Flight Theory and Aerodynamics. Joseph R. Badick
Чтение книги онлайн.

Читать онлайн книгу Flight Theory and Aerodynamics - Joseph R. Badick страница 27

Название: Flight Theory and Aerodynamics

Автор: Joseph R. Badick

Издательство: John Wiley & Sons Limited

Жанр: Техническая литература

Серия:

isbn: 9781119772415

isbn:

СКАЧАТЬ Mach number for the aircraft.

      CHAPTER OBJECTIVES

      After completing this chapter, you should be able to:

       Identify and provide examples of primary and secondary flight controls and their purpose on an aircraft.

       Describe the importance of an airfoil and summarize airfoil terminology.

       Identify the variables in the geometry of an airfoil and how airfoils are classified.

       Characterize the development of forces on airfoils and the relationship to Bernoulli’s principle.

       Determine the relationship between aerodynamic force and the center of pressure.

       Compare and contrast the development of pitching moments on a symmetrical airfoil and a cambered airfoil.

       Define aerodynamic center and how it changes with aircraft speed.

       Review an aircraft accident summary and correlate to the importance of primary and secondary flight controls for safety of flight.

      Up to this point, you may have considered the wing to be the only aerodynamically important structure of an aircraft. But in fact the entire structure of the airplane plays a role in the efficiency of an aircraft in flight, and identifying how, and to what extent, each part of an airplane structure plays a role is an important first step. We will begin with a review of the more prominent structures discussed in aerodynamics, because their direct role on lift and drag provides the foundation for more complicated discussions in the future.

Schematic illustration of modern transport category control surfaces.

      Source: U.S. Department of Transportation Federal Aviation Administration (2008a).

      Airplanes are flown in various configurations of gear and flaps, but for this textbook we will commonly refer to clean and dirty as the two reference configurations. In a clean configuration, the gear is retracted (when applicable), and the flaps and other high‐lift devices are retracted. In the dirty configuration, the gear is considered down and locked, and the high‐lift devices are fully deployed.

      Primary Flight Controls

       Ailerons

Schematic illustration of helicopter flight controls.

      Source: U.S. Department of Transportation Federal Aviation Administration (2016b).

Schematic illustration of differential ailerons.

      Source: U.S. Department of Transportation Federal Aviation Administration (2008a).

      When the yoke/stick is moved to the left, the ailerons deflect in opposite directions, the aileron on the left wing rises and the aileron on the right wing deflects downward. This action results in more lift on the right wing and a resultant roll to the left around the longitudinal axis. Later in Section 3.3 of Chapter 4 we will explain why this happens.

Schematic illustration of frise-type ailerons.

      Source: U.S. Department of Transportation Federal Aviation Administration (2008a).

       Elevator/Stabilator

      An elevator or stabilator controls pitch about the lateral axis, allowing for varying angles of attack during flight. An elevator is attached to the trailing edge of the horizontal stabilizer, which is usually fixed to the empennage, sometimes with an angle of incidence built in. A stabilator is a one‐piece horizontal stabilizer which moves СКАЧАТЬ