An American engineer has developed a drone of an unusual design: it has three wings and one propeller on each of them. Thanks to this, it can hang in place, as well as fly in an airplane. Since the drone has a laser rangefinder, when rotating it works like a lidar, determining the distance to surrounding objects. A video describing the project is published on YouTube.
Unmanned aerial vehicles with a multicopter design are popular due to their simplicity: they only need a few screws and do not need any additional mechanical devices. In addition, they take off and land vertically, so they are much easier to use in small areas. At the same time, aircraft-type drones are much more efficient than multicopters due to the lift from the wing.
There are projects that use both designs. Most often, these are aircraft-type drones with additional propellers for vertical takeoff and landing. But there are also individual examples when the screws are fixed directly on the wing and the drone is essentially a propeller on a propeller. We talked about several similar projects, and in all of them the engineers used a pair of wings and screws. One of the problems with this solution is that the drone behaves unstable when flying with screws up, since only two screws are used.
The American engineer Nicholas Rehm, who designs unusual aircraft in his spare time, created a largely similar device, but with three wings and screws on them. In the center there is a control unit, a battery and electric motors that turn the wings. A small screw is installed at the end of each wing.
The drone can fly in three modes. In the first, the wings are perpendicular to the ground and it flies like a multicopter using only screws. In the second mode, the wings turn and the drone begins to rotate in place due to the thrust of the screws. And in the third mode, it tilts and goes into airplane mode with two wings at a slight angle to the ground and one from above perpendicular to it.
In order for the drone to fly at the same altitude in airplane mode, Rem installed a laser rangefinder in the central part. He implemented and demonstrated altitude control in practice, and also showed that hypothetically the rangefinder can be used for another task. Since the drone has a rotation mode and a rangefinder, in fact it works similarly to a two-dimensional lidar, which sends laser beams in different directions and calculates the distance to objects around by the speed of reflection. In the case of a drone, the situation is complicated by the fact that its rotation is not strictly parallel to the ground, but the engineer showed that even with tilt fluctuations, large objects such as a fence can be detected.
The measurements showed that the drone consumes the least power in the on-site rotation mode, and not in airplane mode: about 35 watts versus about 70. The engineer assumes that this is due to the wing, which in airplane mode is located on top and does not create lift. In the multicopter mode, the drone predictably showed the lowest efficiency — just over 100 watts.
We also talked about other amateur drones with an unusual design, for example, a longitudinal bicopter that looks like a flying stick.
Grigory Kopiev
