Page 293 - Aircraft Stuctures for Engineering Student

274 Airworthiness and airframe loads

Tail CP
I
Thrust
line +

I 7.625m
'/ b.915rn
AC
Fig. P.8.5

Calculate the tail load necessary for equilibrium in the turn. The necessary data are
given in the usual notation as follows:
Weight W = 133 500N dCL/da! = 4.5/rad

Wing area S = 46.5m2 CD = 0.01 + 0.05Ci
Wing mean chord C = 3.0m CM,o = -0.03
Ans. 73 160N.

P.8.6 The aircraft for which the stalling speed V, in level flight is 46.5m/s has a
maximum allowable manoeuvre load factor nl of 4.0. In assessing gyroscopic effects
on the engine mounting the following two cases are to be considered:
(a) pull-out at maximum permissible rate from a dive in symmetric flight, the angle
of the flight path to the horizontal being limited to 60" for this aircraft;
(b) steady, correctly banked turn at the maximum permissible rate in horizontal
flight.

Find the corresponding maximum angular velocities in yaw and pitch.
Ans. (a) Pitch, 0.37 rad/sec; (b) Pitch, 0.41 rad/sec, Yaw, 0.103 rad/sec.
P.8.7 A tail-first supersonic airliner, whose essential geometry is shown in
Fig. P.8.7, flies at 610m/s true airspeed at an altitude of 18300m. Assuming that
thrust and drag forces act in .the same straight line, calculate the tail lift in steady
straight and level flight.

CG
Tail CP

c-

W centre
I 50 rn 1

Fig. P.8.7