Aerodynamics
THREE AERODYNAMIC DESIGN GOALS
From an aerodynamics standpoint, Falcons are designed to meet three major goals. Calling on robust solutions, they must offer:
- High cruise efficiency
- Low-speed performance and safety
- Impeccable handling characteristics
Meeting all three of these goals means a design that is very close to the aerodynamic ideal. To push design close to perfection, each part of the aircraft has to be designed concurrently with the wing, which is of course the main aerodynamic element.
This allows design engineers to integrate all aerodynamic interaction phenomena between the various elements, in particular the wing, fuselage, tail, engine pylons, nacelles and nose.
ACHIEVING HIGH/LOW-SPEED COMPATIBILITY: THE VARIABLE GEOMETRY AIRFOIL
During the initial design of a business aircraft, the decisive factor in choosing the wing airfoil is its high altitude cruise performance.
But at the same time, business aircraft must offer good performance-and irreproachable safety-during the takeoff and approach phases.
Any airfoil with a fixed shape obviously represents a compromise between high-speed and low-speed operation, with the priority given to one or the other. Fixed airfoils inevitably lead to poor cruise performance (in the case of oversized wings, for instance, demanding overly powerful engines and causing high fuel consumption) and/or poor low-speed performance.
The solution is the "variable geometry" airfoil, meaning that its shape can be changed to provide efficient performance in both high-speed and low-speed modes. This is the most effective solution available today, since it offers the high efficiency needed for cruise, without compromising low-speed performance.
Dassault Aviation applies these principles on all Falcon business jets, in the form of high-lift devices. These devices are more familiarly known as flaps and slats, and are used to change the airfoil camber along the leading and trailing edges, respectively, to increase lift whenever necessary.
The same principle is used on all modern jetliners, by Airbus and Boeing alike.
By opting for these solutions, Dassault has refused to compromise on aerodynamics. A variable geometry airfoil means not having to compromise the fundamental qualities of performance and safety -the operator's two primary concerns.
NO AERODYNAMIC GADGETS
Dassault's refusal to compromise also explains why Falcons are free of all aerodynamic "gadgets", such as vortex generators, stall strips or stick pusher. These add-on devices are generally used to make up for a lack elsewhere, such as a performance shortfall in a given configuration, or to increase the safety margin in this configuration. Although real talent is needed to develop these sometimes highly sophisticated devices, this energy could have been put to better use on developing a satisfactory aerodynamic solution in the first place!
At Dassault Aviation, the basic corporate strategy is to build in all specified performance, with significant safety margins. This approach translates into "clean" aerodynamic solutions, providing sound handling and performance—without gadgets!
For Monsieur Dassault, the purity of a wing with nothing added was a prerequisite for it to be beautiful.
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