Ch 8 - Aircraft Axes And The Aircraft Wing

Question 1

Aircraft Axis

Answer 1

Longitudinal -> Roll -> Elevator

Lateral -> Pitch -> Horizontal stabiliser

Normal -> Yaw -> Rudder

Question 2

Wing Area

Answer 2

Gross wing area = Planform including the fuselage section (the outline shape of the wings and inboard section)

Question 3

Taper Ratio

Answer 3

Taper Ratio = Tip Chord / Root Chord. (Always <1)

Question 4

Average Chord

Answer 4

The mean geometric chord length of the wing

Question 5

Aspect Ratio

Answer 5

Ratio of the wing span to the average wing chord

Aspect Ratio = Span / Average Chord

For a tapered wing:
Aspect Ratio = span^2 / wing area

Question 6

Wing Loading

Answer 6

How hard each ‘square inch’ is working to provide lift

A jet fighter has a high wing loading and a low aspect ratio

Question 7

Sweep Angle

Answer 7

Used mainly for high speed flight

Short haul ~ <25’
Long haul ~ <35’

You measure it 25% back from the leading edge of the wing the whole way along

Question 8

Mean Aerodynamic Chord

Answer 8

A primary reference for longitudinal stability and mass + balance equations (OAA)

• Used to help with the CofG limits, fwd/aft limits

Most efficient = CofG as far as AFT as possible (within limits)

Question 9

Rigging Angle / Angle of Incidence / Rigger Angle

Answer 9

High speed aircraft have a decreased rigging angle (for the cruise)

Low speed/training aircraft have an increased relative rigging angle

Defined by the manufacturer

For training aircraft, the angle remains constant.
On larger aircraft, the angle can change along the span of the wing through;
- Washout
- Decreased camber towards the tips
- Decreased thickness towards the tips

Question 10

Dihedral

Answer 10

Wings are angled up slightly

(Wing tips are higher than the root)

Good for stability

Question 11

Anhedral

Answer 11

Wing tips are angled down below the root

Don’t get as easily affect by ground effect