Dassault Aviation's new Falcon 7X near-sonic corporate jet has emerged with flying colours from a spectacular first simulated flight. This was a key initial test as development and construction of the future ultra-long range aircraft gets under way on schedule.
The new trijet will become the world's first fly-by-wire bizjet. Dassault Aviation chairman Charles Edelstenne says of the 7X: "A new age of business aviation takes flight."
A grand novelty for business jet aircraft, fly-by-wire permits the pilot's command inputs to be transmitted electrically over considerable distance with fidelity, speed, a minimum of energy and without distortion.
The technology, which Dassault Aviation has used for decades on its Mach 2 Mirage 2000 fighters and Rafale combat aircraft, allows the use of control laws to simplify the plane's piloting, providing pilot aids and assistance with significant gains in safety and passenger comfort. If the pilot decides to change the flight path, he merely tells the system where he wants to go and the system will guide the aircraft. Control inputs are provided by two independent sidesticks.
American and European fighter jet aircraft are all equipped with fly-by-wire controls, as are some newer commercial airliners. But the designers and engineers at Dassault Aviation are among the first to recognise that the benefits of this technology, including flexibility, manoeuvrability and ease of maintenance, can be readily translated to a corporate platform.
Relaxed
The Falcon 7X is designed to allow a state of relaxed static stability, enabled in a large part by the fly-by-wire flight controls. By relaxing the margins of stability, aerodynamicists have optimised performance of the aircraft within those parameters. This assists the pilot by lowering the workload, particularly during the busiest phases of flight, increasing the precision of handling and adding margins of safety.
Pilots will also be able to extract maximum performance in situations such as windshear encounters or collision avoidance man¦uvres.
The simulated flight, which took place at Dassault Aviation's headquarters in the Paris suburb of Saint Cloud, has established a preliminary standard for the Falcon 7X's controls and handling qualities through the whole flight envelope.
"This virtual 'first flight' was very exciting," says Yves "Bill" Kerherve, Dassault Aviation's chief test pilot and former French Navy's Aeronautique navale "Aeronavale" fleet air arm test pilot. "I was particularly impressed by the superb handling qualities through the whole flight envelope," he says.
Kerherve and fellow test pilot Philippe Deleume worked together to evaluate the flight controls.
"Fly the trajectory," adds Kerherve as a means of explaining how simple fly-by-wire will be for corporate jet pilots. In other words, without any input, the 7X will maintain its flight path.
Stunning
"A stunning advancement in business aviation," says Kerherve. "Not only will the 7X benefit from the latest generation, high-transonic wing, but it will be the first full fly-by-wire corporate jet."
One of the driving principles of fly-by-wire on the Falcon 7X is the power the pilot will have in managing the flight envelope. The "hard limits" built into this particular electronic flight control system give the pilot the freedom to manœuvre to the maximum aerodynamic capacity of the aircraft, without fear of breaking the flight envelope.
"At Dassault, we had the luxury of having a very experienced test group," says Olivier Villa, vice-president Dassault Aviation Falcon programmes. "They contributed their philosophies as well as their first-hand feedback and experience. Their comments were an important part of many of the decisions we made regarding the fly-by-wire system."
The Falcon simulation bench (FSB), on which Kervehe and Deleume "flew" the new aircraft, comprises a 7X flight deck functional mock-up coupled to a real-time simulation bench, with an artificial environment projected onto a screen in front of the cabin. It can perform simulated flights - from takeoff to landing, testing the brakes, flaps, slats and gear configurations over different weights, speeds and centres of gravity (CG).
By next year, the FSB will be linked to a global test bench (GTB), which will be fully representative of the entire flight control system of the aircraft, including hydraulics and electrical power generation. Dassault test pilots and engineers will be able to begin testing and validating the aircraft's systems and control laws prior to the maiden flight.
During the flight test period, the GTB will be enriched with actual flight test data and will be used to fine-tune control laws and help in the certification process, says Dassault.
Final definition of the 7X has been reached, and all external shapes have been optimised and "frozen", ruled Dassault on May 6, 2003. Metal cutting for the first production series aircraft promptly followed suit.
Precision aircraft models have been created for wind tunnel testing. The 7X models (one for high-speed, the other for low-speed testing) are about 3m (10ft) long and weigh almost 400kg (1,000lb).
The high-speed model has just undergone a series of tests that confirmed the accuracy of earlier predictions of drag and buffeting margins. The low-speed model is being tested in other specialised facilities, one of which, in Holland, is capable of simulating ground effect.
The front fuselage section has been built in the Paris suburb of Argenteuil, in order to perform development and certification tests. As for the whole aircraft structure, individual parts assembly holes have been completely drilled during the machining phase, permitting the assembly process to be reduced to a minimum without any adjustment or sophisticated tooling. Construction of the aircraft and manufacture of components is well under way. Engine certification is scheduled for December 2004, with first flight planned for the summer of 2005, leading to certification and first deliveries in 2006.
Fractional
About 50 chief executives of multinational companies and fractional ownership operators, who have paid deposits are eagerly awaiting their aircraft. New orders are for 2008 and beyond. The manufacturer expects to produce more than 15 planes annually in 2006-07, and might step up the production rate to meet market demand.
Dassault at this juncture will give no names of Falcon 7X customers. But between programme launch during the previous Paris airshow and 1 June 2003, more than 35 firm orders have been registered, 50% in the USA, 30% in Europe and 20% in Asia-Pacific and other parts of the world.
With the first two years of production already confirmed, Dassault Aviation is no longer taking options, only firm orders for 2008 and beyond.
Source: Flight Daily News
