Avoiding Rotor Flap (continued)
If a flap occurs that is anything but a minor bump in
the cyclic, stop and inspect the rotor system and any
other related components for damage.
Most normal takeoff rolls include a pre-rotation above
100 rotor rpm (“RRPM”) to as much as 200 RRPM. In
general, once the rotor exceeds 160 RRPM it is
appropriate to be slightly more aggressive adding
throttle. Above, 200 RRPM, it is generally save to
add full throttle and the possibility of a flap is very
unlikely.
Note that strong winds require additional care in
adding throttle as excessive wind through the rotor
system is the cause a flap. Note too, that even if you
pre-rotate to 200 RRPM or greater, it may take
several moments to begin moving at a speed that
will support that RRPM. You may lose RRPM during
your initial roll and end up with too much throttle and
a flap if you hurry things. Instruction in short roll
takeoffs is recommended.
It is a reasonable practice to taxi with the rotors
spinning in certain situations, such as exiting a
runway or taxiing on a taxiway for a pending
departure. NEVER taxi with the rotors below 80
RRPM. If the rotors decay to a speed below 80 RRPM,
you must stop and engage the rotor brake or
immediately pre-rotate to a more stable RRPM to
avoid a flap.
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Takeoff Procedure
1. Pre-rotate to desired RRPM and set the pre-rotator
OFF (green indicator light).
2. Move the cyclic full aft at a moderate pace, but
with deliberation. Do not jerk the cyclic back. The
cyclic should remain centered left to right)
throughout the takeoff roll. If there is a crosswind,
the cyclic may be held very slightly left or right into
the crosswind to compensate.
3. Place feet on rudder pedals for steering and
release the wheel brakes.
3. Gradually increase the throttle. Ensure the RRPM
is increasing.
Steer with the RUDDER PEDALS
ONLY. NEVER try to steer left or right with the
cyclic while the main wheels are on the runway
on takeoff or landing.
4. Continue gradual throttle increase through 160
RRPM. After 160 RRPM, throttle increase may be
slightly more aggressive.
5. The nose will rise somewhere between 240 and
300 RRPM, depending primarily on the weight of the
front seat pilot and density altitude. Immediately
move the cyclic forward and do not allow it to
continue moving up. This is especially important in
gusty wind, when the nose may try to point straight
up if the cyclic remains full aft. The ideal angle for
takeoff is nose wheel 4” above the ground.
6. Holding the takeoff angle will require increasing
the cyclic forward pressure as speed increases.
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