Flight Instructors Training Procedures _revised AIC_x

iii. Discuss the effects of density altitude.
DRAG (D)
With the aid of a graph discuss:
i. Induced drag.
ii. Profile drag.
iii. Total drag – total thrust required.
iv. Speed – minimum drag (Vmd).
v. Speed – minimum power (Vmp).
vi. Effect of flap/landing gear.
vii. Effect of weight.
viii. Effect of altitude.
3. COMBINE THRUST / DRAG GRAPHS
Explain:
i. Max/min speed for straight and level flight.
ii. Selected airspeeds for straight and level flight – adjustments in power as well as
attitude.
iii. Two airspeeds for one power setting – ‘on the step’.
iv. Effect of altitude.
v. Effect of flap/landing gear
4. BALANCE OF FORCES
i. Couples.
ii. Effect of tailplane.
5. AIRCRAFT STABILITY
LONGITUDINAL STABILITY
The main factors which longitudinal stability is governed by:-
i. Relative position of CG/CP:
CG at most forward limit – stable.
CG as it moves aft – stability decreases.
ii. Design of the tailplane and elevators − usually negative lift on tailplane.
iii. Example of longitudinal balance provided by the tailplane:
a. Main plane and tail plane at different angles of attack – for purposes of
explanation assume main plane at +4º and tailplane at +2º, angles of attack.
b. When the aircraft is disturbed by a gust, it will assume a different attitude, but
will remain temporarily on it’s original flight path due to inertia.
c. For a change of 2º nose up. Mainplane moves 4º + 2º = 50% change in angle
of attack. Tailplane moves 2º + 2º = 100% change in angle of attack.
d. Therefore the greater proportional increase in lift over the tailplane will cause it
to rise, resulting in a lowering of the aircraft nose and thereby return the aircraft
to the original trimmed position.
LATERAL AND DIRECTIONAL STABILITY
Because roll effects yaw and roll, lateral and directional stability are inter-related.
LATERAL STABILITY
i. Geometric dihedral.
ii. High wing/Low wing
iii. Pendulum effect – high wing relationship to CG.
iv. De-stabilizing
a. Slipstream
b. Flaps
DIRECTIONAL STABILITY
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