PHYSICS OF THE ATMOSPHERE
2. AERODYNAMICS Study of objects moving through the air and the
forces that produce said movement. THE ATMOSPHERE
3. ATMOSPHERIC CONTENT • Air composition: - 78% - Nitrogen 21% -
Oxygen 1% - Other gases (argon, carbon dioxide, hydrogen, helium, neon, etc.)
OXYGEN Human respiration Fuel combustion keeps airplanes flying THE ATMOSPHERE
4. PRESSURE "Air has weight" Weight pressure (force)
Column of air pressing down on a given area extending from sea level up
Weight decreases with increasing height
Atmospheric pressure at sea
level under standard conditions (15 ° C / 59 ° F) 14.69 psi or 29.92 in Hg. o
1013.25 millibars o 101.325 kPa PRESSURE
5. Atmospheric pressure decreases with altitude PRESSURE
6. TEMPERATURE o Decreases with increasing altitude from Constant
(-55˚C) above 55,000 feet (12 km) o Decreases at a fall rate of 1.98 1.C per
1000 feet o Standard daytime temperature in the sea Solar irradiation level 15 / C / 59˚Heat o
Temperature does not affect the aircraft much in flight, but humidity
variations do affect the atmosphere o Humidity affects flight operation The
earth absorbs heat (increases Hot air increases, expands, cools the air
temperature on the surface)
7. Temperature change with height TEMPERATURE
8. Effect of temperature on takeoff run and rate of climb COLD
WINTER DAY HOT SUMMER DAY • The aircraft requires a longer runway to take off
on a humid day than on a dry day HUMIDITY
9. DENSITY "Air is compressible" Dense compressed air
(less space occupied by air) Density = measure of air thickness Density varies
directly with pressure Low altitude denser High altitude less dense Density at
the level of the sea is 1,225 kg / m3
DENSITY
10. Density affects the aerodynamic performance of the aircraft
HIGH ALTITUDE Altitude LESS Density Higher speed and distance LOW Altitude
HIGHER density Same power Less speed and less distance DENSITY
11. HUMIDITY Amount of water vapor in the air (humid or humid
condition) Temperature influences the maximum amount of water vapor that the
air can hold Higher air temperature absorbs more water vapor Density of air
varies with humidity Density on a humid day (hot day) is less than the
density on a dry day (cold day) HUMIDITY
12. THE ATMOSPHERE All air mass that extends upwards for hundreds
of miles from the earth (320 km deep) THE ATMOSPHERE
13. LAYERS OF ATMOSPHERE THE ATMOSPHERE
14. INTERNATIONAL STANDARD ATMOSPHERE (ISA) o Atmospheric
conditions TEMPERATURE vary throughout the world • 15˚C due to changes in the •
59˚F properties of the atmosphere PRESSURE • 14.69 psi • 29.92 in Hgo
Established for provide a common reference • 1013.25 millibars for • 101.325
kPa temperature, pressure • 1 atm and density at different altitudes DENSITY •
1.225 kg / m3 ISA
15. Q CODE • To simulate the altitude reference of all aircraft •
Due to variable atmospheric conditions around the world • 3 types of code: -
QFE: height of the aircraft above the aerodrome - QNH: height of the aircraft
above sea level (local condition) -
QNE: Height of the aircraft above sea level (ISA condition)
16. AIR VELOCITY • The speed of sound is 331 m / s at sea level
with a temperature of 0ºC • The Mach number as a reference to the speed of
sound at that altitude • The speed of sound is reduced with the reduction of temperature
• Indicated airspeed (IAS) is a direct meter reading measured by the aircraft's
dynamic air pressure • Actual airspeed (TAS) is true flight speed based on
actual atmospheric condition • IAS is lower than TAS at altitude.
