NASA's Bid to Silence Drones Using Innovative Tech and Multiple Engines
Tam from NASA has developed a way to silence the low buzz that drones emit. The latest in a series of prototypes from NASA’s Langley Research Center in Hampton, Virginia, the GL-10 is made from carbon fiber and has a three-meter wingspan, with eight engines on the wings and another two on the tail. Efficient electric propulsion is one goal of the project, though the large number of engines also reduces noise, with several small motors being quieter than a few large ones. Leading Edge Asynchronous Propeller (LEAP) technology, which prevents the propellers’ individual sounds from combining into one loud noise, is another feature of the GL-10. Project controller Mark Moore says that the large number of propellers allows each to be digitally operated at a slightly different rpm (revolutions per minute), allowing smaller harmonics be spread out across frequencies.
Spectrum spreading renders the GL-10 inaudible when it flies at heights of 30 meters. Also able to take off vertically, it’s an ideal urban parcel courier for payloads of up to 5 kilograms. According to Moore, drones must be ultra-safe and ultra-quiet since package delivery is a key objective for the technology. Quieter drones could also make a positive impact on conservation work. Serge Wich of Liverpool John Moores University, UK says that animals such as birds and elephants could be monitored without being scared off. The GL-10 might also prove beneficial in military operations. Predator and Reaper drones currently patrolling places such as Afghanistan produce an incessant hum that’s audible on the ground, which is why locals often refer to them as “machar” (mosquitos). Larger aircraft planned by NASA would be the same size and speed as the missile-carrying Predator drones, while manned aircraft using the same technology is anticipated in the future.