What makes a propeller work

In an ideal world, a variable-diameter propeller would be most efficient, with a large diameter for low airspeeds and a smaller diameter for high airspeeds. Due to structural, control, and weight issues, variable diameter propellers just aren't practical. Instead, the diameter of most propellers is sized to allow for a "happy-medium" between slow and fast airspeed operations. Propellers convert engine horsepower into thrust by accelerating air and creating a low-pressure differential in front of the propeller.

Since air naturally moves from high to low-pressure, when your prop is spinning, you're being pulled forward. Become a better pilot. Subscribe to get the latest videos, articles, and quizzes that make you a smarter, safer pilot. To: Separate email addresses with commas. Now What? All Videos. Planes Careers. Recommended Stories. How DME Works. Fewer thunderstorms and less turbulence mean more days in the air for you.

Here are the advantages of fall weather flying in a GA aircraft. Easy Mental Math For Pilots. If you're like us, you probably don't consider yourself a math expert. Angle of attack is the angle a wing makes with the oncoming airflow. Pitch angle is the angle a propeller blade makes with its plane of rotation. A wing has nearly the same angle of attack across its entire length. But a propeller blade has a twist, so its pitch angle varies along its length.

On a controllable-pitch propeller, the pitch of the entire blade can be altered during flight to give the best performance at different air speeds. This is similar to changing gears with a car or bicycle.

To handle the power supplied to the propeller from the engine. For small engines with relatively small horsepower, only two blades are necessary i. All of the above. As we discussed in our post about the history of propeller design , early airplane propellers operated more like screws. It took the ingenuity of the Wright Brothers to develop a propeller that acted not like a screw but like a twisted airplane wing.

Think about it this way: when you toss a paper airplane it will generate a small bit of lift before eventually settling on the ground — provided you folded the paper right, of course!

The paper plane took flight because the design of the wing worked in tandem with the force that you applied to it your throwing motion. Now imagine if you were able to catch the plane in mid-flight and quickly re-throw it to extend its travel.