1) Why doesn't a Plane's altitude meter (gyroscope) pitch up and down constantly if it's a round earth? NASA says the curvature is 8 inches per mile. The average speed of a plane is 580mph......how come the altitude meter stays mostly constant?
2) How come there are dead spots for GPS...but if you move a mile left or right, you get GPS connection. You mean a satellite cannot account for 1 mile difference?!?!? Before GPS, there was LORAN (
https://en.wikipedia.org/wiki/LORAN)
3) How come there are several space ballon videos showing a direct hotspot under the sun? How come the sun appears very very close and not millions of miles away?
Hi,
The altimeter in an airplane is a pressure device:
In aircraft, an
aneroid barometer measures the
atmospheric pressure from a
static portoutside the aircraft. Air pressure decreases with an increase of altitude—approximately 100
hectopascals per 800
meters or one
inch of mercury per 1000
feet near
sea level.
The aneroid altimeter is calibrated to show the pressure directly as an altitude above
mean sea level, in accordance with a mathematical model defined by the
International Standard Atmosphere (ISA). Older aircraft used a simple
aneroid barometer where the needle made less than one revolution around the face from zero to full scale. This design evolved to altimeters with a primary needle and one or more secondary needles that show the number of revolutions, similar to a
clock face. In other words, each needle points to a different digit of the current altitude measurement. However this design has fallen out of favor due to the risk of misreading in stressful situations. The design evolved further to drum-type altimeters, the final step in analogue instrumentation, where each revolution of a single needle accounted for 1,000 feet, with thousand foot increments recorded on a numerical
odometer-type drum. To determine altitude, a pilot had first to read the drum to determine the thousands of feet, then look at the needle for the hundreds of feet. Modern analogue altimeters in transport aircraft are typically drum-type. The latest development in clarity is an
Electronic flight instrument system with integrated digital altimeter displays. This technology has trickled down from
airliners and military planes until it is now standard in many
general aviation aircraft.
Modern aircraft use a "sensitive altimeter,". On a sensitive altimeter, the sea-level reference pressure can be adjusted with a setting knob. The reference pressure, in
inches of mercury in
Canada and the
US, and hectopascals (
previously millibars) elsewhere, is displayed in the small
Kollsman window,[5] on the face of the aircraft altimeter. This is necessary, since sea level reference atmospheric pressure at a given location varies over time with temperature and the movement of
pressure systemsin the atmosphere.
Diagram showing the internal components of the sensitive aircraft altimeter.
In
aviation terminology, the regional or local air pressure at mean sea level (MSL) is called the
QNH or "altimeter setting", and the pressure that will calibrate the altimeter to show the height above ground at a given
airfield is called the
QFE of the field. An altimeter cannot, however, be adjusted for variations in air temperature. Differences in temperature from the ISA model will accordingly cause errors in indicated altitude.
In aerospace, the mechanical stand-alone altimeters which are based on
diaphragmbellows were replaced by integrated measurement system which is called
Air data computer (ADC). This module measures altitude, speed of flight and outside temperature to provide more precise output data allowing automatic flight control and
Flight leveldivision. Multiple altimeters can be used to design a
Pressure Reference System to provide information about airplane's position angles to further support
Inertial navigation system calculations.
LOVE,
