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Irish Army R-R Merlin powered Churchill Tank

Grey Havoc

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Excerpt from "Irish Army Vehicles: Transport and Armour since 1922" by Karl Martin (2002 edition)[with some minor editing]:

The Rolls-Royce Merlin powered Churchill

On the 14th of February 1955, Capt. Collier of the Cavalry Workshops suggested replacing the existing Bedford engine in a Churchill with an ex-Air Corps Rolls-Royce Merlin aircraft engine. He thought that the Merlin would need to have its fuel system changed from 'forced induction to atmospheric induction, since we have not room to accommodate the supercharger'.

Given the difficulties with the existing Churchill engines his suggestion appears to have been quickly acted on by his superiors because on March 1st, Col. Lawless, the Director of Cavalry, wrote to the QMG (Quarter Master General) about the matter. A note dated 11th March 1955 states '....the Director visited the QMG this date. The QMG agreed to the proposed fitting of a RR Merlin engine to a Churchill tank and instructed the Director to obtain the engine from the Air Corps'.

A Merlin Engine was forwarded to Cavalry Workshops almost immediately by the Air Corps, suggesting that some preliminary discussions were held between Capt. Collier and his opposite number, Comdt. Ryan, in the Air Corps' Workshops. Indeed, Comdt. Ryan is recorded as claiming that he had seen Merlins fitted to Churchills during an earlier visit to Britain. There is no record of any Merlin powered British Army Churchill tanks, so perhaps he was thinking of the Rolls-Royce Meteor engine in the Cromwell and Comet tanks - the 600 hp V-12 Meteor was derived from the Merlin. It would appear that Churchill ZD 5052 was chosen as the 'guinea-pig' as it had been immobile since November 1954.

Progress on producing a Merlin powered Churchill was slow. On March 16th, 1956, a year after the first Merlin had been sent to the Cavalry Workshops, the Director of Cavalry wrote to the QMG to inform him that Merlin no. 190921 had been fitted in a Churchill and that 'tests carried out to date indicate a reasonable degree of success has been achieved and justifies fitting of similar engines in the remaining Churchills as the occasion demands'.

The Air Corps had five other Merlins ready - including numbers 191406, 190911 and 191281. These were all Merlin Mk. 55M engines formerly fitted in Air Corps Vickers Supermarine VS.506 Seafire LF III fighters, the last of which had been withdrawn from service in 1955.* Seafire parts were also available that were thought might be useful for engine cooling purposes.

Sadly, for reasons that are not recorded, this imaginative attempt to breathe new life into the Churchill fleet failed and no more conversions were attempted.


*See 'Wings over Ireland' by Donal MacCarron, 1996, Midland publishing Ltd., ISBN 1 85780 0575.
 

PMN1

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Something i've never been able to get an answer to is the engine bay size of various tanks the UK used so this is very interesting given the longivity of the Churchill.

From what i've read, a Meteor was fitted in a Crusader for trials purposes of the Meteor but I have not seen if that required and enlarged engine bay.
 

Grey Havoc

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A cut-away view (from the side) of the Churchill Mk VI that might give you some idea of it's original engine bay layout is on page 57 of "Irish Army Vehicles". You could find the original though at the Tank Museum Collection at Bovington. It's Print no.5770/C6.
 

thebig C

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I wonder was one of the engines used for this project actually from a Motor Torpedo Boat (MBT). Ireland purchased 6 1939/40. However, they were disposed of in the early post war years partly due to complaints by the penpushers in the Dept of Finance.

One of the reasons was their extremely thirsty engines....which if I'm not mistaken may have been aircraft engines, hense their speed. I know at least one MTB was sold to Col. Fitmaurice (of transatlantic flight fame). Some others might have been scrapped....or parted out.

C
 

SleeperService2

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Something i've never been able to get an answer to is the engine bay size of various tanks the UK used so this is very interesting given the longivity of the Churchill.

From what i've read, a Meteor was fitted in a Crusader for trials purposes of the Meteor but I have not seen if that required and enlarged engine bay.
I've been researching the Meteor engine recently. Short answer is that the engine had to fit in the space occupied by a Liberty. Cooling was an issue with the Meteor getting quite hot very quickly. There were other issues as well such as the roadwheel bolts unscrewing which meant that the engine could only be run for a short time. Some of the suggested cooling upgrades appear in the Cavalier and the forward engine deck of the Cromwell. The trial vehicle was unmodified though.
 

JohnR

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How would a Meteorite have fit and performed in a Chuchill?
 

SleeperService2

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How would a Meteorite have fit and performed in a Chuchill?
Sorry for the delay I had to self-isolate and my Churchill stuff was stored elsewhere.
The Meteorite was essentially a cut down Meteor so physically it should fit OK. In fuel-injected form it offered 400hp at 2500 rpm compared to the Meadows' 350hp at 2200 rpm. Assuming comparable torque to the Meadows' 960 lb ft it would have been a bit more agile and quicker accelerating. The extra 300rpm should translate to maybe 1.5mph extra over the MK VII and VIII 12.5mph or the 15.5mph of earlier marks. Whether this would make much difference in reality is another matter.
 

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