Total Drag

Question 1

What is Skin Friction Drag?

Answer 1

-Skin Friction is caused by air sticking to the surface as it passes the aircraft

Question 2

What are the two sections of Parasite Drag?

Answer 2

• Skin Friction

- Form Drag

Question 3

What is Form Drag?

Answer 3

• Form Drag is caused by air getting out of the way

- Form Drag can be reduced by changing the shape of the object

Question 4

What is Induced drag?

Answer 4

• Induced drag is caused by the modification to airflow as it interacts with any LIFT- PRODUCING surface
• The main source of induced drag is spanwise flow deflection of airflow

Question 5

What is streamlining?

Answer 5

-Altering the shape of the object to reduce drag

Question 6

What design features keep drag low?

Answer 6

• Wheel spats
• Wing root fairings
• The streamlined cross-section for lift struts

Question 7

How do you reduce induced drag?

Answer 7

-Keep wingtip as small as possible

Question 8

What affects the amount of parasite drag experienced by aircraft?

Answer 8

• Speed
• AOA
• Position of flaps and undercarriage

Question 9

What happens to parasite drag as speed increases?

Answer 9

Parasite Drag Increases

Question 10

What is the rate that parasite drag increases with speed?

Answer 10

Parasite drag equals the square of the speed

Question 11

What is spanwise flow?

Answer 11

Sideways deflection of airflow

Question 12

What is an Eddie?

Answer 12

Deflected airflow from top and bottom surface meet at the tip to form small scale vortices

Question 13

What two factors affect how much air spills across the wingtip and therefore the degree of vortex?

Answer 13

• Magnitude of pressure difference

- Time available for air to complete journey

Question 14

At low speeds; is tip vortex and spanwise flow less or more?

Answer 14

Greater

Question 15

Does Induced drag increase or decrease as speed increases?

Answer 15

Decreases as speed increases

Question 16

What is Low aspect ratio?

Answer 16

• Short Span

- Long Chord

Question 17

What is a high aspect ratio?

Answer 17

• Long Span

- Short Chord

Question 18

Does a low or high aspect ratio wing have a higher stallin g angle?

Answer 18

Low aspect ratio wing has higher stalling angle

Question 19

Does a high or low aspect ratio wing produce the most lift at the same Angle of Attack and Speed?

Answer 19

High Aspect ratio wing produces the most lift

Question 20

What is wake turbulance?

Answer 20

-Vortices which trail behind large aircraft tend to create large amounts of roll or yaw for following aircrafts

Question 21

Which direction do Vortices rotate from the left wing?

Answer 21

Clockwise

Question 22

Which direction do Vortices rotate from the right wing?

Answer 22

Anticlockwise

Question 23

How fast do vortices sink?

Answer 23

400-500fpm

Question 24

When do Vortices tend to stabalise?

Answer 24

900 ft below flight path

Question 25

At what height do vortices tend to stop sinking and move horizontally at about 3 or 4 knots?

Answer 25

At about 200ft

Question 26

In stable conditions how long can vortices persist?

Answer 26

- Commonly 3 minutes | - At height; they may persist for 5 minutes

Question 27

How far do the trails of vortices extend?

Answer 27

2-5 miles

Question 28

Will vortices be present if no lift is being produced?

Answer 28

No

Question 29

How far c an thrust stream and jet exhaust extend behind heavy aircraft?

Answer 29

500m

Question 30

Are vortices more or less pronounced with flaps extended?

Answer 30

Less pronounced

Question 31

What configuration creates the most wake turbualnce?

Answer 31

Slow speed and Flap extended

Question 32

Separation standard reference?

Answer 32

AIP ENR 1.4 Para 9.2.2

Question 33

Separation Standards for: | Light Aircraft landing behind Heavy aircraft

Answer 33

3 minutes or 6nm

Question 34

Separation Standards for: | Light aircraft landing opposite direction to departing heavy

Answer 34

2 minutes or 6nm

Question 35

Separation Standards for: | Light Aircraft departing after heavy

Answer 35

2 minutes or 6nm

Question 36

Separation Standards for: | Light aircraft taking off from mmre than 150m from heavy aircrafts commencement of takeoff run

Answer 36

3 minutes or 6nm

Question 37

At low speed what drag is higher?

Answer 37

Induced drag

Question 38

At high speed what drag is higher?

Answer 38

Parasite Drag

Question 39

If an aircraft is flown at the minimum total drag speed what will it achieve?

Answer 39

- Max range in nil wind conditions - Best Air Nautical miles per gallon - Least gallon per nautical mile - Best lift/ drag ratio - Best gliding range in nil wind conditions

Question 40

What phases of flight are vortices present?

Answer 40

From lift off to touch down

Question 41

Lateral drift rate of vortices once at ground level?

Answer 41

3- 4 knots

Question 42

Minimum distance to avoid rotordownwash?

Answer 42

3 rotor diamaters

Question 43

Wake turbulance is worst when....

Answer 43

A heavy aircraft is flying slowly