DRONES ACCESSORIES

Quadcopter Motors: Understanding The Driving Force of The Drones

Quadcopter Motors
Jack Brown
Written by Jack Brown

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Drones have become one of the most interesting possessions these days and more and more people are now spending their time adventuring in this new and exciting world. Flying a drone is indeed one of the best ways to spend your free time or enjoy your job to the max! Today we’re going to talk about what makes a drone used in aerial photography drone (or a quadcopter) tick: the quadcopter motors.

The motor is positioned immediately under the quadcopter propeller and controls its rotation and speed. So, for a quadcopter, you will receive 4 motors in the box. That is, if you buy a quadcopter kit or a quad that is not ready to fly out of the box. With complete models, motors are already attached and you don’t have to worry about selecting them.

Buying a drone motor may sound simple, but in reality it depends heavily on the type of drone you are building and what you personally want to do with your drone.

In the case that you are making a DIY quadcopter, or are looking to replace a motor on one of your quadcopters, there are many factors that should be brought into consideration while choosing the motor that will suit your needs. If you are interested in finding more about these motors, continue reading. We searched for the most important details and laid them out for you.

How to choose the best motor for your quadcopter?

Where do you start? While looking for motors for your drone, the first step would be having an idea of the total weight of the copter. Approximate weight estimation can be done by considering all the components of the device. For instance, you could start with the frame of the device you are building, and to find out more about this, we suggest that you also read our article about quadcopter frames.

This will give you an idea of how heavy the other parts should be. If you have a slightly bulky frame, you should opt for the lighter components. You also need to bring into consideration the weight of the potential camera and gimbal you might be using to take photos. After making an estimate of the weight, you can then go ahead and plan on the other aspects of the motor.

Proper motor efficiency therefore relies heavily on the other aspects of the drone you are building, so it is important to consider the drone as a whole when you are making this choice. Also, consider how you want to use your drone. These decisions are much easier to make up front, so that you don’t make a purchase decision you regret.  

Thrust to weight ratio

The one rule of thumb for choosing your motors – ideally, your drone should be able to hover in midair at about half throttle. This means that when you choose the apt motor for your drone, it should be able to produce 50% more thrust than the multirotor. Your quadcopter motor will have to remain stable and function well even in times of slightly windy conditions.

Disc type motors on the table

Let us give you an example: suppose you have a quadcopter frame with the total weight of components of around 800 grams. In this situation, the quadcopter motor should be efficient enough to produce a thrust of about 400 grams each or a totally of 1.6 kg on the whole. This is a great rule to keep in mind when choosing a motor. Because if you want an effective drone, it needs to be able to function even in the harshest of conditions. 

If you are considering mini quads, then agility will be the most important feature. For this, you would need motors with high thrust to weight ratios. A powerful motor is key here, as it will help your drone perform what is likely its primary function. 

On the other hand, if you are keen on drone photography, you could make do with a lower thrust to weight ratio. This is because with these types of drone you would be flying much more gently. These drones require smooth, stable flight to take high quality pictures and videos. This gives you another advantage as well. Since it saves a lot of weight on the frame, you get the option of adding some other components to the drone, like an extra battery (or a few!) or a heavier camera.

For a better insight on the topic of building a drone, we suggest checking out our article that explains how to build a drone.

Efficiency of the motor

Once we are clear about our stand on the thrust to weight ratio, it is now important to move on to the efficiency of the motor. Before we start, what do we mean by the efficiency of the motor? It is nothing but the ratio of the thrust produced to the power used. A more efficient motor will thus produce use less power when creating thrust. 

The more efficient your motor is, the longer it is likely to fly. That means more the thrust produced by the motor as compared to the power utilized the smoother and longer will be your flight. Motor efficiency is key in prolonging your drone’s flight, so it is a very important factor to take into account. 

Efficiency of the quad motor

Ideally, a motor with an efficiency of 7 or higher might be a good idea. However, there are certain large motors that work with an efficiency of 18! This is especially useful for copters that are used for aerial photography, as you will want your drone to be in the air for as long as possible to get the perfect shot.

On the other hand, if you choose to make your drone do a few acrobatic turns in the air and have agile movements, you might want to opt for a motor with higher RPM. In this case, the efficiency will be slightly reduced, but your drone will be quicker.  In a nutshell, the amount of motor efficiency you need will entirely depend on your mode of use.

Motor movements

The movement of drones like quadcopters involves the movement of two motors in a clockwise direction while two others move in an anti-clockwise direction. This ensures a higher stability of the motors and effectiveness of the device. 

Drone Motor Movements

You might wonder what it might be like if you installed motors that move in the same direction. As a matter of fact, it is entirely possible to attach 4 motors to your quadcopter, all moving clockwise or anticlockwise, but it’s not a good idea of course! This would make it rather hard to fly the object, as it would not be responsive to the direction you want it to go. So, for smoother flight characteristics, you need to buy a pair of motors that move clockwise and another pair that moves anticlockwise. Luckily, most quadcopter motors you purchase will contain two of each. 

Pole count

Next up is the pole count of the motor. You might have two options in this regard.

First is quadcopter motors with a higher pole count. These will require more voltage during its flight but produce a greater motor torque. But with these conditions comes the lower RPM of the motors. Ideally, it is best to use larger blades with these motor devices.

Diy Drone

On the other hand, you could choose a motor with a lower pole count for achieving a higher RPM. But these devices will then require smaller blades, coming with a smaller torque or lift off the ground. More often than not, quadcopters are seen using motors with higher pole counts in order to eliminate the necessity of a gearbox.

As with any choice you make with a DIY quadcopter, it will depend entirely on your needs and preferences.

Kv value

The next big question at hand is the Kv value of the motor or the RPM/volts. As we understand from the previous point, the higher the pole count, the lower will be the Kv value. By Kv, we basically refer to a constant that gives us the RPM of the motor, when a potential difference of 1 volt is applied across the motor.

Kv value of quad motor

For instance, a motor with a Kv value of 1000 will refer to 1000 RPM in 1 volt. If the motor is a 12 Volt one, then it is likely to rotate at a speed of 1200 RPM and at a voltage of 12 V. When the Kv value decreases, there is an immediate increase in the torque produced by the motor.

This would mean higher acceleration and a more powerful lift. This would indicate that you could include a few pieces of heavy equipment including a camera and the likes on the frame and it will give you a good enough lift. Thus, for drones that require heavier materials, you will need more Kv. 

For such high Kv values, you would need smaller propellers, ones that can guarantee you greater speeds, but lower efficiency.

Propeller – motor combination

It is often a common belief that one should choose the propellers first and then go about choosing the motors that work well with them. If you opt for larger propeller blades, you would be generating more thrust, higher acceleration, and more stable flights. Larger propeller blades are going to be around around 12 inches in size. With these blades, the drone can then carry heavy camera equipment and is best suited for aerial photography.

Propeller- motor combination

On the other hand, the shorter propeller blades will lead to greater speeds and are an excellent choice for mini quads and quad racing where agility is important along with some acrobatic moves. 

For the more acrobatic drones, you would need propellers of about 8 inches or lower.

While choosing your propellers that go best with your quadcopter motor, you need to keep in mind two important factors:

  • Diameter: Propellers with larger diameters produce more thrust and thus can alter the thrust to weight ratio of your motor. Just the opposite happens with smaller diameter propellers which generate less thrust.
  • Pitch: The other aspect essential to be kept in mind while choosing a motor based on the propellers is the pitch. This is defined as the distance covered in one rotation of the propeller. The lower the pitch, the higher is the thrust generated. This also means that the flights will be free from turbulence; the motors will be able to carry heavier weights, and the drone will also have long flight times. Since your drones are mostly intended for hovering in midair, lower pitch propellers will work well with your motors. However, for mini-drones with acrobatic movements, you would have to resort to larger pitch propellers.

Types of motors used in quadcopters

Quadcopters generally consume a lot of power, owing to their usage which generally accounts to aerial photography. The motors used in this case are 3 phase brushless DC outrunner motors. These brushless motors are in use especially because of the superior performance they deliver for this type of drone.

There are two varieties of these motors available in the market: disc and barrel.

Disc type motors

These high power motors are shaped essentially in the form of a disc. More often than not, these motors turn out to be pretty light and thus generate a higher torque during flight. This can also be attributed to the higher number of windings present.

Disc type motors on quadcopter

These also have a higher pole count and thus lower Kv value. This leads to the requirement of larger propellers. Thus, the disc type of motors gives you a longer flight time and more stable flights with minimal turbulence and noise.

Barrel type motors

These motors work with an action just opposite to that of the disc type. These come in the shape of a barrel, are heavier in structure and generate a lot less torque as compared to its counterpart. These motors, as understood, come with lower pole counts and thus higher Kv value. These lead to agile movements, but the flights are not as stable as the disc type of motors.

Because of these features, disc quadcopter motors are not used nearly as often. This can also be explained by their high costs.  Add to that, the fact that a quadcopter requires about 4 of these motors to run smoothly. These reasons are why not too many people invest in the disc type. People who are strong enthusiasts or have taken up aerial photography and videography as a profession or passion tend to go for the disc type of motors.

Barrel type motors

Cutting it short and making the process of selecting some drone motors easier for you, hereunder, we are now going to present to you some of the drone motors that have been most popular amongst drone users.

Best drone motors available on the market today

Parrot AR Drone 2.0 Motor

This motor is specific to Parrot drones but this is one of the most useful devices you will come across.

For starters, let us consider the speed of the motor. It comes with a value of 28,000 RPM which is pretty impressive.

This 15 Watt motor has turned out to be an instant hit amongst the users. This kit also comes packed with the flight controller and some metal screws to give you a complete package.

Parrot AR Drone 2.0 Motor

The motor is attached to the electronic controller for facilitating smoother installation processes. With a sleek and compact design, there will be no issues attaching the device on to the copter frame board. That is why it doesn’t take much time to finish off the installations of these drone devices.

If you have a Parrot drone, this is the perfect motor if you are in need of a replacement!

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Emax Mt2213 935kv 2212 Brushless Motors

Talking about brushless motors for quadcopters, here is another product that might be of great interest to you. This package comes with a set of four motors with a diameter of about 27.9 mm. When we talk about the thrust, this set is capable of providing a value of 850 grams per volt. Installing these motors is also a pretty simple and easy job.

Emax Mt2213 935kv 2212 Brushless Motor

Installing these motors is also a pretty simple and easy job. All you have to do is connect them on to the frame board and check their rotation movements. Checking the rotation movements is imperative since two motors run in a clockwise direction while the two others run in a counter-clockwise direction. In the case that one motor runs in the wrong direction, you need to flip just two of the three wires and your work is done!

These motors have a decent speed and powerful torque. On top of all that, these motors tend to be quiet and quite sturdy, being able to survive a few minor crashes.

This is a great all-around motor for your quadcopter, so check it out if it sounds like it suits your needs!

If you interested in this product please check out the best options available on Amazon:

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Coolplay Motors

This is yet another set of useful motors coming packed with a pair of motors capable of moving in the clockwise direction and another pair which move in the anti-clockwise direction. This set is made from plastic gears, giving it the necessary lightweight structure that seems to last long and generate a stable performance.

Coolplay® Syma X5 X5C X5C-1 Motor

The size of these motors is 7 mm x 20 mm and they have been found to be a good fit on most copter kit boards. Since the wires are color coded, it is easier to assemble them onto the board.

Another great all-around motor for your quadcopter!

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Last updated on June 1, 2020 7:54 am

Holy Stone Motors

The next one on our list of the most popular drone motors comes from Holy Stone. These are made with high-quality materials with the efficient workmanship. Therefore, these are thus some of the most durable motors out there. They that are lightweight in structure and they do not get damaged very easily.

HOBBYTIGER 2 Pairs Main Motor Metal for RC Quadcopter Drone

Available at very reasonable costs, these motors are thus very easy to purchase and replace on your quadcopter board. With colored wires, it is now easier to attach these on to the quadcopter. With stable flight characteristics, these might just be the ideal motors for your drone!

If these seem like the type of motors for you, check them out here: Holy Stone Motors

Yanshon Motors

Next up is another set of four motors for drones. With these motors, two work in a clockwise direction while two others work in a counter clockwise direction. The motors are made from high-quality materials and are designed in a way that reduces the heat generation and will lead to better efficiency of the motors.

iDrones Motors

These motors are light weight at about 16 grams. They are also designed to be quieter than stock motors. The motors also have a very compact design so that they can easily fit into the drone framework. With a diameter of about 7 mm, these will not take up too much space on the quadcopter board.

Each of the four motors is color coded so that installation is a lot more convenient. The color coding is meant to match that of the original drone motor in many cases, so that replacement is as easy as possible.

These are great motors at an affordable price, and allow stable drone performance and ample flight time. These are a great choice for your quadcopter!

If you are interested, check out Yanshon Motors here: Yanshon Motors

In conclusion

Choosing the best motor for your drone is not one of the easiest things to do. There are a number of considerations to be made. Also, there are some compromises to be made as well. For instance, it is difficult getting a motor that gives you the swiftest and most agile acrobatic moves while also promising you flight stability and performance.

A higher Kv value in motors gives you higher speeds, but compromises on efficiency. On the other hand, a lower Kv value motor will make better use of power and give you slower and stable flights. That is why you need to be clear of your purpose of using the drone and choose the motor accordingly.

Overall, it is important that before you purchase your drone motor you have an idea of the overall design of your drone and what you will use it for. The drone depends quite heavily on the weight of the rest of your drone. Additionally, the type of motor you need will differ based on how you will use your drone. A motor is one of the most important parts of your drone, so be sure that you choose one that will facilitate the best performance!

We hope that this article has provided you with insight on the workings and purposes of drone motors, and also some of the best ones on the market today. Making a DIY quadcopter is a difficult process, but the more you understand about how a drone works, the better you can handle it!

Are you still finding yourself confused, or are you still unsure on which motor is best for you? Write to us in the comments and we’ll surely help you settle it!

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About the author

Jack Brown

Jack Brown

Jack is the Chief Pilot at MyDroneLab.com bringing experience, expertise and knowledge in this quite new industry. He is a graduate of the Drone/UAV Pilot Training Certificate program and member of the Association for Unmanned Vehicle Systems International. Besides having all the necessary technical knowledge when it comes to drones, Jack and his team love to spend the time outside by the ocean, working on new features and teaching others how to pilot these amazing and exciting new robots.