A Scalability Study of the Multirotor Biplane Tailsitter Using Conceptual Sizing

Abstract

This paper presents a methodology for preliminary sizing of unconventional rotorcraft using a physics-based approach to estimate the weight of primary load-carrying members and rotor efficiencies. The methodology is demonstrated for a quadrotor biplane tailsitter, a tilt-body configuration that can operate in both helicopter and airplane mode. A beam lattice framework for the airframe structure is iteratively adjusted in the sizing loop to accommodate the limit loads. A similar semianalytical approach is followed to size and estimate weight of the rotor blades. Using this analysis, a consistent combination of vehicle macrodimensions (rotor radius, wing span) and tip speed as well as detailed design parameters (spar height, skin thickness, and cross-section weight) are obtained simultaneously. To compare the effectiveness of various power plants within a weight class, the sizing methodology was modified to identify the payload for three different vehicle takeoff weights: 20, 50, and 1000 lb. To enable operation within constrained urban canyons, the effect of restricting maximum vehicle dimensions to 10 ftfor the 1000-lb designs is also examined. An electric transmission model is used in these designs owing to its relative insensitivity of transmission efficiency to the operating RPM. A variable-pitch and variable-RPM rotor design allows for control redundancy within each rotor.

A Comprehensive Design and Experiment of a Biplane Quadrotor Tail-Sitter UAV

“…Small UAVs refer to remotely controlled or autonomous aircraft with an empty aircraft weight of no more than 15 kg or a maximum takeoff weight of no more than 25 kg [10]. Currently, there are several common hybrid vertical takeoff and landing unmanned aerial vehicles, including tail-sitter [11][12][13], tiltrotor [14,15], and tiltwing compound helicopter [15,16] concepts. Coban, S. realized simultaneous improvement of the longitudinal and lateral flight trajectory tracking performances for hybrid VTOL UAV [17].…”

Adaptive backstepping controller design of quadrotor biplane for payload delivery

“…Hrishikeshavan et al present a step-by-step development of biplane quadrotor for enhanced performance and experimentally examined a few essential design parameters such as wing aspect ratio, aerofoil profile, wing spacing, and offset between propeller axis and wing chord [1]. Sridharan et al [2], propose a methodology for size and estimate the weight of primary load-carrying members as demonstrated on biplane tailsitter. Dawkins et al propose a mathematical model and a PID controller for efficiency analysis of a micro quadrotor drone with airfoils and trim analysis suitable for nominal flight conditions [3].…”

“…Sridharan et al. [2], propose a methodology for size and estimate the weight of primary load‐carrying members as demonstrated on biplane tailsitter. Dawkins et al.…”

Configuration Study of Electric Helicopters for Urban Air Mobility

“…Several additional configuration studies [9][10][11][12][13][14] omitted consideration of a single-mainrotor electric helicopter entirely, with the closest typically considered configuration being a side-by-side helicopter.…”