Design
Dassault is of course known worldwide as a maker of military aircraft, and the Falcon structure is perhaps the area where this influence is strongest. Falcon business jets have always benefited from the advanced technologies and flawless quality demanded of high-performance combat aircraft, as well as experience logged in operations under extreme conditions.
The Dassault Falcon philosophy of design is made possible by three overarching philosophies and practices. The first involves CATIA (a proprietary software program developed by Dassault) which covers the complete process, from design to manufacturing, resulting in high-precision structural assemblies, totally identical for each production run, and the assembly of large subassemblies (such as a wing) without rework.
The CATIA CAD/CAM system introduced the routine use of numerical aircraft models during the advanced design phase, well before the design was finalized. The numerical model offers a virtual three-dimensional view, perfectly replicating reality, and representing the aircraft's structure, cabin and all systems. It is formed by assembling the various parts of the aircraft that are designed on CATIA.
Thanks to this numerical model, engineers can visualize well in advance the general layout, how the parts fit together, and how to optimize location of systems and equipment within the airframe. It means substantial time savings and improved efficiency.
The Falcon 2000 was the first civil aircraft in the world to be designed solely by use of a numerical model (the first Military aircraft was Dassault's Rafale figher).
Furthermore, CATIA allows robots to be programmed off line, which does not require a physical prototype and is much faster than the manual programming required on the first robots. Quite early in the game, Dassault started robotizing an increasing number of Falcon production operations. Robots provide optimum accuracy and reproducibility and assure consistent unmatched quality. The most impressive robotic operation is the automatic drilling for fasteners on the Falcon wing panels. The same people and process are used to assemble wings for both the Mirage 2000 and the Falcons.
The second component of the Dassault Falcon philosophy of design is based on a production process integrating structural technique, calling on monolithic (single-piece) parts, produced from a single block of aluminum, either mechanically or chemically. This process provides clear advantage over multi-piece assemblies, where the junctions and fasteners are often the weak link in terms of strength, fatigue resistance, inspectability and corrosion.
The third component of Dassault Falcon's unique design philosophy is the balance of structure and aerodynamics.
When a preliminary design is first developed, based on a given set of specifications and an applied load model, the structure is initially evaluated according to two main criteria: shape and weight.
Before developing a preliminary theoretical design, which they can refine through a classic iterative process, engineers have to determine several basic parameters, namely cabin size and desired performance.
A perfect balance must be then struck to optimize the relationship between size, weight, fuel capacity and engine thrust.
The heavier the aircraft, the more lift and thrust it needs, and the more drag it generates. Engines capable of delivering this level of thrust are likely to be hefty, which increased total weight still further—causing what is known as the "snowball effect". In other words, it's a never-ending series of compromises, which explains why design engineers must estimate all key parameters from the outset.
Structural engineers then carry out a series of iterations that take into account all key parameters: location of the landing gear and engines, center of gravity, choice of materials, aeroelasticity, etc. At the same time, they apply basic design rules in compliance with regulatory requirements.
This process enables the engineers to fine-tune their design, so that the aircraft will offer the best possible flying characteristics and overall performance. Hence the Dassault Falcon philosophy of design evolves the art and science of structures, including the seemingly endless precautions that designers must take, and the long calculations and painstaking work hidden behind the final coat of paint. This quality is primordial, because it plays a key-role, not only for safety but also for the performance and operating costs of modern aircraft.
|
