Ground
Clearance
Airflow
Rotor
Ground
Clearance
Airflow
Figure 20-3. Decreasing the rotor disc angle of attack with forward cyclic can reduce the excessive amount of airflow causing
the blade flap. This also allows greater clearance between the rotor blades and the surface behind the gyroplane, minimizing
the chances of a blade striking the ground.
20-3
minimize the length of the ground roll that is required
to get the gyroplane airborne.
The prerotators on certificated gyroplanes remove the
possibility of blade flap during prerotation. Before the
clutch can be engaged, the pitch must be removed from
the blades. The rotor is then prerotated with a 0° angle
of attack on the blades, which prevents lift from being
produced and precludes the possibility of flapping.
When the desired rotor speed is achieved, blade pitch is
increased for takeoff.
TAKEOFF
Takeoffs are classified according to the takeoff surface,
obstructions, and atmospheric conditions. Each type of
takeoff assumes that certain conditions exist. When
conditions dictate, a combination of takeoff techniques
can be used. Two important speeds used for takeoff and
initial climbout are VX and VY. VX is defined as the
speed that provides the best angle of climb, and will
yield the maximum altitude gain over a given distance.
This speed is normally used when obstacles on the
ground are a factor. Maintaining VY speed ensures the
aircraft will climb at its maximum rate, providing the
most altitude gain for a given period of time.
[Figure 20-4] Prior to any takeoff or maneuver, you
should ensure that the area is clear of other traffic.
NORMAL TAKEOFF
The normal takeoff assumes that a prepared surface of
adequate length is available and that there are no high
obstructions to be cleared within the takeoff path. The
normal takeoff for most amateur-built gyroplanes is
accomplished by prerotating to sufficient rotor r.p.m. to
prevent blade flapping and tilting the rotor back with
cyclic control. Using a speed of 20 to 30 m.p.h., allow
the rotor to accelerate and begin producing lift. As lift
increases, move the cyclic forward to decrease the pitch
angle on the rotor disc. When appreciable lift is being
produced, the nose of the aircraft rises, and you can feel
an increase in drag. Using coordinated throttle and
flight control inputs, balance the gyroplane on the main
gear without the nose wheel or tail wheel in contact
with the surface. At this point, smoothly increase power
to full thrust and hold the nose at takeoff attitude with
cyclic pressure. The gyroplane will lift off at or near
the minimum power required speed for the aircraft. VX
should be used for the initial climb, then VY for the
remainder of the climb phase.
A normal takeoff for certificated gyroplanes is accomplished
by prerotating to a rotor r.p.m. slightly above
that required for flight and disengaging the rotor drive.
The brakes are then released and full power is applied.
Lift off will not occur until the blade pitch is increased
to the normal in-flight setting and the rotor disk tilted
Best Rate of Climb (VY)
Best Angle of Climb (VX)
30
Figure 20-4. Best angle-of-climb (VX) speed is used when obstacles are a factor. VY provides the most altitude gain for a given
amount of time.
20-4
power applied as soon as appreciable lift is felt. VX
climb speed should be maintained until the obstruction
is cleared. Familiarity with the rotor acceleration
characteristics and proper technique are essential for
optimum short-field performance.
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