Author Topic: P38J - 14 rockets? (Read 1677 times)

killnu · « **Reply #30 on:** October 08, 2005, 09:34:33 PM »

Quote

NS37 had 230% the firepower, 150% the muzzle velocity and 160% the rate of fire of the P-39's M4 cannon.

firepower...37mm doesnt equal 37mm? not sure what you mean by firepower i guess...when i think of firepower, i think of size of the projectile, maybe i am all wrong.

increase in muzzle velocity is going to change the trajectory? i really not sure of that. i can see where it would, but does it change it that much?

so the NS37 was more reliable than the olds 37mm because of all the stuff you posted?

Kweassa · « **Reply #31 on:** October 08, 2005, 10:08:50 PM »

I guess it simply means the Russian NS-37 37mm was a much more superior heavy cannon than the M4 37mm initially equipped on the P-39s. While a direct comparison would be out of context the Soviets seem to very much like their P-39s equipped with M4.

As for why the P-38 didn't use more Hizookas and less .50s.. well.. maybe its just a 'US thing'? I seem to recall most US pilots were much more accustomed to multiple .50s and didn't really like the setups with one or two cannons as major firepower. Maybe that weighed to be a much larger problem than the actual difficulty of producing such a platform...?

Karnak · « **Reply #32 on:** October 08, 2005, 11:51:51 PM »

killnu,

Why do you think the trajectory of the Hispano is so much better than that of the MG/FF? They're both 20mm cannons after all.

20 X 80RB MG/FF 20mm cannon: 600 m/sec muzzle velocity
20 X 110 HS404 20mm cannon: 880 m/sec muzzle velocity

37 X 145R M4 37mm cannon: 610 m/sec muzzle velocity
37 X 195 NS-37 37mm cannon: 900 m/sec muzzle velocity

The faster it is going when it leaves the barrel the flater the trajectory will be. Rate of deceleration will depend on the drag coefficient of the round, but the initial flight trajectory is dependant on muzzle velocity. Take the Bf109E-4 or A6M2 and do deflection shots against the drones offline and then do deflection shots with the Spitfire Mk V or Hurricane Mk IIc. The Bf109E has MG/FF cannon and the Spit and Hurri have Hispano Mk II (HS404) cannon. That'll give you an idea of how different the trajectories are based on about a 300 m/sec muzzle velocity difference.

As to the firepower, that depends on the explosive content of the round. It varried a lot within a given diameter depending on the design of the shells. The Germans in particular were good at loading a lot more explosive into a round.

What we are getting at is that if you base the M4 37mm's possible behavior on the NS-37 of the YAK-9T you are going to be very disappointed. It will be much harder to hit with and will do less damage when it does.

killnu · « **Reply #33 on:** October 09, 2005, 12:06:47 AM »

ok, got it. but was it more reliable than M4? or they both as succeptable to jamming, etc...? what i read about the P38 not using the Old37mm was that it was unreliable. I made the obviously incorrect assumption that the yaks 37mm was similiar to the olds37mm in more ways than it is.

Karnak · « **Reply #34 on:** October 09, 2005, 12:15:42 AM »

The NS-37 was used fairly widely by the Soviets. I don't know how reliable it was, but the usage suggests that it was at least fairly reliable.

I would like to have the Il-2 armed with two NS-37 cannon and loaded with AP ammo. It would be a much better tank killer than our current 23mm VYa armed Il-2.