MK108 30mm Ballistics from Rechlin and Rheinmetall-Borsig

[Babalonian]

the 410 will be a brick IMO, think twin engined fw190 

Twin long-nosed fw, if it makes any difference to you.   

[bustr]

On another forum I think ww2.aircraft.net back around 2009, HoHun, Tony William's colleuge, explained that the British performed tests on about 10 spit and 10 Bleni. 30% were destroyed the rest considered possible destroyed or unservicable.

The explosive preassure and thermodynamic nature of the blast took the path of least resistance.

It skined the area forward of the initial penetration becasue it hit at a shallow angle and sheared up the skin. Any shallower and it would have bounced along the surface of the wing. The fuse body probably penetrated the skin allowing some of the blast to enter to the structure by the apparent blast path. The skin looks like it separated as a panel on the left side with the rivets giving way. While the right side sheared. The pilot may have been able to get a bird with that damage home to either bail over his feild or belly in. The blenhiem photo where they hung the MK108 30mm inside of the fuslage and detonated it was never the norm for how the M-Gesch 500m\sec contacted allied aircraft.

The picture of the B17 on the Internet that had the waist area bulged out from the detonation, the 30mm entered through the open gunners window and detonated inside. If you find all of the pictures related to that B17 you will see that the blast damage from all sides bulges outward. If the round had struck the fuslage and detonated, blast damage woud have been focused in a path away from the detonation point like with the spitfire skin in the YouTube video.

There are some B17 damage photes out there where the blast removes about a 3-5 foot area of aluminum skin becasue the round exploded on contact with the surface. Some photos show the flap or aleron assembly blown off. Alot of 30mm damage photos show the damage consistant with attacking from the rear 180 cone of approch. It was never consistant if the detonation would penetrate the structure or damage the surface. This would be consistant with 500m\sec intitial velocity and how close the round was fired. I think that spitfire test the round was fired from realtively close with a shallow angle of contact. I wonder if they performed testing at contact angles closer to 90 degrees and if the RAF report can be found.

The rational behind the Mineshell was even the explosion at skin contact would be structuraly damaging and did not need to penetrate like with an API or SAPI. Neither the 3 cm M-Gesch. 108 Ausf.A m. Zerl. or 3 cm M-Gesch. L.spur m. Zerl.(day tracer) / 3 cm M-Gesch. .Gl.spur m. Zerl.(night tracer) have the duplex time delayed contact detonator. They both used the ZZ1589 B contact detonator. Penetration will be solely a factor of the distance of travel, angle of contact, time of firing pin travel in response to fuze tip casing crush, and or the fuze structure cap perforates the skin at detonation followed by explosive in gassing. D&D 24 sided hit dice anyone?

There is a B17 picture on the internet of a 30mm hit on the right hand top elevator seam which subsiquently the blast was channeled/reflected into the rear gunner position effectively removing it from the bomber.

Depending on the angle of contact, contact location and blast reflective\channeling surfaces, or distance of intitial firing at the aircraft, you will get very different damage outcomes. Simply loosing a control surface member or loosing a large area of skin is consistant with what can be expected. At that point, unless your aircraft is a bomber, you should be out of the fight worrying about being able to bail out or get home. Not continuing to perform substandard aerobatics.

As I stated earlier the current damage model is not granular enough to do justice to the 30MM Mineshell.

1.} You loose some small peice and keep performing substandard aerobatics...
2.} kill the pilot...
3.} no damage...
4.} all damage...

But, by no means was it always a one shot kill in the real war. Contact with it could reasonably be expected to ruin your day by the RAF testing. 30% destroyed the rest probable or unservicable on landing. At the least 3-5 feet of skin paneling should be gone or turned into origami forceing you to fly funny. You can say it was an All or Nothing experience. If the round contacts your structure and explodes something gets really malformed or busted. Other wise, it missed or low angle deflected off and no go boom.

[Ardy123]

Bustr,
Its important to note that the skin provided some structural strength to the wing. Loosing that skin not only ruined the effectiveness of the wing, it made it weaker.

[bustr]

Depending on the angle of attack and blast vectoring the skin will separate leaving the sub structure reasonably intact.

The final analysis of the British testing was that the probables or unservicables after landing could possibly get home but in a questionable flying state. By the time of the testing they had extensive experience with what pilots could fly home with after damage occured. The airframes are stronger than we give them credit. Even in WW1 as long as too much damage or upper surface fabric was not removed from the wings pilots got their kites home or landed. Airframe designers knew the stresses they were building for in WW2 and were not dummies just becasue they were restricted to slide rules instead of computers.

Pilots simply could not continue to engage in substandard aerbotic displays but, have to make all haste in DDing out of the fight zone for home or a safe area to bail. I've seen 90 degree contact damage photos where the blast punches about a 3foot  hole through the rudder or wing with out much damage to anything else. In those cases some skin perforation happend on contact which allowed focused ingassing(instantaious over pressure) of the explosion to act like an instantanious high pressure plasma torch.

You see the same pictures but smaller holes from 20mm. So extrapolating that to the fuslage, yes with a fighter probably a one shot kill of the pilot due to high pressure ingassing(instantaious over pressure) in a small container. A bomber, probably crew member hamburger. But, the shallower the contact angle the more likely you will just skin the airframe along with throwing micro sharpnel around. Most shooting in WW2 was from the rear 180 cone.

The fluid dynamics, thermodynamics, and instantainious over pressure of contact explosions against malliable structures may not be programed into the Mineshell profile in the game. Our current Mineshell damage profile suggests that: Point of Contact - no damage, some damage, all damage. Nor do we see (90degree contact)3foot holes in our wings, or (low angle contact)5foot skinned areas after a detonation. Nor do we see channeling of over pressure gasses from the point of contact by the airframe structure into an adjacent area unexpectadly obliterating it from the aircraft. At the least from point blank to the rear gun position of any bomber we should see that positions structure completely removed from the airframe and the ride along gunner dead.

The statements attributed to the 3 cm M-Gesch that 1 round will kill a fighter and 5 a bomber by Richlen and Rheinmetall-Borsig were from ideal static test results on aliied airframes and after action reports of ideal firing cricumstances. In between everything else happened more often becasue of the general firing position from the 180 degree rear cone. Ideal fighter to fighter is 50m-100m hitting the fuslage at a 90 degree for a full blast penetration. Ideal for a bomber is 5 rounds in the same area in the waist which cuts the fuslage in half. It took two 262 firing at the same time to get the 5 rounds into the waist on a B24 which was cut it in half over germany or 5 rounds from a close by static stand. Shades of the RAF's testing under ideal conditions........