| Home | Privacy | Contact |

Pilot's Handbook of Aeronautical Knowledge
Flight Controls

Flight Control Systems

| First | Previous | Next | Last |

Pilot's Handbook of Aeronautical Knowledge

Preface

Acknowledgements

Table of Contents

Chapter 1, Introduction To Flying
Chapter 2, Aircraft Structure
Chapter 3, Principles of Flight
Chapter 4, Aerodynamics of Flight
Chapter 5, Flight Controls
Chapter 6, Aircraft Systems
Chapter 7, Flight Instruments
Chapter 8, Flight Manuals and Other Documents
Chapter 9, Weight and Balance
Chapter 10, Aircraft Performance
Chapter 11, Weather Theory
Chapter 12, Aviation Weather Services
Chapter 13, Airport Operation
Chapter 14, Airspace
Chapter 15, Navigation
Chapter 16, Aeromedical Factors
Chapter 17, Aeronautical Decision Making

Appendix

Glossary

Index

aerodynamic efficiency of the horizontal
Figure 5-12. When the aerodynamic efficiency of the horizontal
tail surface is inadequate due to an aft CG condition, an elevator
down spring may be used to supply a mechanical load to lower
the nose.

Stabilator
As mentioned in Chapter 2, Aircraft Structure, a stabilator
is essentially a one-piece horizontal stabilizer that pivots
from a central hinge point. When the control column is
pulled back, it raises the stabilator's trailing edge, pulling
the airplane's nose up. Pushing the control column forward
lowers the trailing edge of the stabilator and pitches the nose
of the airplane down.

Because stabilators pivot around a central hinge point, they
are extremely sensitive to control inputs and aerodynamic
loads. Antiservo tabs are incorporated on the trailing edge to
decrease sensitivity. They deflect in the same direction as the
stabilator. This results in an increase in the force required to
move the stabilator, thus making it less prone to pilot-induced
overcontrolling. In addition, a balance weight is usually
incorporated in front of the main spar. The balance weight
may project into the empennage or may be incorporated on
the forward portion of the stabilator tips. [Figure 5-13]

Because stabilators pivot around a central hinge point, they
are extremely sensitive to control inputs and aerodynamic
loads. Antiservo tabs are incorporated on the trailing edge to
decrease sensitivity. They deflect in the same direction as the
stabilator. This results in an increase in the force required to
move the stabilator, thus making it less prone to pilot-induced
overcontrolling. In addition, a balance weight is usually
incorporated in front of the main spar. The balance weight
may project into the empennage or may be incorporated on
the forward portion of the stabilator tips. [Figure 5-13]

stabilator is a one-piece horizontal tail surface
Figure 5-13. The stabilator is a one-piece horizontal tail surface
that pivots up and down about a central hinge point.

Canard
The canard design utilizes the concept of two lifting surfaces,
the canard functioning as a horizontal stabilizer located in
front of the main wings. In effect, the canard is an airfoil
similar to the horizontal surface on a conventional aft-tail
design. The difference is that the canard actually creates lift
and holds the nose up, as opposed to the aft-tail design which
exerts downward force on the tail to prevent the nose from
rotating downward. [Figure 5-14]

The canard design dates back to the pioneer days of aviation,
most notably used on the Wright Flyer. Recently, the canard
configuration has regained popularity and is appearing on
newer aircraft. Canard designs include two types–one with a
horizontal surface of about the same size as a normal aft-tail
design, and the other with a surface of the same approximate
size and airfoil of the aft-mounted wing known as a tandem
wing configuration. Theoretically, the canard is considered
more efficient because using the horizontal surface to help
lift the weight of the aircraft should result in less drag for a
given amount of lift.

variable-sweep canard
Figure 5-14. The Piaggio P180 includes a variable-sweep canard
design, which provides longitudinal stability about the lateral
axis.

 

5-7