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Dmitry Yudo aka Overlord, jack of all trades
David Lister aka Listy, Freelancer and Volunteer

Sunday, September 24, 2017

Stopgap

In the years after the Second World War the British were worried by the thickness of the armour Russian tanks were carrying. The obvious answer to this was of course bigger guns, however the financial situation was very much against the army, with budgets slashed and a shrinking army. The cost issue meant that it was impossible to bring out new tanks, equally the time frame involved with producing new tanks meant that a war could break out before the UK had its new bigger gun tank in service. To give you an idea, since the end of the war most British armament projects have taken about 10 years. A few have been shorter, but many more have been longer, sometimes by a considerable margin (FRES/Ajax, I'm looking at you, and face the wall!). To this end the British Army took the sensible step of designing a quick and dirty stopgap to carry the bigger gun, one which could be produced right now with minimal work, and was normally based on the chassis of a current in-service tank. It might not be perfect, but it'd get the gun to the front in a very short time. These tanks were the FV4004 Conway and the FV4005. There was also another tank that fits the bill, the FV4101 Charioteer, which uniquely did see service. 
FV4101 Charioteer

This last vehicle was technically a tank, as it had a turret mounted machine gun, which to British thinking of the time classifies it as such (as self-propelled AT guns didn't have the machine gun). It was created for the need to get more 20 pounders to front line service. All things considered it was a pretty dire vehicle though. It managed to break the old engineering adage "if it looks right it is right", for the tank does look good, with sloped armour on the turret and a Cromwell's hull. However, the turret armour was only 38mm thick and all the 20 lb rounds were stored in clips on the turret walls. The protection was just for proof against .50 machine gun fire and shrapnel from a 25 lb airbust. To achieve the balance of the turret the trunnions for the gun were mounted as far back as possible in the turret. In addition, a new 64" turret ring was fitted to the Cromwell, increasing the diameter from 57.5 inches.  
When firing at targets under 1500 yards the gun blast obscured the fall of shot, making adjustments to fire pretty difficult. The crew consisted of three, which meant a two-man turret. The stopgap work around to this was to use the vacant hull machine gunners position to carry a fourth man. This allowed the tank commander to dismount, let the 4th man take over gunner’s duties, while the commander shifted some distance to the side and was able to command the tank and observe the fall of shot without the hindrance of the muzzle blast. Of course this would leave him exposed to enemy action such as artillery and left the tank as more of a fixed emplacement lacking the ability to use its mobility.  
Fv4004 Conway
At about the same time as the Charioteer was issued to units (1952), the Director Royal Armoured Corps announced that the FV4004 Conway was ready to be produced, although it was not intended to do so at this time. This was a Centurion chassis, with a large box turret to mount the L1 120mm gun. The reasoning behind the tank was that a Centurions maximum all up weight was 50 tons, and so the tank had to be designed to that level, limiting the total level of protection that could be fitted along with the gun. Sensibly the reduction in armour was applied to the turret sides. 
The turret on the Conway was a massive box and one can see a resemblance to the FV4101. This monstrosity was dumped on top of a poor unsuspecting Centurion chassis. Although unlike the Charioteer it did have more protection, 132mm sloped at 19 degrees. On top of that was a gun mantlet  which was 140mm in thickness, originally it was quite a small mantlet,however on the prototype the mantlet was extended to cover the machine gun as well. The ammo was much more sensibly arranged, with eleven ready rounds, but only five cartridges in the turret. The rest were stored as fighting rounds in the hull. Luckily the crew was back up to a sensible four, and it had a single coaxial machine gun. Originally a ARV cupola was fitted however this was discarded in favour of a selection of episcopes. The gun recoiled into the bustle where there was a hatch to throw out spent cases, it was planned as the tank developed to include an automatic ejection system. It was also planned ot develop a lower less high profile turret as well as the Conway's service life went on.
Fv4005 Stage 1
The final stopgap was the FV4005. The requirement for it first appeared in November 1950, with a design in place by January 1951. If need be it was considered it could be in production within 18 months. It was an interim measure on the Centurion chassis, mounting the massive 183mm L4 gun. It was to be on standby until the FV215 arrived in service, from the start it was to be a limited traverse mount. It may have had a "C" name like many British tanks. One document, out of many that I have seen on it, refers to it as "Centaur". Now this could have been a typo, for Centurion, or the Vickers project name, as the document isn't an official government one bet was from Vickers. Like the FV4004 it was limited by its upper weight of 50 tons. So with a much more massive gun and ammunition its turret armour was just 14mm to provide protection against small arms fire. 
The decision was taken not to produce the tank in early 1951, however three prototypes were to be constructed. One was an entirely experimental vehicle to test the gun mounting, and the recoil forces involved and how they affect the stability of the vehicle. Then with data gathered two second prototypes were to be constructed. The experimental vehicle, known as Scheme 1, or Stage 1, had a gun mounted that could traverse all the way around the tank, although firing was restricted to a small arc to the fore or rear of the tank.
Scheme 2 however was to be the real prototypes. The gun sight was to be a modified German TZF-12A sight, which was most famously mounted in the Panther tank. The loading system for two gunners was worked out and was described as: "A very simple form of hand loading which can be operated by two men has been evolved for use in this vehicle." 
In use, the Stage 1 developed some problems with its concentric recoil system, however as the Stage 2 used hydro-pneumatic recoil no problems were encountered and the tanks fired over 150 rounds without any problems. In late 1952 the prototypes were tested at Ridsdale gun range by Vickers, and some modifications were found to be needed.
By 1957 the idea of the 183mm gun had fallen out of favour and the three prototypes were sent to various locations. The Stage 1 was sent to Shoeburyness Proof and Experimental Establishment, and the Centurion hull returned to active service. One Stage 2 was offered to the Royal Military College for Science, and the final stage 2 was kept by FVDRE. 

9 comments:

  1. Nice article. Excellent ghillie suit the Conway commander is wearing...

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    1. I scrolled up thinking "What the heck...?", then had a laugh.

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  2. Another great read, thank you.

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  3. This comment has been removed by the author.

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  4. Another great post. I play World of Tanks and always like to know more about the unusual vehicles thay have in the game.

    Sunday (almost here again) and your latest article are always keenly anticipated.

    No edit button and my previous comment was riddled with errors.

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    1. Thanks, and no worries on the errors.. you should see my articles before the proof reader gets to them...

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  5. I think like I get a clear cut understanding while reading the content than anywhere else. Keep continuing this journey...!

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