Performance and Limitations

What factors affect aircraft performance?

Temperature, wind, airplane configuration, weight and balance loading, the airport conditions.

How does temperature affect performance?

The warmer the air the less performance you get from the airplane?

Why does temperature affect performance?

Higher temperatures have lower air density

How does air density effect performance?

Hot air means the air density is lower and there are less air molecules available to flow over the aircraft surfaces and into the engine

Why do we takeoff into a headwind?

To help move more air in and around the airplane to generate lift over the wings

Explain how lift is created

There is low pressure on the top of the wing and high pressure on the bottom of the wing. When air moves over the wings it is deflected downward, and from the downward deflection comes an upward force known as lift.

Why do we do weight and balance calculations?

To make sure our aircraft is within its weight and CG loading limits

What is the forward CG limit?

82 inches aft of the datum

What is the aft CG limit?

93 inches aft of the datum

What are characteristics of a forward CG?

Harder to rotate and flare. Easier to recover from a stall, better stability, slower cruising speed, increased stall speed.

What are the characteristics of an aft CG?

Easier rotation, harder to recover from a stall, less stability, higher cruising speed, lower stall speed.

how does humidity effect performance?

High humidity decreases performance due to the water molecules in the air taking up space

what do flaps do? How?

They allow for a steeper descent without increasing airspeed by increasing lift and drag

What are the different types of drag?

parasite drag and induced drag

what are the different types of parasite drag?

Form drag, skin friction drag, and interference drag

Explain form drag

Air moving around different aircraft surfaces.

Explain interference drag

different airflows disrupting each other

Explain skin friction drag

At the microscopic level the airframe/paint is rough and that causes air molecules to get stuck on the rough parts.

What is induced drag?

Drag as a result of lift

What is an example of induced drag?

wingtip vortices

how do you calculate pressure altitude?

standard altimeter divided by current altimeter times 1000 plus the field elevation

how do you calculate density altitude?

current temp minus standard temp times 120 plus the pressure altitude

when would you use Vx over Vy?

When you have an obstacle ahead that you want to clear or anytime you want to get up in the shortest amount of distance

what is Va?

Maneuvering speed. The maximum speed at which you can apply one full deflection of a flight control without structural damage.

What happens if you exceed your maneuvering speed?

You run the risk of structural damage if you apply a full deflection of a control surface.

How do you calculate maneuvering speed?

Square root of landing weight over max gross weight times the maximum maneuvering speed (113)

why do we use our landing weight instead of our takeoff weight?

It will give us a more conservative maneuvering speed because the lighter the aircraft the lower the maneuvering speed.

what is Vg and what does it give you?

Best glide speed and it