CH 5 HW

If an airplane weighs 4,500 pounds, what approximate weight would the airplane structure be required to support during a 45° banked turn while maintaining altitude? A. 6,750 pounds. B. 4,500 pounds. C. 7,200 pounds.

Answer A is correct. Look on the left side of the chart in Fig. 2 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 lb. × 1.414). The closest answer choice to this value is 6,750 lb.

What determines the longitudinal stability of an airplane? A. The location of the CG with respect to the center of lift. B. The relationship of thrust and lift to weight and drag. C. The effectiveness of the horizontal stabilizer, rudder, and rudder trim tab.

Answer A is correct. 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.

What causes an airplane (except a T-tail) to pitch nosedown when power is reduced and controls are not adjusted? A. The downwash on the elevators from the propeller slipstream is reduced and elevator effectiveness is reduced. B. When thrust is reduced to less than weight, lift is also reduced and the wings can no longer support the weight. C. The CG shifts forward when thrust and drag are reduced.

Answer A is correct. 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.

What force makes an airplane turn? A. The horizontal component of lift. B. Centrifugal force. C. The vertical component of lift.

Answer A is correct. 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 airplane said to be inherently stable will A. not spin. B. require less effort to control. C. be difficult to stall.

Answer B is correct. 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 left turning tendency of an airplane caused by P-factor is the result of the A. clockwise rotation of the engine and the propeller turning the airplane counterclockwise. B. propeller blade descending on the right, producing more thrust than the ascending blade on the left. C. gyroscopic forces applied to the rotating propeller blades acting 90° in advance of the point the force was applied.

Answer B is correct. 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.

Changes in the center of pressure of a wing affect the aircraft's A. lift/drag ratio. B. aerodynamic balance and controllability. C. lifting capacity.

Answer B is correct. Center of pressure (CP) is the imaginary but determinable point at which all of the upward lift forces on the wing are concentrated. In general, at high angles of attack the CP moves forward, while at low angles of attack the CP moves aft. The relationship of the CP to center of gravity (CG) affects both aerodynamic balance and controllability.

In what flight condition must an aircraft be placed in order to spin? A. Partially stalled with one wing low. B. Stalled. C. In a steep diving spiral.

Answer B is correct. 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.

Structural damage or failure is more likely to occur in smooth air at speeds above A. VNO. B. VNE. C. VA.

Answer B is correct. Never exceed speed (VNE) is a design limit speed where load factors could be exceeded with airspeeds in excess of VNE from a variety of phenomena. Operating above this speed is prohibited since it may result in damage or structural failure.

A positive load factor of 2 at 80 mph would cause the airplane to A. break apart. B. stall. C. operate normally, as it is within the normal operating range.

Answer B is correct. The Velocity vs. G-loads chart (Fig. 72) has indicated airspeed on the horizontal axis and load factor on the vertical axis. Locate the intersection of 2 on the vertical axis and 80 on the horizontal axis. Notice that operating where these coordinates intersect, which is the blue shaded area, would be indicative of a stalled condition.

An airplane loaded with the Center of Gravity (CG) aft of the rear CG limit could A. increase the likelihood of inadvertent overstress. B. make it more difficult to flare for landing. C. make it easier to recover from stalls and spins.

Answer B is correct. The increased instability from an aft CG makes the aircraft more difficult to flare for landing.

An airplane has been loaded in such a manner that the CG is located aft of the aft CG limit. One undesirable flight characteristic a pilot might experience with this airplane would be A. a longer takeoff run. B. difficulty in recovering from a stalled condition. C. stalling at higher-than-normal airspeed.

Answer B is correct. 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.

Loading an airplane to the most aft CG will cause the airplane to be A. less stable at slow speeds, but more stable at high speeds. B. less stable at high speeds, but more stable at low speeds. C. less stable at all speeds.

Answer C is correct. 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.

As altitude increases, the indicated airspeed at which a given airplane stalls in a particular configuration will A. decrease as the true airspeed decreases. B. decrease as the true airspeed increases. C. remain the same regardless of altitude.

Answer C is correct. 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.

What load factor would be created if positive 15 feet per second gusts were encountered at 120 mph? A. 2.8 B. 3.0 C. 2.0

Answer C is correct. Begin at the bottom of Fig. 72 by locating 120 mph and then move up vertically to the positive 15-feet-per-second (+15 fps) diagonal white line. Next, move left horizontally to determine the load factor of 2.0.

During a spin to the left, which wing(s) is/are stalled? A. Neither wing is stalled. B. Only the left wing is stalled. C. Both wings are stalled.

Answer C is correct. 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.

If an airplane weighs 3,300 pounds, what approximate weight would the airplane structure be required to support during a 30° banked turn while maintaining altitude? A. 1,200 pounds. B. 3,100 pounds. C. 3,960 pounds.

Answer C is correct. 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 lb. × 1.154). The closest answer choice to this value is 3,960 lb.

If an airplane weighs 2,300 pounds, what approximate weight would the airplane structure be required to support during a 60° banked turn while maintaining altitude? A. 2,300 pounds. B. 3,400 pounds. C. 4,600 pounds.

Answer C is correct. 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 lb. × 2).

The airspeed indicated by points A and J is A. maximum structural cruising speed. B. maneuvering speed. C. normal stall speed.

Answer C is correct. Points A and J are the normal stall speed (VS1). At this speed in the clean configuration, the airplane will stall. The normal stall speed is shown on the airspeed indicator at the low-speed end of the green arc.

The amount of excess load that can be imposed on the wing of an airplane depends upon the A. abruptness at which the load is applied. B. position of the CG. C. speed of the airplane.

Answer C is correct. 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.

In what flight condition are torque effects more pronounced in a single-engine airplane? A. High airspeed, high power, high angle of attack. B. Low airspeed, low power, low angle of attack. C. Low airspeed, high power, high angle of attack.

Answer C is correct. 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.

During an approach to a stall, an increased load factor will cause the aircraft to A. have a tendency to spin. B. be more difficult to control. C. stall at a higher airspeed.

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

What is the effect of advancing the throttle in flight? A. Airspeed will remain relatively constant but the aircraft will climb. B. The aircraft will accelerate, which will cause a turn to the right. C.

Both aircraft groundspeed and angle of attack will increase. Answer C is correct. When advancing the throttle, initially the groundspeed increases due to the corresponding increase in airspeed. This causes the aircraft to pitch up, increasing the angle of attack. Airspeed and lift continue to increase until the opposing forces equalize. Then, the aircraft will climb at a relatively constant airspeed due to the increase in lift caused by excess thrust and additional airflow over the wing.

Which basic flight maneuver increases the load factor on an airplane as compared to straight-and-level flight? A. Climbs. B. Turns. Answer B is correct. C. Stalls.

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.