Hybrid RotorWing design transitions from fixed to rotary wing mid-flight

The unmanned and remote piloted aerial vehicles market is seen as the natural first step for the technology

Attempts to combine the vertical take-off and landing (VTOL) capabilities of a helicopter with the high-speed flight and long range capabilities of a fixed-wing aircraft have been tackled in a number of different ways – from tiltrotor designs, such as the V-280 Valor and Project Zero, to fixed rotor aircraft that transition from vertical to horizontal flight, such as the SkyTote and Flexrotor. Australian company StopRotor Technology has taken a different approach with its Hybrid RotorWing design concept which features a main rotor that switches from fixed rotor to fixed wing in mid air.

Similar to the SiMiCon Rotor Craft concept, StopRotor Technology’s Hybrid RotorWing can take off vertically and hover with the main rotor spinning like a helicopter’s, or take off and fly like a conventional fixed wing aircraft. To transition between rotary and fixed wing flight modes, the aircraft is plunged into a fall involving high angle of attack flight that aligns the airflow with the rotation axis of the rotor system. This symmetrical airflow over the main rotor provides a stable environment that allows the blades to be started or stopped.

The design features a powered main rotor, anti torque system and forward propulsion engines. These various components can either all be powered by a single engine with appropriate transmissions, or by multiple engines performing dedicated roles.

The Hybrid RotorWing can operate in five different flight modes.

• Fixed Wing Flight: where the RotorWing is locked to operate as a fixed wing
• Rotary Wing Flight: The RotorWing rotates like a helicopter rotor providing sustained hover capability
• Compound Rotary Wing Flight: where the rotors requirement to produce lift and thrust is off loaded to other lifting surfaces or propulsion engines
• Autogiro Flight: a form of rotary wing flight where the rotor is driven by the relative airflow and not directly by the engine
• Transition Flight Mode: where the conversion from fixed to rotary or rotary to fixed wing flight occurs

The company says this versatility translates into unprecedented adaptability with conventional, short or vertical takeoff and landing options, plus on-ground as well as in-flight mode transition with no negative impact on load capacity. The design also features a conventional fuselage that helps open up the technology to a host of applications.

While the StopRotor team says the design is suitable for scaling up to manned applications, the unmanned and remote piloted aerial vehicles market is seen as the natural first step for the technology.

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