Private Pilot Flight Training and Instruction
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Why Takeoff Pitch Changes
The initial lift off attitude at Vso is slightly higher than
that required for Vy (best rate of climb) but is about right for
Vx (Best angle of climb) so for a best rate climb after takeoff
the nose needs to be lowered slightly to allow acceleration to
65 kts. The reasons behind this procedure are because the rotation
of an aircraft while on the ground is about the axels of the main
landing gear. Once airborne the rotation of an aircraft occurs
about the centers of lift and balance..
On the ground an aircraft rotates in pitch about the wheels,
in the air the same aircraft rotates about the center of gravity.
This difference is the reason that on takeoff once an airplane
leaves the ground there will be a perceptible difference in yoke
feel and authority. The pitching moment in flight is usually much
greater than when on the ground. For this reason a pilot should
be prepared to counter this momentary change by immediately allowing
the nose to lower after liftoff. For the same reason you should
apply additional back pressure on the yoke on landing. This is
needed at touchdown to hold the nose wheel clear of the runway.
Additionally you should not set your trim for a liftoff but
rather for climb. This means that you will apply back pressure
to the yoke for liftoff and relax this pressure to meet the 'takeoff'
setting used for climb. I have noticed that this effect is most
apparent with Piper aircraft in certain loading conditions.
The art of the smooth takeoff begins before lining up with
the runway. The yoke should be held back so that the application
of takeoff power will raise the nosewheel clear of the runway.
Hold the nose so that it just touches the far end of the runway
and the airplane will lift off the ground so gently and smoothly
that you may not even notice breaking ground. Once off lower the
nose to attain Vy since the difference in rotational forces from
being on the ground and in the air makes it necessary. Knowing
that this change is required is part of the art of anticipation
that will make you a better pilot.
Written by Gene Whitt
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