The FPV drone landscape is often dominated by the venerable quadcopter, a design so prevalent it has become synonymous with the hobby. However, this established paradigm often limits innovation and overlooks the unique flight characteristics offered by alternative configurations. In the video above, Drew from Rotor Riot explores these fascinating alternatives with none other than David Windestål, the legendary RC Explorer, diving into the historical significance and modern resurgence of the **tricopter** and even the enigmatic **bicopter**. This exploration isn’t merely a nostalgic trip; it’s a call to action for the FPV community to embrace variety, challenge design norms, and rediscover the sheer joy of flying something truly different.
David Windestål, a pioneer in the multirotor world, challenges the notion that the quadcopter is the ultimate form factor. He reminds us that early in the hobby’s evolution, the **tricopter** was, in many ways, superior due to critical hardware and software limitations of the era. Understanding these historical nuances and appreciating the technical hurdles overcome can provide valuable insights for future drone development, pushing pilots and builders alike to rethink what’s possible in drone flight dynamics and control. The journey from rudimentary flight controllers to the sophisticated systems we have today offers a profound lesson in iterative design and the power of community-driven innovation.
The Tricopter Resurgence: A Blend of Nostalgia and Modern Tech
For those unfamiliar, a **tricopter** achieves yaw control not by differential motor speed alone, as a quadcopter does, but by tilting its rear motor. This elegant solution provided a crucial advantage in the early days of multirotors. Back then, ESCs (Electronic Speed Controllers) were sluggish, typically updating at a mere 50 Hz, and flight controller software lacked the sophisticated algorithms to rapidly manipulate four motors for agile yaw. Consequently, early quadcopters with their large 10-inch or even 14-inch props struggled with slow, unauthoritative yaw, often leading to undesirable “jello” effects in footage due to vibrations and erratic movements.
1. **Addressing Early Quadcopter Limitations:** David explains that the inherent challenge with early quadcopters was their reliance on spinning up two motors faster and slowing two others down to achieve yaw. This method compromised overall thrust and stability during yaw maneuvers, making them less controllable and less efficient. The tricopter, with its 45-degree tilting servo, offered a more direct and powerful yaw authority, maintaining constant prop speed across all motors while achieving precise rotational control. This made them considerably more stable and efficient for the flight profiles of the time, often used for carrying gimbals and capturing smoother aerial footage.
2. **Modern Tricopter Mechanics:** Today, with advancements like 32-bit BLHeli ESCs and gyros updating at blazing speeds up to 8 kHz, the landscape has changed dramatically. The primary challenge for a modern tricopter of this size is the servo’s speed. While modern gyros process data at incredibly high frequencies, a standard servo might only update at 250 Hz, creating a bottleneck. David’s solution incorporates a fourth servo lead, providing crucial feedback to the flight controller. This allows the flight controller to know the servo’s exact position at all times, enabling more efficient and precise corrections without overshooting or unnecessary movements, thus significantly improving responsiveness and overall flight performance.
3. **Unique Flight Characteristics:** Flying a **tricopter** with modern mini quad gear presents a unique set of challenges and rewards. As Drew discovers during his flight, the yaw authority is indeed impressive, but the craft behaves differently, especially at low throttle. Unlike quadcopters that use “air mode” to maintain control even with props barely spinning, a tricopter requires constant thrust to generate the necessary P-force for yaw control. This means pilots must be smoother on the throttle, avoiding sudden cuts that can lead to uncontrolled spinning. Mastering this different control scheme offers an engaging and deeply satisfying experience, highlighting the distinct personalities of various drone configurations.
Deconstructing the Bicopter: The Ultimate Challenge
If the **tricopter** reintroduces a classic challenge, the **bicopter** takes it to an entirely new level. Featuring just two motors, each mounted on a tilting servo, the bicopter presents a minimalist yet incredibly complex flight control problem. As Drew aptly puts it, it’s about controlling all degrees of freedom with fewer rotational points, relying heavily on the synchronized tilt of the motors for both pitch and roll, while yaw is achieved through differential thrust and tilt. This configuration pushes the boundaries of drone design and flight controller programming.
1. **A Unique Control Philosophy:** The bicopter’s control scheme is fundamentally different from a quadcopter or even a tricopter. Pitch and roll are primarily managed by tilting both motors forward/backward or left/right simultaneously, while yaw requires a sophisticated interplay of differential motor speed and tilt. This demanding setup makes it notoriously difficult to fly, especially in rate (acro) mode. David reveals that his prototype, literally cut just before the show, is still in its early tuning stages, emphasizing the experimental nature of the project. It flies more like an airplane, requiring constant forward motion for stability and exhibiting unpredictable behavior when attempting to fly backward.
2. **The Allure of the Challenge:** Despite its quirks and the steep learning curve, the **bicopter** holds a distinct appeal. Its sleek, minimalist design is undeniably cool, a major design goal for David. More importantly, it embodies the spirit of challenging the status quo in the FPV hobby. For seasoned pilots seeking a fresh, demanding experience, the bicopter offers a unique opportunity to test their skills and adaptability. It forces pilots to relearn ingrained muscle memory and develop a deeper understanding of flight dynamics, making every successful maneuver incredibly rewarding. The fact that it can perform rolls and loops, even in its prototype state, is a testament to its potential and the ingenuity behind its design.
Beyond the Quad: Why Innovation Matters in FPV
The conversation shifts to a deeper philosophical point: the importance of continuous innovation and avoiding complacency in the FPV hobby. As another speaker in the video eloquently states, many people stop innovating once a “better” solution (like the quadcopter) becomes dominant. This stagnation can stifle creativity and prevent the discovery of new possibilities. The mini quad, for example, wasn’t initially designed to carry heavy DSLR cameras, yet it spawned an entire industry because enthusiasts were simply having fun and pushing its limits.
1. **The Spirit of Experimentation:** David Windestål’s work on the **tricopter** and **bicopter** is a powerful reminder that the journey of exploration often yields unexpected results. By revisiting older concepts with modern technology, or by daring to strip down configurations to their bare essentials, designers can uncover new efficiencies, flight styles, and problem-solving techniques. This experimental mindset is crucial for the hobby’s evolution, preventing it from becoming overly serious and ensuring that the joy of discovery remains at its core.
2. **Community-Driven Development:** David’s plan to offer the **tricopter** as a kit, running on stock Betaflight but with potential for custom “Triflight” code integration, fosters community collaboration. By making these unique platforms accessible, he invites pilots and developers to contribute to their refinement, sharing insights and tuning strategies. This collaborative spirit, where individuals experiment and share their findings, is how many of the most significant advancements in FPV have come about, including the rise of mini quads themselves. The opportunity to fly a unique **tricopter** and contribute to its development allows enthusiasts to actively shape the future of drone flight.
Unspinning the Rotors: Your Q&A with David Windestål
What kind of FPV drones are usually seen, and what are tricopters and bicopters?
FPV drones are most commonly quadcopters, which have four motors. Tricopters have three motors, and bicopters have only two motors, offering unique alternative designs.
How does a tricopter fly differently compared to a standard quadcopter?
A tricopter achieves turns (yaw control) by tilting its rear motor, whereas a quadcopter changes the speed of its motors. This tilting mechanism provided a crucial advantage for control in earlier drone technology.
What is a bicopter, and why is it considered challenging to fly?
A bicopter is a drone with just two motors, each on a tilting servo. It’s very challenging to fly because it relies on complex, synchronized tilting and speed changes of these two motors to manage all movements.
Why are people exploring these different drone designs like tricopters and bicopters?
Enthusiasts explore these designs to encourage innovation, challenge the standard quadcopter design, and find new and exciting ways to fly. It’s about rediscovering the joy of different flight experiences and pushing boundaries.
