Analysis of a hydrogen fuel cell-PV power system for small UAV

Improving Electric Powered UAVs’ Endurance by Incorporating Battery Dumping Concept

This paper discusses the conceptual design and proof-of-concept flight demonstration of a novel variable pitch quadrotor biplane Unmanned Aerial Vehicle concept for payload delivery. The proposed design combines vertical takeoff and landing (VTOL), precise hover capabilities of a quadrotor helicopter and high range, endurance and high forward cruise speed characteristics of a fixed wing aircraft. The proposed UAV is designed for a mission requirement of carrying and delivering 6 kg payload to a destination at 16 km from the point of origin. First, the design of proprotors is carried out using a physics based modified Blade Element Momentum Theory (BEMT) analysis, which is validated using experimental data generated for the purpose. Proprotors have conflicting requirement for optimal hover and forward flight performance. Next, the biplane wings are designed using simple lifting line theory. The airframe design is followed by power plant selection and transmission design. Finally, weight estimation is carried out to complete the design process. The proprotor design with 24 deg preset angle and -24 deg twist is designed based on 70% weightage to forward flight and 30% weightage to hovering flight conditions. The operating RPM of the proprotors is reduced from 3200 during hover to 2000 during forward flight to ensure optimal performance during cruise flight. The estimated power consumption during forward flight mode is 64% less than that required for hover, establishing the benefit of this hybrid concept. A proof-of-concept scaled prototype is fabricated using commercial-off-the-shelf parts. A PID controller is developed and implemented on the PixHawk board to enable stable hovering flight and attitude tracking.

Systematic design methodology for development and flight testing of a variable pitch quadrotor biplane VTOL UAV for payload delivery

This paper presents a multi-disciplinary analysis methodology for a box-wing aircraft configuration optimised for a given mission scenario. This conceptual design methodology and associated toolchain combines well-established vortex lattice analysis and a newly developed structural analysis tool called WingMASS, allowing the design space to be explored from a combined aerodynamics and structural design perspective. For a given mission scenario, the method optimises a box-wing configuration and compares it with an equivalent conventional configuration. This study shows that, for a given mission, a boxwing configuration can lead to a fuel burn reduction of up to 5% by optimising aspect ratio, horizontal and vertical wing separation.

Multi-disciplinary analysis and optimisation methodology for conceptual design of a box-wing aircraft

A vehicle, includes a main body. A fluid generator is coupled to the main body and produces a fluid stream. At least one fore conduit and at least one tail conduit are fluidly coupled to the generator. First and second fore ejectors are fluidly coupled to the fore conduit, coupled to the main body and respectively coupled to a starboard side and port side of the vehicle. The fore ejectors respectively comprise an outlet structure out of which fluid flows. At least one tail ejector is fluidly coupled to the tail conduit. The tail ejector comprises an outlet structure out of which fluid flows. A primary airfoil element is coupled to the tail portion. A surface of the primary airfoil element is located directly downstream of the first and second fore ejectors such that the fluid from the first and second fore ejectors flows over the such surface.

Configuration for vertical take-off and landing system for aerial vehicles

The overall air vehicle performance of a multipl e lifting surface configuration has been studied with respect to both structural and aerodynamic considerations for a candidate mission similar to that of the AeroVironment Raven . The configuration studied is a biplane joined at the tips with endplates. M ore specifically , this study aims to determine if this particular nonplanar wing concept can meet the requirements of the mission for a small Reconnaissance, Surveillance and Target Acquisition UAV. The mission capabilities of small UAVs are constantly gro wing by implementing recent developments in miniature computers and peripherals, electronic sensors, and optical sensing equipment at affordable cost. The requirements for the mission profile of a small UAV using the aforementioned equipment are defined w ith an emphasis on the potential advantages that can be offered by the nonplanar concept wing under investigation. A structural analysis using the finite element software ADINA and an aerodynamic analysis based on wind tunnel experimental data and vortex p anel code results are performed. The results, compared under varying assumptions specific to an equivalent monoplane and a biplane, suggest potential efficiency gains for the new configuration may be possible using the nonplanar wing configuration under ex plicit conditions . The results also show structural characteristics and not aerodynamics alone are critical in determining the utility of this nonplanar concept.

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Giuseppe Landolfo

Papers

Aerodynamic and Structural Design of a Small Nonplanar Wing UAV