Evolutionary National Tank

I'll note in case of any confusion that the Vehicles Department of RARDE (just then recently formed in 1984-85 by the merger of the MVEE into RARDE) was also informally known for historical reasons as the Fighting Vehicles Establishment.
 
Amongst the interesting aspects of this concept is that most of the individual elements were also studied in some depth. As the author of the video states the UK built 140mm guns and a prototype carousel autoloader. The power pack was similarly studied and what follows is largely from a 1986 paper by J.C. Allinson and D.A. Baldwin of RARDE, published in the Proceedings of the Institution of Mechanical Engineers, unless otherwise stated.

It incorporates RARDE thinking, and research and development work, of the time. In terms of engines, RARDE had decided that multi-cylinder diesels were the optimum solution and they were pursuing a range of technologies to increase Brake Mean Effective Pressure (BMEP) at 2500 r/min whilst maintaining "good engine response, torque back-up, startability, reliability and durability". The short term objective was for 22 bar BMEP with 25 bar BMEP being seen as a future rating. The technologies under study were:
  • Variable geometry turbocharging (ultimately used on the CV12 variant for the original US Army Crusader SPH)
  • Ceramic insulation and precision cooling for low heat loss
  • Variable valve timing
  • The extension of digital control for the engine and transmission
Engines would be required to deliver between 750kw (1,000hp) and 1,500kw (2,000hp). The CV8 proposal gives the lower rating and I have seen various references to Perkins suggesting they could get the CV12 to 2,000hp. In a 1996 Jane's IDR article Perkins was reported as projecting BMEP growth in their military engines from 17.2 bar to 27.6 bar. The CV16 (separate from the one proposed by RR in the 1970s) for the US Ground Based Radar generator delivered 1,750hp at 1,800rpm by combining two CV8s together. Perkins thought they could get 2,6000hp (1,300hp per engine block) out of the same configuration with increased supercharging and inter-cooling to meet the AAAV requirement (ultimately met by an MTU883 with a massive turbocharger arrangement).

There is a curious report in the Army Quarterly and Defence Journal from the 1990 British Army Equipment Exhibition (BAEE 90) of an 800hp Perkins engine shown inside a 1 cubic meter frame as part of an engineering challenge. Apparently it took up 25% less space than the CV8 in the Warrior, the first Perkins 1 cubic meter engine had produced 500hp. I can't find any further details though. I mention Perkins as RARDE explicitly stated that the design of future tank engines was entirely the preserve of the engine supplier, RARDE's role being to encourage and assist in research in areas that they thought might result in improvements.

The transmission was all RARDE though. The then modern transmission used in Challenger gave excellent drivability but was less efficient than a manually operated layshaft type using dog clutches for gear engagement and a friction clutch for the coupling to the engine. Greater transmission efficiency allows a smaller engine. Thus, in 1976 RARDE began a research project that converted a Centurion single layshaft transmission (Merrit-Brown Z.51.R) to fully automatic control to provide acceptable drivability. The transmission was installed a Comet tank and proved successful with gear changes taking an average of 0.5 seconds. Further research was therefore undertaken with the objective of getting to 0.25 seconds. There was also a two layshaft transmission that was to be trialled in FV432, this was seen as a lower risk development as gear changes were a certainty but it had a greater volume than the higher risk single layshaft version.

The resulting power-pack proposal, as used in the ENT concept, is shown in the attached image. The transverse engine with the cooling fans and radiators mounted above a compact transmission is almost identical in conception to the EuroPowerPack that uses the Renk HSWL 295TM transmission with the MTU883 engine.
 

Attachments

  • RARDE_Compact_Power_Pack_1986.jpg
    RARDE_Compact_Power_Pack_1986.jpg
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Elan Vital said:
The transversely-mounted CV12 offered on Khalid/Challenger family and used in the PIP 87 and MBT-95 studies.
Click to expand...
transverse-cv12-png.693823
 

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