Hawker Siddeley HS 748 Paper ended most military manned-aircraft development in the UK, and Avro decided to re-enter the civilian market. The Vickers Viscount had the larger end of the short-haul market, and Avro therefore decided to design a smaller regional airliner powered by two Rolls-Royce Dart turboprop engines, intended to replace the many DC-3 Dakotas that were by then reaching the end of their economic lifespan. Original plans were for a 20–30 seat aircraft with a similar configuration to the Fokker F27, but talks with potential customers soon led to a low-wing 40-seat design being chosen for the 748 project. Avro was not
Kuznetsov NK-12 the NK-12MA. The NK-12 remains the most powerful turboprop engine to enter service although the Progress D-27 and Europrop TP400 have come close to this (in 1982 and 2005 respectively). Another engine of similar size, the Pratt & Whitney T57 with 15,000 shp and 5,000 lb jet thrust, ran 3,100 hours before being cancelled in 1957. The NK-12 powers the Tupolev Tu-95 bomber and its derivatives such as the Tu-142 maritime patrol aircraft and the Tupolev Tu-114 airliner (with NK-12MV), which still holds the title of the world's fastest propeller-driven aircraft despite being retired from service in 1991. It also