±Recent Visitors

Recent Visitors to Com-Central!

±User Info-big


Welcome Anonymous

Nickname
Password

Membership:
Latest: freaknikz
New Today: 0
New Yesterday: 0
Overall: 6598

People Online:
Members: 0
Visitors: 72
Total: 72
Who Is Where:
 Visitors:
01: Community Forums
02: CPGlang
03: Downloads
04: Community Forums
05: Home
06: Community Forums
07: Community Forums
08: Community Forums
09: Community Forums
10: Community Forums
11: Community Forums
12: Photo Gallery
13: Community Forums
14: Community Forums
15: Community Forums
16: Community Forums
17: Community Forums
18: Community Forums
19: Community Forums
20: Community Forums
21: CPGlang
22: Photo Gallery
23: Community Forums
24: Community Forums
25: Community Forums
26: Community Forums
27: Community Forums
28: Community Forums
29: Your Account
30: Community Forums
31: Community Forums
32: Photo Gallery
33: Photo Gallery
34: Photo Gallery
35: Community Forums
36: Community Forums
37: Community Forums
38: Community Forums
39: Community Forums
40: Community Forums
41: Community Forums
42: Community Forums
43: Community Forums
44: Community Forums
45: Community Forums
46: Community Forums
47: Community Forums
48: Community Forums
49: Photo Gallery
50: Community Forums
51: Photo Gallery
52: Photo Gallery
53: Member Screenshots
54: Community Forums
55: Community Forums
56: Member Screenshots
57: Photo Gallery
58: Community Forums
59: Home
60: Community Forums
61: Community Forums
62: Community Forums
63: Photo Gallery
64: Community Forums
65: Community Forums
66: Photo Gallery
67: CPGlang
68: Community Forums
69: Community Forums
70: Photo Gallery
71: Community Forums
72: Community Forums

Staff Online:

No staff members are online!
fume extractors-- questions?
The AFV ASSOCIATION was formed in 1964 to support the thoughts and research of all those interested in Armored Fighting Vehicles and related topics, such as AFV drawings. The emphasis has always been on sharing information and communicating with other members of similar interests; e.g. German armor, Japanese AFVs, or whatever.
Go to page Previous  1, 2
Post new topic    Reply to topic    Printer Friendly Page     Forum Index ›  AFV News Discussion Board

View previous topic :: View next topic  
Author Message
oldtop
Power User

Offline Offline
Joined: Mar 16, 2006
Posts: 70

PostPosted: Mon Mar 20, 2006 11:21 am
Post subject: Re: fume extractors-- questions?

The M46A1 had a bore evact, it was an up grade during the Korean war.
Back to top
View user's profile
SHAWN
Power User

Offline Offline
Joined: Jan 30, 2006
Posts: 484

PostPosted: Mon Mar 20, 2006 12:10 pm
Post subject: Re: fume extractors-- questions?

hey fellas,
thanks for the input. learned a little bit more.

ole top, i hadnt fully realized that about the panther, chaulk up one for for the germans thinking.

shawn
Back to top
View user's profile Photo Gallery
Jinx
Power User

Offline Offline
Joined: Jan 23, 2006
Posts: 186
Location: Canada
PostPosted: Mon Mar 20, 2006 1:38 pm
Post subject: Re: fume extractors-- questions?

- mike_Duplessis
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!



Ok, i have been waiting for someone to bring up this topic (so i wouldn't i have to).

Question 1 - "Fume extractor" and "bore evacuator": what is the difference, if any?

Question 2 - How exactly do they work?

I have seen these on many a tank's main gun barrel.....but i have never been able to find out how the accursed things actually work.

Any descriptions and/or diagrams would be greatly appreciated.
Back to top
View user's profile
Chris_C
Power User

Offline Offline
Joined: Jan 28, 2006
Posts: 211
Location: WV, USA
PostPosted: Mon Mar 20, 2006 1:52 pm
Post subject: Re: fume extractors-- questions?

- oldtop
The M46A1 had a bore evact, it was an up grade during the Korean war.
Actually, all M46s should have had bore evacuators, since they were all armed with the 90mm gun M3A1. This weapon first appeared on the M26A1 Pershing in 1948.

Jinx, here's a sketch to show how bore evacuators work. It's hosted on steelbeasts.com.
Back to top
View user's profile Send e-mail Visit poster's website
SHAWN
Power User

Offline Offline
Joined: Jan 30, 2006
Posts: 484

PostPosted: Mon Mar 20, 2006 2:41 pm
Post subject: Re: fume extractors-- questions?

you will get more elaborate and/or more technical definitions for the extractor but it is basically this�
and as the above mentioned link will explain to you...

on firing, fumes are forced into the extractor by the high bore pressure after the shell has passed the extractor tubes. gas flow ceases when the pressure in the extractor is equal to the pressure in the bore. as the shell exits from the muzzle, the pressure in the barrel drops rapidly and the high pressure fumes exit from the extractor towards the muzzle. this then causes fumes remaining in the chamber to be drawn forward, and the barrel is finally purged by air also moving forward when the breech is opened immediately on run-out
Back to top
View user's profile Photo Gallery
oldtop
Power User

Offline Offline
Joined: Mar 16, 2006
Posts: 70

PostPosted: Mon Mar 20, 2006 2:44 pm
Post subject: Re: fume extractors-- questions?

You got remember that all production M46s were reworked M26s, there were no new vehicles (don't get the M46 covertion version mixed up with the T-40s prototypes).. what happened was the Korean war. and the M46s were so badly needed that the M3A1 guns were fitted to the M46, later any left over went to the M26s. Some say that the records show differant but whats in the records ain't carved in stone, if you look at the left front towing clevis mount and front slope plate there are two differant serail numbers one for the M26 and one for the reworked M46.
Back to top
View user's profile
Jinx
Power User

Offline Offline
Joined: Jan 23, 2006
Posts: 186
Location: Canada
PostPosted: Mon Mar 20, 2006 8:16 pm
Post subject: Re: fume extractors-- questions?

- Chris_C
Jinx, here's a sketch to show how bore evacuators work. It's hosted on steelbeasts.com.



Excellent! That was exactly what i was looking for. I really appreciate it.

Of course, this brings up another question : how often does this have to be cleaned? I am guessing that over time residue from the propellant will clog up the vent tubes.....no?
Back to top
View user's profile
Dontos
Power User

Offline Offline
Joined: Jan 23, 2006
Posts: 3436
Location: Vine Grove, KY
PostPosted: Tue Mar 21, 2006 5:13 am
Post subject: Re: fume extractors-- questions?

Currently, crews do PM which can include pulling the Bore Evacuator and cleaning the 'jets' out with pipe cleaners and cleaning the carbon buildup off the gun tube, when ever needed. Frequency is based on use. Its not too difficult a task a length of rope (or several rags), green scratch pad, and some 'breakfree'.

_________________
"Gonna hold my breath until Armor returns home..."
Back to top
View user's profile Send e-mail Visit poster's website AIM Address Yahoo Messenger Photo Gallery
L.Delsing
Power User

Offline Offline
Joined: Feb 09, 2006
Posts: 941

PostPosted: Tue Mar 21, 2006 11:31 am
Post subject: Re: fume extractors-- questions?

[quote="Dontos"][quote="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


Sgt, Scouts Out! Smile


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.

Hello,
So, if I understand correctly you have to put the NBC overpressure system on (which needs the engine) to fire the maingun.

The M1 and Leopard have both the same gun with the gun of the M1 licence built with some minor changes. When firing the main gun (Leopard) I never experienced much fumes. Most of the times with only main gun actions the turretventilator was off because of the noise of it.

Of course when firing the coax the ventilator was on.

Is this NBC thing on M1s because of enviromental/health regulations???

Regards,
Lesley
Back to top
View user's profile
Dontos
Power User

Offline Offline
Joined: Jan 23, 2006
Posts: 3436
Location: Vine Grove, KY
PostPosted: Tue Mar 21, 2006 1:45 pm
Post subject: Re: fume extractors-- questions?

- L.Delsing

Hello,
So, if I understand correctly you have to put the NBC overpressure system on (which needs the engine) to fire the maingun.

The M1 and Leopard have both the same gun with the gun of the M1 licence built with some minor changes. When firing the main gun (Leopard) I never experienced much fumes. Most of the times with only main gun actions the turretventilator was off because of the noise of it.

Of course when firing the coax the ventilator was on.

Is this NBC thing on M1s because of enviromental/health regulations???

Regards,
Lesley


Lesley

The NBC system works thru the engine, so if the engine is off, the NBC system is non-operational.

'Officially' a 'non-operational' NBC system, is a safety deadline. so one can use the system to get work done on a higher priority, if you 'threaten' to deadline the tank.

There is no 'official' prohibition to firing, shutdown.

Firing the main gun has no affect on the NBC system and vice-versa. Going 'COAX', the system cuts on as a turret blower, so if the engine is off, the crew sucks up more fumes....

Hope that clears up things a little.

_________________
"Gonna hold my breath until Armor returns home..."
Back to top
View user's profile Send e-mail Visit poster's website AIM Address Yahoo Messenger Photo Gallery
Jinx
Power User

Offline Offline
Joined: Jan 23, 2006
Posts: 186
Location: Canada
PostPosted: Tue Mar 21, 2006 3:49 pm
Post subject: Re: fume extractors-- questions?

- Dontos
Currently, crews do PM which can include pulling the Bore Evacuator and cleaning the 'jets' out with pipe cleaners and cleaning the carbon buildup off the gun tube, when ever needed. Frequency is based on use. Its not too difficult a task a length of rope (or several rags), green scratch pad, and some 'breakfree'.



Thank you for the info, sir!
Back to top
View user's profile
L.Delsing
Power User

Offline Offline
Joined: Feb 09, 2006
Posts: 941

PostPosted: Wed Mar 22, 2006 12:35 pm
Post subject: Re: fume extractors-- questions?

Thanks Don!

Regards,
Lesley
Back to top
View user's profile
Display posts from previous:   
Post new topic    Reply to topic    Printer Friendly Page    Forum Index ›  AFV News Discussion Board
Page 2 of 2
All times are GMT - 6 Hours
Go to page Previous  1, 2



Jump to:  


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You cannot download files in this forum