Stage III Technologies has completed ground testing of a new exhaust system for Rolls-Royce Spey Mk 511-8 engines, which is designed to bring Gulfstream GII and GIII business jets inside Stage 3 noise limits.
The company claims that its noise-suppression system, consisting of a redesigned external mixer nozzle and fixed-position ejector, has no effect on the take-off performance of the aircraft, although it does result in a "minimal change" in cruise performance. The modified engines also provide a 3% increase in static thrust. The existing thrust reversers of Stage 2 engines will be modified and retained as part of the upgrade.
Proof-of-concept testing has been carried out at Dallas Airmotive's test unit in Texas, and at Rohr's Brown Field outdoor test site in California. "Design refinements were identified from these tests and newly designed hardware is under development," says Stage III Technologies.
Dallas Airmotive will market and distribute the exhaust systems, with first deliveries scheduled for the first quarter of 1998.
Source: Flight International
