Propellers - Aeroclub-IITM/UAV GitHub Wiki

Propellers are the structural units which converts Rotational energy into Thrust.This is because, each section of the propeller blades are airfoil shaped.

Propeller blades are twisted.Because as a blade spins, its tip slices through the air faster than the part near its hub. This rotary motion, combined with the airplane’s forward motion, changes the effective direction of the oncoming air at different points along the propeller blade. Twisting the blade makes it meet the air at about the same angle across its entire length. This provides the most thrust and the least drag.

Its blades are airfoils with varying AOA(Angle Of Attack) and sizes.

Propellers differ according to

○ Diameter of propeller

○ Pitch of propellor

The first number is the diameter of the imaginary disc ('arc') created by the spinning prop i.e. the length of prop from tip to tip.

The second number is the pitch.The pitch measurement of a prop indicates how far, in inches, that propeller will move through the air per single revolution of the engine (i.e. every single complete turn of the prop). However, the pitch measurement of your prop must only be taken as a guideline because real-life factors come in to play to influence this distance.eg: the material of the prop, its condition, efficiency, air density on the day etc..

So, pitch measurement is really only a theoretical value, but it is good enough to help you choose the right size propeller for your machine.

Units are generally inches.

Checkout Airfoil section to understand on its design aspects.