[SIFT] ARMY AVIATION INFORMATION
EXAM QUESTIONS AND ANSWERS
A helicopter is:
A. A type of gyrocraft.
B. A type of rotorcraft.
C. A category of rotary-wing airplanes.
D. A sub-group of gyrocopters. - ANSWER-b
Helicopter turbine engines produce ___ thrust per pound than piston engines:
A. less
B. the same
C. more
D. the same, but only after factoring in the effect of density altitude - ANSWER-c
The main forces acting on a helicopter are:
A. Induced lift, mass, thrust, and form drag.
B. Lift, weight, thrust, and drag.
C. Lift, gravity, air resistance, and rotor vortex drag.
D. None of the above. - ANSWER-b
Helicopters typically have betweeen __ and __ main rotor blade(s):
A. 2, 6.
B. 2, 10.
C. 3, 8.
D. 3, 7. - ANSWER-a
Depending on the type of helicopter, main rotor system components can include:
A. A stabilizer bar, upper and lower swashplates, and counterweights.
B. Pitch horns, teeter or coning hinges, and blade grips.
C. Pitch and scissor links, and control rods.
D. All of the above. - ANSWER-d
The function of the flybar is:
A. To decrease crosswind thrust on the blades and enhance flight stability by keeping
the bar stable as the rotor spins.
B. To increase crosswind thrust and modify flight stability by allowing the bar to spin at a
slower speed than the main rotor.
C. To decrease crosswind thrust and augment flight stability by maintaining the bar at
an acute angle to the main rotor.
, D. To spin in a direction opposite to the main rotor's, thereby reducing induced drag. -
ANSWER-a
Many helicopters have a horizontal stabilizer located:
A. On the mast.
B. On the tail boom.
C. On the fin.
D. None of the above. - ANSWER-b
When a pilot banks a helicopter, causing it to turn, ___:
A. The machine's weight increases.
B. The machine's weight decreases.
C. The machine's gravitational drag increases.
D. The vertical component of the lift vector remains the same. - ANSWER-a
In the case of helicopters, lift is produced by ___ moving through the air at a speed
sufficient to create ___:
A. rotor blades, gyroscopic precession.
B. the flybar, an anti-drag force.
C. airfoils, a pressure differential.
D. None of these. - ANSWER-c
Thrust acts ___ to the aircraft's ___:
A. at an acute angle, driven portion of the tail rotor disk.
B. perpendicular, rotational relative wind.
C. laterally, outer two-thirds of the main rotor disk.
D. parallel, longitudinal axis. - ANSWER-d
Profile drag consists of ___ created by ___ and ___:
A. induced drag, angular momentum, aircraft components that do not contribute to lift.
B. skin friction, surface imperfections, form drag.
C. an inclined main rotor disk, increasing angle of attack, high blade rpm.
D. None of the above. - ANSWER-d
Vortices produced by spinning rotor blades create:
A. Form drag.
B. Rotational drag.
C. Parasite drag.
D. Induced drag. - ANSWER-d
When plotted on a graph, L/DMAX is the point where the helicopter's ___:
A. Total lift-to-drag ratio is the greatest.
B. Induced lift-to-drag ratio is maximized.
C. Perpendicular lift component exceeds the rotational drag vector by at least 50
percent.
EXAM QUESTIONS AND ANSWERS
A helicopter is:
A. A type of gyrocraft.
B. A type of rotorcraft.
C. A category of rotary-wing airplanes.
D. A sub-group of gyrocopters. - ANSWER-b
Helicopter turbine engines produce ___ thrust per pound than piston engines:
A. less
B. the same
C. more
D. the same, but only after factoring in the effect of density altitude - ANSWER-c
The main forces acting on a helicopter are:
A. Induced lift, mass, thrust, and form drag.
B. Lift, weight, thrust, and drag.
C. Lift, gravity, air resistance, and rotor vortex drag.
D. None of the above. - ANSWER-b
Helicopters typically have betweeen __ and __ main rotor blade(s):
A. 2, 6.
B. 2, 10.
C. 3, 8.
D. 3, 7. - ANSWER-a
Depending on the type of helicopter, main rotor system components can include:
A. A stabilizer bar, upper and lower swashplates, and counterweights.
B. Pitch horns, teeter or coning hinges, and blade grips.
C. Pitch and scissor links, and control rods.
D. All of the above. - ANSWER-d
The function of the flybar is:
A. To decrease crosswind thrust on the blades and enhance flight stability by keeping
the bar stable as the rotor spins.
B. To increase crosswind thrust and modify flight stability by allowing the bar to spin at a
slower speed than the main rotor.
C. To decrease crosswind thrust and augment flight stability by maintaining the bar at
an acute angle to the main rotor.
, D. To spin in a direction opposite to the main rotor's, thereby reducing induced drag. -
ANSWER-a
Many helicopters have a horizontal stabilizer located:
A. On the mast.
B. On the tail boom.
C. On the fin.
D. None of the above. - ANSWER-b
When a pilot banks a helicopter, causing it to turn, ___:
A. The machine's weight increases.
B. The machine's weight decreases.
C. The machine's gravitational drag increases.
D. The vertical component of the lift vector remains the same. - ANSWER-a
In the case of helicopters, lift is produced by ___ moving through the air at a speed
sufficient to create ___:
A. rotor blades, gyroscopic precession.
B. the flybar, an anti-drag force.
C. airfoils, a pressure differential.
D. None of these. - ANSWER-c
Thrust acts ___ to the aircraft's ___:
A. at an acute angle, driven portion of the tail rotor disk.
B. perpendicular, rotational relative wind.
C. laterally, outer two-thirds of the main rotor disk.
D. parallel, longitudinal axis. - ANSWER-d
Profile drag consists of ___ created by ___ and ___:
A. induced drag, angular momentum, aircraft components that do not contribute to lift.
B. skin friction, surface imperfections, form drag.
C. an inclined main rotor disk, increasing angle of attack, high blade rpm.
D. None of the above. - ANSWER-d
Vortices produced by spinning rotor blades create:
A. Form drag.
B. Rotational drag.
C. Parasite drag.
D. Induced drag. - ANSWER-d
When plotted on a graph, L/DMAX is the point where the helicopter's ___:
A. Total lift-to-drag ratio is the greatest.
B. Induced lift-to-drag ratio is maximized.
C. Perpendicular lift component exceeds the rotational drag vector by at least 50
percent.
