Specifications
When the tail moves right, the gyro will push it right until the turn is reversed. Since the gyro
can't reverse a right turn by pushing the tail right, the tail will keep spinning right forever.
26.2.2. Tail jerks around when spooling up with HH gyro
• The gyro may be too close to the ESC. On a non-micro heli, the gyro should be at least four
inches away from the ESC.
• Tail belt may be twisted around. Removing the tail rotor assembly from the tail boom and
make sure the tail drive belt isn't twisted.
26.2.3. Tail wags (hunts) constantly with HH gyro
Tail wag occurs because the heading hold gyro cannot precisely control the thrust of the tail ro-
tor. This can be caused by several problems:
1. Inconsistent tail rotor speed
If the tail rotor speed is not consistent, then the gyro will have difficulty controlling the tail
rotor thrust. This is unavoidable on fixed pitch helicopters to some extent. This may be
caused by:
• Tail belt may be loose
• Main gear or other gear may be missing a tooth
Visually inspect the teeth of all gears and ensure no teeth are missing.
2. Tail rotor blade pitch resolution problem
For example, the heading hold gyro may want the tail blade pitch at 10.4 degrees. If there
is a problem, and the tail blade pitch can only be at 10.2 and 10.6 degrees, then the head-
ing hold gyro will alternate the blade pitch between 10.2 and 10.6 degrees. This will cause
the tail to wag back and forth.
This tail rotor pitch problem may be caused by:
• Excessive play in the tail rotor blade pitch control system.
A little play is acceptable in the control system, but you should strive to minimize the
play.
• Tail rotor pitch slider may be sticking to the tail shaft
This is usually caused by a dirty tail rotor shaft and/or dirty pitch slider. The tail rotor
shaft can be wiped with a tissue, and the inside of the tail pitch slider can be cleaned
by using a cotton swab.
Do NOT use oil to lubricate the tail rotor shaft because it will attract dirt and become
sticky. Use powdered graphite instead.
• Tail blade grip bearings may be dirty, damaged, or loctited to the screw.
• Tail blade grip screw may be bent.
• Tail servo has too much leverage on the tail pitch control lever.
Troubleshooting Common Problems
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