Author Topic: WW2 aircraft gun effectiveness (Read 4171 times)

flakbait · « **Reply #15 on:** February 23, 2001, 03:36:00 PM »

Here it is. I had to guess on the Mk-103 case length since no one seems to have that info on the web.

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Flakbait [Delta6]
Delta 6's Flight School
Put the P-61B in Aces High
"For yay did the sky darken, and split open and spew forth fire, and
through the smoke rode the Four Wurgers of the Apocalypse.
And on their canopies was tattooed the number of the Beast, and the
number was 190." Jedi, Verse Five, Capter Two, The Book of Dweeb

juzz · « **Reply #16 on:** February 23, 2001, 04:54:00 PM »

You guessed exactly right!

And the BK 37 was 263mm.

Tony Williams · « **Reply #17 on:** February 24, 2001, 01:23:00 PM »

I can't resist pointing out that scale drawings of all service automatic weapon cartridges 11.35-57mm, plus projectile weights/muzzle velocity data, plus comparative drawings of all WW2 aircraft guns 12.7-57mm and weight/dimension/performance data, are included in my book

Tony Williams
Author: Rapid Fire - The Development of Automatic Cannon, Heavy Machine Guns and their Ammunition for Armies, Navies and Air Forces.
Details on my military gun and ammunition website: http://www.users.globalnet.co.uk/~autogun/

brady · « **Reply #18 on:** February 24, 2001, 05:55:00 PM »

Mr. Williams:
Ya know what I just may buy your book yet...you have been so cool about posting relevant and helpful info I kinda feel indebted to you...

Brady

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[This message has been edited by brady (edited 02-24-2001).]

Tony Williams · « **Reply #19 on:** February 25, 2001, 02:42:00 PM »

Well, I enjoy passing on what I've learned - and learning more myself. The web is great for both!

Tony Williams
Author: Rapid Fire - The Development of Automatic Cannon, Heavy Machine Guns and their Ammunition for Armies, Navies and Air Forces.
Details on my military gun and ammunition website: http://www.users.globalnet.co.uk/~autogun/

funked · « **Reply #20 on:** February 25, 2001, 04:06:00 PM »

Dinger and Hooligan did a quantitative analysis of gun lethality. http://home.earthlink.net/~jayboyer/AHGun102.htm

The Breda 12.7 mm causes 78% as much damage per round as the Browning .50 cal, but it has only 57% as much initial kinetic energy. Looks like Breda HE is working just fine. Nothing is missing.

(PS MG 131 is a different story, looks like KE damage only)

(PPS MG 151/20 does 86% as much damage as Hispano, but with only 56% as much KE. Must be a lot of HE in those Mauser rounds!)

[This message has been edited by funked (edited 02-25-2001).]

bolillo_loco · « **Reply #21 on:** February 25, 2001, 09:22:00 PM »

sorry, I forgot where I found this pic of the rds that the americans used.

Tony Williams · « **Reply #22 on:** February 26, 2001, 01:32:00 AM »

Quote

Originally posted by funked:
(PPS MG 151/20 does 86% as much damage as Hispano, but with only 56% as much KE. Must be a lot of HE in those Mauser rounds!)
[/B]

That would be the M-Geschoss - it had 18-20g HE instead of around 12g for the Hispano.

Tony Williams
Author: Rapid Fire - The Development of Automatic Cannon, Heavy Machine Guns and their Ammunition for Armies, Navies and Air Forces.
Details on my military gun and ammunition website: http://www.users.globalnet.co.uk/~autogun/

juzz · « **Reply #23 on:** February 26, 2001, 05:19:00 AM »

Quote

Originally posted by Tony Williams:
That would be the M-Geschoss - it had 18-20g HE instead of around 12g for the Hispano.

I don't think that is true for the shell in AH.

Type 99 Mk 2, ShVAK(API) and MG 151/20(M-Geschoss) in relation to the Hispano shell:

% KE of the HS 20mm: 50% 54% 58%
% weight of HS 20mm: 99% 74% 71%
% damage of HS 20mm: 92% 86% 86%

Given those figures, I find it VERY hard to conclude that the MG 151/20 is firing shells with 20g of explosive in them...

1. If we assume that it's lower KE is reducing damage when compared to the Hispano, then why is it that the Type 99 can do more damage with even less KE?! Did the Japanese shells have more than 20g of explosive in them?

2. How does the ShVAK manage to do the same damage as the MG 151/20 with even less KE and no HE content at all? OK, maybe it's firing HE shells - but according to the link above they only contained 6.7g of explosive.

Vermillion · « **Reply #24 on:** February 26, 2001, 07:49:00 AM »

Hint Juzz, think mixed ammunition belts.

Look back at it again and consider the results if the MG151/20 included 1 mine shell in every 3 rounds with the others being AP or APHEI. The historical 1944 loadout for the western front.

Then it starts to make more sense.

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Vermillion
**MOL**, Men of Leisure

juzz · « **Reply #25 on:** February 26, 2001, 12:26:00 PM »

Looking at it your way: The Hispano fires a shell that simulates a half AP half HE ammo mix. In that case an individual shell delivers the equivalent of 6g of HE. If the MG 151/20 fires a shell simulating the 1 in 3 M-Geschoss ratio, then each individual shell delivers the equivalent of 5g of HE.

5/6 = 0.83

I think you could be right.

But doing it that way porks the damage results of individual rounds something aweful - a single hit of 20g of explosive must have more effect than 4 individual 5g hits methinks...

[This message has been edited by juzz (edited 02-26-2001).]

Zigrat · « **Reply #26 on:** February 26, 2001, 12:57:00 PM »

hispano using HE was very uncommon until the mk V fromwhat ive seen

Tony Williams · « **Reply #27 on:** February 26, 2001, 01:34:00 PM »

Quote

Originally posted by Zigrat:
hispano using HE was very uncommon until the mk V fromwhat ive seen

At first the RAF used plain steel projectiles because the original HE type had a fuze that was too sensitive, so it would detonate on the surface of the target and do little damage. This was soon fixed, however, and equal numbers of HEI and SAPI became standard long before the Mk V.

Tony Williams
Author: Rapid Fire - The Development of Automatic Cannon, Heavy Machine Guns and their Ammunition for Armies, Navies and Air Forces.
Details on my military gun and ammunition website: http://www.users.globalnet.co.uk/~autogun/

Hooligan · « **Reply #28 on:** February 26, 2001, 01:35:00 PM »

It is not as simple as adding up HE content.

HE type rounds ae better at causing structural damage.

AP type rounds are better at penetrating to a critical component.

Everybody used mixed ammunition beltings in their 20mm cannon for good reasons. AP and HE type shells both have advantages and disadvantages. An AP/I round is much better against pilot armor. An HE round is much better against a rudder or elevator. But the AH damage model doesn't really model these differences so we end up with "hybrid ammunition" and "hybrid results".

Hooligan

Zigrat · « **Reply #29 on:** February 26, 2001, 01:42:00 PM »

thx tony i defer to your expertise since you are obviously more learned on the subject than I

personally i have no problems with a2a gunnery in the game, its hispanos ability to bust PZIV that bothers me