Performance, Limitations, & factors that affect them

Define Performance

The action or process of carrying out or accomplishing an action, task, or function

What factors (limitations) are most affected by performance?

• T/O & LDG distance

• Climb rate/ Ceiling

• Payload

• Range

• Speed

• Maneuverability

• Stability

• Fuel burn

What are some things about an Airport Environments Runways & Layout that would affect performance?

Whats the runway surface made of?

• Any surface that is not hard and smooth increases ground roll

• Braking Effectiveness 

  • Soft surfaces slow an aircraft much faster than smooth and slick surfaces

  • Wet runways reduce braking effectiveness and can result in hydroplaning 

• Runway Gradient: The change in height over the length of the runway, expressed as a percentage

• Runways available based on wind conditions

What are some things about an Airport Environments Surrounding Terrain & Obstacles that would affect performance?

Various Obstacles including towers, buildings, construction equipment, Trees?

• Can the aircraft clear the obstacles based on the specific conditions?

• Is a max angle versus max rate of climb required

• Are there specific noise abatement or climb rate procedures requiring specific performance

Differences between calculated & actual performance?

Even with having all the numbers, your pre-flight calculations will never be perfect

• Stick to the POH only for any aircraft specific calculations needed

• We plan for set configurations for a flight, deviating from that could mean less performance

What factors does weight & balance directly affect with the aircraft?

• Weight affects Performance

• Balance affects Stability

What are some affects increasing weight has on the aircraft T/O & LDG?

• Higher T/O & LDG speed

• Longer T/O run & LDG roll

• Reduced rate and angle of climb

What are some affects increasing weight has on the aircraft cruise performance?

• Lower maximum altitude

• Slower cruise speed

• Reduced range & Increased fuel consumption

What are some effects of overloading the weight of the aircraft?

• Degraded climb performance

  • May not even be able to takeoff

• Overheating during climbs

  • Added wear on engine parts

• Over stressing the aircraft

How does CG affect an aircraft's controllability?

Stability & controllability have an inverse relationship:

• As stability increases, the control forces required to overcome that stability become greater, meaning controllability decreases.

What are the effects on Stability & Controlability with a to far forward CG?

• Problems controlling and raising the nose, especially at low airspeeds (takeoff and landing)

• “Heavier” and consequently slower than the same airplane with a further aft CG

  • Requires a higher AOA to maintain altitude, resulting in more drag which produces a higher stalling speed

• More controllable in a stall

  • The longer arm from the CG makes the elevator more effective

    • The nose heavy loading results in a tendency for the nose to drop, or assist in breaking the stall

What are the effects on Stability & Controlability with a to far Aft CG?

• It produces very light control forces which makes it very easy to over-stress the airplane

• “Lighter” and consequently faster than the same airplane with a more forward CG

  • Less back pressure & lower AOA needed to maintain altitude

  • Lower AOA = Less drag, & produces a Lower stall speed

• Less controllable in a stall/spin

  • Due to the shorter arm of the CG to the elevator

    • Greater deflection is required to produce the same result as with a farther forward CG

      • Can lead to a Flat spin

What are the effects on Stability, Controlability, & CG with a Laterally Loaded Aircraft?

Unbalanced loading can have adverse effects 

• Trim, or maintain constant control pressure

  • Increases drag, decreases efficiency

When is Parasite drag most prevalent?

At higher airspeeds

• More air moving over uneven surface of aircraft

When is Induced drag most prevalent?

At low airspeeds

• Lower AOA & smaller Vortices

Define Thrust

Force or pressure exterted on an object

Define Power

A measurement of the rate of performing work &/or transferring NRG

• Horsepower or kilowatts

Define Angle of Climb (AOC)

Comparison of altitude gained relative to distance traveled

• Vx is used for this performance

Define Rate of Climb (ROC)

Comparison of Altitude gained relative to the time needed to reach that altitude

• Vy is used for this performance

Range VS Endurance?

Range

• Amount of distance you can travel

Endurance

• Amount of time you can stay in the air

What are the dangers of exceeding aircraft limitations?

• Needing more runway than is available for T/O or LDG

• Not enough performance to clear any obstacles

• Not having enough fuel to reach your destination

• Damage caused by exceeding strucural or aerodynamic limits

• Loss of control for T/O & LDG by exceeding Max crosswind component