German 20mm Cannon Effects On US Bombers

[togor]

This guy is making a number of YouTube videos on US bombers, and they are quite interesting. Here is one on the German 20mm Autocannon.


https://www.youtube.com/watch?v=bdr4ngshWl8

[Major Tom]

Very interesting! I don't believe any of our fighter planes had 20mm cannons installed? Tho, 6 50s' did a number on the japs and germans planes!

[Art]

Very interesting! I don't believe any of our fighter planes had 20mm cannons installed? Tho, 6 50s' did a number on the japs and germans planes!

The P38 had 4 .50 Cal machine guns and one 20mm cannon. in the nose

The P39 had a 37 mm cannon in addition to its machine guns.

The .50 cal was effective against WWII fighters but against bombers, cannon were good to have. One or two cannon shells exploding on the flight deck of a bomber usually meant a destroyed aircraft.

Once jets replaced piston engine airplanes it was discovered that due to their fuel, which was basically kerosene, and the lack of oxygen at the altitudes jets operated at, machine guns wouldn't make an airplane you hit burn any more. From the 1960s cannons replaced machine guns on fighter aircraft.

[togor]

Edited: Art beat me to it with much of what is below. :)

IIRC the P-39 was built around a 37mm Autocannon that made it useful ground attack missions. The AAF never faced a force of heavy bombers, and it found the 50 BMG in quantity sufficient to bring down enemy fighters and medium bombers. Although the AAF was not altogether opposed to cannons, putting one in the nose of the P-38.

The problem with big bombers is that there's a lot of empty space in them, and it takes a lot of hits of MG fire to bring them down. So they went to exploding shells, hence cannon.

I thought the chart showing a low rate of loss to cannon > 20mm and larger ordnance was misleading. But as he points out, this is examination of surviving aircraft. I have understood from other sources that the Mk108 30mm cannon, though of slow velocity, was an effective bomber killer.

[barretcreek]

Interesting video, thank you. Cannon was application specific, whereas the .50 Browning has a wide range of uses. Doubt the cannon would as useful in ground combat vs the range of the .50.

[Art]

Interesting video, thank you. Cannon was application specific, whereas the .50 Browning has a wide range of uses. Doubt the cannon would as useful in ground combat vs the range of the .50.

Many a fighter fell to the 20mm cannon shells of German, Japanese, British and Russian fighters. Some German and most Russian 20 mm cannon had pretty darn high rates of fire, 800-900 rounds per minute. The big drawback was low ammo supply. An old boy could shoot himself dry in a hurry with cannons. A P38 carried 500 rounds for each of its "fifties" but only 150 for its cannon.

[dryheat]

Imagine the millions of rds of ammo that are laying all over Europe. Must be hard to do any metal detecting unless you collect bullets.

[Allen]

Imagine the millions of rds of ammo that are laying all over Europe. Must be hard to do any metal detecting unless you collect bullets.

The way things are going we'll be saying the same about NYC and Chicago soon.

[togor]

The way things are going we'll be saying the same about NYC and Chicago soon.

How about keeping this stuff in the political section. Too much to ask that it not be out where anyone can see it???

[tmark]

My dad knows what a 20 mm shell can do! One exploded in his B17s ball turret over Germany by a fw190 wounding him.

[Vern Humphrey]

Many a fighter fell to the 20mm cannon shells of German, Japanese, British and Russian fighters. Some German and most Russian 20 mm cannon had pretty darn high rates of fire, 800-900 rounds per minute. The big drawback was low ammo supply. An old boy could shoot himself dry in a hurry with cannons. A P38 carried 500 rounds for each of its "fifties" but only 150 for its cannon.

A high rate of fire is critical in aerial warfare. The sights are going to be on target only a fraction of a second, and you need to pump out as many bullets as you can in that time. Six .50 machineguns could pump out 60 shots a second, so in the quarter of a second when you were on target, you could get about 15 hits -- and the .50 was WAY more effective than the rifle caliber machineguns most of our enemies used.

Just before WWII our intelligence knew the Japanese Zero was faster than our new naval fighter, the F4F Wildcat and more maneuverable. We couldn't dogfight them and we couldn't run away from them. Lieutenant Commander John Thatch compared the two planes on paper.

Speed -- the Zero was faster.
Maneuverabiitiy -- the Zero could turn faster.
Construction -- the Wildcat was built like a truck. The Zero was almost flimsy.
Pilot protection -- the Wildcat had an armored seat. The Zero had none.
Self-sealing gas tanks -- the Wildcat had them, the Zero did not.
Armament -- the Wildcat hat .50 machine guns, the Zero had rifle caliber plus one 20mm. Advantage to the Wildcat.

He figured if he could arrange it so Wildcats and Zeros traded shots, the Zeros would fall out of the air before the Wildcats. The result was the Thatch Weave, and it worked.

Then in the Battle off Samar, our planes had no torpedoes or armor-piercing bombs -- they used .50s against battleships and cruisers and chewed their topsides up.

[togor]

The Germans came to a different conclusion regarding the narrow windows for firing solutions. Rather than a lot of rounds, they went for more destructive rounds. Eventually postwar the USAF came around to doing *both*. The M61 Vulcan cannon in the F-16 and other fighters has high rate, high velocity and high explosive.

[Art]

A high rate of fire is critical in aerial warfare. The sights are going to be on target only a fraction of a second, and you need to pump out as many bullets as you can in that time. Six .50 machineguns could pump out 60 shots a second, so in the quarter of a second when you were on target, you could get about 15 hits -- and the .50 was WAY more effective than the rifle caliber machineguns most of our enemies used.

Just before WWII our intelligence knew the Japanese Zero was faster than our new naval fighter, the F4F Wildcat and more maneuverable. We couldn't dogfight them and we couldn't run away from them. Lieutenant Commander John Thatch compared the two planes on paper.

Speed -- the Zero was faster.
Maneuverabiitiy -- the Zero could turn faster.
Construction -- the Wildcat was built like a truck. The Zero was almost flimsy.
Pilot protection -- the Wildcat had an armored seat. The Zero had none.
Self-sealing gas tanks -- the Wildcat had them, the Zero did not.
Armament -- the Wildcat hat .50 machine guns, the Zero had rifle caliber plus one 20mm. Advantage to the Wildcat.

He figured if he could arrange it so Wildcats and Zeros traded shots, the Zeros would fall out of the air before the Wildcats. The result was the Thatch Weave, and it worked.

Then in the Battle off Samar, our planes had no torpedoes or armor-piercing bombs -- they used .50s against battleships and cruisers and chewed their topsides up.

All Zeros had 2 20mm cannon though the early versions suffered from low ammuntion load and a slow rate of fire. The late war
A6M5s were a different breed of cat. While they could never match the better American planes They carried two 20mm cannon with a much higher ammunition load and a rate of fire of 700 to 750 rounds per minute. Their machine gun armament was improved too with most of the "5" models carrying at least one and usually two 13mm heavy machine guns. The lmost heavily armed "Zeke" and one of the most common was the A6M Model 52c with two 20mm cannon and two 13mm machine guns in the wings and one 7.7mm machine gun in the engine cowling. All of the later Zeke's had reinforced wings and thicker fuselage and wing skin to improve their "do not exceed" speed. The improvements added enough weight that even with a more powerful engine they couldn't exceed 360 miles per hour on "War Emergency Power."


While there were numerous straffing attacks from American escort carrier's aircraft engaged at Samar the escort carriers did indeed have torpedoes embarked. The heavy cruiser Chikuma was left unmaneuverable after a torpedo hit aft from a TBM from the Manila bay, she was finished off by Avengers from Kitkun Bay what put two more torpedoes in her plus more torpedo bomber attacks later in the day from other escort carriers which finished her off. H.E. Bomb very near misses set off long lance torpedoes in the Suzuya leaving her an unsalvageable wreck.