Hoplite - a conceptual design environment for helicopters incorporating morphing rotor technology

The SABRE project has been initiated under the EU’s Horizon 2020 programme for development of blade morphing technologies for helicopter rotors. The project targets reductions in fuel burn and NOx emissions of upto 5-10% through the use of morphing rotor blades. A new design tool for rotorcraft, HOPLITE, is being developed to investigate the effects of rotor morphing on engine emissions and fuel burn. HOPLITE uses low-fidelity models for quick and reasonably accurate force and power calculations for major components of the vehicle. The main rotor is modelled using the Blade Element Method, and accounts for changes in blade shape due to rotor morphing and other geometrical modifications. Additionally, a robust fuselage parameterization method, and an equation based engine model have been incorporated in HOPLITE to include the impact of rotor morphing on the design of the helicopter as a whole. The main argument behind the development of HOPLITE is to combine various low-fidelity methods, such that quick design assessments can be performed for various purposes, and, simultaneously, have sufficient fidelity to capture changes in blade shape due to rotor morphing. Actuator disk models can perform a quick analysis, but are unable to match the required level of fidelity. In comparison, traditional CFD simulations or experimental campaigns will be cost and time intensive. Hence, there is a need for a new tool. Due to a multidisciplinary and modular approach used by HOPLITE, it can be used for a wide range of tasks, such as design space exploration and optimization. Furthermore, it can be used in conjuction with high fidelity methods. This paper describes the current work done towards the development of various modules of the tool, theoretical aspects of engine, fuselage and rotor modelling, and initial results obtained during development and testing of individual modules. Theoretical aspects of conceptual design capabilities of the tool have also been briefly described in this paper. Future work will involve development and integration of conceptual design functions in HOPLITE for conventional helicopters, and expansion of these algorithms to non-conventional rotorcraft designs.