P-39 Tank Busters (1 Viewer)

[MIflyer]

I think that we have all heard the old untrue story about the 37 MM in the P-39 being used by the Soviets to bust tanks, but in the book "Turning the Tide" about the USAAF in the Med, another related mistake is mentioned.

After they Kasserine Pass debacle the USAAF and RAF decided they'd better get their act together in the theater and, among numerous other changes, issued a directive that P-39's would no longer be used for tank busting. Henceforth the P-39 used for ground attacks would only be for strafing troops and soft-sided vehicles.

I guess that not everybody saw the memo that someone should have produced on that subject. When the RAF first came up with the Hurricane IID. equipped with two 40MM cannon for tank busting, the USAAF bragged that the 37MM in the P-39 could do the job. But the RAF did testing using an actual captured German tank and found that the 37MM in the P-39 could not penetrate German armor. The 37MM in the P-39 was not even the equivalent of the 37MM used in the Stuart tank. It was designed only for air-to air use and had not nearly the required velocity to punch through armor.

One P-39 pilot in the Med said that the 37MM did a nice job of clearing the decks of barges, but nobody talked about the round penetrating significant armor.

 

[Shortround6]

The 37MM in the P-39 was not even the equivalent of the 37MM used in the Stuart tank.

The 37mm in the P-39 had about 1/3 the muzzle energy of the 37mm in the Stuart tank.
The 40mm in the Hurricanes had almost double the energy. In large part because it used 1130g projectile instead of a 753g one.
The Stuart used 870g projectile and fired it at 884m/s instead of 556m/s.
The P-39's gun did have an AP projectile, It just wasn't very good.

 

[SaparotRob]

Well, we finally found something wrong with the P-39.

 

[Thumpalumpacus]

I think that we have all heard the old untrue story about the 37 MM in the P-39 being used by the Soviets to bust tanks, but in the book "Turning the Tide" about the USAAF in the Med, another related mistake is mentioned.

After they Kasserine Pass debacle the USAAF and RAF decided they'd better get their act together in the theater and, among numerous other changes, issued a directive that P-39's would no longer be used for tank busting. Henceforth the P-39 used for ground attacks would only be for strafing troops and soft-sided vehicles.

I guess that not everybody saw the memo that someone should have produced on that subject. When the RAF first came up with the Hurricane IID. equipped with two 40MM cannon for tank busting, the USAAF bragged that the 37MM in the P-39 could do the job. But the RAF did testing using an actual captured German tank and found that the 37MM in the P-39 could not penetrate German armor. The 37MM in the P-39 was not even the equivalent of the 37MM used in the Stuart tank. It was designed only for air-to air use and had not nearly the required velocity to punch through armor.

One P-39 pilot in the Med said that the 37MM did a nice job of clearing the decks of barges, but nobody talked about the round penetrating significant armor.

I know an expert who can look this over.

 

[hw97karbine]

Apparently the 37mm M80 armor piercing round could go through an inch of armor at 500 yards, definitely insufficient for medium and heavy tanks past the first years of WWII.

One thing to consider about airborne tank-busters is that performance is generally better than a ground mount, the shell comes in from a higher angle negating any slope advantage and it has a higher effective muzzle velocity because it is being fired from a moving platform, but that would not have made any difference in this case. The BK 3,7 fitted to German aircraft like the Junkers Ju 87 G could achieve around twice the armor penetration firing tungsten-cored HVAP rounds.

 

[Frog]

Well, we finally found something wrong with the P-39.

Erratum : a less effective quality.

 

[MIflyer]

Apparently the 37mm M80 armor piercing round could go through an inch of armor at 500 yards, definitely insufficient for medium and heavy tanks past the first years of WWII.

I recall reading where a RAF unit in the BoB had a hunk of damaged Spit fuselage and decided to rig up a test to show their pilots how effective the armor they had installed was.

And the round went right through it like it wasn't even there. And that was a .303!

I wonder what the Germans thought when they ran into the .50 cal in US airplanes.

As I have mentioned before I read of a case where an USMC Wildcat dove on 3 Zeros that were shooting up a PBY near the 'Canal. They had borrowed the visiting Admiral's PBY for a torpedo attack on the IJN and wanted to give it back in nice condition. So he just dove on the Zeros, spraying lead, trying to scare them off. And scare them off he did; they all beat feet. It was not until well after the war that he he found he had shot down all of them. In each case just one .50 cal round hit a good fatal spot, a fuel tank, an oil line and an engine. None of them made it back to Lae.

Of course in WW2 for tank attacks they seized upon rockets as the answer. A quantity of 5 inch HVAR was donated by the USN and went into action on P-47's soon after D-Day.

 

[special ed]

"Borrowed" you say? Those damned Marines.

 

[MikeMeech]

I recall reading where a RAF unit in the BoB had a hunk of damaged Spit fuselage and decided to rig up a test to show their pilots how effective the armor they had installed was.

And the round went right through it like it wasn't even there. And that was a .303!

I wonder what the Germans thought when they ran into the .50 cal in US airplanes.

As I have mentioned before I read of a case where an USMC Wildcat dove on 3 Zeros that were shooting up a PBY near the 'Canal. They had borrowed the visiting Admiral's PBY for a torpedo attack on the IJN and wanted to give it back in nice condition. So he just dove on the Zeros, spraying lead, trying to scare them off. And scare them off he did; they all beat feet. It was not until well after the war that he he found he had shot down all of them. In each case just one .50 cal round hit a good fatal spot, a fuel tank, an oil line and an engine. None of them made it back to Lae.

Of course in WW2 for tank attacks they seized upon rockets as the answer. A quantity of 5 inch HVAR was donated by the USN and went into action on P-47's soon after D-Day.

Hi
Have you got a source for the BoB 'incident'? (For information on the subject of aircraft armour a useful book is 'Knights of the Skies - Armour Protection for British Fighting Aeroplanes' by Michael C. Fox).

I suspect, like any flyer, the Germans did not like running into .50 cal fire, like they probably did not like running into RAF 20 mm fire.

Mike

 

[Greyman]

I think I've read of some instances where, at the squadron level, armour from u/s aircraft was removed and subjected to impromptu firing trials. When complaints were registered the big wigs had to get the point across that the armour thickness was selected with consideration given to the protection afforded by the aircraft structure, and so when subjected to direct attack -- was liable to fail every time.

Even still, when officially (Orfordness) tested in early '41:
7% of bullets (or bullet fragments) penetrated the Spitfire's rear armour
19% of bullets (or bullet fragments) penetrated the Hurricane's rear armour

These were
- 7.92 mm AP rounds
- fired from 6 o'clock at the area presented by the armour plate
- through the aircrafts' structure

 

[Barrett]

I know an expert who can look this over.

View attachment 835849

Pawn Stars is one of the few programs on The "History" Channel (some of us who've appeared therein just call it The Channel) with history content.
Rick has some knowledge of aviation but he can get confused. He looked at an F4U photo from the Hell Hawks Squadron (VMF-213) and pronounced it a P-47 from the Hell Hawks GROUP (365th, 9th AF).

 

[MIflyer]

Pawn Stars is one of the few programs on The "History" Channel (some of us who've appeared therein just call it The Channel) with history content.

One of the embarrassing things about the History Ch and the Discovery Ch is that some of their material is just flat out made up. No one who had as much read a Barrett Tillman or Bill Gunston book would ever come up with that stuff. I recall one show in particular in which that had some really neat film of two P-80A that were the first to arrive in the ETO. They explained in the voice over that they were P-80's rather than F-80's because they were prototypes. I think I knew that was nonsense before I hit 10 years old. I can only assume that they were scrambling madly for a way to answer the obvious question of P versus F and then recalled that RAF prototype aircraft had a circle with a P in it painted on the side and grasped that as a explanation.

Of course on the Internet that kind of error has been exceeded by at least a couple of orders of magnitude. I especially liked the the Youtube video that showed the IJN Mushasi being sunk by a USAF AC-130; another showed a Japanese Zero encountering a flying saucer in 1955.

 

[SaparotRob]

…another showed a Japanese Zero encountering a flying saucer in 1955.

You're laughing now but just you wait.

 

[smutny]

Rick has some knowledge of aviation but he can get confused.

Now that he learned how to fly, I'm hoping I'll be able yell less at the TV during the aviation segments....

 

[SaparotRob]

Yelling at the screen is one of my favorite things.

 

[MIflyer]

Now that he learned how to fly, I'm hoping I'll be able yell less at the TV during the aviation segments....

If so, it'll only be because you are throwing up.

 

[GTX]

Speaking of this topic, here's a FICTIONAL Whatif story I've just done along with some artwork of a good friend:

Stinging Cobras

Stinging Cobras

beyondthesprues.com

 

[SaparotRob]

Speaking of this topic, here's a FICTIONAL Whatif story I've just done along with some artwork of a good friend:

Stinging Cobras

Stinging Cobras

beyondthesprues.com

View attachment 859111

I never knew the Groundhog was a Caribou. Interesting bit about the nose armor.

 

[tomo pauk]

Speaking of this topic, here's a FICTIONAL Whatif story I've just done along with some artwork of a good friend:

Stinging Cobras

Stinging Cobras

beyondthesprues.com

Interesting story and lovely profiles.
(the Finns getting the P-39s in early 1940 is interesting idea; the MK 103 was a bit lighter than the M4, however)

 

[GTX]

(the Finns getting the P-39s in early 1940 is interesting idea; the MK 103 was a bit lighter than the M4, however)

You want to check that:

Gun	37 mm Automatic Gun, M4	MK 103
Caliber	37 mm	30 mm
Length	2.27 m	2.335 m
Gun Mass	97 kg	141 kg
Rate of Fire	150 rpm	420 rpm
Muzzle Velocity	610 m/s	940 m/s
Armour Penetration	34 mm @ 100 m using AP-T 25 mm @ 500 m using AP-T 18 mm @ 1000 m using AP-T	55 mm @ 100 m using AP-I 44 mm @ 500 m using AP-I 33 mm @ 1000 m using AP-I