Author Topic: MK108 damage photos, please ? (Read 11436 times)

straffo · « **Reply #105 on:** March 26, 2004, 03:06:43 PM »

Merci Henning

It proove that my German is not completly rotten ... but is almost dead

Karnak · « **Reply #106 on:** March 26, 2004, 03:20:11 PM »

Quote

Originally posted by VO101_Isegrim
`cos that`s the effect of two DUD MK 108 shells merely passing through. If you weren`t so dumb as you are, you could read that already.

I've seen a photo of a P-51D that was hit behind the cockpit by a dud MK108 shell. It simply made a small hole on each side of the fuselage.

To cause that much damage the MK108 shells had to have gone off. They may have gone off a little late, but they definately went off.

The MK108 did not guarantee a kill with a single hit. The German munitions are notably better than the Allied munitions, but be real here, we're not talking sci-fi blasters or some such.

Orka · « **Reply #107 on:** March 26, 2004, 03:55:52 PM »

Any way to proof visually wich weapon (30mm or 20mm) did those damage?

Batz · « **Reply #108 on:** March 26, 2004, 04:19:17 PM »

this image is captioned

http://pages.zdnet.com/vancell/sitebuildercontent/sitebuilderpictures/320blu4z.jpg

Quote

Attack by a Me 262 jet on this 320th Bomb Group B26 left wing is damaged by 20mm cannon. He had only enough fuel for one pass and the 26 made it home OK. It was a blessing that the Germans didn't develop and use the Me262 jets sooner. (Me262 pictures on Page 10) They were so fast... in and out of range before we knew it. They could zip through a bomber group and shoot down planes before we could react. Fortunately at that time they had a very limited range and had to return quickly. Our fighters waited for them near their airbases and shot them down while they were trying to land. War is hell... winning is everything.

So it unclear atleast in this image what round caused the damage. Unless someone has better info on the pic I am not sure what round caused the damage.

HoHun · « **Reply #109 on:** March 26, 2004, 04:43:07 PM »

Hi Orka,

>Any way to proof visually wich weapon (30mm or 20mm) did those damage?

No certain way.

Visual impression:

30 mm creates very big holes (50 x 50 cm^2 to 100 x 100 cm^2).

Often, the damage doesn't stop at a row of rivets but tears the skin right off so that it's peeled off and the rivet perforation is visible.

The holes often look "square" because all of the skin is torn off one or several rib/spar fields up to the point where the power of the explosion doesn't suffice to defeat the riveting.

(20 mm can make square holes, too, but only if it strikes small rib/spar fields, or control surfaces.)

30 mm can also deform the nose box of a wing completely, but you will only see that in ground tests because it will render the plane unflyable immediately. (The Luftwaffe destroyed a Hs 124 wing with one such 30 mm hit in a ground test.)

Often, a 30 mm hit takes out both the upper and the lower surface in the area of the hit.

This photograph matches most of the 30 mm effects I described above:

http://pages.zdnet.com/vancell/sitebuildercontent/sitebuilderpictures/320blu4z.jpg

Regards,

Henning (HoHun)

VO101_Isegrim · « **Reply #110 on:** March 26, 2004, 06:52:37 PM »

This picture was already posted in BW form. Read the caption.

http://www.x-plane.org/users/isegrim/Bordwaffen/B26dudMK108-1.jpg

VO101_Isegrim · « **Reply #111 on:** March 26, 2004, 07:00:38 PM »

Fritz Hahn: Deutsche Geheimwaffen

MINENGRANATEN

..So riB tin Flächentreffer an einer "Fortress"
tin Loch von einer GröBe 100X175 cm durch die Verwendung einer 30-mm- M.Gr. mit 72 g Sprengstoff. In einem anderen Falle wurde mit der gleichen Munition ein Treffer in den hinteren Rumpfteil des P-51-Jägers "Mustang" erzielt, mit dem Ergebnis, daB die Beplankung in über 3 m Längevöllig abgerissen wurde - die Maschine stürzte ah. "

Basically it notes two such cases, one being a single B-17 wing hit, that resulted the skin being torn of in an area of 1m x 1.75 m.
In the other case, the fusalage of a P-51 was hit, result being the skin being ripped of on a whole 3 m lenght - the plane went down.

VO101_Isegrim · « **Reply #112 on:** March 26, 2004, 07:23:43 PM »

Now what caliber was that ?

HoHun · « **Reply #113 on:** March 26, 2004, 07:27:07 PM »

Hi Isegrim,

>This picture was already posted in BW form. Read the caption.

Hm, quite interesting, but in my opinion the caption is in error.

A dud would only have made a (keyhole-shaped) entry and an irregular exit hole. (Only slightly more damaging than an amour-piercing round ;-)

Look at the way the panels are damaged and bent up. The corresponding picture of the wing's lower surface probably shows it even better, with the aluminium skin pushed out.

That can only be achieved by a rather violent explosion within the wing.

Just look at the size of the affected area - that must be something like 1.5 m x 0.5 m of skin that's blown out and without any structural function, and 0.5 m x 0.5 m at the underside.

That's a very serious structural hit, not enough to bring the plane down, but with another hit of this kind in the same wing ...

The second hit is an illustration of the statistic nature of terminal ballistics. It has hit the aileron, striking a rib directly, blowing off just 0.4 m x 0.4 m in a non-structural part so that it doesn't weaken the wing at all.

That's why 4 hits only bring down a heavy bomber with 50% probability - if for example it gets 2 or 3 hits in one wing, it's down. If it gets 1 in each wing, 1 in the fuselage, and 1 in some control surface, it might fly on.

It's a kind of roulette where any individual game is impossible to predict. The only certainty is that in the long run, the bank wins ;-)

Regards,

Henning (HoHun)

Karnak · « **Reply #114 on:** March 27, 2004, 01:46:16 AM »

Quote

Originally posted by VO101_Isegrim
This picture was already posted in BW form. Read the caption.

http://www.x-plane.org/users/isegrim/Bordwaffen/B26dudMK108-1.jpg

And we know the caption writer is a reliable expert because...?

butch2k · « **Reply #115 on:** March 27, 2004, 04:14:18 AM »

Yes Hohun i have the tables and the whole document, but i have to find it back within tenth of thousands of other pages... I had this sentence marked down a few months ago because it explained some of troubles encountered with non detoning MK108 shells.

SunTracker · « **Reply #116 on:** March 27, 2004, 06:33:19 AM »

A 20mm or 30mm shell would have tore that wing apart had it exploded.

MiloMorai · « **Reply #117 on:** March 27, 2004, 07:01:36 AM »

The USAAF noticed that a/c hit by heavier flak had more damage done from the nose end of the shell. Their conclusion was the velocity of the shell added to the nose end damage and detracted from the back(shell) end damaged.

From this one can conclude that the British tests were done with exploding a stationary 30mm shell in the fuselages.

VO101_Isegrim · « **Reply #118 on:** March 27, 2004, 08:56:31 AM »

HoHun, if that shell would gone off, I would except similiar damage as on other pcitures - HUGE surfaces being blown off. But in this case, it`s opened like with a tin can opener, forced out one side..

If you look at the picture that shows the bottom wing, the panels are forced open evenly in a clean line along the riveting, and notice it opened near the trailing edge. Why ? The shell passed through from below (typical 262 attack style BTW), punched a hole on the lower wing surface, and completely knocked out an upper panel, exited without exploding.
Then what happened was the airflow entering the hole in the wing top, and forcing open the lower panel like a door, effectively creating a neat ducting like as a radiator.

The hit at the ailerons obviously did not explode - you expect anything remaining of that fabric surface after mine shell?- not even the ribs are scratched, just some smashing movement on the left one, but that`s clean, too.

No signs of fragments and hundreds of tiny holes. All shining aluminium, no sign of burn, smoke, explosion... clean as in a laboratory.

The shell either didnt go off, or it was an incendinary MK 108 shell that did not contain any explosives - effectively being an AP in not hitting a fuel tank.

HoHun · « **Reply #119 on:** March 27, 2004, 10:56:28 AM »

Hi Isegrim,

>HoHun, if that shell would gone off, I would except similiar damage as on other pcitures - HUGE surfaces being blown off.

1.5 m x 0.5 m is HUGE :-)

>Then what happened was the airflow entering the hole in the wing top, and forcing open the lower panel like a door

Hm, the wing top is a low pressure area. Air pressure alone wouldn't suffice to rip aluminium off its rivets, either.

>The hit at the ailerons obviously did not explode - you expect anything remaining of that fabric surface after mine shell?

If it's fabric, this explains why little damage was done - fabric rips apart without allowing a really destructive pressure to build up.

>No signs of fragments and hundreds of tiny holes. All shining aluminium, no sign of burn, smoke, explosion...

They didn't use black powder, you know ;-) Mine shells have very little fragmetation effect, due to the thin-walled shells it's almost all blast.

Regards,

Henning (HoHun)