Cycloidal Rotor Drone: The Cyclocopter
These aircraft configurations produce lift to stay in the air using the same principle. An airfoil is rotated around the vertical axis and as it spins, it produces an upward thrust to stay in the air. In the case of the standard helicopter theres one main rotor and in the case of the multi rotor theres, multiple rotors. But what if i told you theres a different way to generate lift for vertical flight? This thing is called a cyclocopter and were going to talk about how it flies. A cyclocopter is a hovering vehicle that utilizes cycloidal rotor propulsion to stay in the air, its not really a new concept, but was only recently able to successfully fly at the model scale. This particular cyclocopter has two cyclorotors that do most of the heavy lifting and a conventional propeller in the nose ill talk more on why that propeller is needed. In a few minutes, the cyclo rotor blades are made from carbon fiber, ribs and rods, wrapped in lightweight monocoat. Film, so how does the cyclo rotor use this to produce thrust as we can see, the cycloreader blades actually rotate about the horizontal axis, rather than the vertical axis, like a regular propeller. If we watch just one blade as it rotates around, we can see that the pitch is changing according to where its located along the rotation. So by pitching the blade to have a relative positive angle of attack at the top and at the bottom.
And no relative angle of attack on the sides. We can generate a net upwards thrust force. This little offset linkage at the bottom is what allows for the asymmetric pitching of the blades. By rotating this, we can actually change where the maximum pitch angle occurs, and thus the thrust direction. Changes too. The airflow in and around this rotor is pretty interesting. The rotation and cyclic pitching of the blades actually makes the airfoil appear to be curved relative to the air like a cambered wing. So even though the airfoils are symmetric, theyre generating lift as though they were cambered. The cyclic pitching also delays the onset of blade stall. Where the airflow detaches from the top of the airfoil, so we can get away with much higher angles of attack in excess of 40 degrees. A typical helicopter blade would only take about 15 to 20 degrees before it stalls so for control of this vehicle. Theres. Three motors and two servos and the motors in the rear are spinning the cyclo rotors and by varying the rpm differentially between the left and right side. We can actually get a rolling moment and for pitch control. We vary the rpm of the nose rotor, and the center of gravity on this vehicle is actually pretty far back, so the cyclo rotors are doing most of the heavy lifting the only real reason we need the nose. Rotor is because the axis of rotation of the cyclo rotor causes a nose down pitching moment that needs to be countered by this rotor in the front and finally, for yaw control.
We just vary the thrust vector direction with the cyclo rotors, using the two servos to actuate. That control linkage offset a typical quadcopter needs to pitch its whole body forward in order to move forward. The cyclocopter can fly just fine like this too, but by fixing the pitch angle of the cyclocopper to be level in the flight controller and mapping our pitch stick input to the forward and backwards cycloorder thrust vector direction. Instead, the cyclocopter will actually translate forward and backward without needing to pitch forward or backward Music Music Music. Now, a regular propeller sees different flow velocity along the length of its blades. According to the position, along the blade with the tip experiencing the highest velocity and decreasing linearly as you move in with a regular rectangular blade, this means that the tip will generate far more lift than the root, but a uniform lift distribution over the entire rotor disc Is far more aerodynamically efficient and desirable from a structural point of view, so engineers have to get creative, with specialized blade, taper and blade twist to achieve a semi, uniform and more efficient lift distribution. But with the cyclo rotor, the whole blade sees the same airflow velocity because of the different axis of rotation. So, from a blade optimization point of view, the cyclo rotor is actually pretty attractive in order to avoid the nightmare that is, helicopter rotor blade design. So this works – this will probably be the first front flip performed by cyclocopter ever so lets see how it goes Music.
So shockingly everything looks like its okay, so were gon na go for another. Try on that. So actually i lied. The landing gear is actually a little bit messed up and uh theres a little bit of duct tape holding this together, but it just needs to get up in the air, and then we dont need landing gear. I guess i was a little too optimistic that time. The landing gear got caught in the grass and it flipped over and looks like yeah cyclo rotor is broken. Oh well, the cyclocopter is a really cool concept that really inspires me to think outside the box, even when theres already an existing solution available, but i dont think the cyclocopter will be replacing these guys anytime soon. So dont worry about that theres. Definitely some drawbacks to this design that lead to performance loss. So for now i think the cyclocopter will just stay a cool demonstration of unique aerodynamics and engineering.