I am currently wrestling with the Commander Models MBT 70; I note that on the rear of the turret is what appears to be an ejection port; it could of course be some kind of inspection/maintenance panel.

Without pursuing too much "What-iffery" I am hoping to display the model (eventually!) as envisaged in service.

I am aware that the 152mm gun used combustible ammunition but wonder if in fact, a case stub remained after firing, and thus was ejected through said port.

I ask as scrutiny of several images show that the stowage rack appears to have a removable section in line with this apparent opening. Therefore, one could query that on operational vehicles (or those prototypes involved in live firing), would the stowage rack have been of a different configuration, clearing this ejection port, assuming that is what it is?

Can anyone help clarify this?

I note that on pictures of the Dragon KPz 70 there is a circular port in the same place.

Thanks in advance.

Brian

I would say that it is probably an injection port instead of an ejection port.
The magazine for the auto-loader occupies most of the rear end of the turret, the Abrams also has a magazine there.
Maybe the port was used when loading the magazine? In that case the stowage basket would need to be swung aside when loading. If it was an ejection port the basket would have to be swung to the side all the time, in case the enemy needs to be shot at ...

Ejecting shell case stubs through this port would mean that they would have to be sent through the magazine. Doesn't sound like a clever solution to me ....

This is supposedly the actual magazine, I can't guarantee anything:


Walkaround from the German armour museum in Münster
https://www.net-maquettes.com/pictures/mbt-70-experimental-walk/?afg705_page_id=2#afg-705
/ Robin

Robin,

I take your point but I believe the magazine was reloaded by a large hatch underneath the turret rear; in fact, the Commander model has this detail moulded on. As I understand it the turret was traversed to 90 degrees, the hatch lowered and replacement rounds re-stowed.

The ghosted drawing you feature though would indicate that indeed, any ejected stub would somehow have to negotiate the magazine itself, which doesn't make much sense.

I wonder if the Hunnicutt book (is it titled Main Battle Tank?) would have the answer; I do not have a copy.

Thanks anyway.

regards,

Brian

Hi!
Here is a magazine and loader scetch with descriptions. Maybe that helps:

https://i.redditmedia.com/8q1SPekBvbikhR3ySVzaL5-_CofE7711g-5xOsFO27o.jpg?s=910d57a23ca96bb9ec9f5d4b6961a3d7

The hatch seems to be at the backside of the rammer. A service access hatch maybe?

Andreas

Andreas,

Many thanks; I suspect you're right. My only concern is the disparity of the hatch details on the Commander Models kit, and the more circular one on the Dragon Bundeswehr version. That said of course, there were countless other major and minor differences between the 2 vehicles so perhaps I shouldn't worry too much.

I think that with this answer I can now proceed with installing the stowage rack as originally configured and not worry about it fouling any ejected cases.

Thanks again and for the diagram (I'm glad I never had to work on one of those as a mechanic).

Brian

Hi Brian,

Could it be the opening that the barrel is removed through when changing it. Chieftains & Challenger 1s had a hatch behind the turret mounted NBC pack for exactly that purpose. The NBC pack was unbolted and swung out of the way on hinges which revealed the bolted on access hatch. L11 barrels when changed were unscrewed forwards releasing them from the breach ring which was suspended from the turret roof. Once clear of the breach ring it was then slid rearwards through a tunnel in the rear of the turret and out of the hatch. I've had to do this numerous times whilst working as winter maintenance crew in BATUS many moons ago. You can see the hatch behind the NBC pack trunking on this Mk2

Max,

I don't think so for the following reasons:

a. The hatch/aperture isn't on the central axis - which would mean a very awkward transit for the barrel.

b. The 152mm is pretty massive - and the aperture relatively small.

c. The rear of the turret is rammed full of the magazine/automatic loader stuff (stuff being the technical word in my case).

But good call - and even food for thought - I could well be wrong! If it is indeed the means of removing the barrel, then I can still install my stowage basket, which is where I came in.

This is the relative joy of Armorama - solutions and very few problems.

Thanks to all.

Brian

Hi Brian,

If the hatch isn't on the same axis as the barrel and assuming the kit is correct in the hatch placement then it is unlikley it is for barrel removal as there is no way the barrel would come out. That being said as barrel changes are few and far between in normal use and usually done in a workshop environment it is possible that the removal of the magazine would be part of the process. Projectile stowage had to be removed in the turret prior to doing this task and due to barrel length and weight the breech ring and recoil mechanism in a Chieftain was fairly immense and it was a major operation to remove the barrel.

Max,

Good points; it may well be that the barrel change on MBT 70 was effected by withdrawing it towards the rear, especially, thinking about it, that the magazine assembly drops as part of the reload process (or so I understand); with the magazine Gubbins out of the way it may well have been possible I should think, although looking at the model, with no visible turret roof access panels, I can't quite think where they'd put the breech.

Thinking on a bit further, I suspect there's just too many crew "capsules" in the way for the barrel to get to the rear, but perhaps the whole were hoisted out of the way. Workshops can generally achieve anything in my experience!

Anyway, the good news is I think I can install my stowage rack with (relative) confidence.

Max, It might be an unloading port for unused ammunition. The S tank has a small port at the bottom of the rear hull plate which was used for that purpose.

From the Hunnicutt book "ABRAMS".

I have a Facebook page about MBT-70/Kpz70 with a fair bit of reference material. Go to files for some PDF info
https://www.facebook.com/groups/MBT70/files/

Notice that technical manual illustration of the magazine is a mirror image of the magazine photo configuration and the phantom illustration. The port is on the opposite side from the trapezoidal component and that component switches sides.

KL

Closed group = No access.

KL

Steve,

That just about nails it I think; in any case, I can continue the construction of the kit without having to factor in any modification to the stowage basket.

Interesting to note that the magazine rack is loaded singularly through the hatch; I had thought that hitherto the turret would be traversed, and the hatch under the rear of the turret dropped to facilitate loading. perhaps that was for maintenance.

Anyway, many thanks for the Hunnicutt extract, and full steam ahead on my build!

Thanks again, and to all.

Brian

Michael,

Thanks for the offer; sadly I'm not a user of Facebook so am probably denying myself lots of useful info, but thanks anyway.

Brian

I would believe that dropping the loader was more for service and repair of the loader system.

All you have to do is to ask to join.

Could you post some photos of the Commanders kit as you progress?

Do you know Jim, that's a timely call; God knows I get enough info from this site, so probably more than time that I put something back in.

I'll certainly work on that but give me a couple of months or so. At the moment I'm up against the clock (self-induced of course) to finish the beast for the Belgium IPMS annual thrash next month.

I'm already someway through the construction process but will try and take pictures to augment any subsequent report; that said the sad thing is, as at the moment, Commander Models have ceased production of this - to my mind - important vehicle.

Regards,

Brian

PS Just in case anyone (especially the European modelling community) is interested see:

http://www.plasticandsteel.be/

Steve,

In the light of the Hunnicutt extract I suspect you're right. I suppose I imagined some sort of almost palletised re-load, such as would be found re the MLRS system.

This a is certainly an interesting beast dare I say it, even after all these years - in my case having first espied a cutaway drawing in my Eagle comic (UK) - of, say, around 1967?

Perfectly happy to be corrected by those of not dissimilar vintage...!

Brian

I realize that. I guess what I'm thinking was that the original post should have read:

"I have a Facebook page about MBT-70/Kpz70 with a fair bit of reference material. It's a closed group, so first you have to apply for membership, then, if you are approved, you can go to files for some PDF info."

If I had seen that in the first place I wouldn't have even bothered to click on the link. I would end up having the same amount of info mind you, but I would have saved a step or two that ended up just looking at a brick wall. A minor annoyance, to be sure, but an annoyance just the same.

KL