Author Topic: Differences between the "Type 99" and MG-FF?  (Read 1526 times)

Offline HoHun

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Differences between the "Type 99" and MG-FF?
« Reply #30 on: April 29, 2002, 01:52:59 AM »
Hi Tony,

>When the RAF tested the German 20mm against the Hisso, they concluded that although the M-Geschoss was highly effective when it exploded in a confined space (eg a wing box), the Hisso would penetrate deeper and stood more chance of inflicting structural damage.

Removing the load-bearing skin of a stressed-skin airframe actually means structural damage :-)

I fact, the entire point of a mine shell is that it's unecessary to penetrate deeply or hit any special component to inflict strucural damage.

A fighter's fuselage was a valid target area for mine shells, too, by the way. The space confined within was small enough for mine shells to be effective.

Regards,

Henning (HoHun)

Offline Tony Williams

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Differences between the "Type 99" and MG-FF?
« Reply #31 on: April 29, 2002, 06:37:57 AM »
True enough, Henning, although it did depend on the construction. The older types (especially fabric covered, like the Hurricane and Wellington) were relatively unaffected by blast damage. There were more subtle differences between different types of metal construction too, depending on the details of the structural design.

The main advantage in blowing off bomber wing sections seems to have been not so much that the target was immediately brought down, as that the aerodynamic penalty meant that the bomber was unlikely to make it back home. And of course, the fuel tanks were in the wings and fire was by far the greatest bomber-killer. This is why the Luftwaffe were showing a marked interest by the end of the war in HEI, with the emphasis on the I, in conjunction with hydrostatic fuzes.

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.quarry.nildram.co.uk
Military gun and ammunition discussion forum:
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Offline Tilt

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Differences between the "Type 99" and MG-FF?
« Reply #32 on: April 29, 2002, 07:37:07 AM »
Quote
Originally posted by HoHun
Hi Tony,A fighter's fuselage was a valid target area for mine shells, too, by the way. The space confined within was small enough for mine shells to be effective.


Although comparing different calibres with different ROF........ the Russians seemed to find this as well when comparing the  20mm and 37mm Yak versions......... in terms of fighter kills per round.

As Tony's book shows the 37mm packed a much bigger explosive punch..........

Tilt
Ludere Vincere

Offline HoHun

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Differences between the "Type 99" and MG-FF?
« Reply #33 on: April 29, 2002, 02:08:21 PM »
Hi Tony,

>The older types (especially fabric covered, like the Hurricane and Wellington) were relatively unaffected by blast damage.

Sure, but except for the RAF, all major air forces could afford modern stressed-skin aircraft ;-)

>The main advantage in blowing off bomber wing sections seems to have been not so much that the target was immediately brought down, as that the aerodynamic penalty meant that the bomber was unlikely to make it back home.

Killing a target immediately is exactly what mine shells were made for.

The stressed skin is a soft target, but it's just as important for the structural integrity of an aircraft as the rigid wing spar. You don't need to pierce the heavy main spar - it's just as effective to tear off the light alloy skin. With a large hole, you don't even need to touch the spar - the wing will twist itself off under the aerodynamic loads. And while the main spar is hard to hit, and hard to damage, the skin is easy to hit and easy to damage.

Slow bomber deaths result from component damage from penetrating projectiles (or by collateral damage from mine shells). Quick bomber deaths result from structural failure, brought about by extensive destruction of the target's load-bearing aluminium skin.

Regards,

Henning (HoHun)

Offline Karnak

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Differences between the "Type 99" and MG-FF?
« Reply #34 on: April 29, 2002, 02:39:38 PM »
HoHun,

It seems to me that you put to little stock in the ability of a round to penetrate into the aircraft.  Blowing a hole in the fuselage skin is useful and does weaken the structure, but not nearly so as breaking the spar or punching a 20mm+ hole in the engine or pilot.

Tony,

I will definately be picking up you next book.
Petals floating by,
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             As she remembers me-

Offline Tony Williams

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Differences between the "Type 99" and MG-FF?
« Reply #35 on: April 29, 2002, 03:05:07 PM »
Quote
Originally posted by Karnak
HoHun,

Tony,

I will definately be picking up you next book.


Glad to hear it. Please form an orderly queue :)

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.quarry.nildram.co.uk
Military gun and ammunition discussion forum:
http://forums.delphiforums.com/autogun/messages/

Offline HoHun

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Differences between the "Type 99" and MG-FF?
« Reply #36 on: April 29, 2002, 03:36:01 PM »
Hi Karnak,

>It seems to me that you put to little stock in the ability of a round to penetrate into the aircraft. Blowing a hole in the fuselage skin is useful and does weaken the structure, but not nearly so as breaking the spar or punching a 20mm+ hole in the engine or pilot.

I think I should clarify that I'm not talking about my personal opinion, but about German WW2 research here. Mine shell development was started because of the proven ineffectiveness of hole-punching. One has to punch that hole just in the right place, after all.

A typical WW2 fighter might present as little as 10% critically vulnerable surface - but with mine shells, as much as 90% of the target area can be hit effectively. That's a big lethality advantage for the mine shells, obviously.

But that's just for illustration - the Luftwaffe invented and perfected the mine shell, and they built most of their air-to-air weaponry program around it. Evidently, both research and combat experience had totally convinced them of the mine shell's effectiveness.

Not that there's no merit in punching holes - but the Luftwaffe was thinking in terms of weapons systems.

Regards,

Henning (HoHun)

Offline HoHun

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Differences between the "Type 99" and MG-FF?
« Reply #37 on: April 29, 2002, 03:39:59 PM »
Hi Tony,

>Glad to hear it. Please form an orderly queue :)

I'll join behind Karnak so we can talk shop while we wait ;-) Will your new book be available from Amazon (like "Rapid Fire" was)?

Regards,

Henning (HoHun)

Offline Karnak

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Differences between the "Type 99" and MG-FF?
« Reply #38 on: April 30, 2002, 01:05:23 AM »
HoHun,

I'm not talking about AP 20mm shells.  I'm talking about the difference in an HE shell that explodes on, or near, the surface like the German Mine shells compared with an HE shell that explodes deeper in like the British Hispano HE rounds.

Both explode, but I wouldn't entirely dismiss the effectiveness of the British HE rounds.  It seems to me that you are thinking of them as simple AP rounds.
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Offline Tony Williams

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Differences between the "Type 99" and MG-FF?
« Reply #39 on: April 30, 2002, 01:27:58 AM »
Quote
Originally posted by HoHun
Hi Tony,

I'll join behind Karnak so we can talk shop while we wait ;-) Will your new book be available from Amazon (like "Rapid Fire" was)?

Regards,

Henning (HoHun)


I expect so, but we haven't got around to talking about that yet.

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.quarry.nildram.co.uk
Military gun and ammunition discussion forum:
http://forums.delphiforums.com/autogun/messages/

Offline Tony Williams

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Differences between the "Type 99" and MG-FF?
« Reply #40 on: April 30, 2002, 01:32:52 AM »
Quote
Originally posted by Karnak
HoHun,

I'm not talking about AP 20mm shells.  I'm talking about the difference in an HE shell that explodes on, or near, the surface like the German Mine shells compared with an HE shell that explodes deeper in like the British Hispano HE rounds.

Both explode, but I wouldn't entirely dismiss the effectiveness of the British HE rounds.  It seems to me that you are thinking of them as simple AP rounds.


The German shells had a fuzing problem (too fast-acting) until sometime in 1941, when delay fuzes were introduced. However, even after that the greater kinetic energy and stronger construction of the Hisso shells allowed them to penetrate further into the plane's structure (assuming the fuze didn't go off too soon).

The Hisso shell generated less blast pressure but threw larger and heavier fragments around, which had a kinetic energy of their ownand copuld inflict serious damage depending on what they hit.

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.quarry.nildram.co.uk
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Offline HoHun

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Differences between the "Type 99" and MG-FF?
« Reply #41 on: April 30, 2002, 01:41:18 AM »
Hi Karnak,

>I'm not talking about AP 20mm shells.  

Oh, sorry for the misunderstanding then.

>I'm talking about the difference in an HE shell that explodes on, or near, the surface like the German Mine shells compared with an HE shell that explodes deeper in like the British Hispano HE rounds.

There mine shells had a delayed action fuze that made them blow up within the airframe. This was imperative to get the full blast effect - the shell has to explode in a confined space for the greatest destructiveness.

I think it were the Hispano HE rounds that had the fuzing problems leading to detonation on the surface, not the mine shells.

The greater penetration capability probably gave the Hispano some capability against "hard" components (though a 10 g charge won't blow off the main spar, anyway).

However, with only half the explosive content, it was less than half as effective as the mine shell in destroying the aircraft's load-bearing skin. During mine shell development, it had been recognized that it was essentional not just to blow sections of skin off the aircraft, but to make the damage jump the riveting of the attacked section to weaken the adjacent sections. In that way, a larger charge could do much heavier damage than a smaller charge as it destroyed the load-bearing properties of a much larger skin area. (In the end, this lead to the 30 mm mine shell, of course.)

To get back on the topic of the MG FF: While mine shells were most effective against an aircraft's wings, their effective target area wasn't limited to it. There's one interesting Battle of Britain era photograph that shows a Spitfire which took a single MG FF/M hit into the empty rear fuselage. The entire tail got "soft" and was bent to the point of wrinkling the aluminium skin. Though the pilot got the aircraft down safely (no doubt with great care to avoid any hard manoeuvres), the plane was beyond repair and had to be written off.

Regards,

Henning (HoHun)

Offline illo

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Differences between the "Type 99" and MG-FF?
« Reply #42 on: April 30, 2002, 02:15:55 AM »
Yes, Mgeschoss relies solely on blast effect, not much fragments to talk about. It was very thin walled projectile with maximum amount of HE.

Offline Tony Williams

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Differences between the "Type 99" and MG-FF?
« Reply #43 on: April 30, 2002, 08:05:23 AM »
Quote
Originally posted by HoHun

I think it were the Hispano HE rounds that had the fuzing problems leading to detonation on the surface, not the mine shells.
 


Yes they did, but according to British tests of the German ammo I have seen, the German 20mm HE had exactly the same problem until about 1941.

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.quarry.nildram.co.uk
Military gun and ammunition discussion forum:
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Offline Tony Williams

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Differences between the "Type 99" and MG-FF?
« Reply #44 on: April 30, 2002, 08:06:31 AM »
Quote
Originally posted by illo
Yes, Mgeschoss relies solely on blast effect, not much fragments to talk about. It was very thin walled projectile with maximum amount of HE.


Not quite - it did produce fragments, but they were small and high-velocity. In the right circumstances they could do alot of damage themselves.

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.quarry.nildram.co.uk
Military gun and ammunition discussion forum:
http://forums.delphiforums.com/autogun/messages/