Wing Design Flashcards

1
Q

High Aspect Ratio on lift/drag

A

High Cl
Less wing tip vortices less induced drag from lower span wise pressure gradient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Wing Loading

A

How much lift needed to produce weight
Measured in kg/m2

Small span heavy ac - High wing loaded
Large span light ac - Low wing loaded

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Span Wise Distribution

A

Change in lift across the span

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Methods for reducing Cl peak at tip

A

Camber changes (less towards tip)
Washout - reduce AOI to reduce local AOA at tip
Surface area reduction at tip

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Ellipetical Wing

A

Constant CL
Lift drops towards span
Expensive not used on CAT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Rectangular Wing

A

Greatest lift at root
Cl reduces towards tip
IAOA increases/EAOA reduces/Induced drag increases
More downwash towards tip

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Tapered Wing

A

CL peak at mid span
Ideal taper ratio of 0.5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Sweep back wing

A

Greatest downwash at root
EAOA greatest towards tip
Wing tip vortex thanks to downwash

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Modern A/C design

A

Swept + Tapered
Not great stall characters tip stalling
Economical
Closest to elipetical design

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Sweep Angle

A

Angle at which wing is inclined to the lateral axis
Usually measure at 25% of the chord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Taper Ratio Formula

A

Tip Chord/Root

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Aspect Ratio Formula

A

Wingspan2/wing area

Span2/ area

Span/chord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Thickness/Chord Ratio

A

The ratio of max thickness of an aerofoil on the chord length expressed as a percentage

Usually between 10% to 12%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Mean Aerodynamic Chord is

A

The chord of an equivalent untwisted rectangular wing with the same pitching moment and lift characteristics as the actual wing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Spanwise flow is higher in

A

Slow speed/high aspect ratio ac

(Slow flight less KE so more inclined to flow Spanwise)

(Faster planes/shorter cord less)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Effective AOA is the angle between

A

The angle between the effective airflow and the chord line

17
Q

Induced AOA is the angle between

A

Between the relative airflow and the effect air flow

18
Q

Smaller wing tip vortices means

A

Greater effective AOA and smaller Induced AOA as Effective airflow is less inclined

19
Q

Strong vortices does what to downwash and EAF

A

Increases the downwash inclining the EAF upwards

20
Q

Smaller vortices means

A

Shallow effective airflow angle
Bigger effective AOA
Smaller induced AOA
Less induced drag

21
Q

Wing tip vs wing root on a rectangular ac

A

Wing tip = strong vortices/greater effective airflow/smaller eAOA/larger induced AOA

Wing root = weaker vortices/greater effective AOA

22
Q

Directional flow of trailing tip vortex

A

Span wise flow is always outward from under wing to upper surface

Anti clockwise around right wing
Clockwise around left wing

When viewed from behind

23
Q

What wing produces the lowest induced drag

A

Ellipetical wings produce the most lift for the smallest wing tip vortices

At there tips the pressure differential is almost 0

24
Q

Wing Loading

A

Measured in kg/m2
Weight per unit of the wing area

Greatest on heavy ac with smaller wings = higher wing loading

More intense vortices

25
Which wing planform has the lowest induced drag
Ellipetical wing
26
Which wing has the highest induced drag
Rectangular (longer tip chord)
27
Swept back wing advantages and disadvantages
+ Increases the critical Mach number + Positive contribution to static directional stability + Positive significant contribution to static lateral stability - tip stall and pitch up at stall - lower cl for given AOA which increases stall speed - clmax less and occurs at higher AOA - change in CL per change in alpha is less - must have complex high lift devices to to/ld - must be flown at high AOA than straight wings for cl
28
Wing AOA
Chord to the relative airflow
29
Aeroplane AOA
Longitudinal axis to relative air flow (speed vector)
30
Angle of incidence
Wing root chord to longitudinal axis