Refine
Year of publication
Institute
- Fachbereich Luft- und Raumfahrttechnik (22)
- ECSM European Center for Sustainable Mobility (3)
- Fachbereich Maschinenbau und Mechatronik (3)
- FH Aachen (1)
- Fachbereich Elektrotechnik und Informationstechnik (1)
- Fachbereich Wirtschaftswissenschaften (1)
- MASKOR Institut für Mobile Autonome Systeme und Kognitive Robotik (1)
Document Type
- Conference Proceeding (10)
- Article (9)
- Conference: Meeting Abstract (2)
- Conference Poster (1)
- Doctoral Thesis (1)
- Patent (1)
Keywords
- CFD (1)
- Drag estimation (1)
- Electrical Flight (1)
- Flight Mechanics (1)
- Flight Tests (1)
- Inflight Regeneration, Recuperation (1)
- Multirotor UAS (1)
- Propeller Aerodynamics (1)
- Wind milling (1)
- Wind tunnel experiments (1)
New European Union (EU) regulations for UAS operations require an operational risk analysis, which includes an estimation of the potential danger of the UAS crashing. A key parameter for the potential ground risk is the kinetic impact energy of the UAS. The kinetic energy depends on the impact velocity of the UAS and, therefore, on the aerodynamic drag and the weight during free fall. Hence, estimating the impact energy of a UAS requires an accurate drag estimation of the UAS in that state. The paper at hand presents the aerodynamic drag estimation of small-scale multirotor UAS. Multirotor UAS of various sizes and configurations were analysed with a fully unsteady Reynolds-averaged Navier–Stokes approach. These simulations included different velocities and various fuselage pitch angles of the UAS. The results were compared against force measurements performed in a subsonic wind tunnel and provided good consistency. Furthermore, the influence of the UAS`s fuselage pitch angle as well as the influence of fixed and free spinning propellers on the aerodynamic drag was analysed. Free spinning propellers may increase the drag by up to 110%, depending on the fuselage pitch angle. Increasing the fuselage pitch angle of the UAS lowers the drag by 40% up to 85%, depending on the UAS. The data presented in this paper allow for increased accuracy of ground risk assessments.
Electric flight has the potential for a more sustainable and energy-saving way of aviation compared to fossil fuel aviation. The electric motor can be used as a generator inflight to regenerate energy during descent. Three different approaches to regenerating with electric propeller powertrains are proposed in this paper. The powertrain is to be set up in a wind tunnel to determine the propeller efficiency in both working modes as well as the noise emissions. Furthermore, the planned flight tests are discussed. In preparation for these tests, a yaw stability analysis is performed with the result that the aeroplane is controllable during flight and in the most critical failure case. The paper shows the potential for inflight regeneration and addresses the research gaps in the dual role of electric powertrains for propulsion and regeneration of general aviation aircraft.
This paper discusses a new way of inflight power regeneration for electric or hybrid-electric driven general aviation aircraft with one powertrain for both configurations. Three different approaches for the shift from propulsion to regeneration mode are analyzed. Numerical cal-culation and wind tunnel results are compared and show the highest regeneration potential for the "Windmill" approach, where the propeller blades are flipped, and rotation is reversed. A combination of all regeneration approaches for a realistic flight mission is discussed.