The procedure requires performance that results in the shortest
ground roll and the steepest angle of climb. Two beginning options
are available with little advantage going to either. Takeoff #1
is the rolling-running start where the aircraft tries to gain
speed while entering the runway. Full power is applied in anticipation
with runway alignment. Takeoff #2 places the aircraft so as to
be aligned at the very end of the runway. Power is applied with
the brakes applied until maximum rpm is attained. During the ground
roll the aircraft is held for minimum air resistance and best
acceleration. Figure a 1% decrease in book takeoff distance for
each knot of headwind. Any part of the runway distance not used
for initial acceleration is never to be recovered. Extending partial
flaps at moment of liftoff has not been shown to be an advantage.
Shortly before the best angle of climb speed is attained the aircraft
is rotated to that angle of attack what the pilot believes will
give the best angle of climb airspeed. The aircraft will accelerate
quickly after lift off so this change must be anticipated with
additional back pressure. Failure to hold a constant best angle
airspeed makes a significant difference in the flight angle of
the aircraft.
Pilot techniques will determine how well the takeoff occurs.
Half the aircraft should project off the runway for maximum distance.
Application of power should be such as to avoid 'loading-up' the
carburetor. At full power the aircraft is allowed to accelerate
to rotation speed. Pre-mature rotation is a major mistake and
more common than delaying rotation. The technique for rotating,
obtaining, and holding that attitude which will give the best
angle of climb takes practice. There is a lag in airspeed indications
and aircraft performance which makes much practice necessary.
Using the airspeed indicator usually results in a lower pitch
attitude than required.
Departure on an apparently short runway can contribute to a
series of piloting mistakes which compound the problem. The pilot
may mistakenly attempt to get into the air too soon, before the
airplane is ready to fly, by over rotation. Sure, the nose will
go up. Over rotation will require the nose to be lowered to obtain
climb speeds and result in decreased climb performance both over
time and distance. Aircraft speed is one way to get the lift performance
to overcome an obstruction. At lighter than book speeds the speeds
of performance change at a rate of 1/2 the percentage of weight
change. A 20% reduction in gross weight will allow a 10% reduction
of book speed for maximum performance.
The success of a maximum performance short field takeoff requires
precise control of airspeed and aircraft attitude. Even a slight
deviation of either initially or later will result in a significant
reduction of performance.
What to avoid:
1. Not using all available runway
2. Getting to full power quickly
3. Lifting off too soon
4. Letting airspeed exceed Vx
Last Modified September 24, ©2023 TAGE.COM
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