Specifications
Glass Reinforced Plastic. A type of plastic material often used in helicopter chassis.
Gyro
A device used to help stabilize the yaw of a helicopter by adjusting the tail rotor pitch.
Mechanical gyros use a real spinning disk inside a small enclosure measure the yaw due
to the torque of the main rotor blades. Solid-state gyros achieve the same measurement
without using moving parts, but can still be easily damaged by impact.
Gyroscopic Precession
A tendency of a rotating body to translate an external force into a a new force occuring 90
degrees later in its rotation.
H
Heading Hold Gyro
A gyro which attempts to "lock" the heading of the gyro and keep the helicopter pointed in
the same direction until you choose to turn it via the rudder.
See also Yaw-Rate Gyro
HH
Heading Hold (gyro)
HS Head Speed
The RPM of the main rotor. Most nonmicro helicopters need between 1200-2000 RPM of
headspeed to fly. If the headspeed is too low, then the heli will not lift off or will require ex-
tra pitch to fly, which will make the heli very unstable. For aerobatics, most people raise
their headspeed to about 1800-2000 RPM. Most helicopter rotor hubs are only rated for a
maximum of 2000 RPM. If you exceed 2000 RPM, this places excessive stress on the
main rotor hub and the heli is likely to throw a blade.
Hunting
See Wag
I
Idle-up Mode
A transmitter mode which has a different throttle and pitch curve than the regular mode.
For electric helicopters, we normally use the "normal" mode to arm the ESC and spool up
the helicopter, and use an idle-up mode with a flat throttle setting for regular flying.
Some transmitters have multiple idle-up modes. For example, the Futaba 9C has idle-up1,
idle-up2, and idle-up3 modes. The additional idle-up modes can be programmed for a low
headspeed for duration flight, high headspeed with full negative pitch range for aerobatics,
etc.
This feature can be used to lock the throttle to a specified value so the throttle stick only
controls the collective pitch, which is required for inverted flight.
Io
The no-load current rating for a motor. This is the electrical current used by the motor
when the motor is running at full speed with no mechanical load on the rotor.
J
Glossary
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