Rolls-Royce Dart Rolls-Royce Dart The Rolls-Royce RB.53 Dart is a long-lived British turboprop engine designed, built and manufactured by Rolls-Royce Limited. First run in 1946, it powered the first Vickers Viscount maiden flight in 1948, and in the Viscount was the first turboprop engine to enter airline service, with British European Airways (BEA), in 1950. On 29 July 1948 a flight between Northolt and Paris–Le Bourget Airport with 14 paying passengers in a Dart-powered Viscount was the first scheduled airline flight by any turbine-powered aircraft. The Dart was still in production when the last Fokker F27 Friendships and Hawker Siddeley HS 748s
Vickers hardness test the material. The fin attachment pins and sleeves in the Convair 580 airliner were specified by the aircraft manufacturer to be hardened to a Vickers Hardness specification of 390HV5, the '5' meaning five kiloponds. However, on the aircraft flying Partnair Flight 394 the pins were later found to have been replaced with sub-standard parts, leading to rapid wear and finally loss of the aircraft. On examination, accident investigators found that the sub-standard pins had a hardness value of only some 200-230HV5. Vickers hardness test The Vickers hardness test was developed in 1921 by Robert L. Smith and George E. Sandland