The scaling up of this to aircraft that are able to carry people has only just begun and Krossblade is part of this development. This design has proven to be hugely successful and most modern VTOL drones and hobby aircraft are now multicopters rather than single copters. This fixed pitch design is much simpler than the complex swashplate mechanics that are required for single rotor helicopters.
![quad copter quad copter](https://www.bhphotovideo.com/images/images2500x2500/blade_blh7900_350_qx2_ap_combo_1033303.jpg)
A flight computer constantly monitors the orientation of the copter and corrects for instability by changing not the pitch of the rotors but simply the rpm of the individual motors/rotors. Modern multicopters have an electric motor mated to each rotor, sitting directly below or above it. With the advent of electric motors and especially microelectronics and micromechanical devices, a few years ago it became possible to build reliable and efficient multirotors.
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In the absence of computers, this meant a monumental workload for the pilot.Īs a result, multicopter designs were abandoned in favor of single, or on rare occasions for very large transport helicopters, double rotor designs. DEERC Mini Drone for Kids Adults Beginners with 720P HD FPV WiFi Camera, D23 LED Nano Hobby RC Quadcopter with Five Light Modes, Altitude Hold, Headless Mode, 3 Speed Modes, 360° Flip, 2 Batteries. On the contrary, quadcopters have to be constantly stabilized. As the 4 rotors of a quadcopter are all slightly different from each other, a quadcopter is not naturally stable, simply running 4 rotors at the same speed, while producing enough lift to hover the copter, does NOT produce stable flight. Belts and shafts however are heavy and importantly, subject to breakage. Its engine only had to be mated to only one rotor, and could be mated to it more or less directly over a short distance rather than with a belt over the several meter/yard long extensions/arms connecting the rotors of a multicopter with its fuselage.Įarly quadcopters would typically have the engine sitting somewhere centrally in the fuselage of the copter, driving the 4 rotors via belts or shafts.It was naturally stable because a weight hanging below a single attachment point naturally 'wants' to hang straight down and so naturally corrects unwanted tilting.However, at a time when computers and good electric motors did not yet exist, the single main rotor helicopter design had two huge advantages:
![quad copter quad copter](https://2.bp.blogspot.com/-3nt4zp15nt4/V0lIPjeEObI/AAAAAAAADNU/r1a7yPwK6vAH0fOZafvGD8SlcXKsTzbLwCLcB/s1600/XK_Detect_252_Quad.jpg)
Making large rotor blades, 4 or 5 m long or even longer was a huge problem and larger rotors to this day are proportionally much heavier than smaller ones. Part of the main rotor rotates over the fuselage, pushing down washed air against it, reducing effective lift. The tail rotor on a single rotor helicopter design consumes between 10 and 15% of the engine power yet it creates no lift or forward thrust. The drone can also let go of its host, swim to the surface and fly out of the water.Around the same time George de Bothezat built and tested his quadcopter for the US army, completing a number of test flights before the program was scrapped.Įarly designers experimented with quadcopters, because the alternative, using a single main rotor with a tail rotor to counterbalance the torque created by the single main rotor seemed wasteful, complex and inefficient. And when it sticks to a fish, shark or whale, it can travel for miles without using battery power.
![quad copter quad copter](https://www.bhphotovideo.com/images/images2500x2500/blade_blh8160_350_qx3_quadcopter_ap_1100366.jpg)
The result was a quadcopter drone that can fly as normal in the air and that also maneuvers under the water. The researchers also added waterproofing to the drone and modified the propellers to fold automatically when encountering water. A small motor was added to pump water in and out of the disc and another to control its angle of attack. The design allowed the robot to adhere to nearly any surface, wet or dry, and to remain attached even if part of the disc came free.
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They also added small channels to the underlayers that could be pumped full of water.
![quad copter quad copter](https://justdrones.com.au/wp-content/uploads/2016/10/DM009-Conqueror-Wi-Fi-FPV-Quadcopter.jpg)
The layer on top was flexible, while those underneath were less so. To do so, they created a sandwich of four layers using a 3D printer. Credit: Li et al., Science Robotics (2022). Drone transitioning between water and air.