The Rolls-Royce RB211 is a family of high-bypass turbofan engines made by Rolls-Royce plc and capable of generating 37,400 to 60,600 pounds-force (166 to 270 kilonewtons) thrust.
Originally developed for the Lockheed L-1011 TriStar, it entered service in 1972 and was the only engine to power this type of aircraft. It was not, as often believed, the costs of development which forced Rolls-Royce Limited into bankruptcy, but a financial management error which saw revenue from the RB211 sales to Lockheed retained in the US in US$ bank accounts, whereas all the company's costs were incurred in pounds sterling.
In the mid 1970s, Boeing was considering designs for a new twin-engined aircraft to replace its highly successful 727. As the size of the proposed plane grew from 150 passengers towards 200, Rolls-Royce realised that the RB211 could be adapted by reducing the diameter of the fan and removing the first IP compressor stage to produce an engine with the necessary 37,400 lbf (166,000 N) thrust. The new version was designated RB211-535. On 31 August 1978 Eastern Airlines and British Airways announced orders for the new 757, powered by the -535. Designated RB211-535C, the engine entered service in January 1983; this was the first time that Rolls-Royce had provided a launch engine on a Boeing aircraft.
Poorly Mixed and pretty much does not sound authentic at all. Turbine Sound Studios 757RR sound pack runs circles around this pack. Wish I could get my money back. Avoid at all costs