50 cal lethality .......

[F4UDOA]

Is there any A/C in AH modeled with M3 20 Mil??

[Pei]

http://www.geocities.com/CapeCanaveral/Hangar/8217/fgun/fgun-pe.html

I believe this might help

[Pei]

F4UDOA:

We don't have any a/c that is fitted with an M3 20mm (though the Hispano MKVs on the Tempest are similar). As I understand it M3 were the standard armament of USN/USMC a/c post war.

[Tony Williams]

Originally posted by Pei
http://www.geocities.com/CapeCanaveral/Hangar/8217/fgun/fgun-pe.html

I believe this might help

Yep, Emmanuel's tables are as good as you are likely to find (I'd hope so - I supplied him with much of the information )

Since then, I have been doing some more research into specific loadings of particular ammunition, so if you have any detailed questions I'll try to answer them.

Tony Williams
Military gun and ammunition website: http://www.quarry.nildram.co.uk
Discussion forum at: http://forums.delphiforums.com/autogun/messages/

[Pongo]

A 2 second burst from an average(5%) pilot using a 4 hispano battery will land  4.3 20mm rounds. The same pilot will land 8 50 Cals from a 6*50  mount. The Hispanos have much greater after hit damage potential.
That disparity in leathality is well modeled in AH.

[Hooligan]

Gun Type         PW (g)   MV (m/s)   ROF rnds/min   KE/sec (Kj/s)   Projectile type   
                        
US Browning .50 cal         42.9   928   800   246   M8 AP/I   
US 20mm AN-M2         165.1   799   650   571   M75 AP   
                        
GE 13mm MG 131synchronized         38   710   800   128   AP/I   
GE 20mm MG FF         115   585   520   171   HE/I   
GE 20mm MG 151         115   705   700   333   HE/I   
GE 20mm MG 151         92   785   700   331   HE (Mine) for comparison   
GE 20mm MG 151 synchronized         115   705   630   300   HE/I   
                        
IT Breda 7.7mm         11.3   730   800   40   ?   
IT Breda 12.7mm synchronized         36.7   760   630   111   ?   
                        
Sov 12.7mm UBS         48   840   900   254   AP   
Sov 20mm ShVAK         96   800   800   410   AP/I   

Notes:  

All rates of fire are the Aces High rates of fire.  For what it is worth, Aces High ROF data is a very close match to data from the archival sources that I have.

US data is from a Bureau of Ordnance manual on the M8 AP/I round and from a 20mm data chart that Pyro posted on this BBS.  

German data is from a German 20mm ordnance manual and Reichlen pamphlets.

Italian data is from Gustin’s page.

Soviet data is from “The Machinegun, Vol. II” by George Chin, US Ordnance Bureau.  20mm ShVak’s apparently came in a variety of barrel lengths.  A longer barrel will impart a higher the muzzle velocity for a particular round.  I believe that my figures probably represent a 42Kg ShVak.  Most characteristics of this gun i.e. muzzle length, projectile mass, propellant mass and muzzle velocity are generally close to those same characteristics of the Mg151 firing similar rounds.  I have seen muzzle velocities between 750m/s and 860 m/s listed for rounds of this weight.  AH may model the longer/higher velocity ShVaks or my assumptions may be wrong.  Nonetheless the presented data should be useful for comparative purposes.

Hooligan

[hazed-]

wow thanx all for response for info

[Pongo]

Originally posted by hazed-
wow thanx all for response for info

And dont discount Tonys book hazed. Its not a text book. Its a history of these kinds of weapons.. very good book that I bet you would like and learn alot from.

[SpinDoc1]

Now how come our Mk108 30mm doesn't do this... like it did during an RAF test on a grounded Blenheim?

Jason

[Urchin]

Yea, in AH it just blows the tail clean off.  I'd say we've got it pretty good.

[Vermillion]

Seriously, I use to have that calculation for every gun on Emmanuels page and several others, and posted on my old website.

However, about a year ago, my webhosting service moved to a new server (mysteriously losing all my webpages) at about the same time I had my HD crash on my personal machine.  Which resulted in the loss of the only copies of the data.  I never bothered to reconstruct all the old webpages, since others had done a good job over the years with similar data.

It pretty easy to do with a spreadsheet, Tony's book or Emmanuels webpage.  Its the simple Kinetic energy equals one half the mass times the velocity squared equation, times the number of rounds on target in a minute.

But the major problem with it, is that it neglects the explosive content of the cannon rounds.

A nice indicator of effectiveness, but it does have its drawbacks.

[Tilt]

Originally posted by Vermillion


But the major problem with it, is that it neglects the explosive content of the cannon rounds.

A nice indicator of effectiveness, but it does have its drawbacks.

If I rem correctly your old web page also had some calcs for converting the weight of explosive powder to an additional kinetic component............  I think you called it "chemical energy"

[illo]

Originally posted by Hooligan
Gun Type         PW (g)   MV (m/s)   ROF rnds/min   KE/sec (Kj/s)   Projectile type   
                        
US Browning .50 cal         42.9   928   800   246   M8 AP/I   
US 20mm AN-M2         165.1   799   650   571   M75 AP   
                        
GE 13mm MG 131synchronized         38   710   800   128   AP/I   
GE 20mm MG FF         115   585   520   171   HE/I   
GE 20mm MG 151         115   705   700   333   HE/I   
GE 20mm MG 151         92   785   700   331   HE (Mine) for comparison   
GE 20mm MG 151 synchronized         115   705   630   300   HE/I   
                        
IT Breda 7.7mm         11.3   730   800   40   ?   
IT Breda 12.7mm synchronized         36.7   760   630   111   ?   
                        
Sov 12.7mm UBS         48   840   900   254   AP   
Sov 20mm ShVAK         96   800   800   410   AP/I   

Notes:  

All rates of fire are the Aces High rates of fire.  For what it is worth, Aces High ROF data is a very close match to data from the archival sources that I have.

US data is from a Bureau of Ordnance manual on the M8 AP/I round and from a 20mm data chart that Pyro posted on this BBS.  

German data is from a German 20mm ordnance manual and Reichlen pamphlets.

Italian data is from Gustin’s page.

Soviet data is from “The Machinegun, Vol. II” by George Chin, US Ordnance Bureau.  20mm ShVak’s apparently came in a variety of barrel lengths.  A longer barrel will impart a higher the muzzle velocity for a particular round.  I believe that my figures probably represent a 42Kg ShVak.  Most characteristics of this gun i.e. muzzle length, projectile mass, propellant mass and muzzle velocity are generally close to those same characteristics of the Mg151 firing similar rounds.  I have seen muzzle velocities between 750m/s and 860 m/s listed for rounds of this weight.  AH may model the longer/higher velocity ShVaks or my assumptions may be wrong.  Nonetheless the presented data should be useful for comparative purposes.

Hooligan

AH 109E-4 guns should be MG/FFM not MG/FF. Also ammunition was mainly mine rounds. 109E-3 was last 109 to have MG/FF AFAIK.

[devious]

So, are explosive shells / the fabled M-Geschoss modelled ? If so, how ? Giving them an additional KE bonus seems oversimplified, they explode and don't go faster....

Just asking.

The Mk108 kills just fine, so it seems it has a bonus destructivity - given it's low kinetic energy, I shouldn't be able to rip wings off planes or pound engines dead with a single round, which I do.

[Fishu]

Devious,

that 30mm shell hits the wing and the wing is more or less gone..
If for some reason the wing isn't ripped off, the wind resistance aka drag will do it and rip off the seriously damaged wing.


75mm HE cannon shell would be fine against lighter tanks with 30mm or less armour.
152mm HE will tear apart even the Tigers.
So why can't 30mm with low kinetic energy tear apart a wing..