ROTORwing VTOL Unmanned Aircraft
Imagine an aircraft that can fly an extraordinary distance but also lands without a runway, open field, or catch wire. The takeoff and landing ability of the ROTORwing means that it can easily carry sensors and payloads to obscure locations many miles away, and land, listen, or collect data before taking off and returning to base. This autonomous operation can be performed at distance ranges unachievable with other Vertical Take Off and Landing (VTOL) vehicles.
The ROTORwing concept was discovered during an internal research and development project focused on alternative VTOL aircraft designs compared to traditional Class II/III aircraft. While researching the trades on present day VTOL vehicles such as helicopters or tilt rotor aircraft like the V-22, it was found that the weight of the transmissions of these aircraft could weigh almost three times the weight of the engines alone. These vehicles also have lower aerodynamic efficiency than most aircraft. The key breakthrough was the concept of using the wing as the VTOL rotor while propelling the rotor with the same engines that the aircraft requires for forward flight: the aerodynamic gearbox.
The principle behind ROTORwing is using the wings as rotors, and the flight engines to power the rotors. From a stationary position, tail on the ground, the ROTORwing will lift straight up in VTOL style. To prepare for take-off, ROTORwing first rotates its wings from the flight position (the wing chord parallel to the fuselage) in opposing directions, to the hover position, 75 degrees off the fuselage’s 0 degree axis (vertical, in launch position). This wing rotation orients the plane’s two propellers in opposite directions, which cause the rotor-wings and upper fuselage to spin while the four-finned tail unit remains stationary on the ground. When the the wings and body reach 90 RPM, the flaps (ailerons) are deflected down and the aircraft leaps into the air. A small motor in the tail “de-spins the tail” during the flight. At a height of 2,000 ft AGL, the wings rotate forward to flight position, the wings and fuselage stop spinning, the tail locks and the vehicle then flies like a conventional airplane between 40 and 100 knots. To initiate landing, the wings and fuselage pull-up into a vertical climb at full speed and begin the transition back into the ROTORwing configuration to allow a vertical landing – enabling the UAV to touchdown gently on its tail. Each wing has four actuators for ailerons. In VTOL mode the ailerons are used for collective control (more or less lift) and cyclic control (tilting the rotor) of the VTOL function acting as an electronic swashplate.
The innovation of ROTORwing is that is matches highly efficient, long-endurance flight with vertical takeoff and landing, without needing a giant gearbox between the engine and the rotor. In a conventional helicopter the tail rotor weigh about three times what the engine weighs. This airplane eliminates all that by spinning the wings. The ROTORwing has an engine on each wing, like a totally normal twin-engine airplane. The result is a huge weight savings.