NIFE Aerodynamics 2-4-1 Maneuvering and Hazards

Question 1

Describe a slip

Answer 1

Caused by opposite or insufficient rudder in the desired direction of turn. The yaw moment is to the outside of the turn. If a stall occurs, the wings will roll to level.

Question 2

When can a slip be used

Answer 2

Good for crosswind landings or when trying to increase rate of descent without increasing speed

Question 3

Describe a skid

Answer 3

Caused by using too much rudder in the desired direction of the turn. Yaw moment toward inside of turn. Plane will roll inverted if a stall occurs

Question 4

Describe the effects of low speed P-factor

Answer 4

The yawing moment caused by one prop blade creating more thrust than the other. The down-going blade will create more thrust, causing a yaw in the opposite direction.

Question 5

Two requirements for P-factor to have a noticeable effect

Answer 5

1. Engine must be at high power

2. The thrust axis must be displaced from the relative wind

Question 6

When will P-factor be most noticeable

Answer 6

At AOAs significantly different from cruise AOA, such as high AOA climbs

Question 7

Describe the effects of slipstream swirl

Answer 7

The corkscrewing motion of the air will flow around the fuselage until it hits the vertical stabilizer where it increases the AOA on the stabilizer, causing a leftward yaw.

Question 8

When will slipstream swirl be most noticeable

Answer 8

At a high power setting and a low airspeed

Question 9

How to compensate for slipstream swirl

Answer 9

Right rudder and lateral control stick inputs

Question 10

Define load factor

Answer 10

Ratio of the total lift to an airplane’s weight, also called G’s

Question 11

Describe the relationship between load factor and angle of bank for a level constant speed turn

Answer 11

In a turn, the lift vector is divided into a horizontal and vertical component. Total lift is equal to total weight in level flight, but in a turn, only the vertical component of the lift vector opposes weight. The AOA must be increased to increase lift.

Question 12

Define limit load factor

Answer 12

The greatest load factor an airplane can sustain without any risk of permanent deformation.

Question 13

Define ultimate load factor

Answer 13

The maximum load factor that the airplane can withstand without structural failure. Some permanent deformation may occur but failure will not occur

Question 14

Overstress/Over-G

Answer 14

The condition of possible permanent deformation or damage that results from exceeding the limit load factor. Damage that maybe done to equipment mounted in the airframe due to the wing being overstressed. Always report to maintenance

Question 15

Define elastic limit

Answer 15

The maximum load that may be applied to a component without permanent deformation

Question 16

Describe the boundaries of the safe flight envelope

Answer 16

Within:

• Accelerated stall lines
• Pos and neg limit load factors
• Pos and neg ultimate load factors
• Redline airspeed (Vne)

Question 17

Accelerated stall lines

Answer 17

(aka, lines of max lift) Represent the max load factor that an airplane can produce based on airspeed.

Question 18

What determines accelerated stall lines

Answer 18

CLmax AOA

Question 19

Why are most maneuvers performed with positive accelerations

Answer 19

Pilots cannot sustain a negative acceleration much greater than three G’s. Therefore, designers can save some weight by reducing the plane’s ability to sustain negative G’s

Question 20

Define maneuver point

Answer 20

The point where the accelerated stall line and the limit load factor line intersect.

Question 21

What is the IAS at the maneuver point called

Answer 21

Maneuver speed (Va). Also called cornering velocity

Question 22

Define maneuvering speed/cornering velocity

Answer 22

The lowest airspeed at which the limit load factor can be reached.

Question 23

What is significant about the maneuver speed

Answer 23

Below it, we can never exceed the limit load factor because the plane will stall before it is reached

Question 24

Redline airspeed (Vne)

Answer 24

The highest airspeed that an airplane is allowed to fly without causing structural damage

Question 25

What determines Vne

Answer 25

• MCRIT (critical mach number)
• Airframe temp
• Excessive structural loads
• Control ability limits

Question 26

Describe wake turbulence

Answer 26

Wingtip vortices are spiraling masses of air that are formed at the wingtip when an airplane produces lift and continue aft. This disturbance is often called “jet wash” or “wake turbulence”. Strength is directly related to induced drag

Question 27

Characteristics that increase wake turbulence

Answer 27

• weight
• speed
• wing shape

(aka, heavy, slow, and clean)

Question 28

Wake turbulence characteristics

Answer 28

• All planes produce a vortex hazard
• Not generated until the nosewheel leaves or touches the ground
• Lowering flaps will help decrease vortices
• Sink at 400-500 fpm
• Level off about 900’ below flight path

Question 29

Hazards of wake turbulence

Answer 29

Loss of control due to induced roll

Question 30

Describe procedures to avoid wake turbulence

Answer 30

• Cereal bowl

- 2 minute interval

Question 31

Define wind shear

Answer 31

A sudden change in wind direction and/or speed over a short distance in the atmosphere.

Question 32

Describe how wind shear can be a hazard during landing

Answer 32

As airflow changes, so does dynamic pressure over the wing, affecting lift. Do not make aggressive corrections