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Complete Guide to Drone Propeller Terminology (in 2024)

Updated in 2024 by Paul Posea
drone propeler terms and numbers explained

You’re probably here because you think it’s time to move on from the propeller set that came with your drone. Or perhaps you’re flirting with the idea of building a drone yourself.

Either way, you’ll need to familiarize yourself with the terminology of propellers first.

There’s a bit more to drone propellers than meets the eye. They’re specifically categorized based on their properties. And once you understand these properties, you’ll have insight into how propellers integrate into a drone.

Plus, you’ll be in a much better position to hand-pick a set of propellers for yourself.

What do drone prop numbers mean?

A large part of this post will be dealing with propeller numbers. But what exactly are they? You may have come across them if you’ve already browsed through the market.

Drone propeller numbers are a series of digits used to describe the propeller. These digits identify most, if not all, of the propeller’s specifications, which include the length, pitch, rotation, and blade configuration. However, this number is often formatted in different ways.

The point is, they’re meant to provide just enough information so you — as a pilot — know what to expect out of the propellers.

But there’s a catch.

A propeller number is essentially of no use if you have no idea what the specifications actually mean. In fact, a lot of pilots make inaccurate assumptions early on in their journey and stick with them. 

This is why I’ll be going through the specifications, primarily the length and pitch, before we learn about the formats of propeller numbers.

How do you measure a drone propeller?

When we talk about measuring a propeller, we’re referring to finding its size. Here’s how it's done.

A drone propeller is measured by determining the distance between the furthermost points on blades opposite to one another. This length is also known as the diameter. In other words, the propeller size is twice the distance from the center of the propeller hub to the end of one of the blades.

This length is measured in inches and is typically the first part of a propeller number.

So, now you know what measurement is used to categorize propellers into sizes. It’s the diameter of the circle made by one complete rotation of a blade.

You might be wondering how else this measurement is used.

Well, it’s crucial in the process of choosing a propeller for your drone. Specifically for finding out whether the propellers are compatible with the rest of the components. We’ll be delving into that towards the end of this post.

What is pitch in a drone propeller?

Next up is the pitch. It’s a term heavily associated with propellers but newer drone pilots tend to skip over its concept completely. Here’s a simple explanation.

drone propeller pitch

Pitch in a drone propeller refers to how far it would move per one complete revolution. It’s measured in inches and roughly controls speed (of the air leaving the propeller) and turbulence. Higher pitch results in less low-end speed, high top-end speed, and more turbulence.

To put it another way, a propeller with a higher pitch will travel further than one with a lower pitch in the same amount of time.

But that’s not all. A higher pitch also means the propeller will draw more current from the battery and, hence, decrease flight times.

There are specific details on propeller pitch that are outside the scope of this post. I have, however, done a separate post on the topic. Make sure to check it out if you want to learn more.

How do you read drone prop numbers?

By this point, you know what the specifications mean and (at least) have a faint idea of what they’re for.

But you still may not know how to read propeller numbers. And if that’s the case, they’re just a bunch of random digits telling you nothing. Here’s how you can make sense of them.

You can read a drone prop number by understanding the format used in it. Most commonly, the first, second, and third digits correspond to the size, pitch, and blade configuration respectively. The digits are separated by an x. Sometimes, however, the size and pitch are written with no separation.

The blade configuration refers to the number of blades the propeller has. Let’s take a look at an example.

A propeller number of 5x4.5x3 indicates the propeller has 3 blades, a 5-inch diameter, and a pitch of 4.5 inches.

The same information may also be conveyed in a different format: 5045x3.

In this case, you’re dividing 50 and 45 by 10 to get the size and pitch in inches.

It’s worth noting that not every manufacturer includes the number of blades in their propeller numbers.

What does R mean on a propeller?

Following the numbers, you may also see an alphabet — particularly an R or C. But what do they mean? Here’s the answer.

R on a propeller means it has a clockwise rotation. Therefore, the propeller needs to be installed onto a motor that spins in the clockwise direction to ensure it works as intended. A propeller may also be marked with a C, which means it has a counterclockwise rotation.

A set generally comes with two different propeller models. One is designed to have a clockwise rotation, while the other spins in the opposite direction.

And if they’re installed the wrong way around, the drone wouldn’t even lift. This is because the spinning direction is particularly important to the working of propellers.

What benefit does a BN prop have over others?

A “BN” label on a propeller indicates it has a bullnose edge. In other words, the propeller will have a blunted tip. What are the positives of this? Take a look.

A BN propeller has the most surface area out of all propeller shapes. Its main benefit is that more thrust is created, resulting in a more powerful lift. BN propellers are ideal for small racing drones as thrust is maximized without increasing the propeller size.

But don’t get me wrong, a switch over to them wouldn’t be completely positive. BN propellers draw more amperage. This makes them less efficient compared to the more popular propellers with tapered tips.

I mentioned above how BN propellers are used in place of larger propellers in drone races. There’s one reason for this.

The frames of the small drones typically limit the propeller sizes that can be used. The next two sections focus on why this happens and what the limits exactly are.

How do you measure a drone frame?

The drone frame size comes into play when putting components together. Here’s how you correctly measure a frame.

A drone frame can be measured by determining the distance between motors located on opposite ends. This reading is taken in millimeters. For example, you can measure from the front motor on the right to the rear motor on the left to get the drone frame size.

One thing to note is that manufacturers sometimes round up this measurement. So, don’t sweat it if your reading doesn’t fully match what the specification sheet says. 

Frame sizes often differ by function. Nano drones, for example, generally have a frame size of 100 mm.

On the other hand, top-level consumer drones are equipped with more tech and have somewhat larger frames. The Phantom 4, a full-featured camera drone, has a frame size of 350 mm.

But why all of this really matters is because frame size directly relates to propeller size as well.

How do you know what size propeller you need for your drone?

So, we know that the frame size has some type of role to play. Here’s the full explanation.

You can know what size propeller you need by considering your application and using the frame size of your drone. The latter would tell you the maximum propeller size that can be supported. This length is calculated using the cosine rule. Pilots, however, can simply use a size matching table.

The calculations aren’t particularly complicated but, fortunately, you don’t have to do them regardless. Here’s a frame and propeller size matching table with pre-calculated values.

Frame SizeMaximum Propeller Size
110 mm3 inches
145 mm4 inches
180 mm5 inches
220 mm6 inches
350 mm9 inches

If you do try to install propellers that are over the supported limit, they’ll end up clashing with each other.

The table above is pretty helpful for pilots building their own drones. But if you’re trying to replace the propellers on your consumer drone, you may be better off simply buying a set that’s recommended for your model in particular.

How Long Do Drone Propellers Last?

Drone propellers should be replaced every 200-500 flight hours, or at least once every three months, to maintain optimal performance. Often overlooked due to their low cost, these essential components are easy to replace yourself. 

Regular replacement can help avoid problems such as drone crashes. Most importantly, always ensure you do not operate your drone with damaged or faulty propellers. 

The lifespan of propellers can vary greatly, so it's crucial to replace them at any sign of wear or damage, rather than waiting for a set period or number of flights.

Factors that determine how long props last

Now we'll talk about the key factors that affect the lifespan of your drone propellers, including their material, your flying habits, and how you maintain them.

Material

Different materials like plastic, carbon fiber, and wood are used to make drone propeller blades. Carbon fiber is often preferred for its strength, stiffness, and lightness, which allow for less inertia and vibration, enabling quicker speed changes. 

Plastic propellers offer more flexibility, bending without damage and resisting chips or cracks, thus requiring less frequent replacement. Wooden blades, on the other hand, are heavier and slower to respond to speed changes. 

They are also more susceptible to weather conditions like rain, which can lead to decay.

Usage

Your skill level plays a significant role in propeller longevity. Understanding how the propellers' pitch, weight, size, and design impact your drone's flight can help you avoid accidents and extend the life of your propellers. 

Conversely, if you're new to flying drones, you might find yourself replacing propellers or even the entire drone more frequently due to less precise control and care in the air. 

Remember, different propellers serve various functions, so it's important to choose propellers that are compatible with your drone's intended use to ensure their durability.

Care and Maintenance

The way you care for your drone's propellers significantly affects their lifespan. Being proactive in maintaining your drone ensures the propellers remain in peak condition. 

Regularly check to make sure they aren't bent, warped, cracked, or chipped. Proper maintenance is key to maintaining their performance and extending their life.

How to choose the right drone propeller

Different drone propellers can greatly affect your drone's power and how smoothly it flies. When choosing new propellers, consider these key factors:

Pitch: This is the distance a propeller travels in one revolution. A low pitch means less turbulence and more force, helping the motors carry heavy loads more efficiently and extending flight time as they draw less power. High pitch, however, creates more turbulence and less force.

Make sure the propeller's pitch matches your drone's requirements. Using a propeller with the wrong pitch angle can lead to poor performance.

Diameter: Larger diameter propellers make more contact with the air, providing greater stability when hovering. Smaller diameter propellers, while requiring more effort to maneuver, respond quicker to speed changes.

Other important factors include air density, blade material, maximum noise, power, and RPM. The propeller type you choose should match your drone's intended use for optimal flight efficiency.

Size and Numbers: The size of the propeller you need depends on your drone's use. Smaller blades, usually under eight inches, suit racing and acrobatics, pairing well with high kV motors. Larger blades, over eight inches, are better for carrying heavy loads and work best with low kV motors. Pay attention to the numbers on your propeller blades, as they indicate size, pitch, and blade count, helping you choose the right one for your drone's needs.

For more detailed insight check out my article on how to choose the right propeller

Are larger props better than smaller?

Before choosing larger drone propellers, it's crucial to know how they affect your drone's flight. Larger props can change your drone's speed, stability, and power use. Let's dive into the main points to consider:

Responsiveness and Motor Compatibility: Larger propellers have a higher moment of inertia, leading to slower responsiveness. 

Using 6-inch or 7-inch props on these motors makes the drone less agile. To improve this, larger motors are needed, but they increase weight and require more powerful batteries and electronics.

Thrust and Efficiency: Larger props produce more thrust, making them more efficient. They can carry heavier loads with the same motor, offering more thrust for the same power or the same thrust with less power. This efficiency is beneficial for heavy-lifting tasks.

Vibration and Frame Compatibility: A larger prop size can cause more vibration, especially if the drone's frame is larger and less rigid. This can affect stability and camera footage quality.

Top Speed and Prop Wash Handling: Larger props usually have a lower top speed but handle prop wash better. They maintain higher speeds over longer periods, making them suitable for sustained speed rather than quick bursts.

In conclusion, while larger drone propellers offer increased efficiency and load capacity, they require careful consideration of responsiveness, vibration, and speed requirements. Your choice should be based on your drone's specific needs and capabilities.

Conclusion - where do you find your propeller number?

To wrap it all up, propeller numbers are clearly visible in product descriptions. But what if you don’t remember the model of an old propeller? Here’s how you find its propeller number.

You can find your propeller number labeled on the inside of one of the blades. While some details may be omitted, most manufacturers ensure the rotation is marked due to its importance. At the same time, the propeller number is always mentioned on the box and user manual the set comes with.

On the off chance you just can’t seem to find your propeller number, don’t panic. You’ve already learned how to measure the size and the shape is a clear indication of the propeller’s rotation.

The protruding edge of the blades is always supposed to spin towards the drone frame.

Frequently Asked Questions

Why do some drones have more propellers than others?

More propellers can provide better stability, lifting capacity, and redundancy in case one fails, which is why some drones, especially larger or professional models, have more.

How does weather affect drone propeller performance?

Weather conditions like wind, rain, and extreme temperatures can affect propeller efficiency, causing stability issues and increased wear.

What should I do if my drone propeller gets damaged during flight?

If a propeller gets damaged during flight, land the drone as soon as safely possible to avoid further damage or loss of control, and then replace the damaged propeller.

Do propellers have serial numbers?

Most drone propellers do not have individual serial numbers, but they often have model numbers and specifications printed on them for identification.

author-paul-posea-picture
Hi, I'm Paul.
A big drone enthusiast, reviewing, comparing and writing about drones since 2015. I'm all about helping people enjoy and even monetize their hobby.

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paul posea
Paul Posea
Hi, I'm a long-time drone reviewer and I hope my articles and comparisons on this site as well as Dronesgator's youtube channel are of as much help as possible.
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