Chapter 4 Principles of Flight

Principles of Flight

True altitude

above sea level

Define pressure and what it is measured in.

Pressure is perpendicular force of an object and is measured in force exerted per square inch of an object PSI.

What is standard atmosphere defined?

a surface temperature of 59F/15C, and surface pressure of 29.92 (“hg) or surface of 1,013.2 mb

Standard temperature lapse rate

up to 36,000ft the temperature decreases 3.5F/2c for every 1000ft gained in altitude

(International standard atmosphere)

standard pressure lapse rate

up to 10,000ft the pressure decreases 1”hg for every 1000ft decreased in altitude

(International standard atmosphere)

All aircraft instruments calibrated for

Standard atmosphere

Define pressure altitude

height above a standard datum plane, this is a theoretical level where the weight of the atmosphere is 29.92”hg as measured by a barometer

Pressure altitude helps calculate

density altitude by altimeter by setting it to 29.92”hg

Define density altitude

correct for the nonstandard atmosphere because instruments are set to standard to give a accurate altitude

Density and pressure altitude are measured

at sea level

Density’s correlation with pressure and temperature

proportionally with pressure inversely with temperature

What happens when there is more water content in the air?

Water vapor is lighter than air. More water vapor increases, air becomes less dense.

Humidity is also

relative humidity, referring to the amount of water vapor in the air, expressed in a percentage the air can hold

Warm or cold air holds more water vapor

warm

absolute altitude

above ground level

Boundary layer

molecules that adhere to the planes surface

the effects of altitude on temperature

for every 1000 gained in altitude you lose 2C

the effects of altitude on pressure

for every 1000 gained you lose 1hg

How to calculate pressure density to correct for altitude

29.92 - current pressure altitude = multiplied by 1000 (move decimal over 3 times) than current altitude + (number multiplied by 1000) = pressure altitude

Pressure attitude during climb or descent

From high to low lookout below

Air density effects

lifting ability, engine power, propeller efficiency

AOA is the

relative wind and the chord line between the air foil

Parasite drag

increases with speed

Induced drag

decreases with speed

Parasite drag

not associated with lift, works to slow aircraft movement, increases with airspeed

Induced drag

associated with the increase in lift and decreases as speed increases

Where parasite and induced drag meet it indicates

best glide speed

Positive stability

goes back to normal

Neutral static stability

remains in different position but steady

Negative static stability

completely is moved and changed.

Slow flight

thrust overcomes drag, higher angle of attack, maintained altitude, high power setting, lower speed

Critical angle of attack

max lift and imminent stall

In order to spin

both wings must be stalled

Ground effect can cause the plane

to be reduced in induced drag, causing cushion of air that can cause your plane to float or bounce during landing

Torque

plane turing left because of the propeller

Slipstream

is the left turning tendency due to propeller s

P-Factor

left turning tendency causes the airplane to yaw to the left when at high angles of attack

Density altitude

Pressure altitude corrected for nonstandard temperature

The weight pertaining to the AOA at which an airplane wing stalls will

remain the same regardless of the gross weight

As altitude increases, the indicated airspeed

at which a given airplane stalls in a

particular configuration will....

Remain the same regardless of altitude.

What is Ground Effect?

The result of the interference of the surface of the

Earth with the airflow patterns about an airplane.

Ground Effect is most likely to result in

which problem when taking off?

Becoming airborne before reaching the recommended

takeoff speed.

An airplane said to be inherently stable

will...

Require less effort to control.

An airplane is loaded in such a manner that

the CG is located aft of the aft CG limit.

One undesirable flight characteristic a pilot

might experience will be...

Difficulty in recovering from a stalled condition.

In what flight condition is torque effect the

greatest in a single-engine airplane?

Low airspeed, high power, high angle of attack.

The left turning tendency of an airplane

caused by P-factor is the result of the...

Propeller blade descending on the right, producing

more thrust than the ascending blade on the left.

When does P-factor cause the airplane to

yaw to the left?

When at high angles of attack.

The amount of excess load that can be

imposed on the wing of an airplane depends

on the...

Speed of the airplane.

Which basic flight maneuver increases the

load factor on an airplane as compared to

straight-and-level flight?

Turns.

What force makes an airplane turn?

The horizontal component of lift.

Describe Newtons three laws of motion.

First law: an object at rest will remain at rest or in motion to a particular direction, until imposed forces act on it.

Second Law: The net forces acting on an object are equal to mass x acceleration = force

Third law: For every reaction there is an equal and opposite reaction

Bernoulli’s Principle

The faster the viscosity the less pressure it has. When the air moves over a wing the fast-moving pressure that falls off the wing produces lift.

Chamber

curvatures in the wings are called chambers.

Cord line

a line from the leading to the trailing edge of the chamber

Mean chamber line

a line that follows the middle curvature of the chamber structure