A Tool for Rotorcraft Pre-Design Sizing

The goal for this project was to have the ability to analyze rotorcraft performance with reasonable accuracy, reliability, and robustness and be able to easily and within a reasonable amount of time iterate to an optimal vehicle design in a pre-design sizing study. This was accomplished by developing a stand-alone conceptual design software suite. The architecture of the suite was designed such that it can be used in a generic, rather than ad hoc, manner, while still offering significant transparency and expandability to the user. A simplified blade element analysis method was chosen for rotor analysis, and it was adapted to also be applicable to compound helicopters. This method was selected for its simplicity while still affording general applicability and the ability to accurately predict required power while capturing the high-speed phenomena of advancing blade critical Mach drag rise, retreating blade stall, and reverse flow. A case study was carried out using the software to design a 19-passenger, long range, high speed oil rig transport aircraft. A helicopter of conventional configuration was optimized for the task, and then compounding was used to expand the flight envelope.