1Dk4eXg

magnetic compass
magnetic compass Traditional compass indicating local
horizontal direction of Earth’s magnetic field.
magnetic core Doughnut-shaped ferrite ring storing
either 1 or 0 in either of two stable magnetic states.
magnetic course Course (heading) indicated by simple
magnetic compass after correction for deviation.
magnetic crack detection Magnetic particle.
magnetic crotchet Sudden change in numerical values of
Earth’s field usually ascribed to alteration in conductivity
of ionosphere.
magnetic damping Use of eddy currents or other induced
magnetic field to oppose oscillatory or vibratory motion.
magnetic declination Horizontal angle between terrestrial
field and true N, ie between magnetic and geographic
meridians; also known as variation.
magnetic deviation Errors in magnetic compass indication
caused by local disturbance to field, esp. by ‘iron’
in aircraft.
magnetic dip Angle between local terrestrial field and
local horizontal.
magnetic disc Computer storage in magnetic-oxide
coating on surface of high-speed rotating disc.
magnetic drag cup Aluminium or copper cup
surrounding rotating core in simple tachometer, rotated
by generated eddy current.
magnetic equator Line joining points where angle of dip
is zero.
magnetic field intensity Magnetizing force exerted on
unit pole; also called field strength, symbol H, units Atm –1
[ampere-turns per metre].
magnetic flux Product of area and of field intensity
perpendicular to it (in effect number of lines of force);
kg.m 2 s -2 A -1 =V s ; symbol Φ, unit is weber Wb.
magnetic flux density Measure of magnetic induction;
kg.s -2 A -1 =Vs.m -2 ; symbol B, unit is tesla T = Wb/m 2 .
magnetic induction Induced magnetism in magnetic
material, see previous entry.
magnetic inspection Many NDT methods which attempt
to detect imperfections in magnetic-metal parts by the
anomalies they cause in strong fields.
magnetic meridian Direction of horizontal component
of terrestrial field near surface.
magnetic north North as indicated by the magnetic
meridian.
magnetic orange pipe Brightly painted magnetized iron
pipe filled with Styrofoam for aerial sweeping of maginfluence
mines in shallow water.
magnetic particle inspection NDT for ferrous parts
which when magnetized form N/S poles across cracks
rendered visible by iron oxide powder viewed under UV.
magnetic permeability See permeability.
magnetic plug Removable chip detector.
magnetic RAM Any variety of RAM (2) which relies on
magnetic materials such as very finely divided sintered
nickel zinc ferrite, applied in layers on outside of aircraft
skin; see iron ball.
magnetic refrigerator Cryogenic cooler (eg for IR
materials) operating by magneto-caloric repeated magnetization
and demagnetization of suitable materials.
magnetic storm Transient major disturbance in Earth’s
field.
magnetic surface wave Travels across substrate, esp.
ferromagnetic garnet.
magnetic tachometer Most common speed-measuring
Maica
system in aero engines measures frequency signal from
magnetic and electrical interaction between toothed wheel
and fixed sensor.
magnetic tape Storage system in which information is
recorded on and read off long strip coated with magnetic
oxide.
magnetic track Angle between track and magnetic N.
magnetic turning error Northerly turning error.
magnetic variation Angle between magnetic meridian
and true north, varies throughout globe and with time;
thus used as ± correction to °M to give °T.
magnetizing force Field strength, symbol H.
magneto-aerodynamics Aerodynamics at high hypersonic
speed and near-vacuum conditions, where magnetic
and aerodynamic forces are similar.
magneto drop See mag drop.
magnetohydrodynamics, MHD Science of inter-action
between magnetic fields and electrically conductive fluids,
especially plasmas.
magnetometer Instrument for measuring magnetic field
intensity and direction.
magnetometer navaid Precision position-fixing system
based upon measurement of local terrestrial field, eg
MAHRS.
magnetomotive force Product of flux and reluctance
(resistance), work needed to move unit pole against field;
symbols F or M but unit ampere A.
magnetopause Outer boundary of geomagnetic cavity.
magnetosphere Region around Earth, from T-layer at
350 km to about 15 Earth radii, where magnetic field and
ionised gas are dominant.
magnetostriction Change in dimensions when magnetic
material is magnetized; most pronounced in nickel.
magnetron Pioneer resonant-cavity generator of highpower
microwaves, with spinning electron beam deflected
by transverse field.
magnitude Apparent brightness of stars, planets, on
scale of relative luminosity where × 100 brightness
reduces magnitude by 5; hence brightest bodies have
negative *.
Magnum Missile[s] launched [at surface target].
Magnus effect Force produced perpendicular to airflow
past spinning body; basis of Flettner rotor and swerving
golfball.
MAGR Miniature, or miniaturised, airborne GPS
receiver.
MAGS 1 Miniaturized airborne GPS receiver [MAGR
has also been used for this].
2 Mode-S airport ground system.
Magsat Magnetic-field [measurement] satellite.
MAGTF Marine air/ground task force (USMC).
MAHA Mid-Atlantic Helicopter Association.
MAHL Maximum aircraft hook load (ASCC).
mahogany bomber Non-agile fighter [colloq.].
MAHP Missed-approach holding point.
MAHR Microflex attitude and heading reference for
light combat aeroplanes and helicopters, using strapdown
three-axes magnetometer [S adds system, U unit].
MAHWP Missed-approach holding waypoint.
MAI 1 Moscow Aviation Institute.
2 Mach/airpseed indicator.
Maica Modelling and analysis of the impact of changes
in ATM (7).
398