P-38 Guns

[Tac]

neg skurj, I had heard that with it off caused rubber bullets, even tried it, same result with either thing. Im not saying the guns dont do damage, of course they do. Im just saying that its not proportional to having the firepower concentrated in such a tight spot.

[Blue Mako]

Originally posted by Tac:
But when you got 4 .50's and 1 20mm firing in an area no bigger than a soccer ball... that thing should do some serious damage upon impact!...

On relative moving targets moving THROUGH the stream of fire, the bullets would still hit quite close together...

Sorry but your bullets would NOT be hitting close together.  Even at close range, the spread of the rounds landing on the bandit would still be large because of the high rate at which he crosses your path.  4 mg's and 1 cannon cannot get enough lead in the air to guarantee a fatal hit when the target is not held in your bullet stream.  Think of how long the bandit is flying through your bullet stream.  0.5 sec? 0.1 sec? less?  How many rounds does your plane fire in that time?  20? 10?  How many of them land at the same place?  I think it is pretty reasonable that only a lucky hit will down a plane under such circumstances...

Then again, I might be wrong.  

[Tac]

Widewing, would there be any difference (as far as dispersion/lead concentration) on a P-38's .50's at 200yds when compared to 1000yds? At 1000 yds will the 4 bullets still hit "as one"?

Also, do all 4 .50's on the 38 fire at the same time or did they fire 1 by 1 (albeit milliseconds apart from each other)?

Finally, you know where I can get a copy of the whole set of "HANGAR FLYING" magazine that was issued to 38 pilots during the war?

[Tac]

HT just said that the current .50's have twice the dispersion they should have. I think the answer lies there.

[Widewing]

Originally posted by Tac:
Widewing, would there be any difference (as far as dispersion/lead concentration) on a P-38's .50's at 200yds when compared to 1000yds? At 1000 yds will the 4 bullets still hit "as one"?

Also, do all 4 .50's on the 38 fire at the same time or did they fire 1 by 1 (albeit milliseconds apart from each other)?

Finally, you know where I can get a copy of the whole set of "HANGAR FLYING" magazine that was issued to 38 pilots during the war?

Normal dispersion can be assumed to be related to normal accuracy. Since a well maintained Browning M2 should group its round at something less than 2 inches at 100 yards, I imagine that normal dispersion cone per gun at 1,000 yards should be in the area of 24 inches. If the quality of the ammunition is consistant, all the rounds fired simultaneously should arrive within a very few milleseconds of each other. You should realize that virtually all of the dispersion cones will overlap at longer ranges.

Since all the firing solenoids are switched at the same time, and because each solenoid will pull faster or slower than any other (we're probably talking about microseconds), it is not possible to accurately guess what the firing sequence is. Nonetheless, I feel safe saying that for all practical purposes, they fire at the same time.

As to your last question: I do not know where you can get a full set of the magazines.

My regards,

Widewing

[SFRT - Frenchy]

Originally posted by Tac:

Many times, almost always in fact, a plane begins a tight turn to avoid a diving 38, I get a clean snapshot at it as it banks, the plane is an x-mas tree from nose to tail as it passes by my nose on its turn.

Well it's exactly the same with a P47 and I have 2 times more of those. I think it's the disavantage of the non-conon planes. Take a Niki/F4C/FW, the same x-mas tree will rip a wing.
In those shots with the P47 I see usually 5-8 pings, but with canons I see 3-5 pings, it's probably the rate of fire.
(I'm not criticizing anaything here, I'm just telling my experience).

[HoHun]

Hi Tac,

The vibrations induced by multiple rapid fire weapons lead to a dispersion that's far greater than the individual weapon's error, and the uneven firing sequence of unsynchronized weapons contributes to this.

I've not seen any figures for typical variation of the cycling peroid of machine guns, but I'd say it's great enough to turn the bullet stream into a random sequence within seconds. You can watch it happen on old films showing Il-2s strafing ground targets: One second, both wings spit flames at the same time, the next second they alternate :-)

I think Widewing is accurately describing the first salvo when the gun mounting is in rest. Probably dispersion ramps up to the full value a few cycles after that, but I'm speculating here. Probably the RAE report on their vibration problems with the quadruple machine gun turrets would give the details ;-)

I think for the P-38, the service manual describing the gun calibration procedure would give the desired result with regards to dispersion, so we could be able to find out if we're lucky and someone discovers a copy of that manual.

Regards,

Henning (HoHun)