BMW Rolls-Royce expects to qualify weight-reduction changes to the BR710 powerplant by mid-1997. The manufacturer expects the changes to be incorporated progressively in batches of engines delivered to Bombardier and Gulfstream to power, respectively, the Global Express and Gulfstream V long-range business jets.
Both aircraft manufacturers have acknowledged that the engine is overweight. BMW R-R says that it has "-identified areas where weight can be taken out" of the engine and the nacelle, for which the company is also responsible. "Reduced-weight components will be fed in progressively," says BMW R-R, which expects "batched incorporation of modifications."
Although the weight-reduction solutions for engines powering the Bombardier and Gulfstream aircraft will be similar, there will be differences. The powerplant for the Global Express, for example, includes the engine mounts, while that for the GV does not.
As Bombardier's programme is running about 18 months behind that of Gulfstream, it will be less affected by powerplant changes. BMW R-R is already delivering engines to Gulfstream for customer GVs due to enter the completion centre before the end of 1996. Gulfstream says that GV performance margins will offset the powerplant weight penalty.
BMW R-R, meanwhile, says that Bombardier has dropped its request that the BR710 mechanical-overspeed system be removed to cut weight. The company says that the "high-risk" change would require a technology-demonstration programme and is still under consideration for later engines.
The engine manufacturer says that bench testing of the BR710 has now passed the 3,500h mark with a recent 150h endurance test to qualify life-improvement modifications. Flight testing on four GVs and one Global Express has reached almost 2,500 engine hours. One GV has been flown to Mach 0.96 and 54,000ft (16,500m), Gulfstream says.
Source: Flight International
