UC Irvine

Advanced Air Mobility (AAM) distributed propulsion vehicles are currently being proposed in industry and may be capable of flying various operations such as Short-Takeoff and Landing (STOL), Tilt-Rotor Vertical Takeoff and Landing (Tilt-Rotor VTOL) and Lift plus Cruise Vertical Takeoff and Landing (LPC VTOL). The effects of each propulsor configuration must be assessed for efficient and quiet low-altitude flight procedures. This thesis paper outlines a methodology to assess the aircraft performance of AAM vehicles with open rotor configurations by predicting operating states such as propeller RPM, power, thrust and drag characteristics within a given flight procedure. Such methodology utilizes a polar drag buildup to predict the aerodynamic losses of AAM vehicles during takeoff, transition and cruise conditions. MATLAB is utilized to generate a best-fit line of wind tunnel-tested experimental data from parallel, normal and inclined flow to compute the coefficient of drag. Simultaneously, this methodology utilizes the blade element momentum theory propeller design program XROTOR to size the distributed propulsors capable of operating the mentioned relevant flight segments. The propulsor design methodology outlined in this paper minimizes induced losses at the rotors by constraining a low Mach tip number, to lower community noise levels with a feasible motor torque. Propeller off-design conditions are presented in propeller contour maps obtained from XROTOR for fixed and variable pitch propeller settings, to provide the mentioned relationship between RPM and segment thrust. Such a relationship can be used to build flight procedure dynamics and predict overall efficiency and community noise levels. An application of the described methodology will be presented to determine the low-altitude flight aircraft performance of STOL, Tilt-Rotor VTOL, and LPC VTOL AAM vehicles.