M-Star Medical Transport with a Multi-Ducted Angled Rotor Design

This paper discusses the benefit of the multi-ducted angled rotor (M-DAR) distributed electric propulsion system in a V/STOL aircraft called the M-Star. The M-DAR propulsion system consists of an array of fixed pitched ducted fans. Traditional fan-in-wing designs can suffer from pitch up effects, stall, instability, and momentum drag when transitioning to forward flight as the oncoming air vector increases. In such planar orientations the air must accelerate rapidly into the ducted fan to prevent blade instability. The M-DAR solves these challenges by lowering the angle at which air enters the fans. A 45-degree M-DAR system enables a higher transition speed than 90 degree ducted fans since the air does not need to turn the additional 45-degrees into the ducts. The M-DAR system is comprised of an array of fans which increase the total disk area while the front plate area remains fixed. The fixed fans also eliminate the weight and complexity of actuators-essentially reducing the mechanical challenges of tiltrotor aircraft into programming tasks. In addition, the M-DAR can be operated as a replacement or in conjunction with control surfaces for increased maneuverability and safety. The M-Star incorporates these design benefits which makes the 2-passenger aircraft affordable, safe, and high endurance. SpyDar has successfully developed subscale Group 1 & 2 cargo UAVs using the M-DAR system and intends to scale the concept into the 2-passenger M-Star eVTOL. The mission of this aircraft will be as a medical commuter vehicle for health professionals to rural and underserved areas.