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level flight speed. In this situation, the gyroplane is flying
well behind the power curve and at such a high
angle of attack that unless a correction is made, there
will be little or no acceleration toward best climb
speed. This condition is often encountered in
gyroplanes capable of jump takeoffs. Jumping without
sufficient rotor inertia to allow enough time to accelerate
through minimum level flight speed, usually results
in your gyroplane touching down after liftoff. If you do
touch down after performing a jump takeoff, you
should abort the takeoff.
During a rolling takeoff, if the gyroplane is forced into
the air too early, you could get into the same situation.
It is important to recognize this situation and take
immediate corrective action. You can either abort the
takeoff, if enough runway exists, or lower the nose and
21-2
accelerate to the best climb speed. If you choose to continue
the takeoff, verify that full power is applied, then,
slowly lower the nose, making sure the gyroplane does
not contact the surface. While in ground effect, accelerate
to the best climb speed. Then, adjust the nose pitch
attitude to maintain that airspeed.
COMMON ERRORS
The following errors might occur when practicing a
lift-off at a low airspeed.
1. Failure to check rotor for proper operation, track,
and r.p.m. prior to initiating takeoff.
2. Use of a power setting that does not simulate a
“behind the power curve” situation.
3. Poor directional control.
4. Rotation at a speed that is inappropriate for the
maneuver.
5. Poor judgement in determining whether to abort
or continue takeoff.
6. Failure to establish and maintain proper climb
attitude and airspeed, if takeoff is continued.
7. Not maintaining the desired ground track during
the climb.
PILOT-INDUCED OSCILLATION (PIO)
Pilot-induced oscillation, sometimes referred to as porpoising,
is an unintentional up-and-down oscillation of
the gyroplane accompanied with alternating climbs and
descents of the aircraft. PIO is often the result of an
inexperienced pilot overcontrolling the gyroplane, but
this condition can also be induced by gusty wind conditions.
While this condition is usually thought of as a
longitudinal problem, it can also happen laterally.
As with most other rotor-wing aircraft, gyroplanes
experience a slight delay between control input and the
reaction of the aircraft. This delay may cause an inexperienced
pilot to apply more control input than
required, causing a greater aircraft response than was
desired. Once the error has been recognized, opposite
control input is applied to correct the flight attitude.
Because of the nature of the delay in aircraft response,
it is possible for the corrections to be out of synchronization
with the movements of the aircraft and aggravate
the undesired changes in attitude. The result is
PIO, or unintentional oscillations that can grow rapidly
in magnitude. [Figure 21-1]
In gyroplanes with an open cockpit and limited flight
instruments, it can be difficult for an inexperienced
pilot to recognize a level flight attitude due to the lack
of visual references. As a result, PIO can develop as the
pilot chases a level flight attitude and introduces climbing
and descending oscillations. PIO can also develop
if a wind gust displaces the aircraft, and the control
inputs made to correct the attitude are out of phase with
the aircraft movements. Because the rotor disc angle
decreases at higher speeds and cyclic control becomes
more sensitive, PIO is more likely to occur and can be
more pronounced at high airspeeds. To minimize the
possibility of PIO, avoid high-speed flight in gusty
conditions, and make only small control inputs. After
making a control input, wait briefly and observe the
reaction of the aircraft before making another input. If
PIO is encountered, reduce power and place the cyclic
in the position for a normal climb. Once the oscillations
have stopped, slowly return the throttle and cyclic to
their normal positions. The likelihood of encountering
PIO decreases greatly as experience is gained, and the
ability to subconsciously anticipate the reactions of the
gyroplane to control inputs is developed.
Normal
Flight
Variance from desired
flight path recognized,
control input made
to correct
Gyroplane
reacts
Gyroplane
reacts
Gyroplane
reacts
Overcorrection
recognized, larger
control input made
to correct
Overcorrection recognized,
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