Design and Fabrication of the LA-8 Distributed Electric Propulsion VTOL Testbed

Abstract

The Langley Aerodrome No. 8 (LA-8) is a distributed electric propulsion, vertical takeoff and landing (VTOL) aircraft that is being used for wind tunnel testing and free flight testing at the NASA Langley Research Center. The LA-8 test vehicle provides a low-cost, modular testbed for research in the area of Urban Air Mobility(UAM). The LA-8, a tandem tilt-wing configuration,has the potential to provide superior performance while also enabling researchinto significant areas of risksuch aseffects of winds, subsystem failures, and adequate control power and damping during transition. While all UAM VTOL designs have challenges regarding acoustics and community noise, the LA-8 vehicle can address other equally significant risks to UAM vehicle design.The LA-8 test strategy enables significant project cost reductions through the use of the exact same model for both wind-tunnel and subsequent free flight testing. Previously, wind tunnel andflight testing required separate specialized models, costing much more.The fabrication methods used on the LA-8 provide a relatively rapid and low-cost means to validate aerodynamic, acoustic, and flight dynamics analysis of new electric VTOL and short takeoff and landing (STOL) designs. In addition, the flight vehicle will be used to help develop test processes for FAA flight vehicle airworthiness certification and for the development of robust flight control algorithms that are tolerant of failures. A new approach is being used on test vehicle design that makes extensive use of 3-D printing. Although materials used in 3-D printinghave lower strength-to-weight ratios than traditional materials used for NASA’s wind tunnel and flight models, strategic placement of load-carrying structures allows the aircraft to meet structural criteria. This technique also enables rapid changes to be made in the vehicle design, such as the outer mold line, as well as easy fabrication of replacement parts. Modularity of the vehicle’s main components allows changes to the vehicle overall configuration for comparative evaluation of alternate designs. Finally, a description is given of detailed mass property measurements of the flight vehicle, including center-of-gravity (CG) location, the CG shift associated with wing tilt, and mass moments of inertia using multiple pendulum swing methods.