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SHAWN · ***Power User*** Offline Joined: Jan 31, 2006 Posts: 484

i was just looking over some reading material and ran across some items on the fume extractor, etc. and it then seemed "modern" to me. almost taken for granted in large calibre evolution...

i have never really thought of it before and havent read much in particular to it, but it must have been even more "atmospheric" in many of the larger calibred tanks/SPs of WW2 (especially the russians, few of the germans) considering they had no fume extractors.
as if the creature comforts in the soviet vehicles werent exquisite already.
i can only think this must have been a big problem. glad i wasnt in the vehicle.
can anyone relate?
shawn

Dontos · Posted: Mon Mar 20, 2006 2:59 am Post subject: Re: fume extractors-- questions?

'Bore evacuators' are more nice but not designed as a purely 'creature comfort' with the crew inmind.

I used to love 'smoking' the fumes that filled the turret, when firing with hatches closed. (one of many little quirks, that I have been known for in the past...)

With the NBC system and overpressurization, there is really little fumes in the Abrams turret anymore.

Cracking hatches helps, but the turret fan or blower was designed to circulate or recirculate 'stale' air.

SHAWN · ***Power User*** Offline Joined: Jan 31, 2006 Posts: 484

hey dontos,

you seem to have many a "quirk" dont you...

you know, this new site seems pretty cool for AFVnews, i think i am liking it alot more than the older site, and i really enjoyed that site.
shawn

SHAWN · ***Power User*** Offline Joined: Jan 31, 2006 Posts: 484

okay, i am going to play really dumb on this on dontos, what else was the fume extractor designed for, as far as gun operation, etc.?

Dontos · Posted: Mon Mar 20, 2006 3:16 am Post subject: Re: fume extractors-- questions?

HA...you gotta 'catch up'. Many cool little things here. Cool

Joe_D · Posted: Mon Mar 20, 2006 3:46 am Post subject: Re: fume extractors-- questions?

Shawn,
Don't let Donto's cavalier attitude fool you, them fumes can get pretty bad when the evacuator doesn't work. Until the M1A1 came out that's all you had along with the turret blower. The blower would suck air in to the turret and force the fumes out, a lot of laymen think the opposite. With combustable casings the bore evacuator prevents flareback (IAW the "Book"). It's also all you have unless the NBC overpressure system is on, the blower was replaced by it. Any unburnt residue left in the chamber will flare up as soon as the gun goes back into battery opening the breech and ejecting the cartridge base giving it oxygen. The bore evacuator lowers the atmospheric pressure in the gun behind it. When the breech opens the higher pressure in the turret rushes in and expells the fumes and potential flare towards the end of the gun tube.
With all that, aquestion for Dontos. Riddle me this, was it authorized on the M1A1/A2 to fire main gun with the engine off ???? War time doesn't count.

Joe D

PS: WELCOME BACK Ole Top, I missed you too.

Dontos · Posted: Mon Mar 20, 2006 11:31 am Post subject: Re: fume extractors-- questions?

- Joe_D

Shawn,
With all that, aquestion for Dontos. Riddle me this, was it authorized on the M1A1/A2 to fire main gun with the engine off ???? War time doesn't count.
Joe D

NOPE!! ...do I have to explain?

Roy_A_Lingle · Posted: Mon Mar 20, 2006 11:51 am Post subject: Re: fume extractors-- questions?

- Dontos

- Joe_D

Shawn,
With all that, aquestion for Dontos. Riddle me this, was it authorized on the M1A1/A2 to fire main gun with the engine off ???? War time doesn't count.
Joe D

NOPE!! ...do I have to explain?

For all us NON-M-1 tankers (the M1 was after my time), YES, YES, YES, YES you must explain!

If I could fire my M-139 20mm autocannon on a Lingle in full auto or single shot without any power,

why cann't a M-1 do it?

Sgt, Scouts Out! Smile

Dontos · Posted: Mon Mar 20, 2006 12:40 pm Post subject: Re: fume extractors-- questions?

- Roy_A_Lingle

- Dontos

- Joe_D

Shawn,
With all that, aquestion for Dontos. Riddle me this, was it authorized on the M1A1/A2 to fire main gun with the engine off ???? War time doesn't count.
Joe D

NOPE!! ...do I have to explain?

For all us NON-M-1 tankers (the M1 was after my time), YES, YES, YES, YES you must explain!

If I could fire my M-139 20mm autocannon on a Lingle in full auto or single shot without any power, why cann't a M-1 do it?
Sgt, Scouts Out!

The NBC system which is required to overpressurize the tank, works off of the running engine.

There are a couple of other reasons I can think about but nothing 'official' that I can remember.

I had an 'old' IPM1 in Germany that would 'fire' the driver halon bottle if you ran the heater with the engine off. That was my first 'taste' of halon, during an 'alert'. We were in a tactical shutdown at the "LDA", awaiting upload. Laying on the front slope, talking to the driver,.....PSSSSSSS RIGHT IN THE FACE!!!. Shocked

(MMMM, MMMM Good!!) I was spitting Halon for a couple of days. Mr. Green

Joe, remember the early days of the 120? Unloading a HEAT round? HAHAHA... handing the loader thesash brush and a dust pan...

(to the loader)
JUST SCOOP IT UP Shocked

AND PUT IT BACK IN THE BREECH, THEN SHOVE THE AFT CAP BACK ON!!!! Shocked

"Tower, this is _____, request permission to fire chambered round...Could you pop a target?"

Bring back any memories?

Dontos · Posted: Mon Mar 20, 2006 12:46 pm Post subject: Re: fume extractors-- questions?

QUESTION TO JOE:

Ever use the sledge hammer on the 120 Bore evacuator? ( Mr. Green

)

ANSWER: ??? Shocked

(Me?....once!

)

Joe_D · Posted: Mon Mar 20, 2006 1:19 pm Post subject: Re: fume extractors-- questions?

Yeah,
Better hope you didn't have some hot aft caps on the floor when it did. High adventure then.
Never seen any official written rule about main gun fire requiring the engine on. The round about answer was the Tank was safety deadlined for main gun fire if the NBC main system was down. Never stopped me but I did use that deadline to get all my systems repaired in a timely manner.
Never had a problem getting a 120 evacuator off. Had a few 105's needing the old 10lb solution. They were on M60A1's on their last legs of life. Could always tell who had a sticky one because the back was bashed in. Howz cum yoos got to bash yours???

Joe D

Dontos · Posted: Mon Mar 20, 2006 1:28 pm Post subject: Re: fume extractors-- questions?

- Joe_D

Could always tell who had a sticky one because the back was bashed in. Howz cum yoos got to bash yours???
Joe D

As an 'IP' tanker going into transition onto M1A1's,....

Always had to use the sledge on my ol' M1's & IPM1's, no matter how much lube is applied previously,.... so....

WHACK!!! Shocked

(uh oh,....Hey, wheres that 2404...? I got something else to write down...

)

Joe_D · Posted: Mon Mar 20, 2006 1:33 pm Post subject: Re: fume extractors-- questions?

So that's the rest of the story,

It happens.

Joe D

oldtop · ***Power User*** Offline Joined: Mar 17, 2006 Posts: 70

When firing the 90mm on the M48 (even with it's "bore evacuator") the breech gases were so bad I wore a M14-17 vehicle crewmen's field protective masks, if you left the @#$@ turret blower on you couldn't hear a thing, with the M48A3 you had a air filtering unit and you could plug your mask into it.
....The main gun round ( 90 and even 105) were some what smaller back then and a lot of loaders (me when acting as a loader) would "lap-load" which was when the loader sat on his knees just behind and to the left of the main with four or five rounds across his lap, the gunner cold fire four rounds in 30 sec this way. The breech gases would get very thick .
....On the selfpropelled guns like the M109 ( first versions 155 mm Howitzers) the bore evacuators worK with rolling ball check valve system and in Nam they quickly wore out and became useless (someone forgot to reorder them and the "O" rings in the supply system...something like repair parts for that @#%$# Ontos M50 "PIG"!!!!.
....Sorry I get a little upset when thinking about the Marine Corps so called "supply system" Grrrrrr. Anyway the fumes would get so bad in the gun cabs you worked in a greenish haze and when you stood down from a fire mission your skin was covered with a coating that you had to wash off with soap and water (if you didn't use soap the coating turned to a greenish slime) you also deveolped what was called "gunner's chough" as the slime came out of your lungs
...Even as the Battery maint chief I stood in as a "number one man" in a gun section (thats the rammer-jammer) . As No. 1 you rammed home the projo with your fist (hyd rammers were only used for "danger close" missions) then loaded the propelent charge, hit the breech cam (this relested the the 100 lbs breech block which was under spring pressure, this was watch your fingers time!!) The no.1 man also had his mouth full of primer cartridges and he would insert one in the percussion mechanism and slap it to firing postion, the command was "stand by....fire" and you pulled the lanyard (not jerk) ..band and the gun recoiled back ,the breech open on return to "battery" and the breech cam plate held it open.
...In May of 1969 Kilo 4/12 went into a fire mission at 08:00 and at 08:00 the next morning they were still in that mission, the guns were so hot that the water they were being sponged with was turning to steam and the Hyd fluid was blowing out of the system acculators.. there were greenish fumes that could be seen drifting out the cabs side hatches. This fire mission was in support of the Army troopers fight for "Hamburger hill".
...The empty powder cans and projo pallets were piled over 8' high behine each gun, during this fight kilo 4/12 was under "counter battery" fire by 130mm guns in the DMZ over 30,000 yards away, Kilo never broke from the support mission , they took the enemy fire and kept on firing. At the time Kilo's postion was at a little hell hole of a fire base called "The Rockpile". The Battery fired over 3,000 rounds during the fire mission. A side note, the rate of fire for an M109 by the book was one round per minute, Kilo was firing 3 to 4 per minute...how those boys did shine!
...By the way the German WW II Panther tanks had an "air injection" system to clear the fumes out the muzzle from the breech and gun tube.

mike_Duplessis · ***Power User*** Offline Joined: Jan 24, 2006 Posts: 236

I'm trying to think - who gets credit for first putting a 'modern' bore evacuator can onto a gun barrel? The British 20 pounder? The M47's 90mm gun, or the 100mm gun on the T-54? They all seemed to pop up at exactly the same moment!

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