1. The CW on the propeller refers to the positive paddle, that is, it rotates clockwise when viewed from the top. CCW refers to the counter paddle, that is, it is counterclockwise when viewed from above.
2.1 inches = 2.54 cm; pitch refers to the height of the highest and lowest points of the propeller rotation
3. 9047 on the propeller refers to the length and pitch of the propeller, 90 refers to the length of 9 inches, and 47 refers to the pitch of 0.47 inches.
4. The principle of the propeller generating lift: When the propeller rotates, the inclined surface of the blade pushes the air backwards, so that the blade receives the reaction force, that is, the propulsive force
5. Calculation formula of propeller pulling force: diameter (cm) × pitch (cm) × pulp width (cm) × rotation speed (rev / sec) × 1 atmospheric pressure (1 standard atmospheric pressure) × empirical coefficient (0.00025) = tensile force (g)