For those interested in tanks and armoured fighting vehicles

[peanuts]

7 hours ago, sir douglas said:

Chieftains. easy to find on the maps too, theres also what looks like an fv432

https://www.google.co.uk/maps/@53.485703,-2.3550563,3a,75y,355.83h,88.42t/data=!3m6!1e1!3m4!1sb3JTmRWlPdIPjAj0Y_eTzQ!2e0!7i13312!8i6656

 

quick searching says that the business estate used to be a royal ordnance factory

they also have three or four tracked apcs plus a couple of sixwheel apc s  and an abbot self propeeld gun at their base in Haywood was lucky enough to use some of them as background for a photoshoot some time ago .one of the APCs was used to assist the fire service fighting the moorland fires around winterhill last summer .

 

 https://www.facebook.com/HeywoodTanks/ 

[Ohmisterporter]

Edited July 30, 2019 by Ohmisterporter
No idea how, when or where it happened but think it interesting.

[Clive Mortimore]

32 minutes ago, Ohmisterporter said:

I know it was a long time ago when I was a gun fitter but using my past experience I would say "Pop it over to the workshop  see what I can do".

 

New barrel about 1/2 days work. Or 2 days if the crew didn't keep me supplied with tea and fags.

[spikey]

That's reminded me of a video I saw a year or two ago from some recent conflict or other, which showed some intrepid soul nip up to a tank and drop a grenade down the barrel.  No doubt this would spoil the crew's day somewhat if the breech just happened to be open, but I've often wondered - what would happen if there was a round up the spout when the grenade went off?

[Clive Mortimore]

9 minutes ago, spikey said:

That's reminded me of a video I saw a year or two ago from some recent conflict or other, which showed some intrepid soul nip up to a tank and drop a grenade down the barrel.  No doubt this would spoil the crew's day somewhat if the breech just happened to be open, but I've often wondered - what would happen if there was a round up the spout when the grenade went off?

All the blast from the grenade would come out the open end of the barrel with the breach closed, with or without a projectile. 

 

Armour piecing shot would not be effected and high explosive shells' fuses are designed to take a far greater shock than a grenade would cause from their own propelling charge.

[Ohmisterporter]

What causes a barrel to split like this, and how common is it? 

[Clive Mortimore]

8 minutes ago, Ohmisterporter said:

What causes a barrel to split like this, and how common is it? 

Hi Geoff

 

It is hard to say by just looking at a photo. Barrels tend to explode either due to poor manufacture, common in wartime where standards can drop or problems with the ammunition, an example the German 15 cm sFH18 went through a period of barrel explosions due to faulty HE shell fuses. Excessive wear on a barrel can in some cases cause a shell to explode prematurely but normally the crew of the tank/gun would be complaining about not being able to hit anything long before that could happen. 

 

Photos of barrels where the barrel at the muzzle end looks like a flower opening can be the sign of a gun crew sabotaging the gun when retreating. 

 

An even rarer cause is an enemy shell finding its way down the barrel just as gun fires so two shells going opposite ways in the barrel collide and mushroom. Thus expanding gases blow the breach end of the gun. When I done my examination of ordnance as a trainee gun fitter there was a cross section of a Bofors barrel where that had happened. You can clearly see the shell at the muzzle end was going pointy end towards the breach. I think the number of times that has happened with modern (post 1897) artillery or tank guns in the past 122 years can be counted on one hand.  I know there have been cases of similar things happen with small arms. 

 

Is the tank a T72? with a smooth bore barrel. It would be interesting to know what caused it, the split is only beyond the fume extractor. 

[exet1095]

According to the Indian press, the Indian Army has had more than 200 barrels bursting on its T-72 fleet, and is buying T-90 parts to replace them.

[34theletterbetweenB&D]

50 minutes ago, Clive Mortimore said:

Is the tank a T72? with a smooth bore barrel. It would be interesting to know what caused it, the split is only beyond the fume extractor. 

That's the clue. The crack will have propagated from an aperture in the barrel wall that is part of the fume extractor arrangement. Whether design or workmanship error, or defective finish, below spec. metal properties or a flaw in the metal at that location; once it fails it will then proceed as crack propagation at close to the speed of sound in the material, chasing the round to the muzzle end.

[Clive Mortimore]

3 minutes ago, 34theletterbetweenB&D said:

That's the clue. The crack will have propagated from an aperture in the barrel wall that is part of the fume extractor arrangement. Whether design or workmanship error, or defective finish, below spec. metal properties or a flaw in the metal at that location; once it fails it will then proceed as crack propagation at close to the speed of sound in the material, chasing the round to the muzzle end.

Conversely the hole in the fume extractor acted like the holes in a three hole disc wheel and prevented the crack from continuing along the barrel. The barrel has bulged and split towards the muzzle the cracked both forwards and rearwards.

 

12 minutes ago, exet1095 said:

According to the Indian press, the Indian Army has had more than 200 barrels bursting on its T-72 fleet, and is buying T-90 parts to replace them.

Hi Paul

 

Thanks for that information, that could well indicate a manufacturing or design flaw.

[Barry O]

Russian tanks went smoothbore as they couldn't make rifled guns to a high enough quality. The Indian ammunition is not the best in the world (the UK did buy some on the cheap and had problems with it).

 

Never seen damage like that on L11 tank guns during my time in the Defence Industry. Could be RO Notts got all of their Quality checks correct.

 

Baz

[34theletterbetweenB&D]

12 hours ago, Clive Mortimore said:

Conversely the hole in the fume extractor acted like the holes in a three hole disc wheel and prevented the crack from continuing along the barrel. The barrel has bulged and split towards the muzzle the cracked both forwards and rearwards...

Where the external rupture first occurred is not necessarily where the failure was initiated. It's like derailments, you have to work back from the end evidence to find where the problem started. See, cracks cannot magically track back and 'find' a stress stopper, whereas damage originating from a location and progressing along the barrel with repeat firings will cause a weakness which will do that. I would have enjoyed involvement in the analysis on this one.

[Clive Mortimore]

44 minutes ago, 34theletterbetweenB&D said:

Where the external rupture first occurred is not necessarily where the failure was initiated. It's like derailments, you have to work back from the end evidence to find where the problem started. See, cracks cannot magically track back and 'find' a stress stopper, whereas damage originating from a location and progressing along the barrel with repeat firings will cause a weakness which will do that. I would have enjoyed involvement in the analysis on this one.

You seem to be the expert , I was only a mere REME gun fitter. In my humble but ex professional opinion I would say to the crew, "Looks like you have broken it."

 

Like Barry I was lucky and never had to fix a blown up barrel or attend the funerals of the gun crew.   

[34theletterbetweenB&D]

10 minutes ago, Clive Mortimore said:

You seem to be the expert , I was only a mere REME gun fitter. In my humble but ex professional opinion I would say to the crew, "Looks like you have broken it."... 

.., and that's exactly the point where teams such as I worked with stepped in. Decades of experience in hardware manufacturing engineering, with much 'characterise mechanism of failure, and eliminate from future production and designs' activity in a wide range of fields. Decades of fun telling designers 'Cannot do that: see para XX.YYY.ZZZ' in design definition. Ooh, I so enjoyed that.

[exet1095]

I wonder what the Indian Army’s stoppage drills are for the T-72 main armament..? 

 

“Gun fires all right, gun fires, louder than usual bang, driver complains periscope blocked...”

 

Mine would be “Coax on! Driver reverse!”

[Clive Mortimore]

1 hour ago, 34theletterbetweenB&D said:

.., and that's exactly the point where teams such as I worked with stepped in. Decades of experience in hardware manufacturing engineering, with much 'characterise mechanism of failure, and eliminate from future production and designs' activity in a wide range of fields. Decades of fun telling designers 'Cannot do that: see para XX.YYY.ZZZ' in design definition. Ooh, I so enjoyed that.

What is it with you? This is not the first thread I have commented on where you have picked part of a sentence of mine and quoted it. Have I done something to upset your life or are you just out to pick on some one?

[34theletterbetweenB&D]

1 hour ago, Clive Mortimore said:

What is it with you? This is not the first thread I have commented on where you have picked part of a sentence of mine and quoted it. Have I done something to upset your life or are you just out to pick on some one?

No, just my slightly obsessive nature. I will ignore all your posts from now so as not to cause upset. Just tell me if I forget, I will not be offended.

[Barry O]

During my time in Land Systems my job was to spot and investigate problems. I had some very good colleagues who could spot a metal defect or design flaw very easily. Once they did see a problem it was investigated very thoroughly to ensue the problem was fixed not just this time , but for all future designs.

 

Some of the kit I worked on has now passed out of use but one celebrated its 25th Birthday this week.. Challenger 2

Best regards

Baz

[sir douglas]

you can see a bulge in the barrel  about a foot in from the end which is also where the crack is at its widest as if an internal explosion, and then maybe some metallurgical fault has split because of that

[sir douglas]

 

[spikey]

Cracking good video, that.  Most interesting.  Thanks ever so for posting it.

[tomparryharry]

On 30/07/2019 at 15:45, Ohmisterporter said:

 

Very dirty barrel, perchance?

[sir douglas]

it is the latest of a 87 video series by the museum

https://www.youtube.com/playlist?list=PLBAEOsdxIbLPFEomzphaZQ0A5Vujkpjd8

[Barry O]

Interesting Challenger 1 video.

 

Some bits are incorrect,, for example CHIP was Chieftain Improvement Programme. CAIP was the Challenger Improvement Programme. Charge bins changed as technology progressed (designed for a 1.5l bottle of spirits to fit easily).

 

I understamd that the T72 long range kill was made using standard AFPSDS not the DU variety. 

 

Baz

 

[Barry O]

I noted that the turreted version (Ajax) of the new racked recce vehicles has not met it's delivery targets. GDLS reckon it will be on time for trails. ...just wait until ATDU finish with it.

 

And the Warrior Turret upgrade is now at discussions of a production contract. It has finished trials. 

 

Baz