Aerodynamics Test 2

Front 1

What is the basic drag equation?

Back 1

Drag = CsubD x q x S =

CsubD x density x V^2 x S / 295

Front 2

The coefficient of drag is...

Back 2

ratio of drag pressure to dynamic pressure

Front 3

The aspect ratio =

Back 3

b^2 / S

where b is the wing span

Front 4

When is a wingtip vortex formed?

Back 4

When higher pressure air below wing flows around wingtips into low pressure region, around tips, at the top

Front 5

Are low or high wing aircraft more effected by ground effect?

Back 5

Low wing

Front 6

What are the five types of parasite drag?

Back 6

Skin friction drag,
Form drag,
Interference Drag,
Leakage Drag,
Profile Drag

Front 7

What are three ways to reduce skin friction drag?

Back 7

Skin smoothness, laminar flow airfoils, and laminar flow control

Front 8

How do you find min drag?

Back 8

W / LD max

Front 9

For a jet, what performance points happen at LD max?

Back 9

Dmin
Best engine out glide
Max endurance
Best angle of climb

Front 10

What is the third type of drag?

Back 10

compressibility and wave drag

Front 11

Wingtip vortices create a pattern of ____ ______

Back 11

disturbed air

Front 12

The net downwash about a finite wing tilts the lift vector _____

Back 12

aft

Front 13

The induced AOA is equal to ___ of the _______ angle

Back 13

half ; downwash

Front 14

Upon entering ground effect, what three things happen?

Back 14

Induced drag is decreased ;
Nose down pitching moment ;
AS indicator reads low, falsely

Front 15

Upon EXITING ground effect, what three things happen?

Back 15

Induced drag is increased ;
Nose UP pitching moment ;
AS indicator reads higher, correctly

Front 16

What is the equation for the pitching moment about the CG?

Back 16

MsubCG = CsubM x q x S x c

Front 17

How do wings contribute to static pitch stability?

Back 17

CG forward of AC: stabilizing

CG aft of AC: de-stabilizing

Front 18

What is the effect of the fuselage on static pitch stability?

Back 18

de-stabilizing with gust

Front 19

How do the engine nacelles affect static pitch stability?

Back 19

If engines mounted aft of CG: stabilizing

If mounted forward of CG: de-stabilizing

Front 20

What effect does the vertical tail have on yaw stability?

Back 20

Strongly stabilizing

Front 21

What effect does dihedral have on roll stability?

Back 21

Stabilizing for low wing

Front 22

Which has a lower stall speed with same wing area and weight? Straight or swept wing

Back 22

Straight has lower

Front 23

Compared to a straight wing, a swept wing must fly at a _____ AOA to achieve max lift.

Back 23

higher

Front 24

A straight wing stall is followed by a sudden reduction of CL. A swept wing does not have such a sudden drop off. T/F?

Back 24

True

Front 25

A swept wing aircraft is _____ sensitive to AOA changes than straight wing.

Back 25

less

Front 26

Lift distribution in the span wise direction is in the shape of a(n) _______?

Back 26

Ellipse

Front 27

Maximum lift in a straight wing occurs at the ?

Back 27

Wing root

Front 28

Lift on a straight wing is ____ at the wingtips?

Back 28

Zero

Front 29

Stall of a wing will occur where ratio of _____ CL and ____ CL is _____ ?

Back 29

local ; wing ; highest

Front 30

What is considered to be the most efficient planform?

Back 30

Elliptical; the entire trailing edge stalls at once

Front 31

The taper ratio of a _____ wing is zero.

Back 31

delta

Front 32

Stall starts where ____ _____ is highest

Back 32

wing loading

Front 33

Swept wing AC have (low/high) aspect ratios, which means they have HIGH induced drag

Back 33

low

Front 34

For a jet, the area slower than L/D max is referred to as ?

Back 34

region of reversed command

NOT backside of power curve

Front 35

In the region of reversed command, less thrust is required to maintain altitude at a given airspeed. T/F?

Back 35

False

Front 36

Name three methods to slow an aircraft flying at min drag

Back 36

1) use speed brakes to increase drag
2) retard throttle and reduce thrust (won't be able to maintain altitude)
3) slowly increase AOA with control stick

Front 37

What is the equation for rate of sink in FPM?

Back 37

101.3 X V [ (D - T) / (W) ]

Front 38

What controls the rate of climb or descent in steady flight?

Back 38

throttle setting

Front 39

Wind shears are caused by? (three things)

Back 39

Tstorms, fronts, and low-level jet streams

Front 40

The downward air flow below a Tstorm is called a ?

Back 40

downburst (most dangerous type of wind shear)

Front 41

What three types of bursts are created when a downburst hits the ground?

Back 41

Tailwind, headwind, and Xwind bursts

Front 42

What two factors must exist as a rule to have a possibility of LLWS?

Back 42

Temp gradient of >10 F across a front AND frontal speed of +30 kts

Front 43

What is the most hazardous condition caused by LLWS during takeoff?

Back 43

An increasing tailwind shortly after takeoff, resulting in pitch down motion = crash

Front 44

During approach to landing, what are the two dangerous LLWS conditions?

Back 44

1) headwind to tailwind shift (or reduced HW), causes pitch down and crash

2) Headwind shear causing pitch up and possible overshoot

Front 45

During heavy rain during low level ops, Cd increase and lift values decrease at a studied amount around __%?

Back 45

30%

Front 46

According to a study, 0.1 inch of evenly distributed frost on the aircraft's wings will ______ stall speed by __%, effectively _______ the takeoff run

Back 46

increase ; 35% ; doubling

Front 47

What are the two types of "prop wash"?

Back 47

Thrust stream turbulence - high velocity air from props or jet exhaust (mostly a concern on ground)

Wake Turbulence - caused by wingtip vortices

Front 48

L / D =

Back 48

CsubL / CsubD

W / D

Front 49

The angle that RW leaving the wing makes with the free stream RW is called the _______ angle?

Back 49

Downwash

Front 50

The rearward component of the tilted lift vector is called ______ _____?

Back 50

induced drag

Front 51

Why is induced drag lower in ground effect?

Back 51

Because the downwash is reduced, the physical surface x ft below the plane blocks "shortens" the downwash

Front 52

What is the parasite drag (Dsub p) equation?

Back 52

Csub D (q)(S)

Front 53

On a total drag curve, where does L/D max occur?

Back 53

Intersection of the induced and parasite drag curves