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Gibbage1
04-14-2004, 04:46 PM
OK. Im not talking in-game. We all know there is currently a little problem with the P-38's ammo and Oleg said he would address it with the next patch.

I was doing a little math on the M2 gun. At 750RPM (the average firing time for the aircraft mount, un synced) you should get 40 seconds of firing time with 500 rounds. But the P-38 manual and everything I read about the P-38 states it has 33 seconds of firing time. Can anyone explain this? According to my math, the M2 would need to fire at 900RPM in order to dispense 500 rounds in 33 seconds!

My post's are my asumptions only, and in no way linked to fact. I am not an official 1C, Ubi, or Russian Red Rocket spokesman.

"Most P-39's were sent to the Russians - so I guess that was an American secret weapon against our Russian allies."

Stan Wood, P-38 pilot who also flew the P-39.

Gibbage1
04-14-2004, 04:46 PM
OK. Im not talking in-game. We all know there is currently a little problem with the P-38's ammo and Oleg said he would address it with the next patch.

I was doing a little math on the M2 gun. At 750RPM (the average firing time for the aircraft mount, un synced) you should get 40 seconds of firing time with 500 rounds. But the P-38 manual and everything I read about the P-38 states it has 33 seconds of firing time. Can anyone explain this? According to my math, the M2 would need to fire at 900RPM in order to dispense 500 rounds in 33 seconds!

My post's are my asumptions only, and in no way linked to fact. I am not an official 1C, Ubi, or Russian Red Rocket spokesman.

"Most P-39's were sent to the Russians - so I guess that was an American secret weapon against our Russian allies."

Stan Wood, P-38 pilot who also flew the P-39.

Lav69
04-14-2004, 04:55 PM
And how much fire time do you need? Fly online much? 33 or 40 seconds, who cares. Too many nick picky threads and complaints.

_______________
I'm fixin to.

Gibbage1
04-14-2004, 04:58 PM
Im not talking on-line. Im talking real-life here. If the gun fires on average of 750RPM, how is it going to dispense 500 rounds in 33 seconds?

My post's are my asumptions only, and in no way linked to fact. I am not an official 1C, Ubi, or Russian Red Rocket spokesman.

"Most P-39's were sent to the Russians - so I guess that was an American secret weapon against our Russian allies."

Stan Wood, P-38 pilot who also flew the P-39.

Red_Russian13
04-14-2004, 04:59 PM
I didn't notice a complaint, just a question.

Plus, I sure could use the extra seven seconds. I'm a horrible shot. But all in all it's not a big deal.

Gibbage - I don't know the answer to your question. Far as I know, the 750rpm is correct, but you're right about the math. I'm sure they'll fix it soon...

Red Russian

pinche_bolillo
04-14-2004, 05:37 PM
america's hundred thousand stats 33.3 seconds and that has always baffled me as well. 750-800rds a min is generally accepted as the correct rate of fire for an M-2 so that would mean 40 seconds of fire, which is half of what we get in the game. its only 20 seconds in the game.

perhaps it is a misprint in the book. I have bought a lot of books printed by schiffer publishing, which printed america's hundred thousand. they are usually well researched books that have a lot of pics and data I have never seen before, but they also have a lot of errors such as type os and bogus figures when printing numbers. I mean sometimes the numbers are just impossible to mach up with the performance of the a/c they are talking about. usually somewhere else in the book the data is reprinted, but the figures jibe with the a/c then. every book I have from this publisher has these errors in them. so it could be possible they put 33.3 as an error.

SeaFireLIV
04-14-2004, 05:44 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Lav69:
And how much fire time do you need? Fly online much? 33 or 40 seconds, who cares. Too many nick picky threads and complaints.

_______________
I'm fixin to.<HR></BLOCKQUOTE>

I agree with Lav69. And though Gibbage says it`s not a complaint to do with online FB it looks like becoming one and we know what happens when that begins, don`t we?

Korolov
04-14-2004, 05:47 PM
The M2's ROF is so variable and customizable, it's probably going to be within 30-40 seconds of firing time, especially on a mount like the P-38's.

http://www.mechmodels.com/images/newsig1.jpg

Gibbage1
04-14-2004, 06:05 PM
I have seen 33 seconds of trigger time on many many sources. In order to get that, the M2 needs to fire at 900RPM. Then you get 33.3333333~ with 500 rounds.

I think even the training video on Zeno's said 33 seconds.

My post's are my asumptions only, and in no way linked to fact. I am not an official 1C, Ubi, or Russian Red Rocket spokesman.

"Most P-39's were sent to the Russians - so I guess that was an American secret weapon against our Russian allies."

Stan Wood, P-38 pilot who also flew the P-39.

El Turo
04-14-2004, 06:13 PM
My understanding of ROF is that the listed figures are at beginning state with full ammo.

As the ammo is expended, the weight/resistance decreases and the rate of fire actually increases as you get closer to the end of the belt/drum.

This may account for the difference in firing time vs. listed ROF figures that you are finding.

Callsign "Turo" in IL2:FB & WWIIOL
______________________
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Lightning strikes, süsse träume.

PzKpfw
04-14-2004, 06:25 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Gibbage1:

I was doing a little math on the M2 gun. At 750RPM (the average firing time for the aircraft mount, un synced) you should get 40 seconds of firing time with 500 rounds. But the P-38 manual and everything I read about the P-38 states it has 33 seconds of firing time. Can anyone explain this? According to my math, the M2 would need to fire at 900RPM in order to dispense 500 rounds in 33 seconds!

<HR></BLOCKQUOTE>

The M2's ROF despite being reported alot as 750rpm, was not set in stone Ie, the British tests with the M2 were getting over 780rpm. AHTs data on the M2 puts ROF @ 800 - 900rpm, (15 rounds per sec). Hence an 33.3 sec fireing time.

Also ROF varies, & is affected by other factors Ie, mounting, feed, how many rounds left in the belt, etc. Ie, In tests with the
P-51B's 4 x .50, it was found that the initial rof was 700 - 800rpm, but as the ammo was expended, and weight and drag was lessening as each round was expended, that ROF increased, so that near the end of the belts, the M2's ROF had increased to over 950rpm.

Regards, John Waters


---------
Notice: Spelling mistakes left in for people who need to correct others to make their life fulfilled.

----
The one that gets you is the one that you'll never see.

-----
"The damn Jerries have stuck their heads in the meatgrinder, and I've got hold of the handle."

Lt.Gen. George S. Patton, Jr. December 26, 1944.

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[This message was edited by PzKpfw on Wed April 14 2004 at 05:35 PM.]

Gibbage1
04-14-2004, 06:30 PM
So it starts out at 750RPM, but eventually gets over 900RPM? I can see a little variance, but not THAT much. Remember, an average of 900RPM to despense 500 rounds in 33 seconds. If the gun starts at 750, it would need to end somewere around 1100-1200RPM. Thats just insane ammount of variance because of ammo weight. Also remember how ammo is stacked in the box. Overlapping layers. So its only pulling 1 layer at a time and the bottom layers have no effect. So if an ammo box is 50x10 (50 rounds per layer, and 10 layers) the max the gun is pulling on is 50 rounds, then it pulls less and less till the next layer and then its at 50 rounds. In some gun configs the ammo bin is longer but more shalow like in the P-47 and p-51. I think its 75x3 or something like that. But the P-51 I think is 50x10. Im not sure.

Gib

My post's are my asumptions only, and in no way linked to fact. I am not an official 1C, Ubi, or Russian Red Rocket spokesman.

"Most P-39's were sent to the Russians - so I guess that was an American secret weapon against our Russian allies."

Stan Wood, P-38 pilot who also flew the P-39.

tttiger
04-14-2004, 06:40 PM
Hey Gib!

This is from "The Jungle Air Force," an excellent web site on P-38 real life tactics:

"Our planes are equipped with gun booster. The rate of fire is so increased that a four second burst will burn out the barrels on the first burst. Succeeding bursts must be reduced in length to two second maximums if firing is in quick succession."

That may explain why your math isn't working.

Shhhh..don't tell Oleg or he'll model the barrels meltinghttp://ubbxforums.ubi.com/infopop/emoticons/icon_biggrin.gif

Here's the whole site. A very good read:

http://www.enter.net/~rocketeer/13thtactics.html

Aloha,

ttt

"I want the one that kills the best with the least amount of risk to me"

-- Chuck Yeager describing "The Best Airplane."

pinche_bolillo
04-14-2004, 06:48 PM
if you look at the data that is provided in america's hundred thousand under the "armament section", all 50 cal data is based on 15 rds a second for the 50 cal, which means its based on 900 rds a min. all the fire times on all the 50 cal armed a/c in america's hundred thousand are based on that data, I believe the F6F fire time listed in that book gives the hellcat a rate of fire of 16 rds a second or 960 rds a minute. I dont know is AHT correct? is it really 900 rds a minute? or is the 750-800 rds a minute that is in many other books accurate?

also on the gun barrels being shot out, early guns when cold could fire a 75 rd burst, and then sustain 25 rd busts there after w/ a 2-3 second pause between bursts w/o damaging the barrel. sometime in late 43/early 44 new 50 cal barrels became standard, these new barrels had crome liners in them and the barrel burn out was pretty much a thing of the past.

I have read jungle ace or is it jungle airforce?? as well, that and many other books state similar stories about guys shooting their barrels out because of sustained bursts of fire, if you note when this occured it is always during the 1942/43 years, before the new barrels were used.

HangerQueen
04-14-2004, 07:55 PM
Trigger time - is that like bullet time, then? http://ubbxforums.ubi.com/images/smiley/16x16_smiley-wink.gif

http://server5.uploadit.org/files/HangerQueen-Within_the_Realm_Dying_Sun2copy.jpg

Despite repeated warnings, Jason continued to loiter outside the public lavatories dressed as Pestilence.

VMF-214_HaVoK
04-14-2004, 08:45 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by SeaFireLIV:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Lav69:
And how much fire time do you need? Fly online much? 33 or 40 seconds, who cares. Too many nick picky threads and complaints.

_______________
I'm fixin to.<HR></BLOCKQUOTE>

I agree with Lav69. And though Gibbage says it`s not a complaint to do with online FB it looks like becoming one and we know what happens when that begins, don`t we?<HR></BLOCKQUOTE>

Nobody forces anyone to veiw and/or reply to any threads on these forums. If you see a thread that you dont agree with then why do you feel it is a must that you come in and complain about what you say is a complaint.

And as far as I can see its a question. Remarks from yourself and Lav69 is what turns a simple question into a fireball.

http://www.flightjournal.com/fj/images/hellcat_head_short.jpg

hobnail
04-14-2004, 08:45 PM
I recall reading that groundcrew used to place metal discs (often coins) behind the recoil spring of the M2 to up it's rate of fire. A more official version of this modification was included in the M3 I think.

Not that Oleg simulates unsanctioned and untested field mods, so it's a moot point really.

A130
04-14-2004, 08:48 PM
Very good point on machinegun ROF increasing as the belt gets shorter -- it isn't so noticable with the M2, but you REALLY notice with the smaller guns. Even in a 100 rd. belt, you'll hear the gun picking up speed as it progresses. You'll also hear it slow down if you let the belt dangle out of the feed box...but I digress.

900 RPM sounds a little fast for the M2. Rates of fire can vary quite a bit between different guns; no joke, you can unpack several brand new M2's and run a few belts of ammo through each, and one will probably be noticably faster or slower than the others. ALL MG's change their ROF slightly over the course of the weapon's life as they accumulate wear and tear, but M2's are notorious for it. I haven't seen it specifically mentioned, but I'd think that the aircraft version of the M2 with its lighter barrel would have a noticably higher ROF than the HB version used right now, as the M2 is recoil operated and the mass of the barrel should have a real effect on ROF.

About shooting out barrels...it used to be easier than it is today (no Stellite bore liner, and the aircraft models had barrels that're considerably lighter than what's used presently), but with the airflow provided by the aircraft, it still couldn't have been too easy. I've never read an account that mentioned this, but it could've been that the pilots just didn't notice in all cases. (I'm sure the armorers on the ground did. I've seen barrels with the rifling shot out of them. It's not pretty.) I can say from experience that even if you overheat the things pretty badly, they usually keep on ticking. I've never seen one fail from heat. (In fact, the only M2 I've ever seen seriously damaged was one that was run over by a 10,000 lb. fork truck; after whaling on it with a hammer, I kind of got it to work, but it wasn't reliable and we wound up returning it.)

gates123
04-15-2004, 10:02 AM
My calculator broke.

http://www.fortunecity.com/meltingpot/justin/1087/WWII/Images/Thumbs/TBf109AK.jpg
Did anyone see that or was it just me?

pinche_bolillo
04-15-2004, 12:22 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by A130:

About shooting out barrels...it used to be easier than it is today (no Stellite bore liner, and the aircraft models had barrels that're considerably lighter than what's used presently), but with the airflow provided by the aircraft, it still couldn't have been too easy. I've never read an account that mentioned this, but it could've been that the pilots just didn't notice in all cases. (I'm sure the armorers on the ground did. I've seen barrels with the rifling shot out of them. It's not pretty.) I can say from experience that even if you overheat the things pretty badly, they usually keep on ticking. I've never seen one fail from heat. (In fact, the only M2 I've ever seen seriously damaged was one that was run over by a 10,000 lb. fork truck; after whaling on it with a hammer, I kind of got it to work, but it wasn't reliable and we wound up returning it.)<HR></BLOCKQUOTE>

flying guns by tony williams isbn 1840372273

page 150

"Even at 800 rpm barrel wear was a severe problem, and pilots and gunners were instructed to fire short bursts with adequate time in between them to cool the barrel. A cold gun could fire a burst of 75 rds without damage, but after that the gun was restricted to 25 rd bursts. Too long a burst would heat the barrel too much, the rifling would wear out, and accuracy would be lost. This problem was not solved until January 1944, when stellite lined and chromium plated barrels were approved as standard"

so like I said earlier, stellite lined and chromium plated barrels were used and imployed to solve the problem of burning out barrels quickly. I am sure they could still be shot out, but my point is in the books I have read where pilots complained about shooting their barrels out, it was always during 42/43

BlindHuck
04-15-2004, 12:49 PM
Concerning 0.50-calibre M2 -"In one test as much as 200 rounds per minute difference was recorded between guns in the same fighter. A static test carried out in March 1944 by 4th Group on a P-51B with flash hider and muzzle booster attachments gave a wider variation. Without any attachments the gun fired 694 rounds per minute. With a flash hider this was reduced to 677 rpm. When the booster was fitted 857 rpm was attained but after firing 600 rounds in short bursts the rate rose to 949 rpm."

Of interest - "There were combat tests of experimental ammunition, the most notable was identified as T-48, a concentrated incindiary round intended for use against the low-grade fuel in jet aircraft. Muzzle velocity was 3400 feet (1036 m) per second and fighter aircraft required a new harmonisation pattern to use it effectively. The 56th Group tested T-48 successfully in strafing attacks on airfields in April 1945." Sounds like just the thing for those pesky 162's and 229's, eh? http://ubbxforums.ubi.com/images/smiley/16x16_smiley-happy.gif

Quoted from The Mighty Eighth War Manual page 230.

"I race full real exclusively in IL2:The Forgotten Battles." - Mark Donohue

tttiger
04-15-2004, 02:33 PM
Thank you, Blind Huck. Everyone seemed to ignore my post above from a WWII PTO tactics manual that said the .50s in P-38s had boosters on them. The original topic of this thread was why did the .50 ammo in a Lightning run out so quickly if the cyclic rate was 750? Well, with a booster, the cyclic rate was around 900. I think that explains it.

As to barrels, Pinche is correct in the fact that chromed barrels showed up in mid-war. They were an improvement but not the panacea Pinche claims they were.

Perhaps melt is a bit too strong a word. They warp or bend when they get too hot. And they still do.

That's why us ground pounders carried extra machine gun barrels and those big heavy mitts to protect the hands while removing the old, hot barrel.

It was the mark of a disciplined gunner that he could hold to six round bursts even in close combat. If he didn't, he ruined the barrel and there wasn't time in a firefight to swap it out for a new one.

Sure, I prefer a chromed barrel. But it still doesn't allow you to go cyclic and just hold down the trigger. Been there. Done that. In two wars. And, when I lived in Arizona where it's legal, I used to collect (and shoot) machine guns.

As to gun damage. the worst I ever saw was when the back plate on an M2 mounted on an track blew off at a training range. The back plate literally was embedded in the gunner's abdomen. I was a young MP captain at the time and by chance was driving my Jeep by the range when the gun blew and helped keep the guy alive until we could get a dustoff in there. The roads were so bad the guy never would have survived in a ground ambulance. The Huey pilot flew into this tiny clearing in a wooded area in quirky winds and very heavy fog to pick the guy up. One of the most heroic things I've ever seen. The gunner lived.

Ah, enough war stories. That was another life http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

The simple answer to the original question is: Boosters.

Aloha,

ttt

"I want the one that kills the best with the least amount of risk to me"

-- Chuck Yeager describing "The Best Airplane."

Jippo01
04-15-2004, 02:51 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by PzKpfw:
it was found that the initial rof was 700 - 800rpm, but as the ammo was expended, and weight and drag was lessening as each round was expended, that ROF increased, so that near the end of the belts, the M2's ROF had increased to over 950rpm. <HR></BLOCKQUOTE>


Where do you pick this up? I never heard about such thing or noticed it myself. Rounds are in box in rows or layers, and the gun only pulls the top one. Other layers stay put until they become the top layer and get fed in, thus there can be no difference "in the weight of the belt". So what's this story?

And the chromium barrels don't protect the barrel enough, rifling will get ruined in HMG if a looong burst is fired. Never tried that but I tend to believe it coming from the guys who were instructing. Barrel and the gun heats up that much that snow boils on the gun good fifteen minutes after firing.


-jippo

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