Rolls-Royce Limited its unreliable Rolls-Royce Vulture engines), Vickers Wellington (twin-engine); it also transformed the American North American P-51 Mustang into a competitor for the best fighter of its time, its engine a Merlin engine built by Packard under licence. Over 160,000 Merlin engines were produced, including over 30,000 by the Ford Motor Company at Trafford Park, Manchester. During the war most Rolls-Royce flight testing of engines was carried out from Hucknall Aerodrome. The Merlin crossed over into military land-vehicle use as the Meteor powering the Centurion tank among others. Many Meteor engines used engine blocks and parts that failed requirements for high
Rolls-Royce RB211 of power-to-weight ratio. Despite knowing that the timetable was challenging for an engine incorporating these new features, Rolls-Royce committed to putting the RB211 into service in 1971. Lockheed felt that the new engine enabled the L-1011 to offer a distinct advantage over the otherwise similar DC-10 product. However, Douglas had requested proposals from Rolls-Royce for an engine to power its DC-10, and in October 1967 the response was a thrust version of the RB211 designated RB211-10. There followed a period of intense negotiation between airframe manufacturers Lockheed and Douglas, engine suppliers Rolls-Royce, General Electric and Pratt & Whitney, and the