Stabilizer fin

From RC Helicopter Wiki

A helicopter typically has two so-called stabilizer fins mounted on the tail boom.

• Vertical stabilizer

The vertical stabilizer prevents the tail rotor from touching the ground during landing or ground operation. Particularly on small electric helicopters, it is easy for the tail rotor to end up 'in the dirt' if the ground is even slightly uneven. Before heading hold gyros they would also help the helicopter weathervane into the direction of motion.

• Horizontal stabilizer

The horizontal stabilizer may help dampen rolling and pitching movements slightly, and may help improve forward flight characteristics.

Perhaps the biggest use of both stabilizers is to help recognize the orientation of the helicopter.