A black quadcopter sits on a grey surface. In place of traditional propellers are four figure eight propellers with sharp tips where the top and bottom of the eight would be.

Toroidal Propellers Make Drones Less Annoying

Despite being integral to aviation for more than a century, propellers have changed remarkably little since the Wright Brothers. A team at MIT’s Lincoln Lab has developed a new propeller shape that significantly reduces the noise associated with drones. [PDF via NewAtlas]

Inspired by some of the experiments with “ring wings” in the early 20th Century, researchers iterated on various toroidal propeller geometries until arriving at one that significantly reduces the sound produced by the rotors, particularly in the range of human hearing. The team suspects the reduction in noise is due to vortices being distributed over the whole propeller instead of just the tips.

Experiments show the drones can get twice as close before becoming a nuisance for human ears which should be great news for anyone hoping to launch Skynet commercial drone deliveries. Since the rotors are easily fabricated via 3D printing they should be easy to adapt to a number of different drones.

If you want to explore some more interesting drones, checkout this one that can fly and swim or this one that only uses a single propeller.

Lost Moon Found: The Satellite That Came Back To Life

The late 1950s and early 1960s were a tumultuous time in world history. The Cold War between the East and the West was in full-swing, driving the new fields of nuclear weapons and space exploration and giving the period its dual monikers of “Atomic Age” and “Space Age.”

Changes in these fields often went hand in glove, with developments in one requiring responses in the other. In 1958, the US conducted nuclear tests in the Pacific that effectively destroyed the ionosphere over the test site and shut down high-frequency communications to places like Hawaii and New Zealand. The strategic implications of this were clear, and the US began looking for ways for the military to reduce its reliance on HF communications and ionospheric skip by using space-based assets to communicate at much higher frequencies.

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Retrotechtacular: Wising Up With The SAGE System

The birth of the supersonic jet made the United States’ airstrike defenses look antiquated. And so, during the Cold War, the government contracted a number of institutions and vendors to create and maintain the Semi-Automatic Ground Environment (SAGE) aircraft detection system with Western Electric as project manager.

SAGE was developed at MIT’s Lincoln Laboratory on computers built by IBM. It used the AN/FSQ-7 in fact, which was The Largest Computer Ever Built. SAGE operated as a network of defense sectors that divided the continental U.S. and Canada. Each of these sectors contained a directional center, which was a four-story concrete blockhouse that protected and operated a ‘Q7 through its own dedicated power station. The SAGE computers employed hot standby processors for maximum uptime and would fail over to nearby direction centers when necessary.

Information is fed into each directional center from many radar sources on land, in the air, and at sea. The findings are evaluated on scopes in dimly-lit rooms on the front end and stored on magnetic cores on the back end. Unidentifiable aircraft traces processed in the air surveillance room of the directional center are sent to the ID room where they are judged for friendliness. If found unfriendly, they are sent to the weapons direction room for possible consequences.

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