Gust load alleviation is an increasing concern for the design of fixed-wing aircraft with ultra-high aspect wings. It may have detrimental impacts on flight including increased structural and aerodynamic loads, structural deformation, and decreased flight dynamic performance. Innovators at NASA's Langley Research Center have developed a mechanical solution to control gust-load on fixed plane wings enabling significant improvement over alleviation devices currently in use.
By manipulating the wing's natural response to gust loads, the technology may minimize aerodynamic and structural loads and improve flight efficiency of future aircraft. Current computer-controlled, active gust-alleviation devices delay the wing response such that gust loads experienced are mitigated less than 10 percent while the present invention has demonstrated the ability to improve gust load alleviation up to 30 percent. Along with the reduced response time that alleviates gust load, NASA’s mechanical innovation offers the advantage of a simplified design and potentially improves passenger flight experience during turbulence.
This technology has been demonstrated to improve current gust load alleviation by use of a trailing-edge, free-floating surface control with a mass balance. Immediately upon impact, the inertial response of the mass balance shifts the center of gravity in front of the hinge line to develop an opposing aerodynamic force alleviating the load felt by the wing. This passive gust alleviation control covering 33 percent of the span of a cantilever wing was tested in NASA Langley’s low-speed wind tunnel and found to reduce wing response by 30 percent.
While ongoing experimental work with new laser sensing technologies is predicted to similarly reduce gust load, simplicity of design of the present invention may be advantageous for certification processes. In addition, this passive technology may provide further gust alleviation upon extending the use of the control to the entire trailing edge of the wing or upon incorporation with current active gust alleviation systems.
Importantly, the technology can be easily incorporated into to the build of nearly all fixed-wing aircrafts and pilot control can be maintained through a secondary trim tab. Though challenging to retrofit, passive gust alleviation could enable use of thinner, more efficient wings in new plane design.