User Guide

Flight Simulator

20002000

2000

Microsoft

artificial curve induced by the wing’s engineered

shape (Figure 3). Air flowing below the wing’s flat-

bottom surface remains relatively unbent as it moves

aft.

Because air flowing over the wing bends, it is forced

to travel a greater distance than the air flowing

underneath. Because it travels a greater distance,

the bent air must move faster on its journey over the

wing. It’s this relative increase in wind speed above

the wing that lowers pressure and produces lift.

It’s test tube and Bunsen burner time again;

let’s try another experiment.

1. Take a piece of writing paper and hold

it in such a way that the top surface is

curved downward as shown in Figure

4. With a little imagination, you can see

how the top of the bent paper is similar

in appearance to the wing’s upper

curved surface.

2. Blow over the top of the paper.

What happens? The paper should rise upward. (Do this for kids sometime. They’ll think you’re magic.)

Increasing the velocity of air over a surface reduces the atmospheric pressure on that surface. This

means you have low pressure above the wing and high pressure underneath. Since high pressure

always moves toward low pressure, the wing (which just happens to be in the way) is pushed upward

in the process. Known as Bernoulli’s (pronounced Brr-NEW-lee) principle, this effect is responsible

for much of the lift produced by the wing (and explains the sightings of at least one or two toupees

on windy days).

At a cruise speed of 110 knots, the wing’s shape (its engineered curvature) produces enough lift to

counterbalance the airplane’s weight. The airplane maintains its altitude at a relatively low pitch

attitude. When power is reduced, the airplane slows down, resulting in the airflow over the wing

decreasing in speed. This, in turn, results in a decrease in lift unless we take corrective action to keep

the lift constant. Remember, if lift is less than weight, the airplane will be unable to maintain altitude.

What do we do? We must increase the angle of attack.

Figure 3

Figure 4