Drone propellers are one of the most important components of a drone. They are to a drone what tyres are to a car. Without well-maintained propellers you run the risk of having the propellers break up midflight and without some fancy software your drone will come crashing to the ground! If you want to know more about if a drone can fly with three propellers check out my other article where I also have videos of experiments where they purposely destroy one of the four propellers on a quadcopter – click here.
Drone blades are not normally interchangeable. The size and shape of the propeller as well as the way it connects to the motor is dependent on the make and model of the drone. However, if the size and shape of the drone is similar you can swap some propellers between different makes and models of drones.
There may be a variety of reasons of why you want to change your drone blades. For example, you may want to reduce the amount of noise that your drone is making.
With my Mavic Air 2 I was surprised at the amount of noise that the drone was making. It was so much more high-pitched than larger drones and I was interested in finding propellers with a low noise profile. If you want to replace the propellers on your drone because of noise reasons you need to make sure that you select low noise propellers that are specifically made for the brand of drone that you have got.
There have been some people online which have swapped out the parrot Anafi propellers on a DJI drone. For the noise reasons that I encountered. The parrot Anafi propellers sound is much quieter and lower than the DJ propeller sound. They also found that there was a similar flight time with the Anafi propellers on the DJI drone. Here is a video to the experiment on YouTube:
You may also want to replace drone blades if they become damaged or chipped. You have to do regularly check the quality of the drone propellers to make sure that they do not have any small defects which can cause them to shatter or break up midflight. Do not be tempted to steal propellers from another drone which is not of the same model since the lift and thrust of the propellers has been purposely calculated and engineered for the weight and size of the drone that it has been designed for.
If there is no significant damage drone propellers last for a very long time – let’s take a look at that now.
How long do drone propellers last?
Drone propellers last for many flights. There are some people that recommend that you change your drone propellers at least every three months because of the extreme stress that they go under during flight. The extreme stresses that a propeller encounters can introduce some micro fractures and breakages without having to come into contact with anything.
Plastic is the main material that commercial level propellers are made from and they can easily become sun damage and brittle after exposure to sunlight. A study in 2018 looked at the degradation of polyethylene, polypropylene, and polystyrene under UV irradiation. They find that exposure time to UV radiation in combination with oxygen content and water are important factors that affect the rate of degradation of plastics.
So, if your drone propellers have been exposed to a lot of UV radiation as well as water they are more likely to have degradation-like artefacts on the surface.
If you take good care of your drone propellers and you ensure that they are stalled out of direct UV light and in a dry environment they will last many months. If you are in any doubt as to the quality and condition of your drone blades you should replace them immediately. You send many thousands of dollars up into the air and for the sake of five dollars to $25 you can protect the safety of that expensive equipment.
When should I change my drone blades?
This is not a one size fits all type of question. Wear and tear on the propellers and blades of a drone can vary greatly depending on how you are using the drone, the conditions that you are flying it in and if it has come into contact with any surfaces or objects.
As a general rule of thumb it is very important to replace them if you notice any defects or chips and scratches on the surface of the drone or after about 200 flights. You can track how many flights you have done in your flight software.
This is how I check the quality of my drone blades after each flight:
- with the soft pads of each fingertip run your finger over the entire length of the propellers starting at the centre and making your sweeping movements out to the tip. You are looking for any cracks or bumps that your fingers pick up.
- I run my thumb nail over the leading and trailing edges of the drone propeller so that I can pick up any small chips that may have occurred throughout the flight. It is common in spring that insects get caught up in the propellers and some of the insects in Australia have got very hard shells that can cause chipping on contact with the rapidly rotating propeller.
- Then I perform a visual inspection – I perform a visual inspection of any discolouration of the plastic (which can indicate a bend or UV damage)
Notice that I prefer to use my fingers rather than a visual inspection for checking out the quality and condition of my drone propellers. I find that my fingers and fingernails are able to pick up many more things than my eyes can.
How do you change a drone blade?
How you change a drone blade varies from drone to drone. In general, there is normally a locking mechanism (which can be spring-loaded or screw based) before you twist the drone propeller or blade out of the motor.
You should never force a drone blade if it is not moving easily because it can become damaged with the amount of force and torsional energy you are putting into it. If you have to do apply force beyond a light touch stop what you’re doing and look to see if there is a spring loaded mechanism or screw that you need to push in or remove before replacing the drone blade.
Drones on how to change drone blades:
DJI Mavic mini propeller change
DJI Mavic air 2
DJI Phantom three
Head over to YouTube if you need to find a video for replacing your drone blades because I am certain that there will be one for your type of drone model.
Best drone propellers
the best drone propellers depend on what you define as best. There are some drone purists that say that you should only use drone propellers that are original and manufactured by the company you have all your drone from. On the other hand there are plenty of people who suggest that you can also buy third party propellers which often come with added features such as low noise or smoother flight promises.
Buying the original propellers from the original manufacturer is something that will guarantee that you do not have any problems when you are changing your drone blades. The propellers from a manufacturer of a drone tend to be pretty inexpensive and are a low cost compared to the amount of money that you typically spend on a drone.
By original propellers as a failsafe for all of the issues you may face by buying aftermarket or third party drone blades.
Third party propellers
Sometimes, the manufacturer just doesn’t provide you with drone blades that have the features that you need. For example you may want your drone propellers to:
- have a low noise profile
- look different in terms of design
- be cheaper than original propellers
There are plenty of aftermarket low noise propellers. If you go to any retailer (such as Amazon) and type in low noise propellers and your model of drone you will find a range of low noise, quick release upgrade propellers for your model. They tend to work in a couple of ways
- they reduce revolutions per minute
- stealth propellers have a very smooth surface.
Typical outcomes of using stealth propellers are a reduction in noise by about 3.5 dB, by reducing the revolutions per minute by about 20%. An added side-effect of super-efficient and smooth blades are that you are likely to get a longer flight time with up to 14% more hovering time.
The good thing about using this approach is that there are no setting adjustments to make to your drone to obtain optimum performance. No setting changes need to be made. All you have to do is take off the old propellers and put on the new stealth propellers and the DJI Mavic air will make all of the adjustments. If there has been a software update you can play with the gain to deliver a better performance.
Latest science for drone propellers
In 2018 a Japanese research group published a scientific research paper called Development of Bio-Inspired Low-Noise Propeller for a Drone. In this article they were looking at the development of low noise propellers based on the unique wing structures of insects and birds. They developed a brand-new bio inspired attachment which significantly reduced the aerodynamic efficiency of the propeller and reduce the noise profile.
Throat the experiments there were various attachments to the drone propellers such as serrations at the leading edge, a velvet like surface on the propeller, and fringes at the trailing edge were tested. They found that an attachment at the trailing edge of the propeller can suppress the noise level whilst also maintaining the aerodynamic efficiency of the propeller.
In the same year there was another article that was published where they studied the sound produced by drones operating at a static thrust. That is at a hover. There is a very complicated noise generated from the drone which includes the harmonic noise from the speed controller and motor noise and the main rotor harmonic noise. They also discovered that the sound pressure of the first few harmonics is shown to decrease with the increasing propeller diameter and the number of propellers. This tells us that with an increase propeller diameter we would expect a drone to make less noise.
If you are thinking about changing drone blades between models you should think again. Drone blades are typically not interchangeable but if the drone models are similar in weight and size the drone blades could work when they are swapped. This is generally not advisable as there are many issues that could arise from using a drone propeller that hasn’t been manufactured specifically for the drone you are flying.
Drone propellers have been designed with the weight and size of the drone in mind and therefore it could easily cause unstable flying and significantly reduced flight times.
There are some aftermarket drone propellers which you could use on your drone but you should buy the ones that are purposely designed for your drone make and model. Most drone consumers by drone propellers that have been designed and manufactured by the original drone manufacturer. That is the failsafe way of ensuring your drone returned safely from any flight that you go on.