Airplane Flying Handbook
Preface
Table of Contents
Chapter 1,Introduction to Flight Training
Chapter 2,Ground Operations
Chapter 3,Basic Flight Maneuvers
Chapter 4, Slow Flight, Stalls, and Spins
Chapter 5, Takeoff and Departure Climbs
Chapter 6,
Ground Reference Maneuvers
Chapter 7, Airport Traffic Patterns
Chapter 8, Approaches and Landings
Chapter 9,
Performance Maneuvers
Chapter 10, Night Operations
Chapter 11,Transition to Complex Airplanes
Chapter 12,
Transition to Multiengine Airplanes
Chapter 13,Transition to Tailwheel Airplanes
Chapter 14,
Transition to Turbo-propeller Powered Airplanes
Chapter 15,Transition to Jet Powered Airplanes
Chapter 16,Emergency Procedures
Glossary
Index |
Deploying spoilers results in a substantial sink rate
with little decay in airspeed. Some airplanes will
exhibit a nose up pitch tendency when the spoilers are
deployed, which the pilot must anticipate.
When spoilers are deployed on landing, most of the
wing's lift is destroyed. This action transfers the
airplane's weight to the landing gear so that the wheel
brakes are more effective. Another beneficial effect of
deploying spoilers on landing is that they create
considerable drag, adding to the overall aerodynamic
braking. The real value of spoilers on landing, however,
is creating the best circumstances for using
wheel brakes.
The primary purpose of speed brakes is to produce
drag. Speed brakes are found in many sizes, shapes,
and locations on different airplanes, but they all have
the same purpose—to assist in rapid deceleration. The
speed brake consists of a hydraulically operated board
that when deployed extends into the airstream.
Deploying speed brakes results in a rapid decrease in
airspeed. Typically, speed brakes can be deployed at
any time during flight in order to help control airspeed,
but they are most often used only when a rapid deceleration
must be accomplished to slow down to landing
gear and flap speeds. There is usually a certain amount
of noise and buffeting associated with the use of speed
brakes, along with an obvious penalty in fuel consumption.
Procedures for the use of spoilers and/or
speed brakes in various situations are contained in the
FAA-approved Airplane Flight Manual for the particular
airplane.
THRUST REVERSERS
Jet airplanes have high kinetic energy during the
landing roll because of weight and speed. This energy
is difficult to dissipate because a jet airplane has low
drag with the nosewheel on the ground and the engines
continue to produce forward thrust with the power
levers at idle. While wheel brakes normally can cope,
there is an obvious need for another speed retarding
method. This need is satisfied by the drag provided by
reverse thrust.
A thrust reverser is a device fitted in the engine
exhaust system which effectively reverses the flow of
the exhaust gases. The flow does not reverse through
180°; however, the final path of the exhaust gases is
about 45° from straight ahead. This, together with the
losses in the reverse flow paths, results in a net efficiency
of about 50 percent. It will produce even less if
the engine r.p.m. is less than maximum in reverse.
Normally, a jet engine will have one of two types of
thrust reversers, either a target reverser or a cascade
reverser. [Figure 15-19] Target reversers are simple
clamshell doors that swivel from the stowed position at
the engine tailpipe to block all of the outflow and
redirect some component of the thrust forward.
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Figure 15-19. Thrust reversers.
Cascade reversers are more complex. They are
normally found on turbofan engines and are often
designed to reverse only the fan air portion. Blocking
doors in the shroud obstructs forward fan thrust and
redirects it through cascade vanes for some reverse
component. Cascades are generally less effective than
target reversers, particularly those that reverse only
fan air, because they do not affect the engine core,
which will continue to produce forward thrust.
On most installations, reverse thrust is obtained with
the thrust lever at idle, by pulling up the reverse lever
to a detent. Doing so positions the reversing
mechanisms for operation but leaves the engine at idle
r.p.m. Further upward and backward movement of the
reverse lever increases engine power. Reverse is
cancelled by closing the reverse lever to the idle
reverse position, then dropping it fully back to the
forward idle position. This last movement operates the
reverser back to the forward thrust position.
Reverse thrust is much more effective at high airplane
speed than at low airplane speeds, for two reasons:
first, the net amount of reverse thrust increases with
speed; second, the power produced is higher at higher
speeds because of the increased rate of doing work. In
other words, the kinetic energy of the airplane is being
destroyed at a higher rate at the higher speeds. To get
maximum efficiency from reverse thrust, therefore, it
should be used as soon as is prudent after touchdown. |
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