Ground tests undertaken on Lockheed Martin’s QueSST X-59 demonstrator revealed flight control issues. Despite everything, NASA persists in wanting to fly its supersonic for the first time before the end of this year.
Problematic flight controls
Problems occurred with the flight controls. This is how the situation could be summarized. During a test carried out on the ground with full facts, the QueSST or silent supersonic flight demonstrator was the victim of a structural coupling that occurred in the chain of flight controls, more precisely at the level of the interaction between the structures aircraft flexibility, aerodynamic forces and advanced flight control systems. In July of this year, the aircraft test team moved the X-59 to the airstrip, with the aim of beginning ground testing prior to first flight. Among these were a number of tests aimed directly at the device’s control surfaces to determine the extent of movement and structural vibration tests. Engineers used accelerometers to measure vibration, gathering useful data to verify and improve models.
Calculators at the origin
These were followed by structural coupling tests, during which the team identified the problem of the flight controls, the origin of which would be in the flight control computers. Problem which is complicated by the fact that the flight control system, which is a CDVE, has parts and components from several different suppliers taken from existing stocks when they have not been on the shelf. Thus a certain number of batches of parts come from F-16, F/A-18, in the same way as the Grumman X-29 was built at the time. In themselves, the X-59 CDVEs are probably one of a kind.
A first flight still maintained for this year
Powered by a GE Aviation F414-GE-100 turbojet engine with a thrust of 98 kN, the X-59 was designed to reduce the noise generated by the sonic boom when breaking the sound barrier to the equivalent of a car door. While the program has already fallen behind schedule, as NASA originally planned to fly the plane in 2021, despite this new flight control issue, NASA says it is sticking to the existing plan. which plans the very first flight of the X-59 this year.
