Racing Drone 6020 6X2 Carbon Fibre Direct Mount Propeller Set CW/CCW

Selecting the correct propeller: Choosing the correct prop/motor combination can be challenging. There is a lot of math and science to appreciate how your propellers affect your drone’s flight performance. As a novice, it is very easy to be overwhelmed by all of it, but propeller choice is a very important decision so it’s worth the effort; propellers affect the agility, stability and efficiency of your craft. The correct motor/prop combination needs to be chosen by considering the size and weight of the multirotor, the length of flying time and the power and agility that are desired. 

A multirotor uses clockwise(CW) and counter-clockwise(CCW) propellers to counteract the torque effect of the props. Prop types are also differentiated as “tractor” (counterclockwise) and “pusher” (clockwise). 

Propellers are classified by diameter and pitch. The diameter is the measured length of the propeller, the pitch is how far the propeller will theoretically advanced in one revolution. For example, a 12×4.7 propeller has 12 inch diameter and will travel 4.7 inches in one revolution.

The diameter of a propeller dictates how much thrust can be generated. Propeller efficiency is related to the area of a prop so a small increase in prop diameter will make the multirotor greatly more efficient. Since drones are generally hovering, a low pitch is recommended. If you want to go somewhere fast a higher pitch might be appropriate. Maneuverability and stability of a multicopter is dependent on how quickly you can change the RPM of the props. A smaller / lighter prop is easier to speed up and slow down whereas a large prop takes longer to change speeds. This is one reason why 3 bladed props are generally not appropriate for multirotor use.

In summary, an efficient UAV will have properly sized, low RPM motors with very large props, where as an acrobatic UAV will want smaller, more aggressive props, and faster motors. As a general rule you want a 2:1 thrust/weight ratio for a standard multi rotor and 3:1 or higher for something acrobatic. 

Material selection is another important consideration. Carbon fiber props are generally preferable. They are very lightweight. This makes for a longer flight time and more importantly a more stable platform as lighter props allow motor RPM to change rapidly. Carbon props also have great stiffness, which maintains even lift under rpm changes resulting in higher efficiency. Unfortunately there is a down side to stiff props, all the vibration is transferred to the motor and frame, increasing wear on bearings and adding vibration to the footage. Balanced props can drastically vibrations. It is advisable not to use carbon fiber props for initial tuning as they shatter on impact and are typically expensive. If you aren’t so concerned about weight, wooden props are excellent for vibration damping. However, their added mass means they take longer to change speed and draw more current/power when the flight controller tries to increase RPM which reduces flight time and stability. 

If you are still confused, do some research; see what other experienced pilots are flying with - that way you can find a proven solution for free. You could also do some experimentation, use ecalc - an online multicopter calculator to help you find the best component combinations, or if you have the budget, buy a range of sizes to find the optimal prop.