In 1956, Pratt & Whitney Canada's (PWC) president, Ronald Riley, ordered engineering manager Dick Guthrie to hire a team of gas turbine specialists to design a small gas turbine engine. Demand for the
Wasp radial engine was still strong and its production was profitable but the aim was to become Canada's prime engine company by focusing on a small gas turbine engine. Riley gave Guthrie a modest budget of
C$100,000. Guthrie recruited twelve engineers with experience gained at various places including the
National Research Council in
Ottawa,
Orenda Engines in
Ontario, Bristol Aero Engines and
Blackburn Aircraft. They completed the detailed design of an engine for Canadair's small jet trainer, the
CL-41. It was a thrust turbojet but the design was taken over by the US headquarters, who developed it into the
Pratt & Whitney JT12. The team had to wait for market assessments to define their next engine, a turboprop for twin-engined aircraft, the PT6. The early development of the PT6, which first flew in May-June 1961, was beset with engineering problems, cost overruns and lack of sales. It was almost cancelled. The PT6 first flew on 30 May 1961, mounted as a third engine in the nose of a
Beech 18 aircraft which had been converted by
de Havilland at its Downsview facility in
North York, Ontario. Full-scale production started in 1963, with service entry the following year. The Beech 18 continued as a PT6 and propeller flying test-bed until it was replaced with a
Beech King Air in 1980. The King Air test-engine or propeller replaced one of the standard ones. In 1974 the Beech 18 had been unable to fly fast enough and high enough to test the PT6A-50 for the
de Havilland Canada Dash 7 so a
Vickers Viscount was modified as a PT6 test-bed with a Dash-7 installation in the nose. The first production PT6 model, the PT6A-6, was certificated in December 1963. The first application was the
Beech Queen Air, enticing the U.S. Army to buy a fleet of the
U-21 Ute variant. This helped launch the
King Air with Beechcraft selling about 7,000 by 2012. From 1963 to 2016
power-to-weight ratio was improved by 50%,
brake specific fuel consumption by 20% and
overall pressure ratio reached 14:1. Its development continues and while today its basic configuration is the same as in 1964, updates have included a cooled first-stage turbine vane, additional compressor and turbine stages and
single-crystal turbine blades in the early 1990s. Its pressure ratio is 13:1 in the
AgustaWestland AW609 tiltrotor, the highest that can be used without cooled turbine blades. In response to the
General Electric GE93, in 2017 Pratt & Whitney Canada started testing core technology and systems for a proposed engine to replace the most powerful versions of the PT6. It was considered likely to be a development of the PT6C core, and would fit between the PT6C-67C/E and the
PW100 family. It was expected to be ready to launch by the end of 2017 for an initial
helicopter platform with a 10-15% reduction in
brake specific fuel consumption. This 2,000 hp engine would target a possible new market such as a Super PC-12, a more powerful TBM, or a bigger King Air.
PW100 When
de Havilland Canada asked for a much larger engine for the
DHC-8, roughly twice the power of the Large PT6, Pratt & Whitney Canada responded with a new design initially known as the PT7, later renamed
Pratt & Whitney Canada PW100. ==Design==