A tricopter or a quadcopter? Oh woah, there are octocopters too? What in the world do you pick? What are the differences between the configurations of a tricopter vs quadcopter vs hexacopter vs octocopter?
There are a myriad of mutirotor configurations out there, namely based on tricopters, quadcopters, hexacopters and octocopters. And within those configurations, there are sub configurations. For example, within the quadcopters you can choose between the H-copter, the X-copter or even a V-tail quadcopter. How do you then know what configuration to choose from?
In this post, we’ll address the basic, general rules in picking a multirotor configuration. Primarily, we’ll focus on a general comparison of the tricopters, quadcopters, hexacopters and octocopters. We will discuss each configuration and their strengths and weaknesses first and then conclude with a comparison summary. Read on!
The main advantage of a tricopter is the build cost. Less motors and parts mean less probability of failure, making them more reliable and technically, more “resilient” in that sense, compared to the quadcopter (We’ll soon see how it doesn’t apply with the hexacopter and octocopters).
The tricopter used to be more popular when cost of individual components (i.e price of motors, ESCs etc) were much higher than that of today. Today, this argument might not make as much sense in all cases, especially with smaller crafts, since parts come much cheaper.
The placement of the YAW control at the tail of the craft makes the craft feel agile and “smooth”, especially while performing turns and bank turns. The FPV experience on a tricopter may be hence, unmatched by any other type of multirotor configuration.
Building a tricopter is also more difficult than building a quadcopter. If you are a beginner in terms of building a craft, a tricopter is probably not the way to go at this point.
The most popular multirotor configuration out there in the market today is the quadcopter. This configuration is adopted by a wide range of differently capable multirotors including FPV racing quads and quads that are capable of photography and videography (example being DJI’s phantom or Inspire series).
The quadcopter has more lifting/thrusting power than the tricopter but may feel less agile while turning. This configuration is probably the easiest to setup if you want to build one from scratch. There are plenty of guides out there for building quadcopters of a wide array of different sizes and shapes. If scaling up and carrying larger payloads is what you are looking after, start by looking at the quadcopter instead of a tricopter.
If you are a beginner with little flying experience, go for a small, ready to fly quadcopter and learn to fly a multirotor from there. They come very cheap and offer the most in terms of efficiency for their price.
The hexacopter offers everything that the quadcopter does, plus more. While scaling up to bigger multirotors, this configuration offers more power, efficiency, stability and capacity for carrying heavier payloads than a quadcopter.
They are also pricier than the quadcopter, but they come with an inherent increase in reliability. If one of the motors fail for example, these crafts would still be able to fly fine enough to make a safe landing. With quadcopters or tricopters, this is simply not the case.
If you are a semi professional photographer or a UAV pilot working for a company that does infrastructure inspection, the hexacopter is where you might want to start with.
The big daddy : The Octocopter
Ocotocopters are the most powerful, efficient, stable and capable of carrying heaviest payloads in the large multirotor arena. They are the top tier and are also the most expensive. The upside to this is that they are also the most reliable. Failure of a single motor won’t really affect its flying capabilities, except for efficiency in terms of battery life.
If you are a professional photographer or an experienced UAV pilot and you need your multirotor to be able to carry heavy payloads, (for example a heavy, capable camera equipment) the octocopter is the way to go.
Comparison Summary and general rules
Here are some of the flight characteristics compared, in a nutshell.
Flight time : The argument that tricopters have longer flight times than a quad for example, because of one less motor may not always hold true. There are many factors that have to be taken into account. The main theme revolves around the total amount of work done by the motors to get the craft up. Less amount of motors equal less power and thrust. The existing motors must hence, work harder. Generally, you want a good thrust to weight ratio for maximum flight times. For larger quads capable of carrying heavy payloads, this thrust to weight ratio is best realized with hexacopter and octocopter configurations. For smaller ones, tricopter/quadcopter is probably the way to go.
Agility: Regardless of the configuration, smaller multirotors are generally more agile and manoeuvrable. There is a reason why FPV racing drones are in the 250 size range. Other than size, tricopters can be said to be the most agile due to the way the YAW configuration is setup and not because of the fact that there are less motors. A quadcopter with a V-tail configuration can have similar YAW configuration, making it feel more agile.
Stability: Generally the larger the quad, the more stable it is. However after a certain point, there are diminishing returns with size. It is not possible to indefinitely scale a multirotor and reap the benefits of scaling. As a result, building a multicopter like a hexacopter that has additional motors improves the overall thrust, power and stability of large multirotors that are generally used to carry heavy payloads (like heavy camera equipment).
Payload capacity: Obviously, payload capacity would directly proportional to the size of the multirotor. But like we discussed for stability, size cannot be indefinitely scaled and hence, hexacopters and octocopters are used for managing large payloads.
What multirotor should I pick?
The answer depends on your needs and goals. Though we can give you a general idea, we cannot decide for you:
Intermediate multirotor enthusiasts: Tricopters and quadcopters
Semi-professional photographers and sUAS pilots: Hexacopters
Professional top tier sUAS pilots and photographers: Octocopters
Remember: first decide on what is it that you would do with your multirotor. The focus must be on maximizing flight times, agility, stability and payload capacity while building a craft. Thrust to weight ratio is the primary goal. It is important to remember that you can’t always have the best of all worlds.
For example, if you want agility and the ability to manoeuvre in tight spaces and in between obstacles, you can’t expect to get that with a large octocopter capable of carrying heavy camera equipment.
Price is also a major limiting factor while deciding. You don’t really need to invest all that money into an octocopter if you are a beginner or intermediate multirotor enthusiast just looking to have some fun. Leave that trouble for the professional photographers and sUAS pilots!
And that is all! Do let us know if you have any comments, suggestions or questions!