Drag

Question 1

is all drag bad?

Answer 1

no lol wtf

Question 2

what are the subparts of total drag?

Answer 2

parasite drag and induced drag

Question 3

what are the subparts of parasite drag?

Answer 3

profile drag and interference drag

Question 4

what are the subparts of profile drag?

Answer 4

skin friction and form drag

Question 5

what is the laminar flow?

Answer 5

the smooth sheet of air over an aerofoil, about 2-3mm thick

Question 6

what is the turbulent flow?

Answer 6

the flow after the transition point, where air separates from the aerofoil and becomes turbulent

Question 7

where is the transition point in the boundary layer?

Answer 7

generally at the point of max thickness

Question 8

what is skin friction drag?

Answer 8

drag induced by the shear stress of the layers within the boundary layer

Question 9

what is shear stress?

Answer 9

like when you run your hand across a stack of cards and the higher ones move but the bottom ones stay still, its bc of air viscosity and the RAF dragging the boundary layer with it

Question 10

smoother surfaces result in (less/more) skin friction drag

Answer 10

less !

Question 11

bigger aerofoils create (more/less) drag?

Answer 11

more - measured in Reynolds Number

Question 12

higher AoA results in the transition point of the boundary layer moving (forward/backward)

Answer 12

forward

Question 13

what is form drag?

Answer 13

drag induced by the shape of an aerofoil - a fucking square is gonna be way less aerodynamic than a nice lil dart yk???

Question 14

what is the separation point in relation to form drag?

Answer 14

the point where airflow separates from the body of an aerofoil and gets turbulent and silly

Question 15

low AoA results in a very (far back/far forward) separation point

Answer 15

far back - less form drag overall

Question 16

what is a fairing?

Answer 16

a streamlined shape added to the sharp edges of an aircraft - like where the wing connects to the fuselage - to reduce form drag

Question 17

ice accretion can greatly (increase/reduce) form drag

Answer 17

increase

Question 18

form drag is lower at (high/low) speed

Answer 18

low

Question 19

speed overrules AoA in relation to form drag - true or false?

Answer 19

true asf you go girl

Question 20

what is interference drag?

Answer 20

drag induced by the sharp edges on the wetted area of an aircraft - like where the wingroot meets the fuselage. this is reduced with fairing

Question 21

what is induced drag?

Answer 21

induced drag is drag induced by the production of lift. basically a part of lift lol

Question 22

how does induced downwash do its thing in relation to induced drag?

Answer 22

more downwash results in the AoA being forcibly reduced, resulting in less TR and therefore less lift

Question 23

whats the equation for induced drag?

Answer 23

CL^2
(fixed ratio) (wing efficiency factor) (AR)

Question 24

what is washout?

Answer 24

a decreased angle of incidence at the wingtips to reduce induced drag, when combined with taper

Question 25

list the wingtip modifications used to reduce wingtip vortices

Answer 25

drooping wingtip, winglet, wing fence, wingtip tank

Question 26

whats the equation for the coefficient of total drag?

Answer 26

CD = CD parasite + CD induced

Question 27

whats the formula for drag?

Answer 27

Drag = CD 1/2pV^2 S

Question 28

total drag is (high/low) at slow speeds

Answer 28

low

Question 29

go look at the lift/drag ratio table on page 5-16

Answer 29

go bro