20 mm in action

[Pongo]

Tail wheel gone, radio gone, fairings from the horizontal stab gone.
Nice fusing, Hard to believe he landed it. Ben Afleck wouldn't have been able to.

[Serenity]

Hey, this was taken out by me!

Those shell holes certainly don't match what we have come to expect to be 20mm... would have thought there would be much bigger holes from the explosive.

[Pongo]

Its exactly what I would expect.
The round enters and explodes small hole for entry and lots of shrapnel out the other side.
It says they counted 544 bullet and shell holes, probably 400 of them were caused by those two rounds.
The first day of the war the US had all the evidence they would ever need to commit to 20mm.

[jdbecks]

The first day of the war the US had all the evidence they would ever need to commit to 20mm.

because of the lack of stopping power so to speak?

[Westy]

Great topic Pongo.  got me to wondering about him and the few P-36s that got
airborne that day and I found this:

http://findarticles.com/p/articles/mi_qa3897/is_200210/ai_n9121096/

[Wmaker]

Nice pics Pongo! Hadn't seen these before!

[stran]

those two holes in the first picture look pretty big.

[Pongo]

because of the lack of stopping power so to speak?

Look at that, he has a little bandage on his middle finger for you...

Even if 4 50 cal rounds hit in the same tight area, it would be 8 holes unless you got very very lucky.
The reason those pictures are historic is that that is devastating damage from 2 Oerlikon 20 mm rounds.
IE a hit from a 109e4 would do the same thing.  I presume the P36 had pilot armour like the early P40s. That is likely the only reason he is alive. The back of his pilot armour must be sprinkled with fragments just like the left side of his airframe is.

[Pongo]

From Westys link
"Phil Rasmussen recalled, "At almost the same instant, I was hit by two 20mm explosive cannon; one, in the radio compartment behind my head, shattered the canopy above me. The other, in the tail section, severed my rudder cable and blew off my tailwheel. In addition, I was stitched with 7.7mm bullets. Having hardly any control over the aircraft and scared as hell, I popped into a cloud, struggled to stabilize the plane and headed for Wheeler."
 very minor damage.
"
At that moment, the third Soryu Shotai arrived. P02c Jiro Tanaka-a wingman-attacked Thacker from the side. Thacker says, "A 20mm explosive shell had fractured my tailwheel hydraulic line. That, and other minor damage to the plane by small calibers ... I smelled hydraulic fluid in the cockpit, so I quickly ducked under some clouds and left the scene." P02c Tanaka put in a victory claim on the assumption he had shot Thacker down.
"

3 cannon round hits on 2 planes and hydraulic damage to both. And controls cut.

[Yeager]

explosive = shrapnel.  Depending on the mass of the exploding projectile and the kintetic power unleashed by the explosion.  These pictures I have seen before and am reminded of other accounts of HE rounds detonating upon contact with the aircraft skin causing considerably less damage to the airworthiness of the airframe than if they had delayed a few instants and exploded deeper within the structure.  And of course building airplanes like armored tanks helps out as well.

[Karnak]

Those rounds hit one of the best locations for the receiving fighter to take the hits and survive.  No fuel tanks, no engine, no ammunition and no pilot.  Either one of those hits, in another location, could have downed the P-36.  There is a reason Phil Rasmussen is crossing his fingers in the photo.

I have seen a photo of a Ju88 that was brought down by a single Hispano 20mm hit from a Spitfire to its tail cone.  One hit, and the medium bomber could no longer maintain controlled flight.

[Cthulhu]

Guys, IMO the shrapnel is the least of your worries when hit by cannon rds (except for personnel actually hit by the shrapnel of course). The real damage is done by the explosive overpressure at detonation. Sure, all those holes from shrapnel cause damage, but the real killer is the ruptured/buckled skin panels, bulkhead webs, spar webs, sheared rivets,etc. resulting from a nearby explosion. Airplanes are highly stressed, lightweight structures. There aren't many redundant parts. Punching a hole in the skin is one thing; unzipping a whole line of rivets on the upper wing skin is another thing entirely. 

[Yeager]

Ive seen many pitcures of big nasty looking cannon holes where the skin is all freaked out but none of the major structure underneath is broken to critical failure.  Of course the pics are taken taken back at base after making it down safely.

This is why the .50 BMG AP had such nice effect.  Throw in a few indendiaries and there you go.  Of course throw in a 20mm like the P38 and you have a truly lethal combo.

[danny76]

Great post.

But you're wrong about Ben Affleck, he'd have stuck his sidearm (probably a trusty .45) through the hole in the canopy headshotted his antagonist, scored 3 kills on is way back to the field, then quick trip to Blighty to win the Battle of Britain for the hopeless Brits.

And possibly capture the Enigma machine on return journey

[Cthulhu]

Ive seen many pitcures of big nasty looking cannon holes where the skin is all freaked out but none of the major structure underneath is broken to critical failure.  Of course the pics are taken taken back at base after making it down safely.

This is why the .50 BMG AP had such nice effect.  Throw in a few indendiaries and there you go.  Of course throw in a 20mm like the P38 and you have a truly lethal combo.

The skin, especially the upper wing skin is major structure. You won't see many fighter-sized planes survive more than two or three cannon hits to the upper wing, especially near the root, and especially if he's trying to maneuver to fight or survive. Those are the guys who don't make it home to have their picture taken.