

First 5 :- Not sure of the first one, can anyone help? , 15mm MG 151 (15x96), 20mm MG 151/20 (20x82), 20mm Ho-5 (20x94), 20mm Hispano (20x110)

2nd Group of four :- 60" T17 (15.2x114), .50/60 (12.7x114), 20mm M39/61 (20x102), 20mm Mk 11/12 (20x110 USN)

3rd Group of two :- 20mm FM-K 38 drill round (20x139), 20mm HS 820/Oerlikon KAD (20x139)

4th group of two :- 20mm and 23mm Madsen (20x120 and 23x106)


COmpare to Oerlikon family...

http://www.quarry.nildram.co.uk/Oe1b.jpg

Maybe if the Oerlikons on the Ships fired the Oerlikon 'S' round that is shown above, they may be compatible? They look identical to the Hispano round. What exactly were the Oerlikon guns on the US ships?

I think designation of the round used by the US navy was 20x110RB (similar to the Oerlikon S round pictured) but if you compare it with the Hispano 20x110 round (top picture 5th from the left) you'll notice that the Oerlikon round has a rebated rim and the Hispano round is rimless.

Also the position of the shoulder is lower on the Oerlikon round and the shoulder is more sloped.

Theres a better picture on this web page

http://www.quarry.nildram.co.uk/an_introduction_to_collecting_20.htm the two rounds are on the extreme right.

I think it would be extremely dangerous to fire a RB round in a Hispano cannon!

WTE_Galway
07-02-2008, 09:04 PM
Originally posted by Xiolablu3:

Left to Right :-

First 5 :- Not sure of the first one, can anyone help? ,

Potentially the 1930s 'Short Solothurn'used in Lb 204 and S18-100 AT rifle


http://www.inert-ord.net/atrkts/50-55-20/index.html

http://www.jaegerplatoon.net/AT_RIFLES2.htm

Sama51
07-02-2008, 11:52 PM
Well I would be lead to believe that a large volume of .50 cal incendiary rounds fired at lightweight aircraft prone to leaking fuel would be far more efficient in that it is plenty of firepower to take down the desired target. I don't think there would be much to choose from in terms of what a 20mm or .50 cal round would do to a lightweight Japanese aircraft, a critical hit from either would more than likely bring it down, so you might as well choose the weapon that had the larger ammo capacity.