PRATT & WHITNEY HAVE completed an 850-cycle endurance run on the PW4090 growth engine for the Boeing 777. The 400kN (90,000lb)-thrust engine was run at its maximum turbine-inlet temperatures and was intentionally unbalanced in a ground run simulating between two and six years of airline operations "under maximum conditions", P&W says.

Temperatures exceeding 670¡C represented the maximum for the PW4090 and the 436kN PW4098 also under development, says P&W. The PW4090 is scheduled to enter service on the increased-gross-weight 777-200 in early 1997. The PW4098 is planned to be available in 1998 for the stretched 777-300 and later for even-heavier versions of the 777-200, say P&W.

Source: Flight International