Flybarless

Multiplex Funcopter main rotor head modified into a flybarless version

Close-up of an aftermarket main rotor head of a Blade mCP X helicopter

Skyartec Wasp X3V micro-helicopter factory fitted with an flybarless system

Flybarless (or FBL) helicopters have a direct connection between the swashplate and the rotor blade pitch. This is in contrast to traditional model helicopters which use a flybar to provide stabilisation and force multiplication.

Full-size helicopters do not need flybars because the inertia of the larger aircraft provides sufficient stabilisation. Model flybarless helicopters generally require electronic gyroscopic stabilisation, although other methods such as heavy, flexible blades have been used on some scale models.

Advantages

• Simpler head mechanics
• Higher aerodynamic efficiency
• Quicker response to control inputs
• More accurate scale appearance for scale models
• Multi-blade heads are possible

Disadvantages

• Higher loads are placed on servos
• The gyrocopic stabilisation units are comparatively expensive compared to tail gyros, but prices are continuing to drop.

Flybarless units

Flybarless units integrate several functions:

• Yaw/rudder gyro
• Elevator control stabilisation
• Aileron control stabilisation
• CCPM mixing (for CCPM helicopters)

Cheaper alternatives

For a fixed pitch helicopters and non-CCPM CP helicopters, it should be possible to create a cheaper flybarless system using extra tail gyro units oriented in the other two axis.