Aerodynamics

In unaccelerated (steady state) flight the opposing forces are in equilibrium. Answer (B) is incorrect because thrust must exceed drag in order for the airplane to accelerate. Answer (C) is incorrect because when the airplane is at rest on the ground, the only aerodynamic force acting on it is weight.

Flaps increase drag, allowing the pilot to make steeper approaches without increasing airspeed. Answer (A) is incorrect because extending the flaps increases drag, which enables the pilot to increase the angle of descent without increasing the airspeed. Answer (B) is incorrect because flaps increase lift at slow airspeed, which permits touchdown at a lower indicated airspeed.

The purpose of the rudder is to control yaw. Answer (B) is incorrect because the ailerons control overbanking. Answer (C) is incorrect because roll is controlled by the ailerons.

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

Loading in a tail-heavy condition can reduce the airplane's ability to recover from stalls and spins. Tail-heavy loading also produces very light stick forces, making it easy for the pilot to inadvertently overstress the airplane. Answer (A) is incorrect because an airplane with an aft CG has less drag from a reduction in horizontal stabilizer lift, resulting in a short takeoff run. Answer (C) is incorrect because an airplane with an aft CG flies at a lower angle of attack, resulting in a lower stall speed.

The four flight fundamentals involved in maneuvering an aircraft are: straight-and-level flight, turns, climbs, and descents.

The angle of attack is the acute angle between the relative wind and the chord line of the wing. Answer (A) is incorrect because the angle of incidence is the angle formed by the longitudinal axis of the airplane and the chord line. Answer (C) is incorrect because the dihedral is the upward angle of the airplane's wings with respect to the horizontal.

At slow speeds, the maximum available lifting force of the wing is only slightly greater than the amount necessary to support the weight of the airplane. However, at high speeds, the capacity of the elevator controls, or a strong gust, may increase the load factor beyond safe limits. Answer (A) is incorrect because the position of the CG affects the stability of the airplane, but not the total load the wings can support. Answer (C) is incorrect because abrupt control inputs do not limit load.

A stable airplane will tend to return to the original condition of flight if disturbed by a force such as turbulent air. This means that a stable airplane is easy to fly. Answer (A) is incorrect because stability of an airplane has an effect on its stall recovery, not the difficulty of stall entry. Answer (C) is incorrect because an inherently stable aircraft can still spin.

Flaps increase drag, allowing the pilot to make steeper approaches without increasing airspeed. Answer (B) is incorrect because trim tabs help relieve control pressures. Answer (C) is incorrect because wing area usually remains the same, except for certain specialized flaps which increase the wing area.

The airplane will turn less than 90° at corners 1 and 4. At corner 1, the airplane turns to a heading that is crabbed into the wind, which makes the turn less than 90°. At corner 4, the airplane is crabbed into the wind when the turn is started, and the turn will be less than 90°.

As the airplane is banked, lift acts horizontally as well as vertically and the airplane is pulled around the turn. Answer (B) is incorrect because the vertical component of lift has no horizontal force to make the airplane turn. Answer (C) is incorrect because the centrifugal force acts against the horizontal component of lift.

Referencing FAA Figure 2, use the following steps: 1. Enter the chart at a 45° angle of bank and proceed upward to the curved reference line. From the point of intersection, move to the left side of the chart and read a load factor of 1.5 Gs. 2. Multiply the aircraft weight by the load factor. 4,500 x 1.5 = 6,750 lbs Or, working from the table: 4,500 x 1.414 (load factor) = 6,363 lbs Answer B is the closest.

The angle of attack is the acute angle between the relative wind and the chord line of the wing. Answer (B) is incorrect because there is no specific aviation term for this. Answer (C) is incorrect because this is the definition of the angle of incidence.

Stall speed increases in proportion to the square root of the load factor. Thus, with a load factor of 4, an aircraft will stall at a speed which is double the normal stall speed. Answer (B) is incorrect because an airplane's tendency to spin does not relate to an increase in load factors. Answer (C) is incorrect because an airplane's stability determines its controllability.

One wing is less stalled than the other, but both wings are stalled in a spin. Answer (B) is incorrect because both wings must be stalled through the spin. Answer (C) is incorrect because both wings are stalled; but the right wing is less fully stalled than the left.

Referencing FAA Figure 2, use the following steps: 1. Enter the chart at a 60° angle of bank and proceed upward to the curved reference line. From the point of intersection, move to the left side of the chart and read a load factor of 2 Gs. 2. Multiply the aircraft weight by the load factor: 2,300 x 2 = 4,600 lbs Or, working from the table: 2,300 x 2.0 (load factor) = 4,600 lbs

Referencing FAA Figure 2, use the following steps: 1. Enter the chart at a 30° angle of bank and proceed upward to the curved reference line. From the point of intersection, move to the left side of the chart and read an approximate load factor of 1.2 Gs. 2. Multiply the aircraft weight by the load factor: 3,300 x 1.2 = 3,960 lbs Or, working from the table: 3,300 x 1.154 (load factor) = 3,808 lbs Answer C is the closest. Answer (A) is incorrect because they are less than 3,300 pounds; load factor increases with bank for level flight. Answer (B) is incorrect because they are less than 3,300 pounds; load factor increases with bank for level flight.

When the angle of attack is increased to between 18° and 20° (critical angle of attack) on most airfoils, the airstream can no longer follow the upper curvature of the wing because of the excessive change in direction. The airplane will stall if the critical angle of attack is exceeded. The indicated airspeed at which stall occurs will be determined by weight and load factor, but the stall angle of attack is the same. Answer (A) is incorrect because an airplane will always stall at the same angle of attack, regardless of the CG position or gross weight. Answer (B) is incorrect because an airplane will always stall at the same angle of attack, regardless of the CG position or gross weight.

The location of the CG with respect to the center of lift determines to a great extent the longitudinal stability of an airplane. CG aft of the CL will result in an undesirable pitch-up moment during flight. An airplane with the CG forward of the CL will pitch down when power is reduced. This will increase the airspeed and the downward force on the elevators. This increased downward force on the elevators will bring the nose up, providing positive stability. The farther forward the CG is, the more stable the airplane.Answer (A) is incorrect because the CG is not affected by changes in thrust or drag. Answer (C) is incorrect because thrust and weight have a small relationship to each other, unless thrust is opposite weight, as in the case of jet fighters and space shuttles.

The location of the CG with respect to the center of lift determines to a great extent the longitudinal stability of an airplane. Center of gravity aft of the center of lift will result in an undesirable pitch-up moment during flight. An airplane with the CG forward of the center of lift will pitch down when power is reduced. This will increase the airspeed and the downward force on the elevators. This increased downward force on the elevators will bring the nose up, providing positive stability. The farther forward the CG is, the more stable the airplane. Answer (B) is incorrect because the rudder and rudder trim tab control the yaw. Answer (C) is incorrect because the relationship of thrust and lift to weight and drag affects speed and altitude.

Lift, weight, thrust, and drag are the four basic aerodynamic forces acting on an aircraft in flight.

A change in speed during straight flight will not produce any appreciable change in load, but when a change is made in the airplane's flight path, an additional load is imposed upon the airplane structure. This is particularly true if a change in direction is made at high speeds with rapid, forceful control movements. Answer (A) is incorrect because the load increases only as the angle of attack is changed, momentarily. Once the climb attitude has been set, the wings only carry the load produced by the weight of the aircraft. Answer (C) is incorrect because in a stall, the wings are not producing lift.

The center of pressure of an asymmetrical airfoil moves forward as the angle of attack is increased, and backward as the angle of attack is decreased. This backward and forward movement of the point at which lift acts, affects the aerodynamic balance and the controllability of the aircraft. Answer (A) is incorrect because the lift/drag ratio is determined by the angle of attack. Answer (B) is incorrect because lifting capacity is determined by angle of attack and airspeed.

A spin results when a sufficient degree of rolling or yawing control input is imposed on an airplane in the stalled condition. If the wing is not stalled, a spin cannot occur. Answer (A) is incorrect because the aircraft must be at a full stall in order to spin. Answer (B) is incorrect because an airplane is not necessarily stalled when in a steep diving spiral.

Loading in a tail-heavy condition can reduce the airplane's ability to recover from stalls and spins. Tail-heavy loading also produces very light stick forces at all speeds, making it easy for the pilot to inadvertently overstress the airplane. Answer (B) is incorrect because an aft CG location causes an aircraft to be less stable at all airspeeds, due to less elevator effectiveness. Answer (C) is incorrect because an aft CG location causes an aircraft to be less stable at all airspeeds, due to less elevator effectiveness.

In the half of an S-turn labeled 4-5-6, the bank should begin shallow and increase in steepness as the airplane turns crosswind and become steepest at point 6 where the turn is downwind. If the turn at point 4 is started with too steep a bank angle, the bank will increase too rapidly, and the upwind half of the S will be smaller than the downwind half. The turn will not be completed by the time the airplane is over the reference line.

Lift and thrust are considered positive forces, while weight and drag are considered negative forces and the sum of the opposing forces is zero. That is, lift = weight and thrust = drag.

Bernoulli's principle states in part that the pressure of a fluid (liquid or gas) decreases at points where the speed of the fluid increases. In other words, high-speed flow is associated with low pressure and low-speed flow with high pressure. Air traveling faster over the curved upper surface of an airfoil causes lower pressure on the top surface. Answer (A) is incorrect because these refer to Newton's third law of motion. Answer (B) is incorrect because these refer to Newton's third law of motion.

A constant gliding speed should be maintained because variations of gliding speed nullify all attempts at accuracy in judgment of gliding distance and the landing spot.

The angle of attack is the acute angle between the chord line of the wing and the direction of the relative wind. Answer (A) is incorrect because the angle of lift is not an aerodynamic term used in aviation. Answer (C) is incorrect because the angle between the chordline of an airfoil and the longitudinal axis of an aircraft is known as the angle of incidence.

A downwind landing, using the same airspeed as is used on a normal upwind landing, will result in a higher approach ground speed, with the likelihood of overshooting the desired touchdown point. The ground speed at touchdown will be higher than normal, and the ground roll will be longer. Answer (A) is incorrect because the airspeed will be the same, and the control throughout the landing roll will be less due to the higher ground speed. Answer (C) is incorrect because the ground roll will be longer, and there will be a greater likelihood of overshooting the touchdown point.

An increase in altitude has no effect on the indicated airspeed at which an airplane stalls at altitudes normally used by general aviation aircraft. This means that the same indicated airspeed should be maintained during the landing approach regardless of the elevation or the density altitude at the airport of landing. Answer (A) is incorrect because true airspeed does not decrease with increased altitude, and indicated airspeed at which an airplane stalls does not change. Answer (B) is incorrect because the indicated airspeed of the stall does not decrease with increased altitude.