All about Multirotor FPV Drone Propellers

FPV Drone Propellers Blade Configuration

Blade configuration refers to the number of individual blades on a propeller. The most Efficient propeller is actually single bladed, but due to it’s imbalance it is not practical for use in most flying aircraft.

Increasing the number of blades on a propeller is a suitable substitute to increasing the size where space is constrained, and has very similar characteristics. This is why small fighter planes in WW2 used to have 3 and 4 bladed propellers, they needed more thrust and power but could not fit larger propellers because they would hit the ground, so they added more blades.

Originally multirotors largely used 2 bladed propellers like planes, they are more efficient for their size because they only have two blades creating drag in the air. But as motors became more powerful, higher performance was required and frames became smaller, there was not enough space to increase the size of the propellers to get the required thrust and power needed.

Due to complicated physics and fluid dynamics, increasing the number of blades is not as efficient as increasing size. So a prop with double the number of blades will not perform as well as one twice the size but it does provide more thrust at the cost of slightly more power.

Similar as discussed in the size section, increasing the number of blades will increase the amount of thrust and grip in the air, at the cost of responsiveness and increased power consumption. If you are planning to fly somewhere where you will be making lots of fast flowing turns and need lots of grip in the corners, more blades will be suitable. Just like increased prop size, more blades will have a more floaty feel, and feel like it will glide off throttle.

Less blades are preferable where faster motor response is needed and thrust is not as critical. Serious racers with new ultralight racing frames will quite often use bi-blade propellers because the frame is so light that the amount of thrust required is much less, and therefore the faster response of the lighter and less ‘draggy’ props can be realised.

In the most common 5 inch category, it is generally agreed that tri-blade (3 blades) FPV drone propellers provide the best balance of efficiency, thrust and grip.

One aspect of prop configuration that is often overlooked is durability. If you are just beginning to get into FPV you will be crashing A LOT! It is also highly likely that you will not be using the full power of your multirotor. So while all the pilots that inspire you run tri-blades, it can be a very good move to learn on bi-blade props. Just like old school road spikes, there is no way for a tri-blade propeller to hit the ground without contacting two blades before the hub/motor hits the ground. This means that you are likely to bend or break a blade in most crashes. Bi-blades simply by design can rotate out of the way in a crash, and because of this are much less likely to bend or break. Depending on how long it takes for you to become proficient with flying, this can add up to a significant saving over the course of the learning period.