HeliX: Ahead of the Curve
The HeliX is the University of Maryland’s (UMD) winning submission (graduate category) in response to the Request for Proposal (RFP) for the 2013 AHS Student Design Competition, co-sponsored by Eurocopter. The HeliX is a variable diameter tiltrotor concept designed to have unprecedented capabilities in the realms of range, speed, and endurance. In addition to boasting advanced performance characteristics, careful consideration was put into the design of the command structure, decreasing pilot workload while ensuring the safety of all occupants. It is these key components that make the HeliX a superior Search and Rescue platform, ideal for rescues in a vast array of operating conditions.
The RFP has specified three separate missions that require the vehicle to be easily and quickly reconfigurable. The three missions are: 1. Fast deployment and rescue coordinattion, 2. Aid distribution, and 3. Search and rescue. Because of the nature of the requirements and the need for multi-role capability, a variable-diameter tiltrotor (VDTR) configuration was selected. The VDTR configuration has a higher technology readiness level (TRL) than compound helicopters, demonstrates success as a transport in demanding operating environments, and is primed for improvements to meet the configuration’s full potential. The key components and features of HeliX are shown in Fig. 1.
Tiltable outboard wing extensions
Mechanism for proprotor tilt
Fig. 1: Salient features of HeliX
Proprotor hub with mechanism for VDR
The RFP outlines requirements for a fleet of highly autonomous aircraft to perform reconnaissance, aid distribution, and SAR tasks. To demonstrate that the HeliX can fulfill this requirement with ease and proficiency, a real-world, well-known natural disaster was selected as a model. This simulation employed optimized path planning to route a small fleet of two aircraft out to rescue several groups of stranded, injured people spread over hundreds of square miles of the Gulf coastline, spanning three states.
The ability of the HeliX to navigate the disaster zone is second to none, shown clearly by the evaluation of well-defined comparison metrics. Flight paths are defined by priorities to rescue critically-injured persons while minimizing fuel consumption. Ultimately, these metrics are used to estimate the performance of the HeliX in a disaster of a large magnitude. Figure 2 shows a chart depicting the path planning algorithm and the performance metrics of HeliX compared to other rotorcraft in service during the disaster.
Fig. 2: Search and rescue simulation using HeliX and a path planning algorithm.
The final design report submitted contains more detailed analysis of the aerodynamics, structures, propulsion, drive-train, dynamics, acoustics, operating costs, avionics, HUMS and path planning.
UMD Graduate Team, "HeliX: Ahead of the Curve," Design Report for the American Helicopter Society Student Design Competition, 2013.