Drones And Boats Could Go Into Stealth Mode With These Noise-Killing Propellers
The hum of a boat coasting across the water is a sound that could disturb the tranquil scenes at a beach. Instead, its loud and arresting sounds often come from its propellers as it slices through the water. Drones, helicopters, and other flying machinery are not exempt from this.
MIT’s Lincoln Lab might have landed on a solution in the form of toroidal propellers. These silent devices were inspired by “ring wings” from the early 20th century. One other example of these is bamboo copters with twisted blades that carried them up into the air, used as toys by children in China over 2,000 years ago. Now, the same technology could help silence boats and drones.
The team toyed with various geometric shapes for the rotors before landing on a twisted, almost infinity-shaped design that can quieten the propellers down in the water and potentially the air.
In the experiment, the academics initially tested the device on some drones. They could fly almost twice as close to humans before the noise became an issue.
The toroidal propeller, one of the Lab's @RD100Awards winners, has a unique, closed-form propeller design that makes it a significantly quieter alternative to common multirotor propellers on commercial uncrewed aerial vehicles. https://t.co/hgda3NgYIz pic.twitter.com/5XkIxNVPHd
— Lincoln Laboratory (@MITLL) January 6, 2023
What allows it to move around silently is that the noise is distributed via the vortices throughout the propeller instead of just the tip.
Whether or not such advancements will be a prospective alternative to propellers used on helicopters, eVTOLs, and other much larger machinery is unknown. However, with drone delivery taking off, such a discovery could aid companies in making their UAVs quiet enough to fly around civilian areas.
Having stated that, a company named Sharrow Marine is already making such rotors for boats. In the case of its Sharrow MX, you may converse with the people on board while traveling up to 30 mph with any outboard motor linked to it.
[via New Atlas and Hackaday, cover image via Sharrow Marine]
