TheRolls-Royce RB.53 Dart is aturboprop engine designed and manufactured byRolls-Royce Limited. First run in 1946, it powered theVickers Viscount on its maiden flight in 1948. A flight on July 29 of that year, which carried 14 paying passengers betweenNortholt andParis–Le Bourget Airport in a Dart-powered Viscount, was the first regularly scheduled airline flight by a turbine-powered aircraft.[1] The Viscount was the first turboprop-powered aircraft to enter airline service -British European Airways (BEA) in 1953.
Designed in 1946 by a team led by Lionel Haworth, the Dart engine was derived using experience gained from the earlier more powerfulRolls-Royce Clyde turboprop. A two-stage centrifugal compressor was specified to achieve the desired overall pressure ratio. A 3 stage, shared load, axial turbine was used to drive both the load (via a reduction gearbox) and the compression system. A photo showing a cutaway section of typical Dart engine is given below.
Unlike the Clyde, the engine lacked a free power turbine. Consequently, under normal operating conditions, the power delivered to the propeller could not be modulated at a fixed prop speed.[2]
The Dart was initially rated at 890 shp and first flew in October 1947 mounted to the nose of a convertedAvro Lancaster.
Improvements in the design boosted power output to 1,400 shp in the RDa.3, which went into production for the Viscount in 1952. The RDa.6 increased power to 1,600 shp and the RDa.7 to 1,800 shp by incorporating various improvements including a larger diameter second impeller.
Later Darts were rated up to 3,245 shp and remained in production until 1987, with approximately 7,100 produced, flying some 170 million hours.[3]
Largely associated with the very successfulVickers Viscount medium-rangeairliner, it powered a number of other European and Japanese designs of the 1950s and 60s and was also used to convert American-manufactured piston aircraft to turboprop power. The list includes:
Fokker F27 Friendship : Small airliner from Dutch aerospace and aviation manufacturerFokker. The original model on which several other airliners were based (such as the abovementioned F-27 and FH-227).
Grumman Gulfstream I (G-159) : Executive transport & small airliner. Includes the stretched Grumman Gulfstream I-C (G-159C).
NAMC YS-11 : Short/medium range airliner (Japanese aircraft)
SomeDouglas DC-3 transport aircraft have been upgraded to use Darts. DC-3s in BEA service with this update were called Pionairs. Another conversion is theConroy Turbo Three.
Power output was around 1,500 hp (1,120 kW) in early versions, and close to twice that in later versions, such as those that powered theNAMC YS-11 airliner. Some versions of the engine were fitted with water methanol injection, which boosted power in hot and high altitude conditions.
