Just because it's the weekend doesn't mean you have to switch your brain off completely. Smarter Every Day continues its video series on the physics behind helicopters with a look at how choppers use something called a swashplate to vary the pitch of its rotor blades to climb higher and fly in any direction.

It's also another opportunity to see ace RC pilot Carl Groover show off his skills as he provides real world demonstrations of the science being explained. [YouTube]