Singapore Air Show

Falcon redesigns 7X to give it longer legs

 - December 6, 2006, 7:44 AM

Dassault is working on a significant performance improvement for its Falcon 7X business jet, currently in flight tests. On the eve of the Asian Aerospace show, the French-based manufacturer told Aviation International News how the new range target– 6,000 nm instead of 5,700 nm miles–could be reached. Dassault engineers have designed winglets, a modified vertical tailplane and an additional fuel tank.

“In terms of options, equipment and cabin layout, our customers’ choice is heavier than expected,” a company spokesman said. This would have meant telling many of them that they could not take advantage of the full 5,700-nm range. Hence the choice for a higher target, which will give some margin.

The 4.6-foot-tall winglets add a total 75 pounds to the aircraft’s weight. They slightly improve the fuel burn when in cruise flight. In the forward fuselage, the new tank adds 1,800 pounds of fuel.

In the lower fin section, part of the rudder has been made immobile. “Thanks to better-than-expected damping performance, we could reduce the size of the rudder,” the spokesman explained. The now-fixed part has been refined aerodynamically. In addition, eliminating a servocontrol has made it simpler and lighter.

The first production-conforming 7X is to fly in March. After a series of tests, Dassault will release the new performance figures, especially the range. As of February 10, the fleet of three test aircraft had logged 450 hours in 150 flights with the original configuration.

Separately, Dassault (Stand D422) had to redesign the bleed air system. According to the spokesman, a new U.S. rule on bleed air temperature has limited it to 200-deg C. Current Falcons use 330-deg systems.

The redesign and the range increase have made the aircraft heavier. The Pratt & Whitney Canada PW307A engines have therefore been uprated from 6,100 to 6,400 pounds of thrust. All this should translate into a 50-percent increase in payload and an unchanged approach speed. Moreover, the brakes have proved more efficient than expected.

Certification and early deliveries of the Falcon 7X, however, have slipped. Instead of the fourth quarter of this year, they are now respectively pegged for the first and second quarters of 2007. The delivery schedule should be back on track in 2008.