What Is a Flybar on an RC Helicopter? Flybar vs Flybarless Explained
A flybar is the short, weighted bar (often with paddles) mounted across the rotor head at 90° to the main blades. Spinning with the rotor, it acts like a gyroscope: it resists sudden changes, damps the rotor’s response to gusts and the pilot’s inputs, and feeds a smoothed control signal to the blades through the mixing levers. That made early helicopters flyable. Today most hobby helicopters are flybarless: an electronic gyro unit (FBL controller) does the stabilising, giving a simpler head, less drag and more precise control.
By Kyle HilsonUpdated: October 20264 min read
How a flybar works
A spinning flybar behaves like a gyroscope: it wants to stay in the plane it’s spinning in. When a gust tilts the helicopter, the flybar briefly keeps its own plane, and the linkages between flybar and blades change the blade pitch to counter the disturbance. When the pilot moves the cyclic stick, the swashplate tilts the flybar first (in the Bell system) and the flybar then pitches the blades, so the response is softened. The common Bell-Hiller system combines direct swashplate input (Hiller part) and flybar input (Bell part) through mixing levers to give both stability and responsiveness.
Flybar vs flybarless
| Flybar | Flybarless (FBL) | |
|---|---|---|
| Stabilisation | Mechanical (gyroscopic bar) | Electronic 3-axis gyro |
| Head complexity | Many links and levers | Simple, fewer parts |
| Drag and efficiency | More drag | Less drag, longer flights |
| Setup | Mechanical tuning, paddle weights | Software setup of the FBL unit |
| Feel | Soft, smooth | Crisp, adjustable |
| Today | Toys, coaxials, vintage | Nearly all hobby helicopters |
Flybars on toy helicopters
Many coaxial toy helicopters still have a simple flybar on the top rotor, a weighted bar on a pivot. It makes the helicopter self-levelling and slow to react, which is ideal for beginners and children. If a coaxial toy suddenly becomes unstable after a crash, check that this bar is intact and moves freely.
How flybarless systems replaced it
A flybarless controller measures rotation on three axes and corrects the swashplate many times per second. That removes the need for the mechanical bar, simplifies the head and lets pilots tune response in software: agility, stability, and how the helicopter holds its attitude. Rescue modes that level the helicopter at the flick of a switch are a further benefit. Gyro technology is explained in helicopter gyros.
Which should you choose?
- Learning or 3D flying: flybarless with a stabilised/rescue mode.
- Scale models: flybarless, often with multi-blade heads.
- Vintage restoration: keep the flybar for originality, or convert with an FBL head kit if available.
- Children’s toys: coaxial with flybar is fine.
Maintaining a flybar head
- Check that the flybar is straight: roll it on a flat surface.
- Paddles should be parallel to each other and to the swashplate at neutral.
- Remove play from the mixing levers and ball links.
- Balance the paddles and keep them equal distance from the centre.
- Replace a bent flybar rather than straightening it.
More repair steps are in how to fix an RC helicopter.
Tuning a flybar
Paddle weight and position change the helicopter’s feel. Heavier paddles, or paddles further out, make the helicopter more stable and slower to respond; lighter or closer paddles make it quicker. Flybar pilots tuned the head this way the way FBL pilots now adjust gains in software. If a flybar helicopter feels sluggish, check the paddle setup before blaming the servos.
FAQ
What does a flybar do?
It stabilises the rotor mechanically and smooths control inputs.
Do modern RC helicopters have flybars?
Most hobby helicopters are flybarless; many toys still use one.
Is flybarless better?
For most uses, yes: more efficient and tunable.
Can I convert a flybar heli to flybarless?
Often, with an FBL head kit and controller.
More on this topic: the complete RC Helicopters guide covers the basics behind this article.
About 20 years in RC. Mostly boats in the NAVIGA Mini Eco Expert class, with many self-made parts; also a King Motor Baja 5B, a home-built electric plane, home-built nitro planes he has flown, and an RC helicopter. More about SwellRC
