PT2 CHP6 Aerodynamic Forces Flashcards
Describe what the forces are when an aircraft turns.
- Total lift = a horizontal lift component and a vertical lift component
- The opposing force of the horizontal lift component is centrifugal force (load factor/G force)
- The vector between the centrifugal force (load factor) and weight is load factor
Which component of the force vectors causes the aircraft to turn right or left
Horizontal Component of Lift
What is a coordinated turn?
- When making a turn, apply the correct amount of rudder to ensure the turn is coordinated (ball on turn coordinator is in the middle)
- Horizontal component of lift = centrifugal component (load factor)
Which force vectors determine whether a turn is coordinated?
- If the horizontal component of lift equals the centrifugal force (load factor), then the turn will be coordinated
In a coordinated turn, what is a standard rate turn?
3˚ per second
A turn at a rate of 3˚ per second is known as what?
A coordinated turn
What is a slipping turn?
- An uncoordinated turn
- The nose is facing to the outside (opposite) direction of the turn
- the centrifugal force (load factor) vector is shorter than the horizontal component of the lift
- the ball is on the left side of turn/slip coordinator
An uncoordinated turn when the nose is facing to the outside (opposite) direction of the turn and results in the centrifugal force (load factor) vector to be shorter than the horizontal component of the lift is known as what?
A slipping turn
How do you counteract a slipping turn?
Kick the rudder to the left
By kicking the rudder to the left in a slipping turn, what will the result be?
This coordinate the turn
What is skidding turn?
- An uncoordinated turn
- The horizontal force will be shorter than the centrifugal component (load factor)
- the nose is facing to the inside direction of the turn
- the ball is on the right side of turn/slip coordinator
An uncoordinated turn when the horizontal force is shorter than the centrifugal component (load factor), which causes the nose is facing to the inside direction of the turn (the ball is on the right side of turn/slip coordinator), is known as what?
Skidding turn
What is the danger of a skidding turn?
It can cause the aircraft to enter a spin
How do you counteract a skidding turn?
Kick the rudder to the right
By kicking the rudder to the right in a skidding turn, what will the result be?
Coordinate the turn
Is a slipping or a skidding turn more dangerous and why?
A slipping turn is more dangerous because it can cause the aircraft to enter a spin
What is Rate of Turn (ROT)?
The number of degrees (˚) of heading change per second that an aircraft makes
The number of degrees (˚) of heading change per second that an aircraft makes is known as what?
Rate of Turn (ROT)
What must be done to maintain the same rate of turn?
If the speed increases, the bank angle must be increased
What is the Radius of Turn?
- The distance (radius) it takes to fly a distance based on the rate of turn
- Directly related to the rate of turn
- If bank angle is constant and speed is increased, radius of turn will increase
- If the bank angle is increased and speed is constant, radius of turn will decrease
- Remember, the steeper the turn, the more load factor is felt
Describe the Radius of Turn if the airspeed is constant.
- If the airspeed is constant at 50 knots, then the bank angle will change the radius of turn.
- The steeper (narrow angle) the bank angle at a constant airspeed, shorter radius of turn
- The shallower (wide angle) the bank angle at a constant airspeed, longer radius of turn
Describe the Radius of Turn if the bank angle is constant.
- If the bank angle is constant (20˚), the radius of turn will differ based on the speed.
- The slower the aircraft with a constant bank angle, will have a shallower radius of turn.
- The faster the aircraft with a constant bank angle, will have a steeper radius of turn.
Describe the forces (RW and lift) before the plane climbs.
- Before the plane climbs, the relative wind (RW) is parallel and opposing the aircraft; the Lift will be perpendicular to the RW
Describe the forces (RW and lift) to get the aircraft off the ground.
- More lift will be required, increase the AOA and the RW will be parallel to the nose
- For a split second the lift will increase and result in the aircraft to climb
Describes the forces (RW and lift) once the aircraft is established in a climb.
- Once established in the climb, the RW is parallel to the path; the lift is perpendicular
What is a stall?
A rapid decrease in lift caused by separation of the airflow from the wing’s surface.
A rapid decrease in lift caused by separation of the airflow from the wing’s surface is known as what?
A stall
Is lift still generated when the aircraft stalls?
Yes, just not enough to sustain flight
When can a stall occur?
At any pitch attitude or speed
When does a stall occur?
When the critical angle of attack is reach?
What is the critical angle of attack?
The angle at which at which if exceeded, the airfoil cannot produce enough lift to sustain flight
What occurs when CLmax is reached and why?
The aircraft stalls because the critical angle of attacked was reached
What is laminar airflow?
The flow of air over the airflow, which relates to the ability to stick. The better the laminar flow, the better the air will flow and vice versa
As the angle of attack increases, how does that affect laminar airflow?
There is less laminar airflow
Which part of the aircraft is designed for stalls and why?
Wings are designed to stall at the root in order to main aileron control due to stalls creating a nose-down tendency
Why is it important to recognize a potential stall?
In order to PREVENT it from happening
What are stall warnings?
A system that is installed to recognize when the angle of attack is close to critical (some aircraft have stick shakers and others have stall horns)
What is one sign of the controls when close to a stall?
The controls will feel “mushy”, they won’t have the same reaction when flight at higher speeds)
What are the possible signs of a stall?
- High pitch (vision, wont be able to see the ground)
- Engine sound (hearing, at a high pitch or slow speed, quiet engine)
- Buffer/shaking (feel, the aircraft will shake)
What is the key to recovering from a stall?
- Reducing the angle of attack from the critical angle of attack
- Push on the controls to reduce the angle of attack and add power as necessary
What are two types of stalls for training?
Power-on and Power-off
When is a power-on stall?
Simulates a nose-high attitude during a high-power maneuver (TO/GA, apply full power, pitch too much, results in slow airspeed and start to stall)
A nose-high attitude during a high-power maneuver simulates what?
A power-on stall
What is a power-off stall?
Simulates stretching a glide after the engine has failed, or low on the approach to landing
Stretching a glide after the engine has failed, or low on the approach to landing simulates what?
A power-off stall
What is a spin?
An aggravated stall that occurs when the aircraft is stalled in a yawed condition
i. The aircraft will continue to climb, reach the critical angle of attack, stall while in a yawed position, then fall forward nose down and spin
An aggravated stall that occurs when the aircraft is stalled in a yawed condition is known as what?
A spin
Why does a spin occur?
The outboard wing is less stalled than the inboard wing
What is the process to recover from a stall?
- The nose will pitch up due to the stall
- Pus the nose down
What is the process to recover from a spin?
- Reduce power to idle (due to gaining a lot of speed because of the forward nose-down attitude)
- Ailerons to neural
- Apply full opposite rudder against the rotation (due to the rudder being used the wrong way)
- Apply positive, brisk, and straight forward elevator
- Neutralize the rudder after spin rotation stops
- Apply back elevator pressure to return to level flight
(NEVER practice a spin in an aircraft not approved for spins or practice spins alone)
What are load factors measure in?
Gs (acceleration of gravity
How many Gs is an object at rest?
1G
When are G forces generated?
- when the aircraft turns
i. aircraft are designed to withstand a certain amount of positive (felt when being pushed into your seat, then pull back) and negative (push on the control abruptly, then start to life off the seat) G forces
What may be a result of too many G forces?
It can lead to overland and structure damage/failure
How is the stall speed affected by an increase in load factor and why?
- In straight/level flight, lift = weight
- When a turn is initiated, we must make sure to have the same amount of lift as in straight/level, which lift is split into horizontal and vertical components
- To generate more lift, pull back on the controls, which will increase the angel of attack (AOA), but also increase it closer to the critical angle of attack (CAOA)
- Along with lift increase, the centrifugal forces will increase
Stall speed is increased, which will result in stalling the airplane sooner
- The critical angle of attacked is reach much sooner than at a lower angle of attack, gives the aircraft less time to slow down. This causes the aircraft a faster speed than normal.
What are the categories and load factor limits?
- Normal, 3.8 to -1.52G (exceeding the limits may result in bending a part of the aircraft)
- Utility (mild acrobatic and sport), 4.4 to -1.76G
- Acrobatic, 6.0 to -3.00G
