VTOL (vertical take-off and landing) drones already have some advantages over multicopters and fixed-wing drones, but could they offer even better functionality? The designers of the ROTORwing seem to think so, as their aircraft's wings actually double as its rotor blades.
Ordinarily, VTOLs have both fixed wings and copter-style horizontal propellers. Those props allow them to take off and land vertically, so they don't require a runway. Once they reach their cruising altitude, the propellers either tilt forward or a vertical rear pusher prop kicks in, taking the drone into faster, more energy-efficient forward flight than would be possible for a conventional multicopter.
The ROTORwing takes a much different approach. Created by US aerospace company DZYNE Technologies, it has a top-mounted set of wings that are able to rotate horizontally as one connected unit, relative to the aircraft's main body. Each wing can in turn flip over relative to the wing unit's central hub, allowing its electric motor/propeller to face backwards relative to that on the other wing.
When the drone is taking off, one of its wings is indeed facing backward. With the two props thus producing thrust in opposite directions, the wing unit proceeds to spin around like the rotor blades of a helicopter, lifting the aircraft off the ground.
Once it's time to go into forward-flight mode, the two wings both briefly pivot neutrally upward, and then pivot down so that both props are facing forward – the wing unit is now locked perpendicular to the drone's body. The propellers then pull the ROTORwing forward, with the wings providing lift like those of a fixed-wing airplane. When it's time to land, or just to hover on the spot, the process is simply reversed.
It all seems very clever, but how is it supposedly superior to traditional systems?
According to Shane Skopak, the director of DZYNE's products division, conventional tilt-rotor VTOLs require large, powerful motors and large-diameter propellers in order to attain lift-off. Those motors use up a lot of battery power, while the long props produce extra drag in forward flight. Additionally, the wings tend to be on the short-and-stubby side.
He adds that pusher-prop VTOLs have some of the same drawbacks, plus the four (or more) hard-mounted horizontal motors/props do nothing but add weight and drag in forward flight.
The ROTORwing, on the other hand, utilizes smaller motors and props that consume less power and create less drag. Additionally, the wide wingspan is better for forward flight, while the one large set of rotor blades produces lift more efficiently than the multiple smaller props on a regular VTOL. This feature reportedly allows the drone to lift heavier payloads, without using more power.
It should also be noted that unlike a helicopter, the ROTORwing doesn't require a large tail rotor. Skopak tells us this is because torque isn't being applied in the center of the rotor blades, as it would be on a helicopter with its one engine that turns them. As a result, the aircraft isn't constantly trying to twist sideways. Two small tail rotors are used, however, to point the fuselage in the desired direction.
DZYNE is reportedly already performing flight tests with a working prototype, and hopes to have an operational version of its production model in the air by October – it could be commercially available early next year. Plans call for that first version to weigh 20 lb (9 kg), be capable of lifting and carrying payloads of at least 7 lb (3 kg), and have the ability to fly for up to four hours per charge of its battery pack. It should be priced similarly to other VTOL drones.
And we have actually seen something sort of similar before. BAE Systems has presented a concept in which the entire drone spins to take off and then flies forward using its wings, while a team from the Singapore University of Technology and Design has actually built a functioning prototype that does so. According to Skopak, however, the patent for the ROTORwing had been filed before either of those were announced.
Source: DZYNE Technologies
