How to Sail: Mastering the Basics of RC Sailboat Navigation

Introduction

RC sail boating is a fun and challenging hobby that requires skill, patience, and knowledge. Whether you’re a seasoned sailor or a beginner, mastering the basics of RC sailboat navigation can help you enjoy your hobby to the fullest and avoid common pitfalls that can lead to frustration and disappointment. In this article, we will provide a comprehensive guide to RC sailboat navigation, covering everything from choosing the right location to troubleshooting common problems. By the end of this article, you’ll have a solid understanding of the key concepts and techniques that are essential for smooth sailing.

Topics that will be covered in this article include:

  • Choosing the right location for sailing
  • Setting up the boat and equipment properly
  • Understanding the weather conditions and wind direction
  • Overview of the basic controls (rudder, sails, etc.)
  • Explanation of how each control affects the boat’s movement
  • Tips for adjusting the controls to achieve the desired outcome
  • Tacking and jibing: How to change direction effectively
  • Upwind sailing: Tips for sailing into the wind
  • Downwind sailing: Tips for sailing with the wind
  • Identifying potential obstacles in the water
  • Techniques for avoiding collisions
  • How to recover from a collision
  • Common problems and how to fix them (e.g., capsizing, getting stuck in the weeds, etc.)
  • Tips for troubleshooting on the water

By the end of this article, you’ll be well on your way to mastering the basics of RC sailboat navigation and enjoying the thrill of sailing with confidence and ease.

Getting started

How to Sail – Choosing the right location for sailing:

Choosing the right location is an essential step in RC sailboat navigation. You’ll want to find a body of water that is large enough to sail comfortably, but not so large that you risk losing your boat. Additionally, you’ll want to choose a location that is relatively calm and free from obstacles, such as rocks or debris, that could damage your boat. Popular locations for sailing RC sailboats include ponds, lakes, and bays. Check in with your local club for other recommendations.

Setting up the boat and equipment properly:

Once you’ve chosen your location, it’s time to set up your boat and equipment. Make sure that your boat is in good working condition, and that all the necessary parts, such as the rudder, sails, and batteries, are installed properly. Check your boat’s manual or consult with an expert if you’re not sure how to set up your boat correctly.

Understanding the weather conditions and wind direction:

Before setting sail, it’s important to understand the weather conditions and wind direction. Wind direction and strength will greatly affect the way your boat moves and handles, so it’s important to know what to expect before you head out on the water. Be sure to check the weather forecast and keep an eye on the wind while you’re sailing. This will help you adjust your sails and control your boat more effectively. Additionally, it’s important to avoid sailing in extreme weather conditions, such as high winds or heavy rain, as these conditions can be dangerous and damage your boat.

Understanding the controls

How to Sail – Overview of the basic controls:

The basic controls of an RC sailboat include the rudder, sails, and rarely the keel or ballast. The rudder (typically right stick in North America) is used to steer the boat left or right, while the sails (Typically left stick in North America) control the boat’s speed and direction. The keel or ballast is used to stabilize the boat and prevent capsizing.

Explanation of how each control affects the boat’s movement:

The rudder controls the boat’s direction by redirecting the flow of water around the boat. When the rudder is turned to the right, the water is redirected to the right causing the boat to turn right. When the rudder is turned to the left, the opposite occurs.

The sails control the boat’s speed and direction by harnessing the power of the wind. When the sails are angled towards the wind, they catch the wind and propel the boat forward. When the sails are angled away from the wind, they allow the wind to pass through them, slowing the boat down.

Tips for adjusting the controls to achieve the desired outcome:

Adjusting the controls requires a delicate balance of steering, sail positioning, and wind direction. To sail in a straight line, you’ll need to position the sails perpendicular to the wind and adjust the rudder to steer the boat. For sailing upwind, you’ll need to position the sails at an angle to the wind and steer the boat into the wind. To sail downwind, you’ll need to position the sails at an angle away from the wind and steer the boat away from the wind. Experiment with adjusting the controls to achieve the desired outcome, and practice regularly to improve your skills.

Sailing techniques

How to Sail – Tacking and Jibing: How to change direction effectively:

Tacking and jibing are two basic techniques for changing direction while sailing. It is a technique used to change direction while sailing upwind, and involves turning the boat through the wind so that the sails switch from one side to the other. Jibing is used to change direction while sailing downwind, and involves turning the boat away from the wind so that the wind catches the sails on the other side. Both techniques require careful attention to the wind direction and sail positioning, as well as precise timing and steering.

Upwind Sailing: Tips for sailing into the wind:

Sailing upwind can be challenging, as the boat needs to sail at an angle to the wind in order to make forward progress. To sail upwind effectively, position the sails at an angle to the wind that provides the most power, while also steering the boat into the wind at a slight angle. Use tacking techniques to change direction as needed, and keep a close eye on the wind direction and sail positioning to ensure maximum efficiency.

Downwind Sailing: Tips for sailing with the wind:

Sailing downwind can be exhilarating, as the boat can pick up a decent speed with the wind at its back. To sail downwind effectively, position the sails at an angle away from the wind that provides the most power, while also steering the boat away from the wind at a slight angle. Use jibing techniques to change direction as needed, and be sure to keep a close eye on the wind direction and sail positioning to maintain control and avoid capsizing.

Avoiding obstacles

Identifying potential obstacles in the water:

One of the key challenges of sailing an RC sailboat is navigating around potential obstacles in the water. These can include rocks, buoys, other boats, and even underwater hazards like weeds or sandbars. Before setting sail, take a careful look at the area where you’ll be sailing to identify any potential obstacles that may be present. Use your boat’s onboard camera, if available, to get a better view of the area.

Techniques for avoiding collisions:

To avoid collisions with other boats or obstacles, there are several techniques you can use while sailing. One is to keep a close eye on the water ahead of you, looking for any signs of obstacles or other boats. Another is to maintain a safe distance from other boats, and to avoid sailing in congested areas where there may be a high risk of collision. You can also use your boat’s rudder and sails to change course quickly if needed, and to adjust your speed to avoid potential hazards.

How to recover from a collision:

Despite your best efforts, collisions may still occur while sailing an RC sailboat. If your boat collides with an obstacle or another boat, the first priority is to ensure that everyone on board is safe and uninjured. Haha, Ok, just checking if you are still with me. First assess the situation to determine if you should continue sailing to get away from the obstacle. Or your second option, which is to reduce power to zero by letting the sail out to face in to the wind. Once the obstacle clears, bring the boat in or rescue it with a full size boat.

When the boat is back on shore, check for damage, and make any necessary repairs before continuing to sail. Check over the ballast/keel, rudder and the entire hull.

Troubleshooting

Common problems and how to fix them:

While sailing an RC sailboat, several common problems can occur, including capsizing, getting stuck in weeds or other debris, and experiencing electrical or mechanical failures. To fix these problems, you’ll need to have some basic tools and spare parts on hand, as well as a good understanding of how your boat’s components work.

Capsizing:

If your boat capsizes, the first step is to rescue it with a full size boat. Once rescued, you will want to get all the water out of the hull out as quickly as possible. Check for water in the radio area of the boat. If any water has contacted the receiver or servos, use a heat gun with careful to dry it out.

Getting stuck in weeds or other debris:

If your boat gets stuck in weeds or other debris, try using the rudder and sails to maneuver it free. If that doesn’t work, you may need to paddle your full size boat out there and free it by hand. Careful not to bend rudders or break the keel in this process. Yep, I’ve seen this done before.

Electrical or mechanical failures:

If you experience electrical or mechanical failures while sailing, you’ll need to diagnose the problem and make any necessary repairs. Common issues include dead batteries, broken wires, and malfunctioning servos. Make sure to bring spare batteries, wires, and other components with you on the water in case of a failure. Or you could just head home and return if you live close by. You get the point.

Final Tips and Conclusion

RC sail boating can be a fun and rewarding hobby for those who enjoy being out on the water. And for those who love to tinker on an RC vehicle that gets excellent gas mileage. By mastering the basics of sailing, you can enjoy smooth and safe sailing and avoid common pitfalls.

Recap of the main points covered in the article:

  • Choosing the right location for sailing is important to ensure safety and optimal conditions for sailing.
  • Setting up the boat and equipment properly is critical to ensure that everything is working correctly and safely.
  • Understanding weather conditions and wind direction is essential for effective sailing.
  • Knowing the basic controls of the boat, including the rudder and sails, and how they affect the boat’s movement is crucial.
  • Techniques such as tacking and jibing, upwind sailing, and downwind sailing are important to master for effective navigation.
  • Avoiding obstacles and knowing how to recover from collisions are important for safety on the water.
  • Troubleshooting common problems such as capsizing, getting stuck in weeds, or experiencing electrical or mechanical failures can be accomplished with some basic knowledge and tools.

Final tips for mastering the basics of RC sail boating:

  • Practice and patience are essential for learning to sail effectively.
  • Be aware of your surroundings and take precautions to avoid hazards while sailing. Even some of the most moderate wind could be a hazard to your boat. Know the maximum wind speeds that are best suited to your hull or setup.
  • Bring spare parts, tools, batteries or a charger with you on the water.
  • Joining a local RC sailing club or community can provide valuable resources and support for learning and improving your skills.

Have Fun!

The History and Evolution of RC EDF Jets

Radio-controlled electric ducted fan (RC EDF) jets are a thrilling and challenging hobby that has captured the imagination of aviation enthusiasts all over the world. These small, high-performance jets are powered by electric motors and use ducted fans to produce thrust. This helps give them a unique look and feel that’s unlike any other RC aircraft.

In this article, we’ll explore the history and evolution of RC EDF jets, from their early days in the 1950s to the cutting-edge models of today. We’ll discuss the key technological and design advancements that have made RC EDF jets easier to build and fly. We will then look at the different types of jets and what makes them unique. We’ll also examine the growing popularity of RC EDF jets and the exciting future that lies ahead for this thrilling and rewarding hobby. So whether you’re a seasoned RC pilot or just getting started, get ready to take flight and explore the world of RC EDF jets!

80mm Jet Modified for 4.5+KW 250km/h

Early days of RC jets

The history of RC aircraft dates back to the 1930s, but it wasn’t until the 1950s that the first successful RC jet flight took place. These early RC jets were powered by small gas turbine engines that were adapted from military surplus units. They were difficult to control, and only the most experienced RC pilots were able to fly them.

The first RC EDF jet models appeared in the 1970s, using ducted fans to generate thrust instead of gas turbines. These early models were often made from balsa wood and covered with heat-shrink plastic. They were powered by small electric motors that were not very efficient. These model were challenging to fly. This was due to the fact that the ducted fan design made them more prone to tip stalls and other aerodynamic issues.

Despite these challenges, RC EDF jets quickly gained popularity among hobbyists, who were drawn to their unique look and high-performance capabilities. As technology improved and the designs became more refined, RC EDF jets became easier to build and fly, paving the way for the modern models that we see today.

Advances in Technology and Design

Over the years, advances in technology and materials have made it easier to build and fly RC EDF jets. One major breakthrough was the development of lithium-polymer (LiPo) batteries. LiPo batteries are much lighter and more powerful than the older nickel-cadmium batteries that were commonly used in RC models. These batteries have made it possible to build smaller and lighter RC EDF jets that can fly for longer periods of time.

Another key innovation has been the development of more efficient fan blades and motors. Modern RC EDF jets use high-tech materials and designs to improve airflow and reduce drag The result is faster and more agile models that are easier to control. In addition, improved control systems and flight stabilizers have made it easier for pilots to fly RC EDF jets, even in challenging conditions.

Modern technology has also allowed manufactures of jets to create very scale and detailed models. These models can then be made out of a Styrofoam based materials. What is excellent about using Styrofoam is its ability to take on unique shapes and detail in a very lightweight package. The result here is massive improvements to the appearance of a model jet while also maintaining a significant performance envelope.

Customizability and Modifications

One of the most exciting recent developments in RC EDF jet technology has been the emergence of 3D printing and other advanced manufacturing techniques. These technologies make it easier for hobbyists to customize and modify their RC EDF jets. As a result, unique designs and features that would have been difficult to achieve using traditional methods are now possible. This has led to a thriving community of DIY enthusiasts who are constantly pushing the boundaries of what’s possible.

As these technologies continue to evolve, it’s likely that we’ll see even more exciting advances in RC EDF jet technology. This will pave the way for an even more thrilling and rewarding hobby experience.

Types of RC EDF jets

There are several different types of RC EDF jets, each with its own unique characteristics and design features. Let’s look at the 2 most common in the hobby:

Scale Models

One of the most popular types is the scale model. Scale models are designed to replicate real-life military or civilian aircraft in miniature form. These models are often highly detailed and realistic. They can range in size from just a few inches to several feet in length.

Sport Jet Models

Another popular type of RC EDF jet is the sport jet. A sport jet is designed for high-performance flying and aerobatics. These models are typically smaller and more agile than scale models. Sport jets exhibit sleek designs that emphasize speed and maneuverability. Sport jets are a great choice for pilots who want a more challenging and exciting flying experience.

Trainer Jet Models (maybe an old dated type)

For pilots who may be new to the EDF scene, a trainer jet is designed to be best for a beginner. This is not a beginner to RC airplanes, but to faster flying models. Trainer jets have a wide flight envelope allowing them to fly slowly. They typically present the best stall characteristics or best characteristics all around. What is really unique about the modern day trainer is that manufactures have been able to camouflage this Jet among the scale and sport models. This means that you may be able to get that lovely scale model you always wanted as it serves as a trainer jet.

The key differences between these types of jets are primarily in their size, speed, and maneuverability. Scale models are typically larger and more detailed, but they are also slower and less agile than sport jets. Sport jets, on the other hand, are designed for high-performance flying and aerobatics, with smaller, more streamlined designs that allow for faster speeds and more maneuverability. Trainer jets are disappearing as a modern day EDF jets share the flight characteristics that you need and expect in a trainer.

No matter what type of RC EDF jet you choose, each offers a unique and thrilling flying experience that is sure to delight aviation enthusiasts of all ages and skill levels.

Popularity and growth of RC EDF jets

In recent years, RC EDF jets have become increasingly popular among hobbyists and enthusiasts around the world. Thanks to advances in technology and design, these models are now more accessible, affordable, and exciting than ever before. We didn’t speak about affordability before, but yes, this is BIG for the Jet scene. As a result, more and more people are discovering the thrill of piloting these amazing RC aircraft.

One of the biggest contributors to the growth of the RC EDF jet hobby has been the rise of social media and online communities. These platforms have allowed enthusiasts from all over the world to connect, share ideas, and showcase their latest designs and builds. Popular events and forums such as the Jet Power Event in Germany and the RC Jet World Masters in Spain have also played a significant role in bringing together the RC EDF jet community and showcasing the latest trends and innovations in the hobby.

In terms of design and technology, RC EDF jets are constantly evolving and pushing the boundaries of what’s possible. New materials, manufacturing techniques, and control systems are making it easier than ever to build and fly these models. Improvements to the models speed, maneuverability, and overall performance is incredible to see over the years. Some of the latest trends in RC EDF jet design include 3D printing, advanced flight stabilization systems, and cutting-edge aerodynamic features.

Overall, the popularity and growth of RC EDF jets show no signs of slowing down. With new enthusiasts joining the hobby every day and constant innovation driving the design and technology of these models, the future of RC EDF jet flying looks brighter and more exciting than ever before.

And to Sum it Up:

As we look to the future, it’s clear that the sky’s the limit for RC EDF jet enthusiasts. There’s no telling what kinds of amazing designs and innovations we can expect to see in the years to come. With the rise of social media and online communities, there are more opportunities than ever before for enthusiasts to connect, share ideas, and push the limits of what’s possible.

Overall, RC EDF jets are a testament to the ingenuity, creativity, and passion of the aviation community. Whether you’re a seasoned pilot or just starting out, these models offer a thrilling and rewarding experience that is sure to inspire and delight aviation enthusiasts of all ages and backgrounds.

What are Droop Screws, How do they Work?

RC (Radio Controlled) cars have come a long way since their inception and are now more sophisticated and technologically advanced than ever before. Many enthusiasts are always looking to fine-tune their vehicles for maximum performance on the track. This is to of course remain competitive against others. One of the key components that can greatly affect the performance of an RC car is the droop screw.

In this post, we will explore the function of RC car droop screws, how they work, and why they are important in fine-tuning the suspension setup of an RC car. We will also discuss how to adjust the droop screws to optimize the performance of your RC car on the track.

What are RC Car Droop Screws?

Droop screws are simply fasteners that are installed on the chassis plate of the RC Car and contact the suspension arms. They control the amount of suspension compression when the car is under its own weight. They really are essentially limit screws that restrict the amount of downward travel of the suspension arms.

How do Droop Screws Work?

Droop screws work by simply adjusting them to suit the desired performance required. The fasteners are generally situated on the metal chassis of the car. the body of the screw then comes out the other side of the chassis plate to make contact with the control arms of the RC vehicle. When the screws contact the arms, this is where the limitation in travel is established. One may drive a droop screw further in to limit the amount of downward travel. Or, on the other hand, turning the screw out to provide maximum downward travel.

Left Side Rear showing how a Droop Screw significantly adjusted looks vs the Right Side Rear

Benefits of Droop Screws

Restricting Travel

Restricting suspension travel would be more common for RC on road vehicles. This would allow the RC Car to have a stiffer suspension setup when the car is in its natural resting position. Driving the droop screw further in would then further lower the car and stiffen up that initial suspension travel from the natural resting position. Stiffer suspension decreases body roll while cornering, accelerating or braking.

Pros: Stiffer Suspension for on road racing. Lowered appearance or stance.

Cons: minimized grip when the car travels over a bump. Limited Suspension Travel

Un-Restricting Travel

Adjusting the droop screw out so that you get maximum travel, decreases the amount of pre-load on the springs. In this configuration, the natural resting spot in the suspension is not obtained until the RC Car is completely under its own weight. This way the cars weight acts as a force that settles in and matches the force created by the springs in the suspension. As a result, If the car is lifted up slightly, the tires will remain in contact with the ground. This setting is perfect for off-road vehicles and is absolutely critical for rock crawlers where the tire and suspension requires maximum travel.

Pros: Maximum grip when a car travels over a small or large bump in the surface. Maximum Suspension Travel.

Cons: Can not easily lower the car using Droop Screws. Can not pre-load the suspension increasing the amount of spring force when the car is in its natural resting position.

How to Adjust RC Car Droop Screws

To adjust the droop screw, you will need a droop gauge and a droop screw driver. The droop gauge can really be anything that allows you to understand the amount of droop your car has. Consider a ruler for simplicity. There are fancy gadgets and blocks out there, but you really don’t need these. More detail on how a ruler will be used below. The droop screw driver is generally a standard screw driver that is used to turn the screw in or out. This is to increase or decrease the suspension limit.

To adjust the droop screw, follow these steps:

  1. Measure the Fully Extended Height: Start by measuring the distance between the bottom of the chassis and the ground. This measurement is taken with the car on a level surface and without any weight on the suspension. To do this, the cars weight must be fully supported by something other then its own suspension. Example: use blocks under the chassis plate, positioned at a height to allow the tires to barely touch the ground.
  2. Measure the droop: Next, grab your trusty measuring device and measure the amount of compression the suspension undergoes when the RC car is now under its own weight. Measure the same specification as in step 1, but the only difference is blocks are not supporting the car, the car is supported under its own weight. Pro Tip – With the car under its own weight push on the car a few times compressing the suspension and allowing the suspension to lift the car back up in to its normal or natural resting position.
  3. Adjust the droop screw: Based on the measurements taken in steps 1 and 2, adjust the droop screw as needed to achieve the desired amount of droop. Turning the screw in will decrease droop, while turning the screw out will increase the amount of droop.
  4. Re-measure and Confirm: After adjusting the droop screw, re-measure the ride height of the car vs droop. If the desired amount of droop or the desired ride height has been achieved, you are good to go. If not, continue to adjust the droop screws and re-measure.

It is recommended to make small adjustments at a time. Re-test the car after each adjustment to ensure that you are making progress to your desired result.

What is PWM in an ESC? How does an ESC Work?

Electronic speed control (ESC) is an essential component of any RC vehicle that uses an electric motor. An ESC regulates the power delivered to the motor to control the speed and direction of the vehicle. ESCs are widely used in radio-controlled cars, drones, and other similar applications. In this blog post, we will discuss in detail what PWM is, how it is used in ESCs, how an ESC works. We will also discuss a formula that you can use to set PWM frequency.

What is PWM?

Pulse-width modulation (PWM) is a technique used to control the average voltage or power delivered to a load by rapidly switching a voltage source on and off at a fixed frequency. The width of each pulse (i.e., the duration of time the voltage source is turned on) is varied to change the average voltage or power delivered to the load.

Use of PWM in electronics:

PWM is a commonly used technique in electronics to control the speed of motors, the brightness of LEDs, and the voltage supplied to other types of loads. By varying the duty cycle of the PWM signal, it is possible to control the average power delivered to the load. Note that duty cycle is the ratio of on-time vs total time. Using a variable resistor to control the voltage is less efficient than this because the resistor dissipates power as heat, resulting in wastage.

How Does an ESC Work?

Overview of an ESC:

An ESC is a component in an RC vehicle that controls the speed of an electric motor by regulating power. An ESC typically consists of a microcontroller, power electronics, and other components that facilitate communication with the motor and the input signal from a remote control device. This is the radio.

Explanation of the operation of an ESC:

The input signal processor receives the input signal from the RC radio and then sends it to the microcontroller. The microcontroller then generates a PWM signal with a fixed frequency and duty cycle and sends it to the motor driver. The motor driver amplifies the PWM signal and sends it to the motor. This is where it controls the average voltage or power delivered to the motor and hence the motor speed.

The microcontroller adjusts the duty cycle of the PWM signal based on input from the RC radio to regulate the motor speed. The microcontroller can also monitor the motor current and temperature to prevent damage to the motor and the ESC.

PWM in an ESC

PWM frequency and its impact on ESC performance:

The frequency of the PWM signal generated by the ESC can affect its performance. A higher PWM frequency can result in a smoother motor operation and better efficiency. However, it can also increase the heat generated by the ESC. What is interesting is that the ESC may increase in temperature at a higher PWM rate but the system overall will become more efficient. This is because the efficiency of the motor is increasing more than the efficiency of the ESC is decreasing. Overal there is a net increase in the amount of efficiency.

A lower PWM frequency can reduce heat generation in the ESC but may result in a less smooth motor operation and reduced system efficiency.

PWM Rates are typically held constant as the ESC changes the duty cycle within this Rate.

Explanation of how PWM works in an ESC:

The microcontroller in the ESC generates a PWM signal with a fixed frequency, typically between 6kHz and 48kHz, depending on the application. The width of each pulse in the PWM signal is varied by the microcontroller to control the average power delivered to the motor. For example, a duty cycle set to 50% will produce motor power for 50% of the period and be off for the remaining 50%. This will result in an average voltage or power delivered to the motor that is 50% of the maximum.

By varying the duty cycle of the PWM signal, the ESC can regulate the motor speed. A higher duty cycle will result in a higher average power delivered to the motor. Hence a higher motor speed. Similarly, a lower duty cycle will result in a lower average power delivered to the motor. Hence a lower motor speed.

What to Set PWM Frequency on the ESC?

Luckily for us there is a formula that makes this fairly simple. The formula is as follows:

Frequency (Hz) = Kv x Vnom x Pole Count / 20.

Round up to the next available frequency and set this in the ESC.

Try it out and see how it performs.

PWM Tips

PWM frequency cannot really be too high, it only leads to a slight increase in (switching) losses in the controller. The higher the PWM chopping frequency, the smoother the current. A smoother motor current results in lower losses, lower temperature.

Conclusion

An ESC is a fancy piece of equipment that allows us access to the performance a Brushless motor offers. PWM allows us to control speed in our RC vehicles. Now that we understand PWM further, we can use this to alter the factory set PWM rates. Doing so can increase the overall efficiency of our system at only a small fraction of cost. This cost will be additional heat in the ESC.

Does Higher Motor Kv Produce More Power?

In the world of RC, motor Kv is one of the most well known specification for those who build. Chances are, if you’re building an RC vehicle, you’re going to come across this term at some point. It is also safe to assume that most of us know that more power will equate to more speed. This is true, however does higher Kv produce more power? To better understand further about our topic today, we have to dive in to some technical details. Let’s start with a simple kv definition.

For more details or a video version on this topic, view the video below.

Understanding the Term Kv and Kt

Kv is a term that stands for the Velocity Constant of a brushless motor. As such, we can determine the amount of rotational speed that we get from our motor for each volt that we put in. If we know the voltage input we can calculate the unloaded RPM output of a brushless motor. Let’s take an example. Suppose we have a 2000Kv motor with a 11V Battery. The expected unloaded RPM output would be 2000 x 11 = 22,000RPM. Nevertheless, this does not tell us the power output. Consider the mechanical equation for power output.

For those of you familiar with horsepower and torque, the formula for HP is: HP = RPM x Torque / 5252 using imperial units. Whereas for metric units, Power in Watts is simply equal to Rotational Speed in rad/s multiplied by Torque in Nm. For instance, using our Kv specification and Voltage, we can determine RPM but we don’t know the torque value. Interestingly enough, Kv is very much related to Kt. Kt is another motor constant relating to torque. The torque constant can be determined by Kv using the equation Kt = 1/Kv. If you are going to try and use this formula, just make certain to convert RPM to rad/s. What does this now mean for us?

We can Now Get Torque Output!

We can now get the torque output of our Brushless motor. The only missing link is we need to know the amount of current that the motor will be drawing from the battery. Similar to how Kv multiplied by voltage gets us the total RPM, Kt multiplied by current provides us with the torque output.

To illustrate what we have so far covered, RPM = Kv x Voltage and Torque = Kt x Current where Kt = 1/Kv.

Substituting Kv Back in to Mechanical Power Equation

To determine if Kv is going to tell us how much power we get out of our motor, let’s substitute the value in our power equation. We will run through the equation below:

Power (Watts) = Rotational Speed x Torque
-Substitute for Kv and Kt
Power (Watts) = Kv x Voltage x Kt * Current
-Here we know Kt is equal to 1/Kv
Power (Watts) = Kv x Voltage x 1/Kv * Current
-Kv * 1/ Kv is equal to Kv/Kv = 1, therefore we can eliminate Kv from the above equation and rewrite below as
Power (Watts) = Voltage * Current

We just derived a different formula from our original mechanical formula.

Higher Kv equates to more power conclusion

As a result of the the substitution that we have done, there are two takeaways. The first takeaway is that we have been able to eliminate Kv from the equation. Secondly, we have a new power equation. The new equation is the electrical formula for power measured in watts, Power = Voltage x Current. We have been able to show that Kv can be eliminated from the formula quite easily. The truth is, Kv alone does not tell us much about the motors true power output. To really understand power output, we need to know Voltage and Current. Or we can use mechanical characteristics such as RPM and output torque. Even after this determination, let’s not stop here and check in with a typical Motor Manufactures Specification sheet.

Comparing Motor Manufactures Specifications Power vs Kv

Motor Manufactures Specifications for 1700-3270Kv

Firstly, when two brushless motors are compared, one item to keep constant is the size of the motor. To the left is a chart from a manufacture that displays five different Kv values for one specific motor model/size.

Kv vs Power – From the Specs Point of View

The specification in the chart that stays constant is the max wattage for each Kv option. Each motor of a different wind, has a maximum power output of 2400W. One thing to note is that as the maximum current increases, the maximum voltage decreases. It is this relationship that demonstrates to us that a motors Kv value really does not tell us much about the power potential of the motor.