12 free practice questions from the 239 in this chapter of StudyWren Aviation. Pick an answer and check it to see the explanation and its FAA source. Part of the free Private Pilot practice test.
Four ForcesPAR-01-010
You roll into a 45° level turn and add back pressure to hold altitude, but leave the power unchanged. Why does the airspeed decrease?
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The answer is C: The higher angle of attack increases induced drag
Holding altitude in a bank requires more total lift, which at the same airspeed means a higher angle of attack. Induced drag rises with angle of attack, so with no power added, the airplane slows. This is why power is often added in steep turns.
The answer is C: The higher angle of attack increases induced drag
Holding altitude in a bank requires more total lift, which at the same airspeed means a higher angle of attack. Induced drag rises with angle of attack, so with no power added, the airplane slows. This is why power is often added in steep turns.
How does Newton's third law of motion contribute to the lift produced by a wing?
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The answer is A: The wing deflects air downward, and the reaction pushes the wing up
Newton's third law (for every action there is an equal and opposite reaction) explains lift as the reaction to the wing turning the airflow downward (downwash); the reaction pushes the wing upward. The notion that upper and lower air must rejoin at the trailing edge (equal transit time) is not a Newton's-third-law explanation and does not by itself account for lift.
The answer is A: The wing deflects air downward, and the reaction pushes the wing up
Newton's third law (for every action there is an equal and opposite reaction) explains lift as the reaction to the wing turning the airflow downward (downwash); the reaction pushes the wing upward. The notion that upper and lower air must rejoin at the trailing edge (equal transit time) is not a Newton's-third-law explanation and does not by itself account for lift.
If an airplane's airspeed is doubled while angle of attack and air density remain the same, the lift produced becomes
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The answer is C: four times as great
Lift = CL x 1/2 x density x V^2 x wing area. Lift is proportional to the square of airspeed, so doubling airspeed gives 2^2 = 4 times the lift at the same AOA.
Lift = CL x 1/2 x density x V^2 x wing area. Lift is proportional to the square of airspeed, so doubling airspeed gives 2^2 = 4 times the lift at the same AOA.
Ground effect directly reduces which type of drag?
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The answer is B: Induced drag
Ground effect restricts the wing's downwash and wingtip vortices, so its direct effect is a reduction in induced drag. Parasite drag in all its forms, including skin friction, depends on airspeed, shape and surface condition, and proximity to the ground does not change it.
Ground effect restricts the wing's downwash and wingtip vortices, so its direct effect is a reduction in induced drag. Parasite drag in all its forms, including skin friction, depends on airspeed, shape and surface condition, and proximity to the ground does not change it.
In a high-wing airplane, how does keel effect contribute to lateral stability?
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The answer is C: The fuselage weight below the wing acts like a pendulum
With the wing above the fuselage, the fuselage's weight hangs below the wing's lift. When a wing dips, this weight acts like a pendulum (or a ship's keel), tending to return the airplane to wings-level.
The answer is C: The fuselage weight below the wing acts like a pendulum
With the wing above the fuselage, the fuselage's weight hangs below the wing's lift. When a wing dips, this weight acts like a pendulum (or a ship's keel), tending to return the airplane to wings-level.
Many light single-engine airplanes use design features such as an offset vertical fin or rigging so that left-turning tendencies are offset with no rudder input in which condition?
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The answer is C: Cruise power and airspeed
Manufacturers commonly rig the airplane (fin offset, engine cant, or trim tabs) so that it flies coordinated without rudder pressure at normal cruise power and airspeed. At any other power and airspeed combination the pilot must use rudder or rudder trim.
Manufacturers commonly rig the airplane (fin offset, engine cant, or trim tabs) so that it flies coordinated without rudder pressure at normal cruise power and airspeed. At any other power and airspeed combination the pilot must use rudder or rudder trim.
In a coordinated 50° banked turn, you notice the bank angle slowly increasing even though you have not moved the ailerons. What is the aerodynamic cause?
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The answer is B: The outside wing travels faster and produces more lift
In a turn the outside wing travels a larger circle in the same time, so it moves faster than the inside wing and develops more lift. In steep turns this difference is large enough to overcome the airplane's lateral stability, creating an overbanking tendency.
The answer is B: The outside wing travels faster and produces more lift
In a turn the outside wing travels a larger circle in the same time, so it moves faster than the inside wing and develops more lift. In steep turns this difference is large enough to overcome the airplane's lateral stability, creating an overbanking tendency.
In cruise flight, an airplane consistently requires light right rudder pressure to keep the ball centered. Which device would a mechanic most likely adjust on the ground to correct this?
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The answer is C: A ground-adjustable tab on the rudder
Many light airplanes have a ground-adjustable tab on the rudder (or ailerons). It is bent on the ground, then test-flown, until the airplane flies coordinated at cruise without rudder pressure. It cannot be adjusted in flight.
The answer is C: A ground-adjustable tab on the rudder
Many light airplanes have a ground-adjustable tab on the rudder (or ailerons). It is bent on the ground, then test-flown, until the airplane flies coordinated at cruise without rudder pressure. It cannot be adjusted in flight.
An airplane stalls at 54 knots at 2,550 pounds. Rounded to the nearest knot, what is its stall speed at 2,000 pounds in the same configuration?
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The answer is C: 48 knots
Vs (new) = 54 x sqrt(2,000 / 2,550) = 54 x sqrt(0.784) = 54 x 0.886 = 47.8, or 48 knots. 42 knots results from multiplying by 0.784 without taking the square root, and 61 knots inverts the ratio, which would give a lighter airplane a higher stall speed.
Vs (new) = 54 x sqrt(2,000 / 2,550) = 54 x sqrt(0.784) = 54 x 0.886 = 47.8, or 48 knots. 42 knots results from multiplying by 0.784 without taking the square root, and 61 knots inverts the ratio, which would give a lighter airplane a higher stall speed.
Your airplane has fixed slots in the wing leading edges just ahead of the ailerons. At high angles of attack, these slots allow the outboard wing sections to
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The answer is C: reach a higher AOA before stalling
A slot ducts high-energy air from below the leading edge to the upper surface, energizing the boundary layer and delaying separation. The slotted section can reach a higher AOA before stalling, which keeps the outboard wing and ailerons effective.
The answer is C: reach a higher AOA before stalling
A slot ducts high-energy air from below the leading edge to the upper surface, energizing the boundary layer and delaying separation. The slotted section can reach a higher AOA before stalling, which keeps the outboard wing and ailerons effective.
Compared with climbing at VX, climbing at VY to 1,000 feet AGL will
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The answer is A: take less time but cover more horizontal distance
VY gives the greatest altitude gain per unit time, so the airplane reaches 1,000 feet sooner. VX gives the steepest climb angle, so at VX the airplane reaches that altitude over a shorter ground distance but takes longer to do so.
The answer is A: take less time but cover more horizontal distance
VY gives the greatest altitude gain per unit time, so the airplane reaches 1,000 feet sooner. VX gives the steepest climb angle, so at VX the airplane reaches that altitude over a shorter ground distance but takes longer to do so.
Which wing planform has the greatest natural tendency to stall first at the wingtips?
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The answer is C: A highly tapered or swept wing
Highly tapered and swept wings carry relatively high lift loading toward the tips and tend to stall there first, which reduces aileron effectiveness. Designers counter this with washout, which lowers the tip's angle of incidence, or with slots and stall strips; stall strips at the root make the root stall first, the opposite of a tip-first tendency.
Highly tapered and swept wings carry relatively high lift loading toward the tips and tend to stall there first, which reduces aileron effectiveness. Designers counter this with washout, which lowers the tip's angle of incidence, or with slots and stall strips; stall strips at the root make the root stall first, the opposite of a tip-first tendency.
