High-bypass turbofan in the context of "Boeing 747"

Air-breathing jet engines typically feature a rotating air compressor powered by a turbine, with the leftover power providing thrust through the propelling nozzle—this process is known as the Brayton thermodynamic cycle. Jet aircraft use such engines for long-distance travel. Early jet aircraft used turbojet engines that were relatively inefficient for subsonic flight. Most modern subsonic jet aircraft use more complex high-bypass turbofan engines. They give higher speed and greater fuel efficiency than piston and propeller aeroengines over long distances. A few air-breathing engines made for high-speed applications (ramjets and scramjets) use the ram effect of the vehicle's speed instead of a mechanical compressor.

The Rolls-Royce RB211 is a British family of high-bypass turbofan engines made by Rolls-Royce. The engines are capable of generating 41,030 to 59,450 lbf (182.5 to 264.4 kN) of thrust. The RB211 engine was the first production three-spool engine.

Originally developed for the Lockheed L-1011 TriStar, it entered service in 1972 and was the exclusive engine to power the L-1011. Mismanagement of the initial development and consequent cost issues led to the company assets being transferred to a new government-owned company, Rolls-Royce (1971) Ltd., to save the workforce and the engine businesses important to the UK and many other aerospace and aircraft operating companies.

The Boeing 737 Classic is a series of narrow-body airliners produced by Boeing Commercial Airplanes, the second generation of the Boeing 737 series of aircraft.Development began in 1979 and the first variant, the 737-300, first flew in February 1984 and entered service that December.The stretched 737-400 first flew in February 1988 and entered service later that year. The shortest variant, the 737-500, first flew in June 1989 and entered service in 1990.

Compared to the original series, the classic series was re-engined with the CFM56, a high-bypass turbofan, for better fuel economy and had upgraded avionics.With a 133,500–150,000 lb (60.6–68.0 t) MTOW, it has a range of 2,060 to 2,375 nautical miles [nmi] (3,815 to 4,398 km; 2,371 to 2,733 mi).At 102 feet (31 m) the -500 is similar in length to the original 737-200 and can fly 110 to 132 passengers.The 110-foot-long (34 m) -300 can seat 126 to 149 passengers while the 120-foot-long (37 m) -400 accommodates 147 to 168 seats.