On this day in aviation history, the 578-DX made its first flight. 578-DX ?? May be Pratt & Whitney / Alison prop-fan 578-DX engine rings a bell? Still not ringing a bell?
Let's have a look at it:
Pratt & Whitney / Alison prop-fan 578-DX engine
In the mid-'80s of the previous century, Allison Engine Company unveiled the 578-DX engine at the Paris Airshow. It was based on the Allison T701 engine, in use in heavy helicopters. Two variants were envisaged, a 10.000 shp and a 16.000 shp variant. In 1986 further development o the engine was undertaken by the specially formed joint venture between Pratt & Whitney and Allison, PW-Allison. Competing with the GE36 UDF (unducted Fan Engine)
Claims from PW-Allison about the engine in comparison with jet engines were promising; - 30% fuel saving - Quieter (because of lower rpm of the prop-fan)
- Better take-off and landing performance
PW-Allison aimed for certification of the engine in the early '90s.
PW-Allison pitched the engine as the power source for the
- Boeing 7J7 (a proposed B727 replacement)
- MD-91X/MD-92X (Competitor of the Boeing 7J7)
- FIMA (Future International Military/Civil Airlifter - a proposed replacement for the Hercules and the Transall)
Some interesting facts on the 578-D engine:
- 6 bladed propfan (Hamilton Standard) 11.6 ft (3.5 meters) diameter
- Proposed Mmo 0.80-082
- 3 or 4 stage Low Pressure Compressor (depending on thrust varient)
- 13 stage High Pressure Compressor
- 2 stage HPT
- 3 or 4 stage LPT (depending on thrust varient) The engine was only flown for just 20 hours in May 1989. With the cost of the engine ~40% higher than its competitor on the MD90 airframe, the IAE V2500, and the dropping fuel prices there were no orders and the program came to an end.