FAA Written Private Pilot Test – Airplane & Aerodynamics

Extending the flaps increases the wing camber and the angle of attack of the wing. This increases wing lift and induced drag, which enables the pilot to make steeper approaches to a landing without an increase in airspeed.

Extending the flaps increases the wing camber and the angle of attack of the wing. This increases wing lift and induced drag, which enables the pilot to increase the angle of descent without increasing the airspeed.

The rudder is used to control yaw, which is rotation about the airplane's vertical axis.

Lift is produced by the wings and opposes weight, which is the result of gravity. Thrust is produced by the engine/propeller and opposes drag, which is the resistance of the air as the airplane moves through it.

The four forces (lift, weight, thrust, and drag) that act on an airplane are in equilibrium during unaccelerated flight.

When the airplane is in straight-and-level flight (assuming no change of airspeed), it is not accelerating, and therefore lift equals weight and thrust equals drag.

The angle of attack is the angle between the wing chord line and the direction of the relative
wind. The wing chord line is a straight line from the leading edge to the trailing edge of the wing. The relative wind is the direction of airflow relative to the wing when the wing is moving through the air.

The angle of attack is the angle between the wing chord line and the direction of the relative wind. The wing chord line is a straight line from the leading edge to the trailing edge of the wing. The relative wind is the direction of airflow relative to the wing when the wing is moving through the air.

The angle between the relative wind and the wing chord line is the angle of attack. The wing chord line is a straight line from the leading edge to the trailing edge of the wing.

A given airplane wing will always stall at the same angle of attack regardless of airspeed, weight, load factor, or density altitude. Each wing has a particular angle of attack (the critical angle of attack) at which the airflow separates from the upper surface of the wing and the stall occurs.

All the performance factors of an airplane are dependent upon air density. As air density decreases, the airplane stalls at a higher true airspeed. However, you cannot detect the effect of high density altitude on your airspeed indicator. Accordingly, an airplane will stall in a particular configuration at the same indicated airspeed regardless of altitude.

In order to enter a spin, an airplane must always first be stalled. Thereafter, the spin is caused when one wing becomes less stalled than the other wing.

In order to enter a spin, an airplane must always first be stalled. Thereafter, the spin is caused when one wing is less stalled than the other wing. In a spin to the left, the right wing is less stalled than the left wing.

Frost does not change the basic aerodynamic shape of the wing, but the roughness of its surface spoils the smooth flow of air, thus causing an increase in drag and an early airflow separation over the wing, resulting in a loss of lift.

Frost does not change the basic aerodynamic shape of the wing, but the roughness of its surface spoils the smooth flow of air, thus causing an increase in drag and an early airflow separation over the wing, resulting in a loss of lift.

Frost that is not removed from the surface of an airplane prior to takeoff may make it difficult to get the airplane airborne at normal takeoff speed. The frost disrupts the airflow over the wing, which increases drag.

Ground effect is due to the interference of the ground (or water) surface with the airflow patterns about the airplane in flight. As the wing encounters ground effect, there is a reduction in the upwash, downwash, and the wingtip vortices. The result is a reduction in induced drag. Thus, for a given angle of attack, the
wing will produce more lift in ground effect than it does out of ground effect.

Ground effect is most usually recognized when the airplane is within one-half of the length of its wingspan above the surface. It may extend as high as a full wingspan length above the surface. Due to an alteration of the airflow about the wings, induced drag decreases, which reduces the thrust required at low airspeeds. Thus, any excess speed during the landing flare may result in considerable floating.

Ground effect reduces the upwash, downwash, and vortices caused by the wings, resulting in a decrease in induced drag. Thus, thrust required at low airspeeds will be reduced and any excess speed at the point of flare may cause considerable floating.

Due to the reduction of induced drag in ground effect, the airplane may seem capable of becoming airborne well below the recommended takeoff speed. However, as the airplane rises out of ground effect (a height greater than the wingspan) with a deficiency of speed, the increase in induced drag may result in very marginal initial climb performance. In extreme cases, the airplane may become airborne initially, with a deficiency of airspeed, only to settle back on the runway when attempting to fly out of the ground effect area.

When the wings of an airplane are not level, the lift is not entirely vertical and tends to pull the airplane toward the direction of the lower wing. An airplane is turned when the pilot coordinates rudder, aileron, and elevator to bank in order to attain a horizontal component of lift.

An inherently stable airplane will usually return to the original condition of flight (except when in a bank) if disturbed by a force such as air turbulence. Thus, an inherently stable airplane will require less effort to control than an inherently unstable one.

The location of the center of gravity with respect to the center of lift determines, to a great extent, the longitudinal stability of the airplane. Positive stability is attained by having the center of lift behind the center of gravity. Then the tail provides negative lift, creating a downward tail force, which counteracts the nose's
tendency to pitch down.

The recovery from a stall in any airplane becomes progressively more difficult as its center of gravity moves backward. Generally, airplanes become less controllable, especially at slow flight speeds, as the center of gravity is moved backward.

The relative wind on the tail is the result of the airplane's movement through the air and the propeller slipstream. When that slipstream is reduced, the horizontal stabilizer (except a T-tail) will produce less negative lift and the nose will pitch down.

Airplanes become less stable at all speeds as the center of gravity is moved backward. The rearward center of gravity limit is determined largely by considerations of stability.

The effect of torque increases in direct proportion to engine power and inversely to airspeed. Thus, at low airspeeds, high angles of attack, and high power settings, torque is the greatest.

Asymmetric propeller loading (P-factor) occurs when the airplane is flown at a high angle of attack. The downward-moving blade on the right side of the propeller (as seen from the rear) has a higher angle of attack, which creates higher thrust than the upward moving blade on the left. Thus, the airplane yaws around the vertical axis to the left.

P-factor or asymmetric propeller loading occurs when an airplane is flown at a high angle of attack because the downward-moving blade on the right side of the propeller (as seen from the rear) has a higher angle of attack, which creates higher thrust than the upward moving blade on the left. Thus, the airplane yaws
around the vertical axis to the left.

The amount of excess load that can be imposed on the wing depends upon how fast the airplane is flying. At low speeds, the maximum available lifting force of the wing is only slightly greater than the amount necessary to support the weight of the airplane. Thus, any excess load would simply cause the airplane to stall. At high speeds, the lifting capacity of the wing is so great (as a result of the greater flow of air over the wings) that a sudden movement of the elevator controls (strong gust of wind) may increase the load factor beyond safe limits. This is why maximum speeds are established by airplane manufacturers.

Turns increase the load factor because the lift from the wings is used to pull the airplane around a corner as well as to offset the force of gravity. The wings must carry the airplane's weight plus offset centrifugal force during the turn. For example, a 60° bank results in a load factor of 2; i.e., the wings must support twice the weight they do in level flight.

The greater the load (whether from gross weight or from centrifugal force), the more lift is required. Therefore, an airplane will stall at higher airspeeds when the load and/or load factor is increased.

Note on Fig. 2 that, at a 60° bank angle, the load factor is 2. Thus, a 2,300-lb. airplane in a 60° bank would require its wings to support 4,600 lb. (2,300 x 2).

Look on the left side of the chart in Fig. 2 to see that, at a 30° bank angle, the load factor is 1.154. Thus, a 3,300-lb. airplane in a 30° bank would require its wings to support 3,808.2 lb. (3,300 x 1.154). This answer is closest to this value.

Look on the left side of the chart under 45° and note that the load factor curve is 1.414. Thus, a 4,500-lb. airplane in a 45° bank would require its wings to support 6,363 lb. (4,500 x 1.414). This answer is closest to this value.