Story ID: 502
Dassault celebrates 100 years of innovation
By: Thierry Dubois
Caption: From the Eclair propeller to the Falcon 7X's digital flight control system, company engineers have endeavored to put new technologies in service.
Word Count: 875
Dassault (Booth Z091) is celebrating its 100th anniversary this year, as founder Marcel Dassault designed the Éclair (Lightning) propeller in 1916. It was just the first in a series of innovations. Arguably the five most impressive were as follows: the Éclair propeller; the Falcon 20’s servocontrols; the Falcon 50’s wing; the Falcon 7X’s digital flight control system (DFCS); and last but not least, the digital company concept. And although the company has not operated continuously since 1916, few would deny its right to celebrate.

During World War I, Marcel Dassault (whose name was still Marcel Bloch at the time) realized the efficiency of in-service propellers could be significantly improved. He therefore studied how, and came up with a profile that featured a more suitable variation from hub to tip. The idea was to have a constant thrust along the blade’s length. “On two-blade propellers, Marcel Dassault’s design principles are still in force,” Jean-Louis Montel, Dassault Aviation’s senior v-p engineering, told AIN.

The 1916 engineer not only wanted a better design, he also wanted it to be suitable for production. “He took into account that pieces of lumber sufficiently thick to carve a propeller from were expensive; and labor was not,” Montel went on. Therefore, he set thinking how to make propellers from planks of normal width. To make an Éclair, fanned-out layers of wood were glued together, roughly forming the curve of the blade, which was then sanded to its final shape.

In the early 1960s, the Falcon 20 was the first fixed-wing civil aircraft with servocontrols on the pitch, roll and yaw axes, claimed Montel. It involved designing compact servocontrols and associated hydraulic systems for them to be fitted into the wing of a relatively small aircraft. The result was better maneuverability for the business jet. Until then, civil aircraft had at least part of their flight control actuation system consisting of cables, rods and pulleys, Montel continued.

The Falcon 50, which first flew in 1976, was the first civil aircraft with a supercritical wing. On such an airfoil, the point on the chord where the boundary layer separation occurs is farther downstream. “This works very well at high Mach numbers,” Montel noted. As a result, cruise speed can be increased and fuel burn thereby reduced. The successful Falcon 50 airfoil shape was re-used–with the same profile, planform and dimensions–on the much larger Falcon 2000.

In the early 2000s, the Falcon 7X became the first purpose-built business jet with a DFCS. Compared to previous fly-by-wire controls on Airbus aircraft, Montel said Dassault “added permanent autotrim.” Autotrim, as the names suggests, automatically trims the aircraft according to pilot input. As a result, workload is reduced. Airbus aircraft have autotrim only when the autopilot is engaged.

Dassault’s design engineers had the benefit of the company’s military expertise to place such a system in a smaller airframe, while also allowing for civil certification requirements. “We had to be quite creative,” Montel recalled.

Dassault claims to be the only manufacturer in the world to be wholly responsible for manufacturing its own integrated DFCS, as other airframers subcontract servocontrols, computer systems and production to companies such as Thales and Parker Aerospace. “This is a strategic know-how for us,” Montel stressed. For example, he pointed out that making compact and powerful servocontrols involves sophisticated technologies in micro-mechanics. Dassault’s flight control factory is located in Argonay, in the French Alps, an area well known for its expertise in watchmaking.

Dassault Aviation has also been at the forefront of digitization. It has made the most of sister company Dassault Systèmes’ pioneering Catia CAD/CAM software. Catia is also used by other airframers–but Dassault Aviation has always tried to stay one Catia version ahead of the competition. The software has also grown to encompass a broader product-lifecycle-management solution.

As early as 2002, during a press visit, a virtual reality center could be seen at the firm’s Saint-Cloud headquarters in Paris. It was already fitted with 3D-vision goggles, and engineers could virtually walk through the Falcon 7X structure, examining wiring and other features. Meanwhile, customers could choose their cabin interior layout in the virtual reality center, an experience that has become increasingly realistic.

Another benefit of digitization was that it only took seven months to build the first Falcon 7X. The same process on the first Falcon 900, had taken 14 months. The difference was that the machines that make the 7X’s parts used the same data that designers saw on their Catia screens, leading to an unprecedented level of accuracy in manufacturing the structural assemblies.

It was not necessary to build either a mock-up of the 7X or a prototype aircraft. Checking the digital version against the actual 7X, engineers found almost none of the discrepancies usually encountered at this stage. Such flaws often include chafing of parts or a need to reposition some wires and tubing.

Thus, Dassault stands proud as a pioneer among aircraft manufacturers, with its latest aircraft, the 5X, pushing the frontiers even further in flight control systems that borrow again from the company’s expertise in developing the Rafale fighter.