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Question 1

simplest theory in determining aerodynamic of airfoils

Answer 1

ackeret theory

Question 2

a linearized first order theory based on swept assumptions (good results given the conditions:)

-mach no. is not too low
-the airfoil is not too thick

Answer 2

ackeret theory

Question 3

a theory based on the prandtl-meyer equation and shockwave relations

Answer 3

exact theory

Question 4

none of these theory takes account the effects of______

Answer 4

friction

Question 5

characteristics of a supersonic airfoil

Answer 5

thin
symmetry
sharp eading edge
max thick at half chord

Question 6

why Superso airfoils must be thin

Answer 6

to minimize flow deviation that brings shock losses

Question 7

why sharp leading edge?

Answer 7

to keep an attached bow shock wave on the airfoil section and to avoid losses due to a normal detached shockwave
(to remain the shockwave attached at low superso speed)

Question 8

why max t at 1/2 chord

Answer 8

ensures expansion behind max t chord is the same to the compression ahead

Question 9

why symmetry

Answer 9

• For supersonic flows, a positive camber results in a positive zero lift angle of attack which follows that at any given incidence the lift is reduced by the camber of the airfoil section. In addition to this, at slow speeds, the effect of camber is to increase the value of drag. It
  is for these reasons that; supersonic airfoils are symmetrical
  sections.

Question 10

the best wing in supersonic flow is

Answer 10

an infinitely thin flat plate

Question 11

For a given thickness to chord ratio, minimum wave drag is achieved using

Answer 11

double wedge or diamond airfoil

Question 12

Diamond airfoils generate the same amount
of lift as compared to

Answer 12

flat late

Question 13

a type of superso airfoil whose upper and lower surface are formed by equal circular arcs

Answer 13

biconvex section