Aircraft Performance (Aerodynamic Forces)

The load factor in a level, coordinated turn with 60 degrees of bank is:

2.00 Gs. The load factor in a 60-degree bank increases by 2 G Units.

A standard-rate turn is defined as:

A turn rate of 3° per second. A standard-rate turn is defined as a turn rate of 3° per second. The turn coordinator indicates only the rate and direction of turn; it does not display a specific angle of bank.

Which statement relates to Bernoulli's principle?

Air traveling faster over the curved upper surface of an airfoil causes lower pressure on the top surface. Bernoulli said in part that the faster a fluid flows, the lower its pressure. Since the air traveling over the top surface of an airfoil flows faster than the air traveling under it, the pressure on top is lower than the pressure on the bottom.

Induced drag increases with:

An increase in the angle of attack. An increase in angle of attack creates more lift and thus induced drag increases.

The load factor on any airplane during a constant altitude turn is determined by:

Bank alone. At a constant altitude, during a coordinated turn in any aircraft, the load factor is the result of two forces: centrifugal force and weight caused by the degree of bank.

Induced drag increases when airspeed is:

Decreased. Induced drag is always present if lift is produced. The greater the lift the greater the induced drag. The lower the lift the lower the induced drag.

When are the four forces that act on an airplane in equilibrium?

During unaccelerated flight. In unaccelerated flight (steady flight) the opposing forces are in equilibrium.

Skin friction drag can be somewhat reduced by:

Flush riveting, smooth paint, and waxing. In order to reduce the effect of skin friction drag, aircraft designers utilize flush mount rivets and remove any irregularities that may protrude above the wing surface.

Which statement is most correct regarding form drag?

Form drag increases as airspeed increases. Form drag is the portion of parasite drag generated by the aircraft due to its shape and airflow around it and increases with velocity

The load factor on an airplane increases with:

Increase in weight, steep turns, and abrupt changes in airplane attitude. An airplane's load factor increases with added weight, in a steep turn, or abrupt changes in airplane attitude.

Parasite drag increases when airspeed is:

Increased. Parasite drag is comprised of all the forces that work to slow an aircraft's movement. It is the drag that is not associated with the production of lift. The faster the airplane moves through the air the greater the parasite drag.

What is the relationship of lift, drag, thrust, and weight when the airplane is in straight-and-level flight?

Lift equals weight and thrust equals drag. In unaccelerated flight the opposing forces are in equilibrium. Lift equals weight (plus tail down force) and thrust equals drag.

In steady unaccelerated flight:

Lift equals weight. In steady flight, the sum of these opposing forces is always zero. Therefore lift equals weight.

In what flight condition is torque effect the greatest in a single-engine airplane?

Low airspeed, high power, high angle of attack. Low airspeed, high power, and high angle of attack all tend to increase torque effect.

Most U.S. built aircraft engines rotate the propeller clockwise, as viewed from the pilot's seat. When the aircraft's wheels are on the ground during the takeoff roll, torque reaction causes:

More weight to be placed on the left main landing gear. When the aircraft's wheels are on the ground during the takeoff roll, an additional turning moment around the vertical axis is induced by torque reaction. As the left side of the aircraft is being forced down by torque reaction, more weight is being placed on the left main landing gear.

Drag is produced by:

Moving the airplane through the air. Drag is the force that resists movement of an aircraft through the air.

The movement of the air affects the speed at which aircraft move:

Over the Earth's surface. Motion of the air affects the speed with which aircraft move over the Earth's surface. Airspeed, the rate at which an aircraft moves through the air, is not affected by air motion.

In straight-and-level flight, if thrust exceeds drag then:

Speed increases. If the engine power is increased, thrust becomes greater than drag and the airspeed increases.

Select the four flight fundamentals involved in maneuvering an aircraft.

Straight-and-level flight, turns, climbs, and descents. There are four fundamental flight maneuvers upon which all flying tasks are based: straight-and-level flight, turns, climbs, and descents.

When an aircraft is flying at a high AOA, the downward moving blade of the propeller has a higher resultant velocity, creating more lift than the upward moving blade causing:

The airplane's nose to pull to the left. Since the propeller blade is an airfoil, the increased resultant velocity means increased lift. The down swinging blade has more lift and tends to pull (yaw) the aircraft's nose to the left.

What causes an airplane (except a T-tail) to pitch nosedown when power is reduced and controls are not adjusted?

The downwash on the elevators from the propeller slipstream is reduced and elevator effectiveness is reduced. This answer is the most correct. The downwash from the wings has an effect on the horizontal stabilizer. The "prop blast" also has an impact due the angle of incidence built into the horizontal stabilizer.

What is parasite drag?

The drag caused by the fuselage and other protrusions disrupting the flow of air. Parasite drag is comprised of all the forces that work to slow an aircraft's movement.

What force makes an airplane turn?

The horizontal component of lift. As an aircraft turns, lift becomes the result of two components, vertical lift which opposes gravity and horizontal lift which opposes inertia. It is the horizontal lift component that turns the aircraft.

What is the critical angle of attack?

The point at which the wing will stall. "If speed decreases enough, the required AOA will increase to the critical AOA. Any further increase in the AOA will result in the wing stalling."

What is induced drag?

The rearward retarding force caused by the wings creating lift. Induced drag is inherent whenever an airfoil is producing lift and, is inseparable from the production of lift. Consequently, it is always present if lift is produced.

(Refer to Figure 72) What does the vertical line connecting points E and F represent on the airspeed indicator?

The red line. The vertical dashed line on the Vg diagram represents the Never Exceed Speed. It is represented by the red line on an airspeed indicator. It is also the upper limit of the yellow arc.

Which basic flight maneuver increases the load factor on an airplane as compared to straight-and-level flight?

Turns. Coordinated, level turns increase the load factor. Additional lift must be generated as the total lift becomes divided between horizontal and vertical components. The vertical component must be equal to the weight of the aircraft to maintain level flight.

When does P-factor cause the airplane to yaw to the left?

When at high angles of attack. Asymmetric propeller loading or P-factor occurs when the airplane is at a high angle of attack (AOA). The aircraft's AOA results in the descending blade of the propeller having a higher AOA causing additional thrust on that side of the propeller.

Changes in the center of pressure of a wing affect the aircraft's

aerodynamic balance and controllability. The center of pressure (CP) changes with the angle of attack. The airplane's aerodynamic balance and controllability are governed by changes in the center of pressure.

The angle between the chord line of an airfoil and the relative wind is known as the angle of

attack. The angle of attack is the acute angle between the chord line of the airfoil and the direction of the relative wind.

(Refer to figure 1.) The acute angle A is the angle of

attack. The angle of attack is the acute angle between the wing chord line and the direction of the relative wind.

The term 'angle of attack' is defined as the angle

between the wing chord line and the relative wind. The angle of attack is the angle between the wing chord line and the direction of the relative wind.

The term 'angle of attack' is defined as the angle between the:

chord line of the wing and the relative wind. The acute angle formed between the chord line of an airfoil and the direction of the air striking the airfoil.

An aircraft leaving ground effect during takeoff will

experience an increase in induced drag and a decrease in performance. An aircraft leaving ground effect after takeoff encounters just the reverse of the aircraft entering ground effect during landing, it will experience an increase in induced drag and thrust required; a decrease in performance if thrust is unchanged.

(Refer to figure 72.) The positive limit load factor is represented by the

horizontal dashed line from C to point E. The horizontal dashed line from C to point E represents a positive limit load factor of 3.8 g's as found on the vertical axis of the Vg diagram. 3.8 g's is the positive limit for Normal Category airplanes.

The four forces acting on an airplane in flight are

lift, weight, thrust, and drag. Lift opposes weight and thrust opposes drag.

(Refer to figure 72.) The horizontal dashed line from point C to point E represents the View Figure 72

positive limit load factor. This figure is a VG diagram. The line C to E represents the maximum load factor for the airplane. Flight beyond this may cause structural damage.

The left turning tendency of an airplane caused by P-factor is the result of the

propeller blade descending on the right, producing more thrust than the ascending blade on the left. Asymmetric propeller loading or P-factor occurs when the airplane is at a high angle of attack (AOA). The aircraft's AOA results in the descending blade of the propeller having a higher AOA causing additional thrust on that side of the propeller.

An airplane said to be inherently stable will

require less effort to control. A stable airplane will tend to return to the original condition of flight if disturbed by a force such as turbulent air and requires less effort to maintain control.

The amount of excess load that can be imposed on the wing of an airplane depends upon the

speed of the airplane. At slow speeds, the maximum available lifting force of the wing is decreased. The wing will stall at lower excess loads and relieve the load.