A two-dimensional navigation system which provides azimuth and distance to a fixed ground station for navigation in piloted aircraft. Distance is determined by pulse interrogation of the ground station with time comparison to the returned pulse. Azimuth is provided by comparison of a navigation continuous-wave audiosignal from pulse amplitudes to reference pulses.
2. The action of an aircraft as it becomes airborne.
3. To perform the action of a take-off. Said of a rocket vehicle or aircraft.
2. A container for storage of liquid oxygen, liquid fuel, or other liquid propellant until transferred to the rocket's tanks or some other receptacle.
3. In computers, a container of mercury, or other liquid, and associated components used as delay-line storage.
2. An object which reflects a sufficient amount of a radiated signal to produce an echo signal on detection equipment. See radar target.
See constellation.
A nondimensional number arising in problems of a rotating viscous fluid. It may be written
where f is the coriolis parameter (or, for a cylindrical system, twice the rate of rotation of the system); h represents the depth of the fluid; and v is the kinematic viscosity. the square root of the Taylor number is a rotating Reynolds number, and the fourth root is proportional to the ratio of the depth h to the depth of the Ekman layer.
The case a = 0 is called a Maclaurin series.
2. The theorem of G.I. Taylor in the statistical theory of atmospheric turbulence:
where x is the distance traveled by a particle in the time interval T ; u is the fluctuation or eddy velocity of the particle; and R (
) is the Lagrangian correlation coefficient between the particle's velocity at time t and t + .
2. The electronic unit which transmits the signal in a telemetering system.
2. Automatic radio communication intended to indicate or record a measurable variable quantity at a distance.
See constellation.
2. In statistical mechanics, a measure of translational molecular kinetic energy (with three degrees of freedom).
3. In thermodynamics, the integrating factor of the differential equation referred to as the first law of thermodynamics.
A prefix meaning multiplied by 10E12.
2. Pertaining to a final condition or the last division of something, as terminal ballistics.
2. = terrestrial refraction error.
The unit of magnetic flux density, one weber per square meter.
2. A similar procedure or action taken to determine the reactions, limitations, abilities, or skills of a person, other animal, or organism.
2. A flying test bed.
2. A vertical air current caused by differential heating of the terrain.
where k is the thermal conductivity; H the rate of heat conduction across a surface per unit area and per unit time; and
the temperature gradient normal to the surface. Also called heat conductivity, coefficient of thermal conduction, coefficient of heat conduction.
2. = thermodynamic efficiency.
where pa and Taare the pressure and absolute temperature, respectively, in one vessel and pb and Tb are the pressure and absolute temperature, respectively, in the other.
where pQ is the rate of energy addition per unit volume by heating (including the effects of radiation, molecular conduction, condensation water vapor, and the generation of heat by friction); T is the Kelvin temperature; cv is the specific heat at constant volume; p is pressure; and
is density. See energy equation.
2. A battery of thermocouples connected in series to form a single compact unit. The output voltage of N pairs of series-connected thermocouples is N time the voltage developed by a single pair, whereas the current developed by N pairs of parallel-connected thermocouples is N times the current developed by a single pair. Thermopiles are used in thermoelectric radiation instruments when the output of a single pair of thermocouples is not large enough.
2. The force exerted in any direction by a fluid jet or by a powered screw, as, the thrust of an antitorque rotor.
3. (symbol F). Specifically, in rocketry, F = mv where m is propellant mass flow and v is exhaust velocity relative to the vehicle. Also called momentum thrust.
2. The thrust of an engine-propeller combination expressed in horsepower. It differs from the shaft horsepower of the engine by the amount the propeller efficiency varies from 100 percent.
2. In loose usage, a propulsion system.
)The hour of the day reckoned by the position of a celestial reference point relative to a reference celestial meridian. Time may be designated solar, lunar , or sidereal as the reference is the sun, moon, or vernal equinox, respectively. Solar time may be further classified as mean or astronomical if the mean sun is the reference, or as apparent if the apparent sun is the reference. Time may also be designated according to the reference meridian, either the local or Greenwich meridian or, additionally, in the case of mean solar time, a designated zone meridian. Standard and daylight saving time are variations of zone time. Time may also be designated according to the timepiece, as chronometer time or watch time , the time indicated by these instruments.
2. In photography, a time indication registered on the film to serve as a time reference for interpretation of the date recorded on the film.
About an axis, the product of a force and the distance of its line of action from the axis.
)See emissivity.
The integral of the thrust F over an interval of time t :
Total impulse is related to specific impulse Isp by where
= propellant flow weight rate.
2. = impact pressure.
3. The pressure a moving fluid would have if it were brought to rest without losses.
4. The pressure determined by all the molecular species crossing the imaginary surface.
2. To observe or plot the path of something moving, such as an aircraft or rocket, by one means or another, as by telescope or by radar - said of persons or of the electronic equipment, as, the observer, or the radar, tracked the satellite.
3. To follow a desired track.
2. A motion given to the major lobe of an antenna so that a preassigned moving target in space remains in the lobe's field as long as it is within viewing range.
2. The apparent passage of a celestial body across the face of another celestial body or across any point, area, or line.
3. An instrument used by an astronomer to determine the exact instant of meridian transit of a celestial body.
4. A reversing instrument used by surveyors for accurately measuring horizontal and vertical angles; a theodolite which can be reversed in its supports without being lifted from them.
2. The arbitrarily defined temperature in a range in which the ductility of a material changes rapidly with temperature.
2. = transmittance.
)1. A measure of the amount of incident radiation which remains in a beam after it passes through a unit thickness of a medium. It is comparable in concept to the extinction coefficient (or attenuation coefficient) and is related to the extinction coefficient
as follows:
Where
is the transmission coefficient. Its relationship to transmissivity r is expressed: x
where x is the total thickness of the medium. Compare absorption coefficient.
2. The fraction of the solar radiation normally incident upon the top of the atmosphere which survives passage through the atmosphere to the earth's surface. As so defined, a better term might be atmospheric transmissivity.
3. The ratio of the sound transmitted through an interface or spectrum between two media, exposed to the sound field, to the sound energy incident on the interface or septum.
The ratio of the radiant flux transmitted by a medium or a body to the incident flux. See transmission coefficient. The transmittance T of radiant flux through a medium of thickness x is related to the transmission coefficient
of the medium by T =
An electron tube in which a stream of electrons interacts continuously or repeatedly with a guided electromagnetic wave moving substantially in synchronism with it, and in such a way that there is a net transfer of energy from the stream to the wave.
See constellation.
2. Actual, as contrasted with fictitious, as true sun.
3. Related to a fixed point, either on the earth or in space, as true wind; in contrast with relative.
4. Corrected, as true altitude.
2. The actual altitude of a celestial body above the celestial horizon. Usually called observed altitude.
See constellation.
2. Of a gyro, to precess suddenly and to an extreme extent as a result of exceeding its operating limits of bank or pitch.
2. A longitudinal protuberance on a rocket body used to house wiring, piping, etc., so as to not route the wiring through the propellant tanks.
If Iois the flux density of the solar beam just outside the earth's atmosphere, I the flux density measured at the earth's surface with the sun at a zenith distance which implies an optical air mass m , and Im,w the intensity which would be observed at the earth's surface for a pure atmosphere containing one centimeter of perceptible water viewed through the given optical air mass, then Linke's turbidity factor 
is given by
= ( ln Io - ln I )/( ln Io - ln Im,w )2. A turbine wheel.
3. A turbine engine. See blowdown turbine, explosion turbine, free turbine, gas turbine, impulse turbine, partial-admission turbine, reaction turbine, single-stage turbine.
2. A craft propelled by a turbojet engine. See jet engine.
These fluctuations often constitute major deformations of the flow and are capable of transporting momentum, energy, and suspended matter at rates far in excess of the rate of transport by the molecular processes of diffusion and conduction in a nonturbulent or laminar flow.
Twilight is designated as civil, nautical, or astronomical, as the darker limit occurs when the center of the sun is at zenith distances of 96 degrees, 102 degrees, and 108 degrees, respectively.
Temperature may be deduced without knowledge of the emittance if (and only if) the object is a gray body. The method is applicable to gases and to opaque objects.