Author Topic: The great TankBuster...the Spit? (Read 1770 times)

flakbait · « **Reply #75 on:** April 03, 2001, 09:38:00 AM »

I've done some digging through old archives and can't find a copy of that article. Plus the publisher's web site doesn't have a DNS entry. Lucky me!! As I've stated above, the only case I know of (based on limited resources) is a one inch penetration difference with an angle change of 30º. Calculating the actual penetration depends entirely on the round used and armor type hit. Different metals have different denseities. If we break the basic theory down we get the amount of penetration difference.

7.5º = .25 inch
15º = .5 inch
22.5º = .75 inch
30º = 1 inch
37.5º = 1.25 inch
45º = 1.5 inch
52.5º = 1.75 inch
60º = 2 inch
67.5º = 2.25 inch
75º = 2.5 inch
82.5º = 2.75 inch
90º = 3 inch

Unfortunately this is just me guessing. As the ramp angle of the plate changes so does the penetration. So while breaking the basic theory down says a 3 inch penetration difference at 90º we know that can't be true. Why? 90º is perfectly flat, and directly in line with the projectile's flight path. I've been doing some hunting for calculating the penetration of a round algebraically, but can't find anything. It seems I'll have to yell at a ballistics expert to find this one out.

-----------------------
Flakbait [Delta6]
Delta Six's Flight School
Put the P-61B in Aces High
"With all due respect Chaplian, I don't think God wants to hear from me right now.
I'm gonna go out there and remove one of His creations from this universe.
And when I get back I'm gonna drink a bottle of Scotch like it was Chiggy von
Richthofen's blood and celebrate his death."
Col. McQueen, Space: Above and Beyond

Tony Williams · « **Reply #76 on:** April 03, 2001, 12:59:00 PM »

OK guys, I've done some more digging and turned up official German penetration data for two MG 151/20 rounds, the AP and APHE.

The AP penetration is as follows:

24mm/100m/90 degrees
12mm/100m/60 "
8.5mm/100m/30 "

23mm/300m/90 "
11.5mm/300m/60 "
8mm/300m/30 "

15mm/600m/90 "
7mm/600m/60 "
4mm/600m/30 "

And for the APHE:

17mm/100m/90 degrees
12mm/100m/60 "
7mm/100m/30 "

15mm/300m/90 "
10mm/300m/60 "
7mm/300m/30 "

There are figures for other loadings but these are probably the most relevant. Note that the fall-off with striking angle is not the same; this depends very much on projectile design.

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/

Pongo · « **Reply #77 on:** April 03, 2001, 01:34:00 PM »

The way I was shown to calcualte the effect of slope on armour thickness was like this
90 /slope * actual thickness

So a 45 degree slope doubles the thickness of armour and a 30% slope triples it.
The effect of deflection is not factored in.

Sturm · « **Reply #78 on:** April 03, 2001, 01:44:00 PM »

So from this we should be able to kill Ostwinds at a level plane. Try it now in a FW and you will meet your maker every time. Do to the ostwinds light shielding in its turret which was not greater then 23mm we should be able to open them up rather easily.

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Sturm6 StaffelKapitän
JV44 Platzschutzstaffel
Airfield Defense Squadron

Nashwan · « **Reply #79 on:** April 03, 2001, 02:37:00 PM »

Quote

Originally posted by pzvg:
Nashwan, Why? would the increase in velocity affect the rounds ballistic performance versus sloped armor in any way?

The increase in veocity would apply to al guns of course, but if you are trying to work out penetration you need to know the muzzle velocity of the round. For that you have to add the velocity of the plane to the published (static) muzzle velocity of the gun.

GRUNHERZ · « **Reply #80 on:** April 03, 2001, 04:41:00 PM »

Tony can you e-mail that info to HTC?

Tony Williams · « **Reply #81 on:** April 04, 2001, 05:34:00 AM »

Quote

Originally posted by GRUNHERZ:
Tony can you e-mail that info to HTC?

Who he?

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/

GRUNHERZ · « **Reply #82 on:** April 04, 2001, 05:44:00 AM »

HTC is HiTechCreations, the developers of this simulation.

Apparently our MG151/20 doesn't model any sort of AP ammo or the AP modeling is very much weaker than the data you posted.

Perhaps if the developers saw your information, especially with your expertise in the field, they would fix the innacuacy.

CJ · « **Reply #83 on:** April 05, 2001, 03:45:00 PM »

For any of the cannon and heavy machine gun rounds, how much does the extra ~500 ft/sec of the aircraft speed closing with the tank increase the penetration of the round? The kinetic energy increases approximately 40%, so would penetration increase this much too? This could somewhat reduce the effects of sloping armor. Someone else said that the tests were done with non movement between the cannon and the test target, but were any tests done with adding 500+ ft/sec to the round's velocity? I'm not saying that the Hispanos or MG151's or anything should be better or worse than it is, just a factor that sometimes gets overlooked in these posts.

CJ

Tony Williams · « **Reply #84 on:** April 06, 2001, 12:59:00 AM »

Yes, the extra speed of the aircraft was a factor. 250 mph would add around 110 m/s. However, penetration would not increase in proportion to muzzle energy; it would be linked more closely to momentum (a much less dramatic increase).

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/

chisel · « **Reply #85 on:** April 06, 2001, 01:33:00 AM »

There was one Hell of a thread on the WW2online board discussing this very thing many months ago about 5-10 pages long!!

"Could a 20mm Hispanoe kill a tank?" or some such IIRC

Prolly got zapped but Somebody must have saved it?

BTW: how quickly would the round in question bleed off that extra 500fps?

mauser · « **Reply #86 on:** April 06, 2001, 03:35:00 AM »

While digging around old posts here for comments on "Panzer Elite," I came across an old post from Pyro when he spoke about introducing ground vehicles. The gist of it I think was that GV's would be a secondary thing wrt the sim, i.e. although the GV's aren't half baked, HTC chose not to go that deep into modelling GV's. So the GV's probably won't be "fixed" because they server their secondary purpose in the sim.
Btw, anyone got a copy of Panzer Elite they want to part with? Tanking in AH got me mildly interested, and Panzer Elite supposedly had the best modelling/AI of them all... little low on the graphics, but that's fine with me.

mauser

funked · « **Reply #87 on:** April 06, 2001, 05:35:00 AM »

Mauser I understand their perspective and I actually agree. But they could fix some of the glaring stuff in the GVs without adding much complexity. Make the Panzer immune to 20 cal and lower weapons, make the Ostwind turret vulnerable to weapons of all calibers, replace the GE Minigun on the Panzer with an MG 34, and 99% of the player gripes about vehicles will vanish.

Tony Williams · « **Reply #88 on:** April 08, 2001, 09:26:00 AM »

Quote

Originally posted by chisel:
BTW: how quickly would the round in question bleed off that extra 500fps?

Well it was only 110m/s or so, which is equivalent to 150-180m added distance.

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/

Author Topic: The great TankBuster...the Spit? (Read 1770 times)

Sturm

chisel

funked