Coandâ Effect UAVs
Writing by Evan Ackerman on Thursday, 30 of July , 2009 at 3:01 am
We wrote about Coandâ effect flying saucers years ago over on OhGizmo, but not much has been heard regarding development of these UAVs until this video popped up on YouTube a few days ago. The Coandâ effect is the tendency of air (or any fluid) to stick to a curved surface. In the case of the UAVs in the video above, a propeller at the top of the UAV thrusts air downward over its curved body to create lift. Why bother? Simple: the rotor is completely enclosed and smaller than the diameter of the UAV, which means that the UAV can bump into things while maintaining a hover, ideal for use indoors or in any other restricted environment where exposed blades would be a bad thing. You know, like around humans, with our soft, fleshy necks.
Those of you with a passing familiarity with helicopters, or a knowledge of basic physics, are probably wondering a.) why the body of the UAV isn’t spinning out of control in the opposite direction to the rotor blade and b.) how the heck it steers. The vanes you see around the sides of the UAV are slightly rotated, directing the downward thrust sideways to counteract the torque. Some of the vanes are movable, and in combination with flaps around the bottom of the UAV, you’ve got your pitch, yaw, and roll. Another big advantage over helicopters is that a Coandâ effect UAV is dynamically balanced, making it much more resilient to impacts or failures.
So why isn’t everybody and their dog using one of these things? Generally, they’re not nearly as efficient as a helicopter, which means significant reductions in both payload capacity and endurance. But as engine efficiency increases, the advantages of Coandâ effect UAVs are going to pay off, and I imagine we’ll be seeing a lot more of these things in the future.
[ AESIR ] VIA [ Danger Room ]
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Category: Military
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