Spoiler alert: “Getting coffee” turned out to be a surprise helicopter ride.
Tyson, presumably concerned with the little boy’s safety, responded on Twitter:
Almost immediately, Tyson received a volley of tweets contradicting this statement.
One came from Destin Sandlin, the host of a popular YouTube channel called Smarter Every Day:
In reply, Tyson sent a video message to Sandlin:
“A little birdie told me you took interest in one of my tweets… Now I hear you know of a way to land a helicopter with a busted engine. Well, if so, I want to know about it.”
Destin took him up on the challenge, and rented a helicopter to demonstrate “autorotation,” the technique that pilots use to glide safely down to earth in case of engine failure.
That is, he rented a helicopter and asked the pilot to cut the engines — and filmed the whole thing.
“You’re kind of right,” Destin responded, “if the rotor blade quits turning you are going to fall like a brick — but helicopter pilots have a physics trick to keep that from happening.
Helicopter blades fan the air downwards. When the blades stop moving, the air changes direction.
A control called “the collective” allows helicopter pilots to readjust the tilt of their fans so they can adjust the blades to catch the movement of air. Much like a pinwheel, Destin explains in the video, the air keeps the blades rotating.
Pilots can use the air’s drag on the blades and difference of rotation speeds of the inside and outside of the blade, which move slower and faster, respectively, to find a place where the they can use the movement of the air to make a safe landing.
“There’s a magic point along the blade where it no longer acts like a pinwheel, it acts like a fan,” Destin explains.
All helicopter pilots, he adds, are trained in autorotation — so it sounds like the little boy’s joy ride was probably pretty safe after all.
Your move, Dr. Tyson.
Watch the whole video here for a more in-depth explanation: