Question

For the F104 Starfighter, explain in your own words in terms of fluid mechanics why

(a) Its wings are straight, trapezoidal and very short (AR = b^2/S = 2.45).

(b) The wing leading-edge is very sharp (0.4 mm leading-edge thickness).

(c) The t/c (thickness/chord) is very small (3.36%).

(d) There is a takeoff and landing problem, and how the liability problem has been resolved.

(e) There is very high drag at large angle of attacks while low drag at small angles of attack.

Answer 1

A) Normally,various design including the swept wing and delta wing was in use.Here trapezoidal wing was used for the purpose of attaining supersonic speed(Mach2) and Mid mounted wings provided such privilege.

B)The wing leading edge as a design was swept 26 degree back and trailing edge bit forward by this the lift gets effected (similar to cars spoilers)

C)These were adapted to attain twice the speed of sound and eliminate drag completely.

All the factors a,b,c were of design specifications to attain Mach 2 (twice speed of sound).But there was an disadvantages for this design where maneuver and speed reduction during turns.

D)Because of short wings the pane would land in high speed hence boundry layer control system was developed (BLCS) with this the speed could be lowered to 56km/hr.The take off was given a lift as the wings made to take up air from engine smoothly over the surface.

E)Because aft fuselage in the palne was in the horizontal plane this would make the stance of the plane to be in nose up position which would fly at minimum drag angle of attack and hence the for these issues pitot tube,engine thrust line where lept longitudinal in fuselage position inturn effecting the performance.