The propeller of a helicopter is an example of a simple machine. The rotors revolve around a screw, which is an inclined plane that wraps around a cylinder. As the blades move around the screw, they are able to lift the helicopter in the air. This screw machine also helps the helicopter land slowly instead of crashing to the ground. Sometimes the rotors are considered to be more of a wheel and axle.
Screws are also found all over the aircraft, as they are commonly used to attach parts together. Some parts also use bolts to hold them together. The act of using a wrench to tighten a bolt is an example of a wheel and axle simple machine.
Hinges are an example of a wheel and axle simple machine. Hinges can be found on any door in the helicopter. The wheel part is the frame that is attached to the door. The axle is the rod that holds the frames together.
Gears help the motor turn in the helicopter's engine. Gears are an example of a wheel and axle. The force of one turning will cause another one to move, hence making the motor work.
Use the template from the Utah Education Network to make a simple helicopter out of paper. Cut on the solid lines and fold on the dotted lines. Affix a paper clip to the bottom for weight. Climb on a chair or ladder and let it drop to observe how the propellers move.