You’ve made the decision to get new propeller blades and you can’t wait to see how much of a difference they’ll make. That was, however, the easy part. Once you actually start looking through the market, it’s easy to feel a little overwhelmed.
Fortunately, a little guidance is all you need to ensure you don’t regret your new purchase.
There are two points to focus on when choosing a drone propeller. The first one refers to the compatibility between the specifications of the drone and propeller. The latter relates to exactly how you want to fly your drone. An educated decision can be made by using factors like the propeller pitch.
Before we dive in deep, I’d like you to make a mental note of the following. There is no perfect set of propellers. This is because a compromise is always being made in one department or the other.
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It’s my job to help you figure out which compromise(s) will affect you the least. Ultimately, your new propeller will be perfect for you which is what truly matters.
To do this, I’ll be gradually expanding on the factors I touched on above. You’ll find them to be a recurring theme throughout this post.
Let’s get straight to the point. To find the right set between a vast array of propellers, you’ll need to replicate a process. Here are the specifics.
You can choose the right drone propellers by initially identifying your desired way of flight. The next step is to make sure each propeller property is somehow positively contributing to your intended use. The main properties are the type, size, blade configuration, pitch, and diameter.
The ideal drone propellers will ensure a smooth flight while improving efficiency. Let’s take a deeper look at each property and how they’re connected with different styles of drone flight.
Propeller size directly influences thrust and responsiveness. And as soon as you browse through the market, you’ll see propellers with an obvious size difference.
This is because small propellers and large propellers both have a unique purpose.
Smaller propellers are lighter and work against less air. This makes them more responsive; they’re easy to stop and speed up. These are a popular choice amongst pilots.
Larger propellers consume more power and create a bigger pressure difference. Put simply, they generate more thrust.
At the same time, the heavier weight of the propellers also means they take longer to respond to a change in RPM.
But for drones operating in, for example, the agriculture industry, this characteristic isn’t something to worry about.
Similarly, the ideal propeller size for you solely depends on your drone’s frame and how you plan to fly it.
Next up is the blade configuration. Propellers are often categorized based on their number of blades, just like they are with their size.
This property also has a similar effect on drone flight. In fact, changing the blade configuration is often used as a substitute to changing the size — though not as a perfect one.
Let me explain why.
Increasing the number of blades on a propeller does generate more thrust, but it won’t result in as much of a smooth flight as increasing the size would.
The generation of more thrust also worsens the efficiency, as more blades suck out more energy from the batteries.
You might be wondering what the point of more blades is if we can just buy a larger propeller. Well, as I’ve mentioned before, your drone’s frame is an important thing to consider.
You may not always be able to fit in a larger propeller, which is where the number of blades, fortunately, comes into play.
Dual-bladed propellers are the most commonly used since they’re a balanced option, though three-bladed ones are also used by enthusiastic racers.
The takeaway is that a propeller with more blades is said to perform better at cornering and offer more control in general. This comes at the expense of overall speed.
The pitch is a crucial factor to consider as it’s an important part of propeller specifications. But if you’re just getting into flying drones, you might not be familiar with the term.
It’s defined as the travel distance of the propeller per revolution and is generally measured in inches.
The concept of pitch in drone flight can get a little lengthy, which is why I’ve done an entirely different post on it. I recommend checking it out if you’re actually looking to learn about propeller pitch.
Now, why exactly is the pitch crucial to choosing propellers?
Here’s the thing: the propeller pitch directly affects drone flight in a couple of different ways.
Propellers with a lower pitch spin faster which facilitates higher acceleration. At the same time, less current is drawn.
A higher pitch, on the other hand, means more thrust will be generated. This results in higher top-end speed but comes with the drawback of more power consumption.
Again, the ideal pitch length depends on your drone’s application. For example, specific (confined) settings demand control and stability which makes propellers with higher pitches unfeasible.
The propeller type refers to the material used in its making. And honestly speaking, this property is the easiest to decide on.
You’ll generally be presented with two options: plastic and carbon fiber. The former is, by far, the most commonly used material in modern propellers.
Plastic propellers are affordable and less rigid. Their flexibility makes them more durable, an important feature for beginner pilots.
Carbon fiber propellers are quieter and excel performance-wise. They’re costly but ideal for experienced pilots who are less likely to crash their drones.
I recommend using carbon fiber propellers for sensitive applications where less vibration is key. A good example is recording cinematic footage through a somewhat windy setting.
I’ve emphasized the importance of size and its effect on drone flight. At this point, you might already have a faint idea of what size to go for but here’s a direct explanation.
You can know what size propeller you need for your drone by the application you have in mind. Small propellers are ideal for situations that require sharp movements, while larger ones are integrated into drones that need to carry heavy payloads. Generally, 5-inch propellers are a balanced option.
You’ll often see racing drones using small propellers since they feature acrobatic maneuvers.
On the other hand, drones with larger propellers are popular in (but not limited to) commercial use. They typically carry extra cameras or mechanical equipment.
It’s incredibly important to make sure the size you’re going for works with the rest of your system. For example, larger propellers need to be paired with larger motors to avoid internal damage.
This one’s possibly the most frequently asked question by pilots looking to get a new propeller. Here’s the answer to offer more clarity.
A bigger drone propeller is better in the sense that it can be used to carry heavier payloads and improve a drone’s stability as it hovers. It may also increase drone efficiency. However, a bigger propeller is not better through and through. This is because a smaller one trumps it in responsiveness.
To sum up, a bigger drone propeller can only be declared as the better option if it suits your desired drone application.
I’ve touched on two of these common blade configurations. Is one particularly better than the other? Let’s find out.
3-blade propellers are better than 2-blade propellers for drones when it comes to the smoothness of flights and creating a greater amount of lift. 2-blade propellers, however, have the edge when it comes to speed and efficiency. And since they draw less current, flight times are longer.
The point is this: both configurations come with their own set of pros and cons.
If you’re looking to dive into the specifics, I recommend going through the post I did on propeller blade configurations.
In general terms though, 2-blade propellers are noticeably more popular. This is primarily because they don’t require powerful motors. And for this reason, the drone can stay lightweight which is a sought-after feature in the industry.
The diameter of a propeller refers to the distance between the two tips located on opposite ends.
And if you change the diameter of a propeller, you’ll be changing its size. You might already know where this is going. Here’s what happens.
Changing the diameter of a drone propeller changes how efficiently the flight goes. This applies to little changes as well. A propeller with a larger diameter generates more thrust while maintaining the same speed. On the other hand, a decrease in diameter means the propeller will respond quicker.
The terms size and diameter can be used interchangeably in this case.
In general, however, there’s a distinct difference.
When you change the size, you’ll also be changing the propeller’s overall weight. This affects the propeller’s durability and the drone’s flight time.
A diameter change, though, is only a change in length. The final diameter value determines how much air a propeller blade sweeps through.
Drone pilots are often looking to replace their drone propellers in order to improve efficiency. There are a few properties that are modified to prioritize efficiency. Take a look.
You can increase your drone propeller efficiency primarily by switching it out for one with a better design. An efficient propeller generally has a small size with a curved leading edge of the blade. Other notable ways include increasing the diameter and using a fewer number of blades.
To reiterate, the propeller’s design refers to its shape. A propeller with narrower blade tips ensures an efficient flow of air.
One thing to consider is that you will be losing out on propulsive power with a small size and fewer blades. Therefore, in my opinion, it’s important to strike a balance.
Talking about propeller efficiency, you might be wondering what type particularly excels. Here’s the answer.
The most efficient drone propeller is the single-blade propeller. However, it isn’t a balanced option as it comes with significant vibration issues. This makes the two-blade propeller the most efficient option as it’s practical. As a general rule, efficiency decreases as more blades are added.
A smaller number of blades results in less turbulence, which is key to improving efficiency.
You’ll often see drones sporting three-bladed or four-bladed propellers. Efficiency is deliberately compromised as those propellers do a great job suppressing vibration and improving acceleration. These are features important in, for example, the drone racing industry.
An optimal flight performance cannot be achieved without maintaining a balance.
So, while the single-blade propeller is technically the most efficient, it’s probably not the best option for your drone.
Before we wrap up, I think it’s worth touching on propeller numbers. They specify the properties (which you’ve learned about) of the propellers.
You’re guaranteed to find them in the product descriptions. They’re often labeled onto the blades as well. Here’s how you can decipher them.
A drone propeller number is generally a series of numbers. The first number represents the diameter in inches. The second number indicates the pitch. The last number specifies the number of blades on the drone propeller. However, the number of blades isn’t a mandatory part of propeller numbers.
Here’s an example: 5x4.5x3. This is the propeller number of the HQ V1S.
It shows the propeller is 5 inches long, has a pitch of 4.5, and is three-bladed.
I go into other formats of propeller numbers in another post, where I break down drone propeller terminologies.
Quadcopters are simple, safe, and easy to use. And just like other types of drones, the process of choosing a propeller isn’t any different.
You can choose a quadcopter propeller by deciding whether you want particular features, like efficiency, to excel or a balanced option. You can then use properties like the number of blades, size, and pitch to ensure your goals are met. However, the components also need to work well with each other.
If you do decide on keeping things as balanced as possible, I recommend trying out a three-bladed propeller. They’re incredibly popular in the industry and a solid choice for quadcopter pilots looking to replace their old propeller models.