THE PT6 ENGINE MILESTONES
It’s the remarkable story of a remarkable engine. With more than 51,000 engines delivered to power some 130 different applications, the PT6 engine can tell quite a story of creativity and transformation. While we had a lot to choose from, we’ve put together a list of milestones for the engine as we mark its golden anniversary.
1957 – P&WC assembled a team of 12 talented young engineers after studies showed a market opportunity for 500 shp (shaft horsepower) class turboprop engines in the aircraft market then powered by piston engines. P&WC saw an opportunity to channel some of the profits from its piston engine spare parts business towards the development of gas turbine engines smaller than those made by its U.S. parent.
1963 – It’s what our celebration is all about. In December 1963, P&WC shipped the first PT6 production engine, the PT6A-6, to Beech Aircraft Company for its Beech 87, which later became the King Air. The PT6A-6 was a highly innovative gas turbine that represented a significant advance in technology from the traditional piston-driven engines used to power small aircraft. Gas turbines have a higher power to weight ratio than piston engines.
1967 – Piper’s PA-31 Navajo took its first flight powered by PT6A-20s. Piper had enjoyed enormous success building light aircraft since the 1930s, but it took P&WC years of effort to get Piper to adopt turbine engines and move away from their traditional reliance on piston-driven engines.
1968 – P&WC’s ST6L73 engine (a derivative of the PT6A without the gearbox second stage) entered into service as an auxiliary power unit (APU) for the Lockheed L1011 airliner.
1968 – Bell Helicopter placed its initial order for P&WC’s first turboshaft, the PT6T Twin-Pac® engine
1970 – P&WC’s PT6T Twin Pac® entered into service. It is two engines coupled in a single package to power medium-sized, twin-engine helicopters.
1970 – The United States Military ordered 294 Bell 212s under the designation UH-1N equipped with PT6T Twin-Pac® turboshaft engines. Delivery also began in 1970.
1973 – The second-stage power turbine was introduced on the PT6A-41. This was a step change in engine power and efficiency.
1979 – An Air Tractor agricultural aircraft is powered by a PT6A engine and flies to the National Agricultural Aviation Association convention in Las Vegas – the first time such a combination was displayed in public.