Performance and Limitations

Question 1

What are the four forces that act on
an airplane?

Answer 1

Weight
lift
thrust
drag

Question 2

What is an airfoil? Give some examples.

Answer 2

a streamlined surface, like an airplane wing and propeller blade designed to produce lift when air flows over it, essentially creating more lift than drag

Question 3

What is the angle of incidence, and can it be changed?

Answer 3

In aviation, the “angle of incidence” is the fixed angle between the longitudinal axis of an aircraft (from nose to tail) and the chord line of the wing, meaning it is a set design feature that generally cannot be changed during flight by the pilot; it remains constant regardless of the aircraft’s attitude while flying

Question 4

How is lift created?

Answer 4

Bernoulli’s principle

Newton’s third law of motion states that for every action, there is an equal and opposite reaction

Question 5

Explain Bernoulli’s principle?

Answer 5

Bernoulli’s principle states that as the speed of a fluid (like air or water) increases, the pressure exerted by that fluid decreases

Question 6

How does a wing stall?

Answer 6

A wing stalls when you exceed the critical angle of attack

Question 7

What are some factors that affect lift and drag?

Question 8

What are the types of drag?

Answer 8

Parasitic drag

Induced drag

Question 9

What is induced drag?

Answer 9

Induced drag is a byproduct of lift

occurring as the air flowing over the wingtip creates a low-pressure area, causing the wing to “tip” slightly and generating drag in the process; essentially, it’s a byproduct of lift and increases as the lift force increases

Question 10

What are the different types of parasitic drag?

Answer 10

Form drag
Caused by the shape of the aircraft, which creates turbulence as air flows around it. Aircraft with larger cross-sections have higher drag.

Skin friction drag
Caused by the roughness of the aircraft’s surfaces. Contaminants like dirt, snow, and mud can increase surface roughness.

Interference drag
Caused by the interaction of different air currents over the aircraft, such as where the wings meet the fuselage.
This creates eddies that restrict smooth airflow.

Parasite drag is a type of drag that doesn’t contribute to lift generation. It increases with the square of the airspeed.

Question 11

What is load factor?

Answer 11

Load factor is the ratio of the total load supported by the aircraft’s wings to the aircraft’s weight. It is measured in G-forces, where 1G equals the force of gravity at level flight. In a turn, the load factor increases because the wings must generate additional lift to counteract both gravity and the forces created by the turn. For example, in a 60° bank, the load factor doubles to 2Gs, meaning the wings are supporting twice the aircraft’s weight. This increase in load factor directly impacts the stall speed, making it higher as the load factor grows.

Question 12

What is vertical lift?

Answer 12

Vertical lift is the component of the total lift that acts perpendicular to the Earth’s surface and opposes gravity. In straight-and-level flight, vertical lift fully supports the aircraft’s weight. However, during a turn, the total lift vector tilts, reducing the amount of vertical lift available to counteract gravity. Pilots must compensate by increasing the angle of attack to maintain altitude, which adds to the load factor.

Question 13

What is Horizontal Lift?

Answer 13

Horizontal lift is the component of total lift that acts horizontally, pulling the aircraft into a turn. This is created when the lift vector tilts during a banked turn, with part of the lift directed toward the center of the turn. Horizontal lift works in conjunction with centrifugal force to keep the aircraft balanced in a coordinated turn. The sharper the turn, the greater the horizontal lift required.

Question 14

What is Centrifugal Force?

Answer 14

Centrifugal force is the outward force experienced by the aircraft as it turns, acting opposite to the direction of the horizontal lift. It increases as the turn becomes tighter. To maintain a coordinated turn, the horizontal lift must equal the centrifugal force. If the balance is disrupted, the aircraft may slip (insufficient horizontal lift) or skid (excessive horizontal lift). This relationship is crucial for smooth, controlled turning.

Question 15

What effect does load factor have on stall speed?

Answer 15

A higher load factor directly increases the stall speed of an aircraft, meaning that as the load factor increases, the aircraft will stall at a higher airspeed; essentially, the stall speed increases proportionally to the square root of the load factor.

Question 16

What are the different operational categories for aircraft?

Answer 16

Normal Category
Definition: Aircraft intended for non-acrobatic operations, such as standard maneuvers, including stalls (except whip stalls).
Limitations: Maximum load factor of +3.8Gs and -1.52Gs.
Example Use: Private or business flights.

Utility Category
Definition: Aircraft certified for limited acrobatic operations, including spins (if approved) and steep turns.
Limitations: Maximum load factor of +4.4Gs and -1.76Gs.
Example Use: Training flights for certain maneuvers.

Acrobatic Category
Definition: Aircraft designed for unlimited acrobatic maneuvers without restrictions beyond structural limitations.
Limitations: Load factors vary based on design but exceed utility category limits.
Example Use: Airshows or aerobatic competitions.

Restricted Category
Definition: Aircraft used for specific, non-standard purposes such as agricultural spraying, firefighting, or banner towing.
Limitations: Limited to the specified operation and cannot carry passengers for hire.
Example Use: Crop dusting or aerial photography.

Experimental Category
Definition: Aircraft used for research, development, exhibition, or amateur-built purposes.
Limitations: May not be used for commercial operations or carrying passengers for hire.
Example Use: Homebuilt aircraft or flight testing.

Transport Category
Definition: Aircraft certified for transporting passengers or cargo under rigorous design and safety standards.
Limitations: Typically applies to larger, multi-engine aircraft.
Example Use: Airliners or large freight carriers.

Light-Sport Category
Definition: Aircraft designed for simple operation and limited performance, typically flown under a sport pilot certificate.
Limitations: Max takeoff weight of 1,320 lbs (1,430 lbs for seaplanes).
Example Use: Recreational flying.

Question 17

What category does
your aircraft fall under?

Answer 17

Normal Category
Definition: Aircraft intended for non-acrobatic operations, such as standard maneuvers, including stalls (except whip stalls).
Limitations: Maximum load factor of +3.8Gs and -1.52Gs.
Example Use: Private or business flights.

Question 18

Define maneuvering speed

Answer 18

Maneuvering speed is the maximum speed at which an aircraft’s flight controls can be fully deflected without damaging the aircraft’s structure. Full deflection refers to the maximum value of a flight control surface’s input.

Question 19

What is aircraft stability?

Answer 19

the ability of an aircraft to maintain or return to its original flight condition after being disturbed by an external force

Question 20

What is aircraft controllability?

Answer 20

the ability of an aircraft to respond to pilot controls, particularly in terms of flight path and attitude. It’s the quality of the aircraft’s response to pilot control inputs, regardless of its stability characteristics.

Question 21

What is a spin?

Answer 21

a severe type of stall where an aircraft enters a corkscrew-like descent due to an uncoordinated stall, causing one wing to stall more than the other, resulting in a rotating motion around the vertical axis while descending at a shallow angle;

Question 22

What are the stages of a spin?

Answer 22

Stall: The airplane must be stalled to start a spin.

Incipient: The first few unbalanced turns.

Developed: Balanced forces, though not necessarily auto-rotating.

Recovery: Control inputs might take one turn or more to take effect.

Question 23

How do you recover from a spin?

Answer 23

Step 1) P: Power To Idle. The first step in spin recovery is reducing your throttle to idle.

Step 2) A: Ailerons Neutral

Step 3) R: Rudder Opposite

Step 4) E: Elevator Forward.

Question 24

What are the effects of a forward CG?

Answer 24

A forward center of gravity makes the aircraft more stable but harder to control. It increases drag, reducing cruise speed and fuel efficiency, and causes a higher stall speed due to greater wing loading. During takeoff and landing, more elevator force is required to rotate or flare, and in extreme cases, the elevator may lack sufficient authority. This also results in a longer takeoff roll and reduced overall performance

Question 25

What are the effects of a aft
CG?

Answer 25

An aft center of gravity reduces stability, making the aircraft more difficult to control and more prone to over-controlling. It improves performance by reducing drag, increasing cruise speed, and decreasing fuel consumption. However, stall speed is lower, and recovery from a stall or spin is more challenging due to reduced elevator effectiveness. An aft CG can also make landing more difficult as it requires less force to pitch the nose up, increasing the risk of over-rotation or tail strikes.

Question 26

What are wingtip vortices? How are they formed?

Answer 26

Wingtip vortices are spiraling air patterns that form at the wingtips of an aircraft as it generates lift. They occur because of the pressure difference between the high-pressure air beneath the wing and the low-pressure air above it. Air flows outward under the wing and upward around the wingtip, creating a swirling motion.

Question 27

What aircraft characteristics create the strongest vortices?

Answer 27

These vortices are strongest when the aircraft is heavy, clean (no flaps or spoilers deployed), and slow, such as during takeoff or landing. They contribute to wake turbulence, which poses a hazard to other aircraft, especially smaller ones, following too closely.

Question 28

How should you land and lake off if they are wake turbulence in front of you?

Answer 28

when landing you touch down past the wake turbulence

when take off you rotate before wake turbulence

Question 29

What are the max takeoff weights, and max landing weight for your aircraft?

Answer 29

For a Cessna 172S:

Max Takeoff Weight (MTOW): 2,550 lbs
Max Landing Weight (MLW): 2,550 lbs
For a Cessna 172R:

Max Takeoff Weight (MTOW): 2,450 lbs
Max Landing Weight (MLW): 2,450 lbs

Question 30

How does weight affect takeoff and landing performance?

Answer 30

Increased weight increases takeoff roll and landing distance due to higher inertia and lift requirements.

Heavier aircraft also require higher speeds for liftoff and touchdown, leading to reduced climb performance and longer braking distances.

Question 31

What other factors affect takeoff and landing distances?

Answer 31

Runway Slope: Uphill increases required distances; downhill decreases them.

Wind: Headwind reduces distances; tailwind increases them.

Surface: Grass, snow, or wet runways increase roll distances.

Question 32

What affect does a high density altitude have on takeoff and landing
performance?

Answer 32

High density altitude reduces air density, which decreases engine performance, propeller efficiency, and wing lift. This results in longer takeoff rolls, slower climb rates, and faster ground speeds on landing, increasing landing distance.

Question 33

When would you want to use Vx? Vy?

Answer 33

Use Vx (best angle of climb) when a steep climb is needed, such as to clear obstacles immediately after takeoff.

Use Vy (best rate of climb) to achieve the fastest climb to altitude over time. Ideal for improving overall climb performance during normal operations.

Question 34

What is ground effect?

Answer 34

Ground effect occurs when the aircraft is within one wingspan of the ground, reducing induced drag

Question 35

What is density altitude?

Answer 35

Density altitude is the pressure altitude corrected for non standard temperature

*and humidity. It reflects the air’s density, directly affecting aircraft performance.`

Question 36

How does temperature, altitude, and humidity affect density altitude?

Answer 36

Higher Temperature: Increases density altitude, reducing performance.

Higher Altitude: Reduces air density, increasing density altitude.

Higher Humidity: Makes air less dense, increasing density altitude and degrading performance.

Question 37

What is pressure altitude?

Answer 37

The height above the datum plane 29.92

Pressure altitude is the altitude indicated when the altimeter is set to the standard pressure of 29.92 inHg. It is used to determine performance data and serves as the baseline for calculating density altitude.

Question 38

What would you want to do if you are landing in gusty conditions?

Answer 38

Increase approach speed slightly to maintain better control and avoid stalling in sudden gusts. Aim to land on the first third of the runway and avoid prolonged float.

Question 39

What is your aircraft’s service ceiling?

Answer 39

*approximately 14,000 feet MSL.

Question 40

What are the different types of stability?

Answer 40

Static or dynamic

static is your initial reaction

dynamic is the reaction over time

each one has a positive, neutral, and negative

neutral is when the plane is disturbed and will return to normal

Positive i