How would you have armed the P38 if you were to use it as it was used historically?

[Shortround6]

It also used a lighter shell than the Hispano at a lower velocity. It might have needed a bit more effort or machining time to make too.

 

[davebender]

In 1942 and 1943, the average reliability was about 1 stoppage per 160-180 rounds

Thank you. That's the data we need.

I suspect 20mm reliability was, if anything, even worse during 1938 when the P-38 was being designed.

I don't like arming a bomber interceptor with .50cal MGs. But I don't see any other choice during 1938. I'd rather have .50cal MGs that work then 20mm cannons which are jammed.

 

[Shortround6]

There was no american 20mm Hispano when the P-38 was designed. Most early P-38s, If they had any cannon installed at all, used the 37mm M9 with a 15 round magazine. None of these went over seas. Some of the early planes, if they mounted guns at all, also use two .50s and two .30s. If this seems light the machine guns alone are double the firepower of the in service P-35 and P-36 even without what ever cannon they planed to use.
The 20mm Hispano doesn't show up until the "E" model in 1941.

Reliability of the early 37mm M9 was far worse.

 

[davebender]

How many .50cal MGs can be made to fit on a P-38? I would consider the wing (next to the fuselage) in addition to the aircraft nose. 8 or more would be nice for shooting at enemy bombers.

 

[Shortround6]

Wing next to fuselage is where the fuel tanks were. When P-38 was initially worked on they were expecting 1000hp per engine. They hoped a 2000hp twin would equal a 15edit>00<edit hp single engined plane and since there was no real 1500hp on offer AT THE TIME they went with the twin.

 

[Lighthunmust]

If it is possible to increase the rpg to the four .50s by ditching the cannon that would be my choice of armament with U.S. weapons. With the concentration of fire at all ranges, the relative ease for a few hits to down most axis aircraft, and a target rich environment, four .50 ought to be more than sufficient. As I recall many USN Wildcat pilots were unhappy with the change to six .50s with less ammunition when the F4F-4 replaced the F4F-3. They may have had a point. Perhaps when you consider the marksmanship of the average pilot and lack of todays sophisticated fire control systems; being able to a blast a lot of lead in a long burst or more shorter bursts was better than a lot of lead in a short burst. Even just losing the weight of the cannon and shells may have been a better option to keeping it. Isn't Bong famous for saying what a poor marksman he was during his first tour and how he blasted away at a lot of blue sky.

 

[pinsog]

The P38 faced few, if any opponents that it needed more firepower than 4 concentrated 50's. Would anyone care to figure out how many rounds you could squeeze in if you eliminated the cannon, its mounts and its ammo? If all I was going to face was either German or Japanese single engine fighters, I think 4 Brownings, no cannon and ALOT of ammo would be my preference.

 

[Jabberwocky]

If it is possible to increase the rpg to the four .50s by ditching the cannon that would be my choice of armament with U.S. weapons. With the concentration of fire at all ranges, the relative ease for a few hits to down most axis aircraft, and a target rich environment, four .50 ought to be more than sufficient.

Why bother? The .50s for the P-38 had 500 rpg. At 750-850 rounds per minute, that's 35-40 seconds of firing time. That's 18-20 2 second bursts, more than enough for the BRIEF dogfights of the period.

I don't know that US statistics, but British experience was that Spitfire Mk IX pilots rarely used more than 110 of the 120 cannon rounds available to them (about 10 seconds firing time). Pilots will always want more, just on the oft chance there is another target, but the reality was that only a few pilots were good enough to get more than a few firing solutions in a combat situation.

The problem is not the length of firing time, but the capacity of the gun itself to fire sustained bursts. There are WW2 recommendations to pilots on the relation between the length of the burst and how long they should wait until firing the next burst.

Otherwise, you get nasty things happening, like rounds cooking off in the chamber as the gun heats up massively and sympathetic detonations of the rest of the rounds in the ammo box. I've got a first hand account somewhere of a P-47 pilot who had been on a ground strafing mission who though he was running into flak after rounds in his .50s started cooking off an putting holes in his wings.

Its not a video game, where you can just hose away until all ammunition is expended.

 

[Lighthunmust]

Why bother? The .50s for the P-38 had 500 rpg. At 750-850 rounds per minute, that's 35-40 seconds of firing time. That's 18-20 2 second bursts, more than enough for the BRIEF dogfights of the period.

I don't know that US statistics, but British experience was that Spitfire Mk IX pilots rarely used more than 110 of the 120 cannon rounds available to them (about 10 seconds firing time). Pilots will always want more, just on the oft chance there is another target, but the reality was that only a few pilots were good enough to get more than a few firing solutions in a combat situation.

The problem is not the length of firing time, but the capacity of the gun itself to fire sustained bursts. There are WW2 recommendations to pilots on the relation between the length of the burst and how long they should wait until firing the next burst.

Otherwise, you get nasty things happening, like rounds cooking off in the chamber as the gun heats up massively and sympathetic detonations of the rest of the rounds in the ammo box. I've got a first hand account somewhere of a P-47 pilot who had been on a ground strafing mission who though he was running into flak after rounds in his .50s started cooking off an putting holes in his wings.

Its not a video game, where you can just hose away until all ammunition is expended.

I actually have quite a bit of experience with firing automatic weapons (on the ground) both in the Army and here in Arizona where civilians can own them. You are very right about restrictions on burst times and frequency. Movies, TV, and video games have certainly distorted the perceptions of most people. All the times you return to base with ammunition will not provide much comfort the one time you run out at the wrong time. With in reason more ammo is always preferable. In the Army we knew we could live for weeks with out food and days without water, but maybe not a second longer without ammo. As I recall Bong also ran out of ammunition on more than one occasion. Perhaps ditching the cannon for the weight savings and servicing requirements would be good enough, but I would prefer if practicable to carry a little extra .50 cal. for the most unexpected and critical moments that so often happen in combat.

 

[Shortround6]

to modify the "Thach quote" ----"if you can't hit them in 30 seconds you aren't going to hit them in 40 seconds."

Every ONE second of firing time for four .50 cal guns weighs about 17 lbs. Granted you are ditching the 20mm but that constituted over 40% of your striking power for as long as the ammo lasted or the gun kept working.

How long are you going to be flying around at what power settings in order to fire off more than 35 seconds worth of ammo? A P-38L burns just over 5.5 gals a minute at Military power and 6 gallons a minute at WER.

 

[pinsog]

Jabberwocky, Shortround6

Seriously? Too much ammo? Isn't that like a fighter thats too fast? Too manueverable? A woman thats too hot?

What about strafing? How many stories have you read where they beat up the target until they ran out of ammo? I would like to hear of anyone who ever heard a fighter pilot say "I sure wish my guns didn't shoot so long before they quit".

David McCampbell shot down 9 Japanese divebombers on one mission and ran out of ammo. Hellcats carried 400 rounds per gun, I believe, how many more could he have gotten if he had another 200 or 300 rounds?(and full fuel tanks, he took off with his tanks half full and ran out when he landed on the carrier)

 

[Lighthunmust]

to modify the "Thach quote" ----"if you can't hit them in 30 seconds you aren't going to hit them in 40 seconds."

Every ONE second of firing time for four .50 cal guns weighs about 17 lbs. Granted you are ditching the 20mm but that constituted over 40% of your striking power for as long as the ammo lasted or the gun kept working.

How long are you going to be flying around at what power settings in order to fire off more than 35 seconds worth of ammo? A P-38L burns just over 5.5 gals a minute at Military power and 6 gallons a minute at WER.

I don't think that does Thatch justice. How about Butch O'hare? He might of run out of ammunition with a six .50 F4F-4 before getting all those bombers headed toward the Lexington. No combatant can ever know for certain how many opponents may unexpectedly show up. As I recall it was only because of the British that the F4F was "upgraded" to six guns. As long as weight of fire is sufficient, without sophisticated fire control equipment it may be better to have more of the sufficient than less of the overwhelming. Insufficient excellence is the enemy of enough good enough.

How long will you be flying? Until you land, alive or dead. I don't think running out of fuel in a dogfight happened to often, especially in a P-38.

 

[davebender]

You've got me confused. Are we talking about the original 1937 design for the P-38? Or are we talking about the the P-38L which entered service during June 1944?

The P-38L is 7 years newer then the original specifications. Rather like comparing an Me-109F4 to the original Me-109 prototype powered by a RR Kestrel engine.

 

[pinsog]

Davebender,

Pick a year. Doesn't matter. Obviously if you were intercepting a "German B17", if they had ever built one, you would arm it differently than if you were killing Zero's. I'm looking at the historical aircraft it actually battled, and I think if I were a pilot of the time I would ditch the cannon and add another couple hundred rounds per gun for the 4 Brownings. It would give you a VERY long firing time. Zero's, 109's and 190's just weren't that tough and I think those 4 Browning packed in the nose would have been devastating to any of those 3 single engine fighters.

 

[Lighthunmust]

Davebender,

Pick a year. Doesn't matter. Obviously if you were intercepting a "German B17", if they had ever built one, you would arm it differently than if you were killing Zero's. I'm looking at the historical aircraft it actually battled, and I think if I were a pilot of the time I would ditch the cannon and add another couple hundred rounds per gun for the 4 Brownings. It would give you a VERY long firing time. Zero's, 109's and 190's just weren't that tough and I think those 4 Browning packed in the nose would have been devastating to any of those 3 single engine fighters.

Even for bomber destruction the never dispersing bursts of four nose mounted .50s is pretty devastating. This would be especially so in the head-on attacks such as those practiced by the Luftwaffe against our B-17s. But of course reliable cannon would be more effective against bombers under most circumstances. One thing to consider though is you would have more .50 ammo to fight your way through the escorts to the bombers.

 

[Jabberwocky]

Jabberwocky, Shortround6

Seriously? Too much ammo? Isn't that like a fighter thats too fast? Too manueverable? A woman thats too hot?

What about strafing? How many stories have you read where they beat up the target until they ran out of ammo? I would like to hear of anyone who ever heard a fighter pilot say "I sure wish my guns didn't shoot so long before they quit".

David McCampbell shot down 9 Japanese divebombers on one mission and ran out of ammo. Hellcats carried 400 rounds per gun, I believe, how many more could he have gotten if he had another 200 or 300 rounds?(and full fuel tanks, he took off with his tanks half full and ran out when he landed on the carrier)

EVERYTHING on a fighter is a compromise.

More ammunition = more weight = less maneuverability, lower rate of climb, slower acceleration, lower ceiling, higher fuel consumption ect, ect.

Would you rather have more ammunition to fire, or be better able to get into position to fire?

500 rounds per gun for a HMG is a load-out that few fighters of the period matched.

 

[Shortround6]

You've got me confused. Are we talking about the original 1937 design for the P-38? Or are we talking about the the P-38L which entered service during June 1944?

The P-38L is 7 years newer then the original specifications. Rather like comparing an Me-109F4 to the original Me-109 prototype powered by a RR Kestrel engine.

I used it because those were the figures I had.

I believe you missed the point. There are TWO factors that cover combat duration. One is the ammo capacity (firing time) the other is fuel capacity, how much time can you spend at combat and military power and still get home. Since you brought up the 109 look at the "E" in the Battle of Britain, it carried (if they were full) 1000rounds in the ammo containers for each 7.9mm cowl MG. Nearly a full minute of firing time. How many pilots ever used up the total amount compared to the number that broke off combat due to low fuel? Would the Germans have been better served to trade 1000 rounds of 7.9 ammo (leaving 500 per gun) for another 30-35 liters of fuel?

 

[davebender]

Would the Germans have been better served to trade 1000 rounds of 7.9 ammo (leaving 500 per gun) for another 30-35 liters of fuel?

I've never heard of mounting fuel tanks in the engine cowl. So I don't think this trade off would be possible on the Me-109.

 

[Shortround6]

It probably isn't possible but again, I am trying to point out that combat duration and a fighter's "effectiveness" are dependent on several things. Just having lots of ammo and long firing time (past a certain point) doesn't do much good if the plane is out of fuel.
If the Germans could have gotten the engine mounted gun to work perhaps putting a 3rd MG 17 through the prop with 500rounds would have been a better bet. 20mm guns run dry in 7-8 seconds, having 50 more seconds of firing time for a pair of 7.9mm guns gets how many victories? having 22 seconds more time after the 20's quit for 3 guns might have been better.

 

[pinsog]

Jabberwocky,
I agree everything is a compromise, that is why I said "delete the cannon, cannon mount and cannon ammo and replace it with more 50 ammo". The tradeoff is less weight per second for more seconds of firing. IMHO that is a good tradeoff considering the main opponents for this aircraft were rather lighly built single engine fighterslike the Zero and 109 (the 190 being a bit more durable).

Shortround6,
I understand your point, about a fighter carrying somuch ammo that it runs out of fuel before it can shoot it up, but I think it has little merit for one of the longest range fighters of WW2. It is a very vaild argument for ME109, FW190, Spitfires, Hurricanes, etc, but those fighters were fuel critical before they got to the end of the runway. Again I point out David McCambell who left the Essex with 1/2 tank of fuel, shot down 9 Japanese planes, and still ran out of ammo while carrying 400 rounds per gun. If he had left the Essex with a full tank of fuel, he could have used alotmore ammo.