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General Forums => Aircraft and Vehicles => Topic started by: BaDkaRmA158Th on April 04, 2007, 07:39:02 PM

Title: P-39 37mm Vs. Yak's 37mm.
Post by: BaDkaRmA158Th on April 04, 2007, 07:39:02 PM
What are the number's in muzzle velocity between the P-39 & yak9T?
Did the p-39's 37mm ever carry Ap rounds?
And is the p-39's 37mm the SAME one the Pt boats use?

Thank you. :)
Title: P-39 37mm Vs. Yak's 37mm.
Post by: Karnak on April 04, 2007, 07:50:48 PM
Now that I am home I can help a bit.

Oldsmobile M-4 37mm cannon:
Calibre: 37x145R
Projectile type/weight: HE/608, AP/753
Muzzle velocity: HE: 610m/sec, AP: 556m/sec
Muzzle energy Joules: HE: 113,000, AP: 116,000


NS-37 37mm cannon:
Calibre: 37x195
Projectile type/weight: HEI/735, AP/760
Muzzle velocity: HEI: 900m/sec, AP: 880m/sec
Muzzle energy Joules: HEI: 298,000, AP: 294,000


As you can see, the NS-37 is much more powerful.
Title: P-39 37mm Vs. Yak's 37mm.
Post by: Ack-Ack on April 04, 2007, 08:32:53 PM
the 37mm Oldsmobile cannon was also a POS and not very reliable.


ack-ack
Title: P-39 37mm Vs. Yak's 37mm.
Post by: Karnak on April 04, 2007, 08:34:37 PM
True Ack-Ack, but that won't be modeled in AH so I didn't mention it.

What was it, sually after the second round was fired it jammed?
Title: P-39 37mm Vs. Yak's 37mm.
Post by: BaDkaRmA158Th on April 04, 2007, 08:35:21 PM
hey thank you karnak :aok

Do you know if the Pt boats 37mm is the same also?
"it may help to use the 37mm on pt boat to get a good handle on how the 37mm on the p39 might be "if its added" :)
Title: P-39 37mm Vs. Yak's 37mm.
Post by: tedrbr on April 04, 2007, 11:40:26 PM
After seeing those numbers, I'd rather take the export version of the P-39 with the 20mm Hispano (60 rds to the 37mm's 30 rds) cannon and .50s'

P-39D-1 and P-400 - Lend-Lease version, Hispano 20 mm cannon (60 rds) instead of the 37 mm cannon (30rds)

P-39D - 245 lb of additional armor, self-sealing fuel tanks. Armament increased to 1x 37 mm cannon (30 rounds), 2x .50 cal (200 rounds/gun) and 4x .30 cal (1,000 rounds/gun) machine guns.

or P-39Q with wing .30's replaced with .50's.... which Soviets often removed anyways.

Any way you look at it though, you don't have much ammo to spray and pray (outside of the BB .30's).  You'll need to set up your shots flying a P-39.
Title: P-39 37mm Vs. Yak's 37mm.
Post by: BaDkaRmA158Th on April 04, 2007, 11:52:52 PM
Correct, that is what the .30's are there for,you fire them to get the guns on target,then hammer down with the .50's
The 37mm would be hard to hit a target with,the 20mm version should be much better.

We would probably get all major versions tho.
Ither way i am still locked for the 39's vote.
Title: P-39 37mm Vs. Yak's 37mm.
Post by: Ack-Ack on April 05, 2007, 03:19:17 AM
Quote
Originally posted by tedrbr
After seeing those numbers, I'd rather take the export version of the P-39 with the 20mm Hispano (60 rds to the 37mm's 30 rds) cannon and .50s'

P-39D-1 and P-400 - Lend-Lease version, Hispano 20 mm cannon (60 rds) instead of the 37 mm cannon (30rds)

P-39D - 245 lb of additional armor, self-sealing fuel tanks. Armament increased to 1x 37 mm cannon (30 rounds), 2x .50 cal (200 rounds/gun) and 4x .30 cal (1,000 rounds/gun) machine guns.

or P-39Q with wing .30's replaced with .50's.... which Soviets often removed anyways.

Any way you look at it though, you don't have much ammo to spray and pray (outside of the BB .30's).  You'll need to set up your shots flying a P-39.


The Cactus Air Force had some P-400s as well as some P-39s and those that flew the P-400 preferred that version as it had a reliable 20mm cannon and was lighter than the P-39 with the 37mm Oldsmobile cannon.

ack-ack
Title: P-39 37mm Vs. Yak's 37mm.
Post by: Karnak on April 05, 2007, 10:27:22 AM
I would be very surprised if the 20mm version was added.
Title: P-39 37mm Vs. Yak's 37mm.
Post by: tedrbr on April 05, 2007, 11:09:58 AM
Quote
Originally posted by Ack-Ack
The Cactus Air Force had some P-400s as well as some P-39s and those that flew the P-400 preferred that version as it had a reliable 20mm cannon and was lighter than the P-39 with the 37mm Oldsmobile cannon.

ack-ack


But "light" not a real good thing in the P-39's ammo compartment.  A P-39 being ferried usually had to carry ballast in place of armor, and the spent rounds from the 37mm were kept on board, not ejected, to maintain some ballast.  
Otherwise, the Airacobra had a stability problem, IIRC.  But certainly the Hispano was far more reliable than the Olds.

Russians would remove the Q's .50 wing pods and gain some agility out of it, but there you really limit your ammo capacity, compared to many LW planes in the game.  P-39 will require some skills to do well in it.

Will be interesting if it wins.
Title: P-39 37mm Vs. Yak's 37mm.
Post by: Tilt on April 05, 2007, 12:21:30 PM
Pokryshkin had his P39N trigger re wired to fire all the guns at once.......this became common practice in his regiment and may have been copied across 9GIAD's P39Q's later.

Interestingly I have found no copy relating to the VVS swapping the P39's guns for  Russian equivilants. Which is strange because with the exception of the Hispano's the Russian equivilent is usually superior. I suppose this may also be linked to the CoG problem. (More research is required)

Edit

Except of course to say that it seems that most VVS Pilots had all P39 wing mounted guns removed
Title: P-39 37mm Vs. Yak's 37mm.
Post by: 68slayr on April 06, 2007, 01:31:14 AM
is the yaks 37mm good for GV killing?
Title: P-39 37mm Vs. Yak's 37mm.
Post by: Tilt on April 06, 2007, 07:10:47 AM
I think the NS37 (9T) and NS45 (9K) were the long barrelled recoil loaded versions using 37x195 and 45x185 calibre  respectively. (ref Tony Williams)

The NS37 could have loaded AP/760 ammo.(as kweassa states above)

However it is clear that the heavy ammo Yaks were introduced to bring down LW medium bombers (Ju88 etc) as the VVS had studied the effectiveness of lighter calibres and statistically shown that under combat conditions fatal blows to enemy bombers were more likely from the 37mm gun.

As such they were loaded with HEI rounds for the 37mm and HE for the 45mm.

Actually the M4 also had an API round available to it the AP/753
Title: P-39 37mm Vs. Yak's 37mm.
Post by: Karnak on April 06, 2007, 09:58:18 AM
Kweassa stated no such thing..  :p

And yes, I used Tony Williams as my reference too.
Title: P-39 37mm Vs. Yak's 37mm.
Post by: Tilt on April 06, 2007, 10:38:32 AM
Sorry its a "K" thing you two have such similar verbalage I get you mixed up all the time.
Title: P-39 37mm Vs. Yak's 37mm.
Post by: Tony Williams on April 07, 2007, 12:41:46 PM
The pic below (from the Ammunition Photo Gallery on my website) shows the 37x145R for the US M4 next to the 37x195 for the NS-37. The difference in power is pretty obvious.

(http://www.quarry.nildram.co.uk/WW2aircart2.jpg)

The NS-37 gun was also a long way ahead of the M4. Although heavier (170 kg vs 96) it was slimmer and faster-firing (250 rpm vs 140). The main advantage of the M4 is that the long-recoil action would have given it a softer recoil, much easier to cope with than the NS-37's more violent kick.

However, by the end of WW2 the Russians had the N-37 with the shorter, lower-velocity 37x155 cartridge. This still had a higher muzzle velocity than the M4 (690 m/s vs 610) weighed about the same (103 kg) yet fired at 400 rpm. This saw most combat use in the MiG-15 in the Korean War.

Tony Williams: Military gun and ammunition website (http://www.quarry.nildram.co.uk) and discussion forum (http://forums.delphiforums.com/autogun/messages/)
Title: P-39 37mm Vs. Yak's 37mm.
Post by: Puck on April 07, 2007, 02:20:35 PM
Quote
Originally posted by 68slayr
is the yaks 37mm good for GV killing?


Soft targets only.  No AP rounds were ever made for it.
Title: P-39 37mm Vs. Yak's 37mm.
Post by: Tony Williams on April 07, 2007, 07:21:59 PM
Quote
Originally posted by Puck
Soft targets only.  No AP rounds were ever made for it.

They were made, because they were issued to the Il-2M3.  

The Yak-9T was intended as a fighter, so would have carried HE (I can't swear that it wasn't issued with AP, but I've seen no evidence for it).

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