Generally drones with wings are great for cruising and long distance flights while the drones with rotors are apt for heavier payloads and vertical agility. It is rarely seen that a drone packs both the aforementioned features. However, the drones which do come with vertical agility and cruising capabilities are either military drones or are extremely big to be used commercially. THOR (Transformable HOvering Rotorcraft) is a small concept drone which can either cruise like a two-winged plane or fly like a standard rotorcraft.

At the ICRA (International Conference on Robotics and Automation) in Singapore, researchers from the Singapore University of Technology & Design introduced a new kind of flying robot called THOR: Transformable HOvering Rotorcraft. THOR achieves very high structural efficiency by using all of its aerodynamic surfaces for both vertical and horizontal flight modes. It can transition from a cruising drone to a spinning bi-copter drone in mid air which is truly remarkable.

At an initial glance THOR resembles a monocopter which has a single rotor, using which the drone spins and generates lift. THOR, however, has two rotors or airfoils which spin along with the body of the drone to generate lift. This mode is called the H-MOD by the researchers. In this mode, the airfoils rotate 180° from each other like the rotors in a helicopter. In cruise mode or the C-MOD, the two rotors stop spinning and are aligned in the same direction to give a fixed-wing feature to the drone.

A researcher said, while explaining the transition between the two flight modes, “A cool feature we came across was that the positive angles of attack of both modes of operation mean that a simple rotation of the two servos by approximately 90 degrees flips the craft onto the right side up for cruising. The craft then breaks out of the rotation and maintains altitude using raw motor thrust, after which the wings return to being the primary lift source.”

THOR’s configuration.

THOR has potentially many uses in the drone industry. It can operate with vertical agility as required in package delivery, inspection, surveillance, etc. and also in cruise mode which can enable it to operate for long distances like in agriculture. The team of researchers are further developing and refining their concept so that the transitioning between the two modes becomes more swift and instantaneous.

Watch the THOR as it switches between the two modes: