AE 172 Aircraft PerformanceGeneral Aircraft Knowledge

Prof. Dr. Serkan Özgen

Dept. Aerospace Engineering

February 2019

2

Outline

• Fuselage, wings, tailplane, fin

• Primary flight controls

• Landing gear

• Propulsion system

• Flight instruments

3

Fuselage

• Fuselage forms the body of an airplane to which the wings, tail, engine and landing gear are attached.

• The fuselage of many modern airplanes is of semi-monocoque construction, a light framework covered by skin.

• The internal framework carries almost all of the stress (load), while the skin, which is like an egg shell carries the remaining stress.

4

Fuselage

5

Wings

• The wings designed to generate lift and are exposed to high loads that can exceed the total weight of the airplane during maneuvers.

• Wings generally have one or more spars attached to the fuselage and extending to the wingtips. They carry major loads. They bend upward when there is lift and downward when the airplane is on ground.

• Some wings have struts.

6

Wings with struts

7

Wings

• Ribs are roughly perpendicular to the spars. They providethe airfoil shape and stiffen the skin attched to them. Theribs transmit loads between the skin and spars.

• Ailerons are fitted at the outer trailing edge of each wingand move in opposite directions to control roll.

• Flaps are fitted on the inner trailing edges and are loweredto increase the lift and drag so that an unaccelerated, steepdescent could be maintained during landing.

• Wings may also contain fuel tanks.

8

Wings

9

Tailplane and fin

• The tail is generally similar to the wings and consists of a vertical and horizontal stabilizer to which the rudder and the elevator are attached.

• The elevator and on some airplanes the rudder will have trim tabs.

10

Primary flying controls

• Each of the three primary control surfaces moves the airplane about one of the three axes of flight.

• The ailerons bank or roll the airplane about its longitudinal axis.

• The rudder yaws the airplane about its vertical axis.

• The elevator moves the airplane about its lateral axis changing the airplane’s pitch attittude.

11

Primary flying controls

12

Primary flying controls

13

Primary flying controls

14

Primary flying controls

15

Primary flying controls

16

Primary flying controls

17

Primary flying controls

18

Landing gear

• The landing gear (or undercarriage) supports the weight of the airplane when it is on the ground.

• May be a tricycle type with a nosegear or a tailwheel type.

• Most tricycle landing gears have nosewheel steering through rudder pedals and almost all airplanes have main gear brakes.

• Advanced airplanes have retractable landing gear, while some other have fixed landing gear.

19

Landing gear - tailwheel

20

Landing gear - tricycle

21

Landing gear - retractable

Propulsion system

22

Propulsion system

23

24

Flight instruments

• The altimeter indicates the height of the airplane from the sea-level or a determined reference altitude.

25

Flight instruments

• The airspeed indicator indicates the speed at which an airplane moves through air in knots (nm/h, 1 knot = 1.8532 km/h).

26

Airspeed definitions

IAS CAS EAS TASinstrument

sensor

position error

compressibility

correctionair density

correction

• IAS: Indicated airspeed. What the pilot sees on the altimeter.

• CAS: Calibrated airspeed.

• EAS: Equivalent airspeed.

• TAS: True airspeed. Actual speed of the airplane with respect tothe surrounding air.

𝑇𝐴𝑆 =𝐸𝐴𝑆

𝜎

𝜎 =𝜌

𝜌𝑆𝐿

27

Flight instruments

• The vertical speed indicator displays the rate at which the airplane is climbing or descending in 100 ft/min.

28

Flight instruments

• The gyro-compass or the bearing indicator displays the direction at which the airplane is flying.

29

Flight instruments

• The artificial horizon displays the attitude of an airplane withrespect to the horizon.

30

Flight instruments

• The turn and slip indicator indicates whether an airplane is performing a coordinated turn, i.e. it is not skidding out of theturn or not slipping into the turn.

31

Flight instruments

32

Flight instruments

Assoc. Prof. Dr. Serkan ÖZGEN 33

Otto Lillienthal

34

Otto Lillienthal

Contributions:

• Discovered that a cambered (curved) wing wasessential to produce lift,

• Systematic experimentation and flight testing,

• First aircraft to be produced and sold in quantity.

35

36

Wright Brothers, Wright Flyer IDecember 17, 1903

37

Wright Brothers

38

Wright Brothers

• Inventors of the first heavier than air machine capableof sustained, controlled, powered flight.

• First practical airplane.

• First military airplane.

• Laid down the methodology for modern airplanedesign, manufacture and testing.