Graham Warwick/SAVANNAH
THE GULFSTREAM V business jet is meeting its specific-range guarantee, and is "on track" to achieve its 12,000km (6,500nm) designed range, at Mach 0.8, despite being overweight, the manufacturer says. Senior vice-president, GV programme, Pres Henne, says that the aircraft has sufficient margin to accommodate the weight growth and achieve its design range, but adds that weight-reduction efforts are under way.
The GV's BMW Rolls-Royce BR710-48 engines are beating their specific fuel-consumption guarantee by about 1%, Henne says, but the power plant is the major contributor to the aircraft's overweight, exceeding its 17,250kg manufacturer's empty-weight guarantee, he admits. BMW R-R has identified ways to reduce the engine and nacelle weights, Henne says, but initial aircraft will be delivered to customers with empty weights exceeding the guarantee.
"There is a lot of margin in the aircraft. We may use some of that to accommodate the weight growth and will achieve 6,500nm at Mach 0.8," he says. Empty weight is "improving", Henne says, although the exact weight growth has yet to be determined. The company has so far built four flight-test aircraft and a demonstrator. Some 275 flights have been accomplished with three aircraft, completing more than 610h of the planned 1,200h certification flight-test programme.
The fourth aircraft, is undergoing high-intensity radiated-field and lightning strike testing and is scheduled, to be flown shortly. It will be used for function and reliability testing. US certification is scheduled for the fourth quarter of 1996. The fifth aircraft is being completed as the company demonstrator, having been used for proof-load testing, and will be displayed at the US National Business Aircraft Association convention in November. First delivery begins in the fourth quarter. Gulfstream has firm orders for 63 GVs.
The aircraft is meeting its cruise-speed guarantee of M0.87 and beating its field-performance guarantees, Henne says. Test pilots praise the GV's high-altitude manoeuvre margin and its low-speed performance, both of which are better than expected, he says.
Source: Flight International
