The clean-sheet G650, shown here in an artist’s rendering, Still looks every

Gulfstream announces its biggest jet

The company has ended protracted speculation about how it would address the aging fuselage cross section of its large-cabin business jets.

Ending protracted speculation about how it would address the aging fuselage cross-section of its large-cabin business jets, Gulfstream Aerospace last month unveiled the G650. The model will topple the G550 from its perch as the biggest Gulfstream business jet when it enters service in the first half of 2012. (At least initially, however, the G650 will not replace the G550.)

Compared with its predecessor, the G650 will have a longer, taller, and wider cabin with lower cabin altitude, a larger baggage compartment, a larger main entry door, and new cabin windows that dwarf even the already impressive portholes that have distinguished Gulfstreams ever since the GI turboprop made its debut.

Contrary to much pre-launch speculation, the new Gulfstream retains the metal primary construction of its forebears, although metal bonding will be used in place of rivets in the fuselage. Composites will play the secondary role they have already filled in the G500/550.

Performance targets include a 7,000-nautical-mile range at Mach 0.85 and 5,000 nautical miles at Mach 0.90. The top speed of Mach 0.925 will displace, by 3.31 knots, the Mach 0.92 Cessna Citation X from its title as the world's fastest business jet. With the G650, Gulfstream intends to regain its right to claim "biggest, farthest, fastest" among dedicated business airplanes (as opposed to converted airliners). The company has committed to the project without launch customers and will start taking orders in mid-April.

Gulfstream has worked hard to distance the G650 from the "tubular-er" feel that attended each stretch of the original cross-section. The new cross-section has four radii, with a flattened lower portion to provide more room inside while minimizing what aerodynamicists call "wetted area"-the amount of structure around which the air has to flow while the airplane is in flight.

At a project briefing recently, journalists were invited to sit inside the cabin mockup. Recalling a couple of intercontinental trips in the existing large-cabin Gulfstreams, I can attest to the Savannah manufacturer's success in greatly improving the spaciousness of the breed with the G650's cabin. The added width and bigger windows alone make a significant difference.

Underscoring the clean-sheet origins of this project, the G650 will be certified under an all-new type certificate. The last time Gulfstream (then Grumman) tackled an all-new certification program was for the GII in the 1960s; every Gulfstream large-cabin jet since, through the G550, has been certified based on the GII.

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