Armortek

It all started with a simple question, "what's this for?"



It's a metal plate, bolted to the fixed cupola ring at the seven o'clock position. The top surface of the plate is mostly flat but there is a chamfer on the side nearest the rotating cupola ring facing the right side. It seems to be related to small rotatable lever fixed to the front of the peri-bino protector. I can't find any mention of it in the gunnery manual section relating to the Vision Cupola No 2.



This is the wonderful answer from an Australian former Cent commander:

“We rotated the cupola clockwise until that device came up against a stop at the rear of the cupola. This placed the peribinos in the 6 o’clock position; why we don’t know, but Tubby is checking all his references for an answer. None of us could remember ever using this facility…….more to follow.”

When the stop is flipped to "engage", it only engages the fixed plate when rotated clockwise (looking from inside the turret). Counter-clockwise, it rides over the plate because of the chamfer. That solves the what but we've been unable to explain the why. When the stop is engaged, the peri-binos are held at the six o'clock position, with the hatch, if open, at eleven o'clock and the RCP sight at the 3 o'clock, none of which is very useful to the commander!

Another case of a design feature which was probably redundant and whose purpose is now lost. Someone obviously thought it useful, although it's not fitted to all Cents.

Rotatable stop:



Stop not engaged with fixed plate:



Stop engaged with fixed plate after rotating cupola clockwise:



Stop over-ridden by fixed plate after rotating cupola counter-clockwise:



Another Cent enigma for the weekend!

Regards

Stephen

There must have been a reason for it, however obscure and how little used.
My suggestion is that it was an aid for when the tanks were being transported in a non-combat zone with the turret traversed rearwards and the gun barrel secured in the travel clamp. This feature would put the cupola in a fixed reference position and thereby assist the commander in giving instructions to the driver.
Regards
Mark

Mark, I thought you'd come up with an inspired suggestion and have looked at it. With the gun in the crutch and the cupola stop engaged, the RCP sight is at 11 o'clock and the peri-binos at 2. So that doesn't really make any sense. I'll keep asking around (and have put a post on the Centurion Tank Appreciation Society Facebook page.

All the best.

Stephen

makes my king tiger cupola look simple, great attention to detail, regards simon.

Stephen White wrote:With the gun in the crutch and the cupola stop engaged, the RCP sight is at 11 o'clock and the peri-binos at 2. So that doesn't really make any sense.

Would they not then be roughly aligned with the front corners of the vehicle as well as giving the commander the most unobstructed view over the rear of the turret ? Obviously the sights themselves have no use at this time but their positions would be useful reference points.
Regards
Mark
I vaguely recall their being a different vehicle, which I have either crewed or worked on, which had something similar whereby the cupola was easily fixed in an "optimal" position for the commander to observe "rearwards" but I cannot remember which vehicle it was.

Mark, it's the best solution yet but I'm not entirely convinced. I'll keep asking around.

Re-located the cupola hatch hinges to scale positions:



Revised sizing for the remaining episcope protection:





Cupola hatch lock added:



The episcopes were, like a lot of parts supplied from UK stocks, painted in Deep Bronze Green, sight insides painted with Alclad Steel, glass optics inserted and sights mounted. Final assembly and basecoat paint:

Stephen,

Brilliant work as usual, I am hoping to visit the tank museum on tankmod day if I do make it I look forward to seeing you and your cent.

Regards

David

Hi Stephen
I can only say: Wonderfull!
Kind regards
Frank

Stephen White wrote:Mark, it's the best solution yet but I'm not entirely convinced. I'll keep asking around.

This one has been bugging me and like you I am not entirely convinced that my suggestion is the true explanation. If it was an offiicial modification, why is it missing on other vehicles of the same type ?
What possible reason could there be for putting the cupola at a particular position relative to the turret or hull? One possible reason came to mind this morning but it would make no sense for me in this case unless there was an alternative position for the plate to be mounted or the lever was fitted in an incorrect position and was meant to be elsewhere.
If the cupola was offset to between 2 and 3 o´clock, then use of the auto-align and contra-rotation would enable synchronised traverse of the turrets when passing a saluting-dias. I am working on the british system of the saluting dias being on the right and the barrel is traversed right and depressed for the salute. Maybe the australians did things differently ?

Hi, Mark, you win for inventiveness. I've seen the device on a number of Vietnam Australian Centurions and will look in Bovington at the weekend to see if it's fitted to any of theirs. I believe it to be a service mod, the fittings all appear to be of a standard. It's present on the Cupola Vision No 2 fitted to 064, which does not have contra-rotation and line up. That was only fitted to the Cupola Vision No 4, Mk 1, which had the two clamshell hatches but doesn't seem to have the stop we're talking about.

On with the cupola hatch. The kit hatch is a perfect size but can be re-profiled to be much closer to the original. The outer side needs a flattened top and the inside given its concave shape to accommodate the commander's head and given the outer lip which held the seal.

Before:





After:





With cast texture:



Milling the new hinges with flange for the three position lock to hold the hatch horizontal, at 27 deg or vertical:



I pinned the hinges with brass which expands with brazing heat to lock the position while I applied lumiweld:



And cleaned up:



Thanks for looking.

Stephen

A final flurry of activity before packing up for Tankmod.

The cupola hatch could be opened in three positions, vertical, horizontal and 27 deg to the horizontal. In all the photos I have of Cents in Vietnam, I have only ever seen the latter. It provided a convenient seat and a place to stow the seldom worn flak jacket:



The hatch is held in position by a spring loaded plunger. The original is, of course, fiendishly complicated and since only the top of the plunger will be visible, I chose a much simpler design, although I've retained the T-bar to allow the plunger to be reached and make the hatch positions functional:









I made the plunger spring and the cupola door balancing spring on the lathe, using the methods in this video:





Last bit is the spring cover, which has to be an exact fit to the spring in order to clear the rear episcope housing:





Hatch in operation:











Just got to add the 1/6th flak jacket and head pad.

Regards

Stephen

Hi Stephen
Now thats neat enjoy tankmod

Derek

Stephen White wrote:Mark, it's the best solution yet but I'm not entirely convinced. I'll keep asking around.

The picture confirms for me the angles and positions that previous text had indicated and that it is intended as a navigation aid for the commander to use when giving directions to the driver, either reversing when gun-front (turret hull alignment confirmed by gunner) or going forward with gun in the crutch.
I have commanded an armd vehicle on moonless nights where you cannot see the extremities of the vehicle and could only see gaps in the trees in the distance. I had to rely on what I could feel with my elbows to know my alignment relative to the driver and give him appropriate directions.
Possibly an unofficial modification that was adopted by commanders that knew what it was for. If it was an official mod, it would be documented how and why.
Mark

WOW!
You never finish surprising me with your search of the detail and your skill in realizing them.
Congratulations, Stephen!
Ciao,Iacopo

I've added a video of the Cent running at Tankmod at the weekend to my Channel, Tank Builders, here:



The Tank Museum provided an excellent running area.

Regards

Stephen