Weight and Balance

The manufacturer establishes a maximum allowable weight for each airplane and permissible distribution of that weight

Because they affect the performance characteristics related to stability and controlability

When an airplane is in a state of equilibrium.

When the airplane resists pitching motions such as nose up or nose down

The ability of an airplane to respond appropriately to control surface movements to achieve desired flight condition

How much tail down force will be needed to fly at a constant pitch attitude

The tail down force required for straight and level flight decreases

The tail down force required for straight and level flight increases

The plane will stall at a higher speed because stalling angle of attack is reached at a higher airspeed. The wing is flown with a higher angle of attack to get additional lift to overcome the tail down force.

The airplane will cruise faster because of reduced drag

Increased take off speed
Increased ground roll
Decreased rate of climb
Decreased maximum altitude capability
Decreased operational range
Decreased maneuverability
Decreased controllability
Increased stall speed
Increased approach speed
Increased landing distance

Because performance is affected by how much the airplane weighs and the location of the CG of that weight.

Weight and Tail Down Force

A location in the aircraft that is identified by a number designating its distance from the datum. The datum is station zero