Modern unmanned air vehicles (UAVs) are usually equipped with rotors connected to electric motors that enable them to hover and fly in all directions. The purpose of the paper is to design optimal composite rotor blades for such small UAVs and investigate their aerodynamic performances both computationally and experimentally.,Artificial intelligence method (genetic algorithm) is used to optimize the blade airfoil described by six input parameters. Furthermore, different computational methods, e.g. vortex methods and computational fluid dynamics, blade element momentum theory and finite element method, are used to predict the aerodynamic performances of the optimized airfoil and complete rotor as well the structural behaviour of the blade, respectively. Finally, composite blade is manufactured and the rotor performance is also determined experimentally by thrust and torque measurements.,Complete process of blade design (including geometry definition and optimization, estimation of aerodynamic performances, structural analysis and blade manufacturing) is conducted and explained in detail. The correspondence between computed and measured thrust and torque curves of the optimal rotor is satisfactory (differences mostly remain below 15%), which validates and justifies the used design approach formulated specifically for low-cost, small-scale propeller blades. Furthermore, the proposed techniques can easily be applied to any kind of rotating lifting surfaces including helicopter or wind turbine blades.,Blade design methodology is simplified, shortened and made more flexible thus enabling the fast and economic production of propeller blades optimized for specific working conditions.

Optimal propeller blade design, computation, manufacturing and experimental testing

Electric-powered distributed propulsion aircraft possess a complex wake flow and mutual interference with the airframe, due to the use of many propellers. Accordingly, in the early design stage, rapid aerodynamic and load analysis considering the effect of propellers for various configurations and flight conditions are required. In this study, an efficient panel-based aerodynamic analysis method that can take into account the propeller effects is developed and validated. The induced velocity field in the region of propeller wake is calculated based on Actuator Disk Theory (ADT) and is considered as the boundary condition at the vehicle’s surface in the three-dimensional steady source-doublet panel method. Analyses are carried out by selecting an isolated propeller of the Korea Aerospace Research Institute (KARI)’s Quad Tilt Propeller (QTP) aircraft and the propeller-wing configuration of the former experimental study as benchmark problems. Through comparisons with the results of computational fluid dynamics (CFD) based on actuator methods, the wake velocity of propeller and the changes in the aerodynamic load distribution of the wing due to the propeller operation are validated. The method is applied to the analysis of the Optional Piloted Personal Aerial Vehicle (OPPAV) and QTP, and the practicality and validity of the method are confirmed through comparison and analysis of the computational time and results with CFD.

Development of Panel-Based Rapid Aerodynamic Analysis Method Considering Propeller Effect

Comparison of Multi-Fidelity Prediction Methods for an Integrated Propeller

The propeller of tail-sitter UAV plays the role both in providing thrust and obtaining control forces. The beneficial installation position of propellers considering thrust, L/D and roll moment control force was studied in this paper. RANS CFD method with MRF treatment for propeller rotation regimes was applied. The slipstream of baseline installation makes the aberration of the wing pressure and span load distribution, which make lift reduced by 6.9% and drag increased by 14.3%. 5X5 matrix of installation location was studied by CFD. The stream wise location has significant effect on the cruise L/D, on the other hand the vertical wise location make significant effect on the cruise thrust and hovering control force. Three objectives optimization based on surrogate model was conducted. The cruise L/D and hovering control force were improved by 6.93% and 6.1% respectively with a few cruise thrust loss. 

Propeller Installation Effect and Surrogate Based Optimization of a Tail-sitter Drone

This paper analyzes the effects of propeller flow on the linear coupled longitudinal and lateral dynamics of a 150 mm wingspan fixed wing micro air vehicle (MAV). The effects propeller flow on the ...

Effects of propeller flow on the longitudinal and lateral dynamics and model couplings of a fixed-wing micro air vehicle:

The present investigation addresses two key issues in aerodynamic performance of a propeller–wing configuration, namely linear and nonlinear predictions with low-order numerical models. The develop...

Baizura Bohari

Papers

Aerodynamic model of propeller–wing interaction for distributed propeller aircraft concept: