Development and testing of fuel-cell powered UAV

• Main Author: Lee, Ying Qin.
• Other Authors: Go Tiauw Hiong
• Format: Final Year Project
• Language: English
• Published: 2011
• Subjects: DRNTU::Engineering::Aeronautical engineering::Aviation
• Online Access: http://hdl.handle.net/10356/46158
• Institution: Nanyang Technological University

This report serves to investigate and derive an fuel cell powered unmanned aerial vehicle (UAV) design. Being a fuel cell UAV, this design is centred around the power and thrust output of the fuel cell. Primarily, the drag of UAV must be lower than the thrust provided and the lift must be greater than the weight of the combined system. Subsequently, the UAV is designed to be stable and trim-able longitudinally, directionally and laterally and possesses adequate control authority. In conceptual design phase, Multisurface Aerodynamics (MSA), a vortex-lattice method computational software, and empirical calculations were extensively used in lift and stability analysis. Large combinations of different wing spans, taper ratios, areas and placements were tried both empirically and on MSA before converging to the 1st design. The dynamic thrust of the selected motor was investigated using a close loop wind tunnel. The design’s scaled model was produced and tested in wind tunnel for flow interactive aerodynamic lift and drag parameters. After performing the relevant sensor weight calibrations of wall affected angle-of-attack (AOA) corrections, the wind tunnel indicated similar lift but significantly larger drag in contrast to previous empirical and MSA calculations. Through the consistently accurate application of wing component build-up method to predict lift and drag, the small magnitude of wing-body flow interaction was established. In contrast to empirical and MSA drag estimations, the wind tunnel registered significantly higher drag, deviating from the performance of wings of similar aspect ratios, and was thus considered to be inaccurate. The design process continued with lift estimated from wind tunnel and drag calculated using empirical relationships. In subsequent design modifications, the wing aspect ratios were kept large and experiences were drawn from existing Aeropak powered UAVs to reduce the wing size and the combined take-off weight to 5kg. Being at the first design iteration stage, more than adequate control authority was introduced into the design with, boosting elevator control surfaces found on both the tandem and main wing.