If you enjoy figuring out why the things in the world around you work the way they do, you should subscribe to Smarter Everyday on YouTube. The host is named Destin and he has set out investing money into these YouTube shows so that he can educate the masses and put the proceeds from ads and donations towards his kids’ college funds. He’s a Mechanical Engineer by trade and education and he has a knack for making engineering interesting. For the last couple of months, Destin has been posting a series about the physics that  makes helicopters work. It’s really fascinating because they’re capable of a lot of mind blowing stunts and the way they work is different from how you probably intuitively think they do.

Part 1: Introduction
Destin introduces us to the series and his buddy Carl Groover who flies remote controlled helicopters for the Curtis Youngblood team. Watching Carl at work is a pretty eye opening experience in terms of what a helicopter can and cannot do.

Part 2: Chopper Control
The second video begins to talk about how a pilot is able to control a helicopter. It turns out both the main rotor and the tail rotor spin at a constant speed and direction. Cyclic or collective changes in the rotor pitch are what causes the helicopter to change elevation, pitch and roll. Not how you thought it worked? Get used to it. They’re just getting started.

Part 3: Collective-Cyclic Pitch Mixing
Now that you know what collective and cyclic pitch are, it’s time to watch them in action. Destin sets up a high speed camera to capture a helicopter flying upside down and they attach a GoPro to the body of the helicopter so you can watch the swash plate as Carl does his crazy stunt flying.

Part 4: Gyroscopic Precession
Here’s where things will really start to blow your mind. If you think about tilting a helicopter forward, it’s natural to think that you would lift the back of the body upwards to do it. That makes sense when everything is static and not moving. Once the rotors spin up and have gyroscopic momentum, it’s a totally different story. Input forces on the rotor disc end up having a reaction force that is 90 degrees out of phase. That means lifting the back of the helicopter up will actually cause it to roll to the side. Watch the video if you don’t believe me.

Part 5: Laser Helicopter Blades
In order to provide a visual representation of everything we’ve learned so far (collective inputs, cyclic inputs and gyroscopic precession), Destin and Carl replace the helicopter blades with a laser. That’s right, A FRICKIN’ LASER.

Part 6: Auto-Rotation
Destin and Carl set out to show us why you don’t need a parachute in a helicopter. In fact, it’s almost impossible to crash a helicopter as long as you can change the pitch of the rotors and have enough altitude. The act of the helicopter falling out of the sky will spin the main rotor up which then can be used to provide enough lift to make a safe landing. Carl also does this upside down just because he can.

Part 7: Helicopter Speed Limit
To cap the series off, Destin and Carl do some light painting by putting LED’s on Carl’s helicopter and flying it around at night. The resulting images are astonishing. Lets just say they’ll make the inventor of the spyrograph cry. As cool as the light painting is by itself, Destin uses it to explain why there’s a speed limit for helicopters. It has to do with half of the rotors breaking the sound barrier. Sounds crazy right? You didn’t think this series would end with a plain old intuitive explanation, did you?

Source: Smarter Everyday on YouTube (Subscribe!)