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Hotac
Hotac Hotel accommodation to provide sleep for civil
flight crews.
hot-air balloon Balloon renedered buoyant by heating
the air contained in the envelope, thereby reducing its
density.
hot and high Airfield or helicopter platform where high
altitude above MSL is combined with high ambient
temperatures. These both reduce engine power and the lift
from a wing or rotor.
Hotas Hands on throttle and stick, design of cockpit of
air-combat fighter so that pilot has every control switch,
button or trigger needed in any combat on these two
handholds [A adds aid]. See Hocac.
hot bird Fully functioning satellite.
hot box Stolen item of avionics, for intelligence or
commercial profit.
hot bucket Turbine rotor blade (colloq., US).
hot chaff Pyrophoric material for IRCM dispensed in
covert [not emitting at visible wavelengths] manner.
hot day Standard ISA condition for engine rating,
aircraft performance certification and other temperaturedependent
lawmaking.
hot dimpling Dimpling of holes pre-heated to avoid
cracking.
hotel mode Aircraft on ground with full air-conditioning
refrigeration.
hot end Portion of gas-turbine subjected to high temperatures
from combustion, normally all parts to rear of
compressor (which itself can be hot enough to require
special refractory alloys in final stages but is never
included in this definition); called hot section in US.
hot fire Hot test.
hot-gas recirculation Any mechanism by which hot gas
from a propulsion or lift jet can return to engine inlet.
hot gas system One energized by gas bled from combustion
of solid fuel, or from operating solid rocket
motor.
hot gas valve One used to control hot gas pressure for
TVC purposes.
hot gun Aircraft scrambled with loaded gun[s].
hot isostatic pressing Temperature/pressure cycle for
compacting sintered ceramic or encapsulated powders
close to precise net shape.
hot leg Presentation, or flypast, on which target simulates
IR of hostile jet aircraft.
hot mike Microphone continuously on transmit.
hot mission Particular test (flight or otherwise) which
involves hazards precluding other activity in same area.
Hotol Horizontal takeoff and landing (spacecraft
launch).
hot pit Air refuelling in which fuel is transferred (UK
colloq.).
hot rock Inexperienced pilot eager to show off (colloq.).
hot rocket One in which fuel is burned.
hot round Rocket vehicle equipped with operative
propulsion, in test programme where many are not.
HOTS Hands on throttle and stick; Hotas is more
usual.
hot section Total of all parts of gas-turbine engine
subjected to high temperatures from combustion of fuel,
in modular engine exactly defined and normally including
associated external dressing which in fact remains relatively
cool.
hot shot Method of igniting afterburner fuel [which
Hovercraft
would not otherwise ignite reliably, especially at high altitude]
by spraying extra dose of fuel into engine
combustion chamber to create hot flame which passes
through turbine to afterburner; * lasts too short a time to
damage turbine.
hot soak Standardized tests in which an item is baked at
a selected high temperature for a specified period.
hot spot 1 Place much hotter than environment,
showing on 3–5 micron IR.
2 Local area on radar target giving intense return.
hot standby Satellite (Comsat, navsat) available for
instant use should operating satellite malfunction.
hot start 1 Attempted start of gas turbine abandoned
because of overtemperature indication.
2 Start, or attempted starts, of piston engine soon after
previous run, often thwarted by vapour lock.
hot streak Method of igniting afterburner by injecting
fuel from special (normally inoperative) nozzle in main
combustor, causing long flame to pass through turbine
into afterburner primary zone. Can be synonymous with
hot shot.
hot-stream nozzle That from core engine in turbofan
without mixer.
hot test Static test of rocket engine in which actual firing
takes place.
hotwell Tank or portion of larger tank in which hot
liquid collects.
hot winchback Aircraft pulled into HAS with engines
running.
hot-wire ammeter One measuring current by I 2 R heating
of fine wire; hence * galvanometer, * voltmeter.
hot-wire anemometer Measures airspeed or wind speed
down to 10 mm/s by heating platinum wire to about
1,000°C and either measuring current I for constant T or
resistance at constant I.
hot-wire ignition Use of suddenly heated (but not
exploded) resistance wire to set off rocket engine or gun
ammunition.
hot-wire probe Hot-wire anemometer.
hot-wire transducer Detects and measures sound waves
by change in resistance of heated wire.
hour Mean solar = 3,600 s; sidereal * = 3,590.1704 s.
hour angle Bearing of object on celestial sphere; angle at
pole between hour circles of observer and object, abb HA
(see local **, Greenwich **, sidereal **).
hour circle Great circle of celestial sphere formed by
projecting Earth meridian.
House House of Representatives (US).
house aircraft One used for research or development and
property of user, normally a manufacturer.
HOV Autopilot mode maintaining zero lateral/
longitudinal groundspeed.
hover 1 To fly (usually at low altitude) stationary relative
to Earth, airspeed being that of local wind.
2 Exceptionally, to fly with zero airspeed, carried along
at speed of wind in horizontal plane (while holding height
constant).
3 Uncommon use, to be on station in geostationary
orbit.
4 To operate or travel in air-cushion vehicle; obvious
contradiction in terms.
Hovercraft The original [registered] name of pioneer aircushion
vehicles, still popularly used without initial
capital.
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