Rolls-Royce Meteor - Design and Development

Design and Development

For tank use the Merlin had its supercharger, reduction gear, and other equipment removed from its camshaft, greatly simplifying its construction. It had cast, rather than forged, pistons, and was de-rated to around 600 bhp (447 kW), running on lower-octane pool petrol instead of high-octane aviation fuel. In addition, because weight saving was not so important for a tank engine, some of the Merlin's more expensive light-alloy components were replaced with cheaper, steel components in the Meteor X version. It was also envisaged that the Meteor would use some components rejected on quality grounds for the Merlin, i.e. Merlin scrap. In 1943 an acute shortage of blocks was met by dismantling surplus older marks of Merlins.

Unlike earlier British tank engines, such as the American Liberty L-12 of 340 bhp (250 kW) licence-built by Nuffield and used in the Crusader, the Meteor engine, of virtually the same 1,650 in3 (27 litre) displacement as the earlier Liberty engine, from its R-R Merlin origins was very lightly stressed and reliable, and doubled the power available. Previously British tanks had been regarded as underpowered and unreliable, and the Meteor is considered to be the engine that for the first time gave British tanks ample, reliable power. Initially it was used in the Cromwell tank, which was a further development of the cruiser line and would replace the Crusader tank.

But in 1941 Leyland, who had an order for 1,200 Meteor engines, were still advocating their own diesel tank engine, although it would deliver only 350 hp (260 kW), as they were concerned with the problems of sufficient cooling. Meadows produced some Meteors, but the small factory of 2,000 men was producing 40 different types of engine. So Meteor production was to be by Rover (Tyseley) and Morris (Coventry).

The first Merlin prepared for tank use was tried in a modified Crusader in September 1941 at Aldershot.