According to historians, kids have been playing with helicopter toys for the past 2500 years. All you need is a blade attached to a stem; give it a good rub and set it spinning. In the 1480s, Leonardo daVinci created a design for an "aerial screw" - and in 1906 French inventor Paul Cornu built a machine with 20-foot rotors powered by a small engine. It lifted him a foot off the ground and kept him there for 20 seconds.
Our helicopters won't have engines; they're more "helicopter-gliders". The spinning blades provide enough lift to slow its descent. And since it's a vertical flier, it only goes one direction: down.
When you drop your helicopter, it pushes the air that's around it out of its way. The air pushes the blades into a slanted position (drop it again and watch closely). According to the folks at the Exploratorium, the air under one blade pushes one way and the air under the other blade pushes the opposite direction. Those two forces push the blade around and make it spin.
So what happens if you angle the blades? Put a bend in them?
What happens if you make a 'copter with blades that are twice as long? Or twice as wide?
What if you cut jagged edges on the blades or make them rounded?
What if you have one blade fatter or longer than the other?
What if you make 3 blades? or 4?
What if you add more weight to the stem?
Be a helicopter engineer today! Ask questions! Have fun!
And remember to head over to the STEM Friday round-up to see what other people are posting.