http://ma3naido.blogspot.com/2008/01/structure-of-atmosphere_08.html
STRUCTURE OF THE ATMOSPHERE
The atmosphere is an envelope of air that surrounds the earth and
rests upon its surface. It is as much a part of the earth as the seas
or the land. However, air differs from land and water inasmuch as it
is a mixture of gases. It has mass, weight, and indefinite
shape....view all
http://ma3naido.blogspot.com/2008/01/structure-of-atmosphere_08.html
http://ma3naido.blogspot.com/2008/01/atmospheric-pressure.html
ATMOSPHERIC PRESSURE
Though there are various kinds of pressure, pilots are mainly
concerned with atmospheric pressure. It is one of the basic factors in
weather changes, helps to lift the airplane, and actuates some of the
important flight instruments in the airplane. These instruments are
the altimeter, the airspeed indicator, the rate-of-climb indicator,
and the manifold pressure gauge....view all
http://ma3naido.blogspot.com/2008/01/atmospheric-pressure.html
http://ma3naido.blogspot.com/2008/01/pressure-altitude.html
PRESSURE ALTITUDE
Pressure altitude is the height above a standard datum plane. The
airplane altimeter is essentially a sensitive barometer calibrated to
indicate altitude in the standard atmosphere. If the altimeter is set
for 29.92 in. Hg Standard Datum Plane (SDP), the altitude indicated is
the pressure altitude—the altitude in the standard atmosphere
corresponding to the sensed pressure....view all
http://ma3naido.blogspot.com/2008/01/pressure-altitude.html
http://ma3naido.blogspot.com/2008/01/density-altitude.html
DENSITY ALTITUDE
The more appropriate term for correlating aerodynamic performance in
the nonstandard atmosphere is density altitude— the altitude in the
standard atmosphere corresponding to a particular value of air
density....view all
http://ma3naido.blogspot.com/2008/01/density-altitude.html
http://ma3naido.blogspot.com/2008/01/effects-of-pressure-and-temperature-on.html
EFFECTS OF PRESSURE ON DENSITY
Since air is a gas, it can be compressed or expanded. When air is
compressed, a greater amount of air can occupy a given volume.
Conversely, when pressure on a given volume of air is decreased, the
air expands and occupies a greater space. That is, the original column
of air at a lower pressure contains a smaller mass of air....view all
http://ma3naido.blogspot.com/2008/01/effects-of-pressure-and-temperature-on.html
http://ma3naido.blogspot.com/2008/01/effects-of-pressure-and-temperature-on.html
EFFECT OF TEMPERATURE ON DENSITY
Increasing the temperature of a substance decreases its density.
Conversely, decreasing the temperature increases the density. Thus,
the density of air varies inversely with temperature. This statement
is true only at a constant pressure....view all
http://ma3naido.blogspot.com/2008/01/effects-of-pressure-and-temperature-on.html
http://ma3naido.blogspot.com/2008/01/effect-of-humidity-moisture-on-density.html
EFFECT OF HUMIDITY (MOISTURE) ON DENSITY
The preceding paragraphs have assumed that the air was perfectly dry.
In reality, it is never completely dry....view all
http://ma3naido.blogspot.com/2008/01/effect-of-humidity-moisture-on-density.html