Ever found yourself scrolling through various FPV drone designs, perhaps looking for something a little out of the ordinary? Maybe a unique build caught your eye, one with three arms instead of four, and you thought, “Aha! A tricopter!” It’s a common moment of curiosity for many aspiring drone builders. However, as the video above emphatically illustrates, delving into the world of tricopters in today’s FPV landscape often leads to more headaches than high-flying fun.
The speaker’s directness might be jarring, but it stems from years of experience and observing common pitfalls in the hobby. For anyone considering a tricopter build, understanding why tricopters are generally not recommended is crucial. It’s not just a matter of preference; it’s about a significant shift in drone technology that rendered the tricopter design largely obsolete for performance-oriented FPV flight.
The Rise and Fall of Tricopters: A Historical Perspective
To truly grasp why the FPV community has moved past tricopters, it’s essential to look back in time. Roughly six or seven years ago, the drone technology landscape was quite different. One of the biggest challenges multi-rotors faced was achieving precise yaw control.
Early Yaw Performance Challenges
In the early days, Electronic Speed Controllers (ESCs) lacked advanced features. When a motor needed to slow down to facilitate a yaw maneuver, it relied primarily on prop drag. This passive deceleration was slow and imprecise, making aggressive or rapid yaw movements difficult to control. A quadcopter trying to yaw too quickly could easily become destabilized, leading to erratic flight characteristics.
This limitation was precisely where the tricopter found its niche. Pioneers like David Windestål, often credited as the leading proponent of tricopters, saw the potential. By placing one of the rear motors on a servo and allowing it to tilt, tricopters could actively vector thrust for yaw control. This “swooshiness,” as Windestål affectionately called it, offered a significant advantage in yaw performance over the early, less sophisticated quadcopters.
The Era of Innovation: Triflight and Custom Hardware
David Windestål was so committed to the tricopter concept that he developed Triflight, a specialized fork of flight controller firmware (initially Cleanflight, later adapted). He even designed his own flight controller tailored for tricopters. His efforts highlight the genuine innovation and problem-solving that went into making tricopters viable at the time. Yet, even Windestål, the foremost champion of the design, eventually shifted his focus away, acknowledging that modern advancements had surpassed the tricopter’s utility.
Why Modern Tricopters Fall Short: Inherent Design Flaws
Despite their historical significance, today’s tricopters simply don’t measure up to quadcopters, and the reasons are fundamentally rooted in their design, especially concerning the servo-based yaw mechanism.
The Servo’s Sisyphean Task: Battling Gyroscopic Forces
The core issue with tricopter yaw lies with the servo. To change yaw, the servo must physically tilt a propeller-equipped motor. However, a spinning propeller, much like a bicycle wheel spun up to speed, exhibits a powerful gyroscopic effect. Trying to quickly change the orientation of this rapidly spinning mass generates significant resistance.
The servo is constantly fighting this inherent gyroscopic stability. This struggle translates to:
- Imprecision: Servos, by their nature, are not as precise or as fast-acting as electronic motor control. The slight lag and mechanical slop in a servo system introduce a level of imprecision that is unacceptable for high-performance FPV flying.
- Lagged Response: There’s an inevitable delay as the servo physically moves the motor against the gyroscopic resistance, hindering immediate yaw adjustments.
- Vulnerability: Servos are mechanical components with moving parts, making them susceptible to damage in crashes. A broken servo means your tricopter won’t fly correctly, if at all.
- Throttle Dependency: At very low throttle or idle, the gyroscopic effect of the prop lessens, reducing the servo’s authority over yaw. This can lead to unpredictable handling during critical maneuvers.
The Mechanical Weakness
Beyond precision, the mechanical complexity of a tricopter introduces points of failure. The servo, its linkage, and the pivot mechanism are all additional parts that can wear out, break, or malfunction. A quadcopter, with its fixed motor mounts, eliminates these vulnerabilities, resulting in a more robust and reliable platform.
The Quadcopter Revolution: The Power of ESC Braking
The main reason tricopters became obsolete is the dramatic advancements in ESC technology, specifically the widespread adoption of “damped light” or ESC braking. This feature fundamentally changed how quadcopters achieve yaw and overall flight stability.
How ESC Braking Works
Traditionally, when an ESC needed to slow a motor, it simply cut power, relying on aerodynamic drag to decelerate the propeller. ESCs with braking, however, actively slow the motor down. They achieve this by utilizing the FETs (Field-Effect Transistors) in the ESC to effectively short-circuit the motor windings. This generates a back-EMF (electromotive force) that acts as an electromagnetic brake, rapidly decelerating the motor.
This active braking allows for much faster deceleration of the motor, which is crucial for agile flight. For yaw control on a quadcopter, the flight controller can now rapidly increase the speed of motors on one side while simultaneously *braking* motors on the opposite side. This creates a much stronger, faster, and more precise torque differential for yaw compared to relying on slow, passive drag. The result is superior yaw performance without any mechanical moving parts for thrust vectoring.
Impact on Flight Dynamics
The advent of ESC braking transformed quadcopter flight, offering:
- Enhanced Yaw Authority: Instantaneous and precise yaw control, allowing for quick direction changes and tight turns without destabilization.
- Improved Stability: The ability to quickly adjust motor speeds in both directions (acceleration and deceleration) significantly enhances the flight controller’s ability to maintain stability and recover from disturbances.
- Increased Efficiency: While braking consumes some energy, the overall control efficiency and responsiveness gained often outweigh the minor power loss, leading to more precise and predictable flight.
- Simplicity and Durability: Removing the need for mechanical yaw components makes quadcopters simpler to build, lighter, and more resilient to crashes.
Building Your FPV Drone: Beyond the Tricopter
For someone venturing into FPV drone building today, the choice is clear for most performance-oriented applications. Modern quadcopters offer an unparalleled balance of performance, durability, and ease of building thanks to advanced ESCs, powerful flight controllers running software like Betaflight, and readily available components.
While the speaker in the video humorously suggests that building a tricopter today is akin to being a “glutton for punishment” or a “historical recreationist,” there’s a kernel of truth there. If your goal is to push the boundaries of flight, perform acrobatic maneuvers, or race, a tricopter will undoubtedly hold you back. The performance ceiling for a tricopter is simply too low compared to a quadcopter. Even the “best tricopters,” as the video’s speaker points out, are often “shitty multi-rotors” when judged against modern standards.
So, if you’re asking about a UART config for a tricopter, it’s worth pausing to consider the fundamental limitations. While it might seem like a unique project, you’re investing time and effort into a design that is fundamentally outmatched by its quadcopter counterparts. The FPV world has moved on, propelled by continuous innovation, and for good reason.
Your FPV Questions: What Bardwell Didn’t Want You To Ask
What is a tricopter?
A tricopter is a type of drone design that uses three motors, often with one rear motor mounted on a servo to help with steering (yaw control).
Why are tricopters generally not recommended for FPV flying today?
Tricopters are largely obsolete for modern FPV flying because they have inherent technical flaws, like less precise servo-based yaw control, and are easily surpassed by modern quadcopters.
What is the main problem with a tricopter’s design for steering (yaw)?
The main problem is that tricopters rely on a servo to physically tilt one of the motors for yaw control. This mechanical movement is less precise, slower, and more prone to damage than electronic motor control.
How do modern quadcopters achieve better steering (yaw) control?
Modern quadcopters use advanced Electronic Speed Controllers (ESCs) with ‘damped light’ or ESC braking. This technology allows them to rapidly accelerate and decelerate motors electronically for much faster and more precise yaw control.
