Rolls-Royce Merlin exhaust flow and waste-gates, meant that this option was rejected in favour of the two-stage supercharger. Fitted with the two-stage two-speed supercharger, the Merlin 60 series gained 300 horsepower (224 kW) at over the Merlin 45 series, at which altitude a Spitfire IX was nearly faster than a Spitfire V. The two-stage Merlin family was extended in 1943 with the Merlin 66 which had its supercharger geared for increased power ratings at low altitudes, and the Merlin 70 series that were designed to deliver increased power at high altitudes. While the design of the two-stage supercharger forged ahead, Rolls-Royce also
Rolls-Royce Holdings Margaret Thatcher. In 2003 ownership of Rolls-Royce plc was passed to Rolls-Royce Group plc incorporated 21 March 2003 which issued its own new shares for payment to the previous shareholders. In 2011 in the same way Rolls-Royce Group plc passed ownership on 23 May 2011 to Rolls-Royce Holdings plc a wholly new company incorporated 10 February 2011. Rolls-Royce plc remains the principal trading company. Rolls-Royce Holdings plc, like its immediate predecessor, is merely a holding company. The 1980s saw the introduction of a policy to offer an engine fitment on a much wider range of civil aircraft types, with the