Neil deGrasse Tyson has been educating the masses on Twitter for years now with his self-proclaimed “brain droppings,” and they’re usually golden. But every once in a while, somebody comes along who can’t pick up what he’s dropping down. In this case, that someone was Smarter Every Day’s Destin Sandlin, who took issue with the King of the Cosmos, regarding his assertion that helicopters become “bricks” when their engines cut out.
@chucknicecomic FYI: An airplane whose engine fails is a glider. A helicopter whose engine fails is a brick.
— Neil deGrasse Tyson (@neiltyson) July 20, 2015
In response to Tyson’s tweet, Sandlin posted a video he had already made about the emergency helicopter maneuver known as “auto-rotation,” which allows pilots to (in most cases) land helicopters safely on the ground even without a running engine. But that video was made with an RC helicopter, and to deliver his point even more vividly, Sandlin jumped inside of an actual helicopter—helmed by two very experienced pilots—and demonstrated the emergency maneuver for real.
Auto-rotation, as Sandlin demonstrates in the above video, works because when a helicopter loses engine power, its main rotor can still be pitched to take advantage of airflow. Essentially, when the engine cuts out, the rotor can be set an angle so air flows through it moving upward, causing it to spin like a pinwheel. The rotor can then be pitched forward, and with the rotational momentum it just gathered, push air down (develop thrust), generating lift. This sequence of gathering rotor momentum, then expending it on lift, is done in frequent succession from when the engine cuts out in midair until the helicopter is back on the ground.
Even though Sandlin does show Tyson that emergency helicopter maneuvers may be safer than generally thought, he does point out that Tyson is still technically correct regarding helicopters falling like bricks. But they’re bricks with “physics tricks,” so let that keep you calm the next time you’re in a helicopter in free fall. Or in a Twitter debate with a prominent scientist.
Now tell us, what do you think about auto-rotation? Do you have a whole new appreciation for helicopter aerodynamics, or are these things still basically the motorcycles of the skies? Let us know your thoughts in the comments section below!