Įtienne Oehmichen experimented with rotorcraft designs in the 1920s. In 1908 it was reported as having flown 'several times', although details are sparse.
It was tested only in tethered flight and to an altitude of a few feet. The first heavier-than-air aerodyne to take off vertically was a four-rotor helicopter designed by Louis Breguet. Īlternative power sources like hydrogen fuel cells and hybrid gas-electric generators have been used to dramatically extend endurance because of the increased energy density of both hydrogen and gasoline, respectively. In setting the record, Kickinger used low discharge-rate, high-capacity lithium-ion batteries and stripped the airframe of non-essential weight to reduce power draw and extend endurance. The record was set by Ferdinand Kickinger of Germany in 2016. The longest flight time achieved by a battery-powered quadcopter was 2 hours, 31 minutes and 30 seconds. This has allowed experiments with complex swarming behaviour based on basic sensing of the adjacent drones. The quadcopter configuration is relatively simple to program for autonomous flight. In this case, each arm has two motors running in opposite directions (one facing up and one facing down). In order to allow more power and stability at reduced weight, a quadcopter, like any other multirotor can employ a coaxial rotor configuration. Quadcopter coaxial – OnyxStar FOX-C8 XT Observer from AltiGator Yaw is induced by mismatching the balance in aerodynamic torques (i.e., by offsetting the cumulative thrust commands between the counter-rotating blade pairs). If all four rotors are spinning at the same angular velocity, with two rotating clockwise and two counterclockwise, the net torque about the yaw axis is zero, which means there is no need for a tail rotor as on conventional helicopters. However, early prototypes suffered from poor performance, and latter prototypes required too much pilot work load, due to poor stability augmentation and limited control authority. These vehicles were among the first successful heavier-than-air vertical take off and landing (VTOL) vehicles. A number of manned designs appeared in the 1920s and 1930s. Torque-induced control issues (as well as efficiency issues originating from the tail rotor, which generates no useful lift) can be eliminated by counter-rotation, and the relatively short blades are much easier to construct. In the early days of flight, quadcopters (then referred to either as 'quadrotors' or simply as 'helicopters') were seen as a possible solution to some of the persistent problems in vertical flight. Unlike conventional helicopters, quadcopters do not usually have cyclic pitch control, in which the angle of the blades varies dynamically as they turn around the rotor hub. Pitch and roll are controlled by varying the net centre of thrust, with yaw controlled by varying the net torque. Flight control is provided by independent variation of the speed and hence lift and torque of each rotor. Quadcopters generally have two rotors spinning clockwise (CW) and two counterclockwise (CCW). The small size and low inertia of drones allows use of a particularly simple flight control system, which has greatly increased the practicality of the small quadrotor in this application.Įach rotor produces both lift and torque about its center of rotation, as well as drag opposite to the vehicle's direction of flight. Īlthough quadrotor helicopters and convertiplanes have long been flown experimentally, the configuration remained a curiosity until the arrival of the modern UAV or drone. Typical racing quadcopter with carbon fiber frame and FPV cameraĪ quadcopter or quadrotor is a type of helicopter with four rotors.
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