When you should change your drone’s propeller – 9 symptoms

Drone propellers are a very important part of the drone. They are to a drone what tyres are to a car. They keep the drone in the air and allow you to do a range of really awesome things in 3D space. Drone propellers are inexpensive and, probably, one of the most overlooked replaceable components. Drone propellers are easy to replace yourself and can save you a whole range of issues including drone destroying crashes. In this article, we can look at when you should replace your drones propellers and the sorts of symptoms to look for.

You should change your drones propellers when they have completed about 300 to 500 flight hours and when you notice any significant change in the noise that they make while cutting rapidly through the air. Change when they are chipped, damaged, warped or discoloured.

In the next section we are going to discuss all of the symptoms and features that you should look out for if you need to replace your drone propeller.

When should I replace my propeller?

There are a full range of issues which can signify that you should change your propeller as quickly as possible. Before we get into that the general of the four you should be that if you are unsure whether or not your propellers are fit for purpose you should swap them out immediately.

Propellers can be found online for as little as US$10 – check out the best value ones here – and they will keep your drone from catastrophic accidents and enable you to fly smoother and quieter. I always carry a pair of drone propellers in my back so that I am able to swap out for a fresh pair should be drone propellers come into contact with any overhanging structure or if I just want extra confidence for a flight mission. For example, if I want to fly out over the water.

Here are all of the reasons why you should replace your propeller as soon as possible.

If the blades come into contact with any structure

While you are flying your drone you may be looking for quite ambitious shops which take you through some architectural or natural feature. I have often used my drone to fly through overhanging branches and have achieved some amazing reveal shots by doing so.

The issue you run into when flying through places is that your drone propellers may clip overhanging structures. This may be natural – as in the case of a tree branch – or it may be man-made and concrete in nature as in the example of a doorframe or bridge.

The drone propellers are spinning at an incredible rate and even the smallest of touches can result in significant damage to the leading edge of the blade. Also, the blade tip can become damaged and fractured with the slightest of bumps.

If your drone clips any surfaces you should consider landing as soon as possible to check the blades. If you are unable to land immediately, I would allow the drone to hover for a moment and check for:

  • noise – check for any changes in the noise the drone makes
  • stability – hover for a moment to make sure the drone is able to stay in a stable level flight.

By checking these two items you will be able to determine whether or not the propeller has been significantly damaged to jeopardise the rest of your flight.

After a heavy landing

Drones are incredible tools which we try to protect by taking off and landing smoothly. Sometimes a heavy landing is inevitable if you have high winds or an unstable ground and landing spot. For example, trying to land on a boat which is moving up and down in the water can result in a relatively heavy landing. Also, if your drone does not have an auto land function your manual descent may be too quick which will result in a heavy landing.

If you have come in for a landing and you have noticed that you have landed particularly heavy you should check the drone propellers for cracks in the body of the propeller. This will tell you whether or not you should replace your propellers immediately. If you notice any damage you should swap out the propellers as quickly as possible.

If you notice warping

The only reason drone propellers work is that they have a very specific shape. The shape allows for producing a low-pressure area above the propeller which sucks the drone into the air. Just like the shape of an aeroplane’s wing a propeller relies on air rapidly passing over the surface of the drone propeller for it to work.

This creates lift.

Any small change to the overall shape of the drone propeller can significantly decrease its ability to create lift. Take a look at all of the drone propellers on your drone and make sure that they are all looking the same. I like to run my fingers over the blades of separate drone propellers to check for their shape and similarities.

If you notice any warping of the drone propeller you should swap it out immediately.

Warping can be caused by heat, storage, UV rays, old age and much more. Any twisting bending or bulging in weird places will quickly render the propeller useless and you should replace it immediately.

It has cracks

There are a lot of forces which act on drone propellers while they are spinning rapidly through the air. These forces can create micro fractures and cracks in the surface of the propeller which you may not be able to see you with your naked eye. I recommend that you use the most sensitive part of your fingers i.e. the pants of your fingertips to feel the full surface of each drone propeller.

Your fingertips will be able to detect even the smallest of cracks and if you notice any you should replace your drone propellers immediately.

These are small micro cracks can quickly turn into larger cracks due to the forces which the drone propellers undergo while spinning rapidly on the motors. Catching these micro cracks as soon as possible will be the number-one way that you can assure yourself of a safe future flight.

The leading edge has damage

The drone propeller has two important edges – the leading edge, and the trailing edge. The leading edge is the edge of the drone propeller which faces the direction of the spinning. This leading edge can become chipped or damaged simply through coming into contact with small amounts of debris that it encounters during takeoff or landing. Also, I have noticed that bees can sometimes be attracted to the drone and other insects can cause small chips in the leading edge of the drone propeller if their body is hard enough.

To check if the leading edge has damage you should run your fingernail or thumbnail over the edge and notice any chips.

To make sure that your drone does not pick up any chips in the leading edge of the propellers you can use a drone landing pad to make sure that the dam wash from the propellers do not dislodge any dirt, sticks, all small stones from the surface. You should check out my complete guide to drone landing pads – click here to be taken to article…

Buying a drone landing pad is inexpensive ballet shoes takeoff a whole range of different and unstable services. Including long grass and sand for awesome beach and coastal shots. Certainly worth the small amount of money that you will spend!

The tailing edge has damage

the tailing edge of a drone propeller is the one that is opposite the direction in which it travels. This edge is often curved and is the age which is lower and longer.

Just like the leading edge, you can check the integrity of the drone propeller by running your finger or thumbnail over the length of the tailing edge to check for any chips, dents, or other damage.

The tailing edge of the drone propeller doesn’t have as much an effect on the stability of flight but can significantly change the noise that the drone makes as the motors spin. This is because the drone propeller causes more turbulence as an is leaving the surface of the drone propeller.

Noise is also something that you should pay particular attention to.

You notice a significant change in the noise of the drone

Drones are noisy – there’s no doubt about that. Different drone models make different frequencies and volumes of noise based on the frequency at which the motors spin as well as the size of the propellers.

My DJI Mavic air makes a very high-pitched noise compared to a drone like the DJI Mavic pro. That is because the DJI Mavic hair has significantly smaller propellers and they spent at a much higher number of turns per minute.

As you fly your drone more and more you will become accustomed to the sorts of noises that are normal for your drone to make. I often get worried in high winds because the drone makes a series of different noises that I don’t hear very often. However, the drone noise will be dependent on the model of drone that you have.

If you notice a significant change in the noise that the drone is making either before your flight or during your flight you should land as soon as possible. The drone is kept in the air via a feedback loop from the electronic control unit. If the drone noticed it is drifting in a certain direction it will spool up one side to return it to its GPS location. The drifting can be caused by damage to the propellers and you will hear a motor spool up. If this is a continuous noise or it is unusually buzzy you should consider changing the propeller.

If you notice discolouration

If you notice discolouration in the propeller it is time to change. Drones are flown outside in all sorts of weather conditions. Because the propellers are a polymer composite the plastic can quickly become damaged by UV light and other environmental factors.

The discolouration of plastic is one of the first warning signs that the material is becoming brittle and fragile. Because of the number of forces which are drone propeller undergoes during flight it would be recommended that you change your propeller as soon as you notice even the smallest amount of discolouration to the drone propeller.

I like to compare my drone propellers to ones that have never been flown outside because it can sometimes be hard identify changes if all of the drone propellers are changing at the same time.

Every 300 – 500 flight hours

Sometimes there is nothing wrong with your drone propellers other than you have done a load of flights with them. It is recommended that you change your propellers every 300 to 500 flight hours or every second year – whichever comes first.

You are able to access the number of flight hours via the manufacturers app that each drone has gone through.

This relies on you being proactive about the maintenance and care of your drone and you should consider placing a calendar reminder in your preferred online calendar of choice.

Those are all of the reasons why you should change your drone propellers. Of course there are other things you need to take into consideration which is which propeller is best for your drone and also how you actually change the propellers based on the model of drone that you have purchased.

Which propeller is best for drone?

I highly recommend that if you are replacing your drone propellers that you replace it with a manufacturer original drone blade. There are many third-party options available online but they may not be manufactured to the same quality that an original would be.

Sticking with an official drone propeller may be a little bit more expensive than what you can find online but it will be the thing that protects your drone the most. Also, there is not that much of a difference between the price of a drug hello from the manufacturer and a third-party option which you can find on online marketplaces.

Is a bigger propeller better?

Sometimes, we want to upgrade our drone. The drone propeller is one of the easiest things to upgrade as it is a easily changeable part. We may be tempted to increase the number of blades that our drone propellers have and we may also be tempted to fit a bigger blade to reduce the noise that our drone is making.

A bigger propeller is not better as it relies on the interplay between the amount of power that the motor can produce and the amount of energy it takes to spin a bigger propeller. If you choose a propeller that is too big it will likely overheat your motors.

Always stick with the propeller size that your drone was originally manufactured to hold.

What about a quiet drone propeller?

If you are flying in a highly crowded area and you want your drone to be as quiet as possible there are some options for making your drone quieter. If you want to know more about this check out my other article – how can I make my drone quieter? The ultimate guide – click here to be taken to article.

Ultimately, there are two ways that you can make your drone quieter you either need to replace the propeller with a wider or longer propeller blade, or you can use some aftermarket and third-party accessories to absorb and reflect the noise generated by the 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.

The final option for you if you are concerned that your drone is too loud is to create your own propellers for the drone that matched the size and pitch and depth that reduces the noise. This isn’t an easy option and can quickly cause issues with your flight. Also, DIY and home-made propellers may not be as sturdy and stable as commercial propellers – so use caution if you are going to go down this route.

Here is a YouTube video of someone who created DJI Mavic air quiet props from retrofitted Anafi propellers.

How do you change a drone propeller?

Changing a drone propeller is very simple for a number of models. They really come into different types. Some drones have foldable propellers which make them much easier to store and carry whilst others have a fixed propeller system where the whole propeller can be removed from the motor – not just the blades.

Some of the drones require a small screwdriver to replace the drone blades as they are fixed individually to the motor.

Some require a small screwdriver

If your drone has foldable propeller blades you may need to follow the YouTube video, below, to replace your blades.

Some can be swapped out quickly

I have the DJI Mavic air which has full fixed blades which are secured into the motor via a simple locking mechanism.

To change the blades all I have to do is hold the motor in place with my fingers, gently press down the centre of the propeller and twist anticlockwise to remove the blade. To put the blade back in all I have to do is reverse this process with the new drone propellers.

Very simple.

The exact mechanism may change for your drone model and make but check the manufacturers website or quick start guide if you are unsure.

Summary

There are a variety of reasons why you may need to change your drone propellers. In this article I have shown you that there are a number of symptoms to look out for which may indicate that you need to change your propellers.

The general rule of thumb is that if you think you need to change it – change it.

Propellers are inexpensive and the only thing that keeps your drone safely in the air and is the only thing that creates lift. Changing them even if you want to be extra safe is always a good idea.

The Author

Dr Andrew Stapleton is a writer and YouTuber with a PhD in science. He has written and/or produced videos for Science Alert, COSMOS magazine, and Australia's Science Channel among others. Andy started droneflyingpro.com to share his love and the research of all things drone! He has been a drone pilot for many years and has flown many types of drone. His favorite is still the DJI Mavic Air for the portability and functionality packed into a small and portable drone!