Development of a Validated Design Methodology for VTOL SUAS.
Author: Andrew Loughran
Publisher:
Published: 2024
Total Pages: 0
ISBN-13:
DOWNLOAD EBOOKThere is growing interest in developing fixed-wing small unmanned aircraft systems (sUAS) with vertical takeoff and landing (VTOL) capabilities for many applications. To quickly and effectively design multiple configurations of VTOL sUAS such that the end product performs as intended, this thesis develops a validated, low-computational-cost design method. The design method incorporates a set of low-computational-cost weight and aero-propulsive performance models that were identified, selected, tuned, and validated through fabrication and flight testing of three different configurations of VTOL sUAS. An iterative design model approach was then developed to explore the design space to understand the trends between configurations in the mission space. The Weight and Aero-propulsive models and methods are component-based weight build-up, low-order drag build-up, momentum theory propeller model, and an empirical approach to motor and electronic speed controller (ESC) efficiencies at relevant scales. Subcomponent models were validated by comparing them to the three VTOL sUAS configurations through flight testing in both hover and forward flight. Each vehicle's components were broken down by weight, compared against the design model's weight predictions, and found to be within 8.7% for all three configurations. Vehicle performance models for power draw in hover and forward flight were validated with measured power draw during flight testing in relevant conditions and were found to be within 13.1% of mean test data results for hover and 19.4% of mean test results for forward flight. Predictions were found to be most sensitive to the assumed motor, ESC, and propeller efficiencies, rotational velocity of motors, and accurate prediction of fuselage drag. The validated subcomponent methods were then implemented in an iterative approach that required the convergence of the vehicle's gross weight and the battery weight. A mission space exploration was performed for a fixed-wing VTOL sUAS and a non-fixed-wing VTOL sUAS for comparison. These vehicles were under 55 lbs and it was determined that a maximum of 53 mile cruise for a 2-prop thrust vectoring sUAS and a maximum of 40 minute hover time for a quadrotor is possible. The mission space exploration found that there is a difference between the lightest vehicle and the most energy-efficient vehicle, which emphasizes that vehicle design objectives can vary the resultant vehicle design. In addition to a mission space exploration, this thesis presents a full conceptual design of a 2-prop thrust vectoring sUAS with an expected mission profile of 10 minute hover time and a 5 mile cruise distance with a gross weight of 2.28 pounds.
