Investigation of compound rotorcraft with asymmetric wing and single rotor

초록

Despite advantages of VTOL (Vertical Take-Off and Landing) and hovering, conventional helicopters have significantly lower maximum speed compared to that of fixed wing aircraft due to imbalance of aerodynamic states on the rotor disk. Overcoming the limitations and improvements on the high-speed performance can be achieved by compensation of lift imbalance using auxiliary lift and thrust components and such a configuration is called the compound rotorcraft. In this paper, a new compound rotorcraft concept with an asymmetric wing is proposed. Roll moment due to lift imbalance is compensated by the asymmetric wing installed below the retreating side of the rotor. The new compound rotorcraft with the asymmetric wing with flap that controls rolling moment of the rotor and the propeller for auxiliary propulsion can fly faster than existing compound rotorcraft. A modeling and analysis tool were developed by modifying FLIGHTLAB model template. Trim simulations and trend analysis for compound rotorcraft models with various asymmetric wing configurations were performed, and the tool was verified successfully. A dynamic model of XH-59A, a compound helicopter with coaxial rotors and a propeller, was developed as a reference model to verify usefulness of the proposed compound rotorcraft using the tool. The reference model was validated with various test data from literatures. Based on the reference model, a simulation model of proposed compound rotorcraft was derived, and we performed trim analysis of these models. Trim simulation results comparisons have found that the proposed rotorcraft is more efficient in terms of required power, especially the required power of the proposed model is less than the reference model by 40% in forward speed of 240 knots that is a maximum speed of the reference model. We derived that the proposed compound rotorcraft with asymmetric wing is more efficient than other compound helicopter configuration in high speed through these simulation results. © 2019 The Vertical Flight Society. All rights reserved.