How to build a simple propeller toy from LEGO parts.
Step 1: Find Your Parts
This simple project only requires two parts:
1x2952 Propeller 2 Blade 9 Diameter
1x3708 Technic, Axle 12
Part numbers are from http://www.bricklink.com/
Step 2: Build It
Push the propeller onto the end of the axle.
Step 3: Fly It
With the propeller pointed up and away from people, place the toy between the palm of your hands. Quickly move one hand forward while keeping it pressed against the other. This should launch the toy into the air.