I'll just pop in to make one or two observations.

The varying trajectories of different gun calibers and MV's really caused no problem to speak of within about 300 yards, the effective air-to-air combat range of most of WW2.

When computing gunsights appeared in 1944, effrective range increased to 400+ yards and differing trajectories began to appear as a problem. And a high MV and flat trajectory over distance became more attractive features

When radar-ranging gunsights appeared in the Korean War, engagement ranges increased to 1,000 yards and high MV and flat trajectory became essential.

As already mentioned, the different MV and trajectories within a couple hundred yards is minimal. Any Luftwaffe pilot who was worth his salt would have known to aim differently for different calibers at greater distances anyway. That is just my thought.
The rate of fire is the bigger issue here, and all pilots were aware as to how important this was. The lower the ROF, the longer you have to keep the target in your sights. Forget about snapshots with a low ROF gun...unless your timing is perfect.

Different trajectories only matter if the guns are all set up the same. They were not, however.. In practice (based on ballistic sheet of G-6/U4) the MK 108 and the cowl MG 131s had almost identical trajectories (the MK 108 was mounted pointing slightly upwards).

I wouldn't call that guy a historian.

All you have to do is look at the specs of the guns and ammo he talks about to know he's blowing smoke.

Nobody is saying the .50 cals were not effective fighter vs fighter weapons in ww2. Saying that they were more effective then the late war cannons is stupid.

Ask him to go up against targets like B-17 or B-24. Should cure him of whatever he's suffering from

Oh boy, I love the rate of fire stuff on cowl mounted weapons.

What's not considered is the ROF shown is test stand stuff: on the ground.

The same in service ROF could not be achieved on cowl mounted weapons because of the need to fire through the propellor arc thus needing an interrupter gear that stopped the max ROF from happening because if it was achieved you'd shoot your friggin' prop off.

So, the same weapon fired through a prop arc could, IN NO WAY POSSIBLE, achieve the ROF it could on a test stand.

Think folks, think.

quote:

Originally posted by BOA_Allmenroder:
Oh boy, I love the rate of fire stuff on cowl mounted weapons.

What's not considered is the ROF shown is test stand stuff: on the ground.

The same in service ROF could not be achieved on cowl mounted weapons because of the need to fire through the propellor arc thus needing an interrupter gear that stopped the max ROF from happening because if it was achieved you'd shoot your friggin' prop off.

So, the same weapon fired through a prop arc could, IN NO WAY POSSIBLE, achieve the ROF it could on a test stand.

Think folks, think.

Extremely good point that I had not thought of.

I guess this refers to all the machine guns fitted to LW single engined fighters, and the two Innner cannon on the FW190A

For the electrically fused guns the Luftwaffe used that meant a rof reduction of about 5-10%.

quote:

Originally posted by Xiolablu3:

quote:

Originally posted by BOA_Allmenroder:
Oh boy, I love the rate of fire stuff on cowl mounted weapons.

What's not considered is the ROF shown is test stand stuff: on the ground.

The same in service ROF could not be achieved on cowl mounted weapons because of the need to fire through the propellor arc thus needing an interrupter gear that stopped the max ROF from happening because if it was achieved you'd shoot your friggin' prop off.

So, the same weapon fired through a prop arc could, IN NO WAY POSSIBLE, achieve the ROF it could on a test stand.

Think folks, think.

Extremely good point that I had not thought of.

I guess this refers to all the machine guns fitted to LW single engined fighters, and the two Innner cannon on the FW190A

Not just LW, any cowl mounted weapon of any nationality firing through the prop arc.

.303s/7.62s were essencially used in early war fighters due to the light materials that the planes were made of. And the chance that you may actually kill the pilot?

.50ins cals/12.7mms were introduced for attacking harder skinned ground targets.
Later they would be used in defensive positions on bombers/Attack craft to allow a punch that would incapacitate an intercepting aircraft.(Through the engine block.(Germany introduced the 13mm for this).

As aircraft were now becoming heavier with metal skin and armour and self sealing tanks. The 20mm was introduced as fighter armmament to allow for Bomber intercept.(For the British) and both intercept and ground attack by the Germans. The advent of multirole fighters. Carrying light bombloads but a better strafing armmament.)

The FW.190 typified this philosophy.With many proficient fighter pilots removing the outer 20mm cannons to save weight and gain manouvrability. The Fw. Attack pilots doing the same but to allow for weight saving and being able to escape after ordinance drop.

The advent of the 30mm 108 was borne about, by the study of Max effect bomber destroyer munitions and Tactics employed within.(There can be nothing more devastating than a full Wing/Gruppe of Bomber interceptors descending on a "Box" Closing to fire with those 30mm 108s).Convergence and disimilar trajectories didn't matter as the were trained to get in close. As seen in many a "Tube video" This gun was never envisaged as "Dogfight" armament. (Far too slow a Rof) Even though a hit from just one shell would often be enough to incapacitate a fighter.
The investigation into higher calibres. 37mm/50mm and 75mm was meerly there, to be able to produce less aircraft with a greater "Standoff" ability. Thus aiding the War economy.A flawed tactic that made the gun carriers "Easy Prey" for the escorting .50 cal fighters.

The USAAF usage of the .50 cal was to my mind, a good compromise.

In multiple form. Firing enough lead in the air/towards the ground. To allow even the average gunner a chance of a hit and a chance to do damage. With this calibre and also having the ability to penetrate much of the ground targets asigned during "Total War" (I.E. Anything. Trucks,cars,trains,barges,hayricks,barns,cows and tractors.)

The .50 cal was able to be produced in large numbers and fitted to large numbers of planes.(And so becomes a "War winner".(The British pilots certainly welcomed it.)

However! it must be said. That when the 20mm MG213 was invented? Discovered by the Allies in Germany. A new era of aircraft armmament was introduced and lasted for 50odd years!

quote:

Originally posted by BOA_Allmenroder:

quote:

Originally posted by Xiolablu3:

quote:

Originally posted by BOA_Allmenroder:
Oh boy, I love the rate of fire stuff on cowl mounted weapons.

What's not considered is the ROF shown is test stand stuff: on the ground.

The same in service ROF could not be achieved on cowl mounted weapons because of the need to fire through the propellor arc thus needing an interrupter gear that stopped the max ROF from happening because if it was achieved you'd shoot your friggin' prop off.

So, the same weapon fired through a prop arc could, IN NO WAY POSSIBLE, achieve the ROF it could on a test stand.

Think folks, think.

Extremely good point that I had not thought of.

I guess this refers to all the machine guns fitted to LW single engined fighters, and the two Innner cannon on the FW190A

Not just LW, any cowl mounted weapon of any nationality firing through the prop arc.

Yeah I realise that mate, however I cant think of any RAF fighter planes with guns firing through the prop. Nor any US ones for that matter. Possibly the early P40's?

USSR used this method a lot, for sure.

quote:

Originally posted by JSG72:
.303s/7.62s were essencially used in early war fighters due to the light materials that the planes were made of. And the chance that you may actually kill the pilot?

.50ins cals/12.7mms were introduced for attacking harder skinned ground targets.
Later they would be used in defensive positions on bombers/Attack craft to allow a punch that would incapacitate an intercepting aircraft.(Through the engine block.(Germany introduced the 13mm for this).
As aircraft were now becoming heavier with metal skin and armour and self sealing tanks. The 20mm was introduced as fighter armmament to allow for Bomber intercept.(For the British) and both intercept and ground attack by the Germans. The advent of multirole fighters. Carrying light bombloads but a better strafing armmament.)

The FW.190 typified this philosophy.With many proficient fighter pilots removing the outer 20mm cannons to save weight and gain manouvrability. The Fw. Attack pilots doing the same but to allow for weight saving and being able to escape after ordinance drop.

The advent of the 30mm 108 was borne about, by the study of Max effect bomber destroyer munitions and Tactics employed within.(There can be nothing more devastating than a full Wing/Gruppe of Bomber interceptors descending on a "Box" Closing to fire with those 30mm 108s).Convergence and disimilar trajectories didn't matter as the were trained to get in close. As seen in many a "Tube video" This gun was never envisaged as "Dogfight" armament Even though a hit from just one shell coukd often be enough to incapacitate a fighter.
The investigation into higher calibres. 37mm/50mm and 75mm was meerly there, to be able to produce less aircraft with a greater "Standoff" ability. Thus aiding the War economy.A flawed tactic that made the gun carriers "Easy Prey" for the Escorting .50 cal fighters.

The USAAF usage of the .50 cal was to my mind, a good compromise.

In multiple form. Firing enough lead in the air/towards the ground. To allow even the average gunner a chance of a hit and a chance to do damage. With this calibre and also having the ability to penetrate much of the ground targets asigned during "Total War" (I.E. Anything. Trucks,cars,trains,barges,hayricks,barns,cows and tractors.)

The .50 cal was able to be produced in large numbers and fitted to large numbers of planes.(And so becomes a "War winner".(The British pilots certainly welcomed it.)

However it must be said that when the 20mm MG213 was introduced? Discovered by the Allies in Germany. A new era of aircraft armmament was introduced and lasted for 50odd years!

Nice write up JSG, my opinion too.

20mm would maybe have been a little better, but as the US didnt have to attack German bombers, the .50's were OK and reliable.

Eric Brown certainly liked the 4x50's on the Wildcat/Martlett.

The Allies didn't use electrically fused projectiles, so the loss in the rof was large. In case of the 0.50 almost 50%. That's why these guns were wing mounted in most installations.

F2A, P-39, P-40 and P-63 were four major US fighter types that had synced guns firing through the prop.

P39? P36? P63? Mk1 Mustang? Gladiator?

OK guys, whatever I know about this kinda stuff is sketchy, but I figured I'd add a little comment. Dr. Hallion (in other parts of the interview) specifically mentioned the jug as the premier fighter of WW2, for flight characteristics, versatility, and armament. The rof was high, muzzle velocity was high. With so many moderately destructive bullets flying around, well, we've all seen the US gun cameras right? It just didn't take that long to down a german plane. The Germans' objectives wasn't even to shoot down fighters late war, it was to intercept bombers. If just say we had no big 4 engine bombers, and they were able to fight jugs/stangs without having to worry about what those bombers were escorting, I think the gerries would've followed a more british style and put maybe 4 20mms on the wings. I think what Hallion was trying to say was that an uninterrupted stream of bullets (50 cal or 20mm) was more effective (when deflection shooting anyway) than the heavy damage of the guns the luftwaffe used to take down fortresses + the 13mm usually thrown in.

Hey! Chunkydora.

Sure The P47s 8 gun armament made it a good fighter/Ground attack aircraft.

But Supposing the U.S. Didn't have 4 engined bombers???!!!!! .

You must be drinking stronger juice than me!

The U.S. fighters, would have been facing Jets much earlier.

Go figure?

Seriously. If the US. didn't have 4 engined bombers and only produced erm.. Twin engined bombers. Well.....

A) they would have taken longer to fly accross.
Thus producing less of a threat.
B) They were tactical and would therfore have contributed nothing to the reduction of the German War Machine, production.
C)They would have been bombing France/Belgium/ Holland! And so allowing less migration of Soviet Front fighters to the Western Front.
D) If? The fighters showed a superiority over the then extant 109s and 190s. (Which they would. In numbers.) Jet fighters Heinkel 280 and even the Me 109 TL? with perhaps Nose mounted. 6x mg131s would have been the order of the day?

quote:

.303s/7.62s were essencially used in early war fighters due to the light materials that the planes were made of. And the chance that you may actually kill the pilot?

I'd contend that rifle calibre guns were still in use then only because they hadn't been replaced in service yet. All major WW2 nations (Italy, Germany, Japa, USSR, UK, USA) were in the process in replacing them, this being planned or in operation from the late 1920s well before any uprating of aircraft construction. In fact even in WW1 some felt rifle calibre guns were obselete. During the relatively peaceful period from 1921-30 there wasn't much urgency, though.

quote:

.50ins cals/12.7mms were introduced for attacking harder skinned ground targets.
Later they would be used in defensive positions on bombers/Attack craft to allow a punch that would incapacitate an intercepting aircraft.

They were used offensively before defensively. The US introduced the one .30 plus one .50 armament in the early 1930s. It took until the very end of the decade for the .50 to find its way into common usage in bombers, with the .30 still being dominant.

quote:

In multiple form. Firing enough lead in the air/towards the ground. To allow even the average gunner a chance of a hit and a chance to do damage.

Ah, this is completely oversold and not supported by the statistics of the situation.

A typical hit rate in WW2 was about 5% but many of these misses were total or were bracketing shots.

If you look at shots fired close to the target (i.e. a wall of lead that is likely to make contact) then perhaps 20% of those shots might hit (seems about what I get in tests in IL2).

If you assume that the chance of any individual shot in the perhaps one second the target is in the firing zone then the number of shots fired might be:

4 Hispanos - 4 x 10 = 40
8 M2 - 8 x 13 = 104
2 MG151/20 - 2 x 11 = 22 (e.g. 190F8 stripped)
1 MK108 - 1 x 10 = 10

Chance of missing enitrely:

4 Hispanos: 0.8^40 = 0.00014
8 M2s 0.8^104 = 0.00000000008
2 MG151/20 0.8^22 = 0.007
1 MK108 0.8^10 = 0.11

So you assuming you are sighted correctly (and assuming each round has a 20% chance to hit) you aren't likely to miss with either of the multi gun setups. Even with one gun you are more likely to hit than not

This IS a grossly simplified example, but the general principle holds.

Even going down to a 5% chance to hit (high deflection, hard manoeuvering) you get:

0.12, 0.004, 0.32, 0.60

Here a gap opens up between them, but the extra chance to hit with 8 guns over 4 is only 0.1196

What having more guns -does- do is give you more hits on target.

At 20% chance (in order): 21, 8, 4, 2 (in reality it is a bell curve of course, around this average).

Multiplying by destructive power (M2=1): 21, 24, 12, 12*

Again really you want to look at the area under the bell curve up to a certain level of destructiveness.

* - taking a low estimate of a 30mm it being only twice as powerful as a 20mm hit.

So in other words, when on a target's 6 (20% hit chance) you're almost as likely to hit with four Hispano IIs as with 8 M2s and will do as much damage. Even in hard maneovering the difference wouldn't be huge.

A theoretical 4 cannon P-47 would have enough ammunition volume in the wings for about 2/3 the firing time of the max ammunition load of an M2 armed version, but with less overall weight (volume for rounds being the limiting factor).

I am sure everyone did these and the full normal distribution calculations in the 1930s and 40s.

So the M2 does not give you that much of an advantage in terms of hitting and larger number of guns are required to make up the damage numbers. But given that the USA lacked an effective 20mm cannon the use of the M2 made perfect sense, especially in the Pacific when logistics were paramount. In multiples of 4 to 8 it is equivalent to 2 to 4 cannon - sufficient for fighter v. fighter.

Aahh Hee Hee Hee! Aaron-Gt.

Much as I like your post.

You forget the BIGGEST! thing.

You are not at War with Germany. It is not 1942/3/4/5.
You! Are not under pressure to produce results.

And! You can Surf.

These all were attributes our fellow Air Combat Enthusiasts could never do. In the War years

Statistics? Pah! They were Born of the Devil.

People are always talking about shooting down bombers...

The Spits also had 20mm right from the Mk IB (when it was indeed a desperate move towards firepower) - but then again, they retained them.

Same with the Tiffie. They fit four of them in there, starting with the IB.

The Japaneese also seemed to like 20mms right early on.

quote:

You forget the BIGGEST! Eekthing.

You are not at War with Germany. It is not 1942/3/4/5.
You! Are not under pressure to produce results.

I noted that lacking an effective 20mm weapon that the use of the M2 made sense.

It's not like the USA didn't try to introduce cannon - it did - it was that the Hispano was troublesome initially as it was designed for engine block mounting and the 23mm Madsen became unavailable and the 37mm cannon was problematic for all nations that tried (all but Italy) as an anti-aircraft (in this case anti bomber) weapon. In the end the USA managed fine with the M2, but I was mostly respondinf to the erroneous idea that multiple (e.g. 8) M2 installations offer the level on increase in chance of hitting that some think, nothing more.

Basically 4 Hispano 20mm cannon and 8 M2 HMGs were roughly on a par with each other in terms of chances to hit and destructive power (MG rounds might change things a bit, though, in the MG151/20).