Page 209 - Aerodynamics for Engineering Students

192 Aerodynamics for Engineering Students

The camber-line equation then is

(4.83)

This cubic camber-line shape is shown plotted on Fig. 4.20 and the ordinates given on the inset
table.
Lvt coefficient The lift coefficient is given from Eqn (4.43) by

So with the values of A0 and A1 given above
C, = 27~. [a - i: (: + ab) 3
f
-
7
Substituting for a = 8.28 and b = - -
8

giving a no-lift angle
6
a0 = -0.518- radians
c
or with ,O = the percentage camber = 1006/c
a0 = -0.3,O degrees

The load distribution From Eqn (4.40)

c c
for the first three terms. This has been evaluated for the incidence a' = 29.6(6/c) and the result
shown plotted and tabulated in Fig. 4.20.
It should be noted that the leading-edge value has been omitted, since it is infinite according
to this theory. This is due to the term
1 +cos8
(a - Ao) 7
becoming infinite at 0 = 0. When

1 +cos8
(a - Ao) becomes zero so (a - Ao) ___
sin 8
becomes zero. Then the intensity of circulation at the leading edge is zero and the stream flows
smoothly on to the camber line at the leading edge, the leading edge being a stagnation point.