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hovering ceiling
hovering ceiling Greatest altitude at which helicopter
under specified conditions can hover (2), normally defined
as IGE (in ground effect) or OGE (out of ground effect).
hovering point Location where V/STOL aircraft picks
up or sets down load without landing.
hovering rig Free-flying rig comprising open spaceframe
in which are mounted jet lift engines and supporting
systems planned for future aircraft to facilitate development
of control systems in low hovering flight. These
qualify as aircraft.
hover pit Test facility for jet VTO or STOVL aircraft.
HOW Handover word.
HOWD Helicopter obstacle warning device.
howdah Open gunner’s cockpit above upper wing of
large aircraft pre-1930.
Howe truss One having upper and lower chords joined
by verticals plus diagonals inclined outwards from
bottom to top on each side of mid-point.
howgozit Basic graphical plot of particular flight for
planning purposes, always on basis of distance and with
vertical scale flight level; includes weights, W/V and
ambient T, and is amended as flight progresses (often
arch.).
howler alert Warns interphone handset is not properly
seated.
Howls Hostile-weapons location system; versatile
phased-array radar.
HOWS Helicopter obstacle warning system.
HP 1 High pressure; suffix number (eg HP 8 ) denotes
stage from which bleed air is taken.
2 Horsepower (undesirable).
3 Host processor.
4 Holding position, or point, or pattern.
hp 1 Horsepower.
2 High-pass filter.
h p Pressure altitude.
h.p. High-pressure.
HPA 1 Human-powered aircraft; G adds Londonbased
Group.
2 High-power amplifier or amplification.
hPa Hectopascal, previously called mb.
HPAL Human performance and limitations.
H-PAPI Helicopter PAPI.
HPBB High-power broadband.
HPBW Half-power beamwidth.
HPC 1 High-pressure compressor.
2 Calibrated pressure altitude.
HPCS High-productivity computing system (Darpa).
HPD 1 High-power discrimination, or discriminating.
2 High-PRF pulse-Doppler.
HPDA Heavy propeller-driven aircraft.
HPEL Hold[ing]-position edge light[s].
HP-EMP High-power electric-motor pump.
HPF High-pass filter.
HPFL High-power fiber/fibre laser (JTO, DoD).
HPFOTD High-power fiber-optic towed decoy.
HPI 1 High probability of intercept.
2 High-power illuminating, or illuminator (radar).
HP/IP The structure, containing two roller bearings,
supporting adjacent ends of the IP and HP compressors.
Hence, HP/LP in a two-shaft engine.
HPIR HPI(1) receiver.
HPL High-power laser (B adds blinding).
HPM High-power microwave[s].
HROD
HPMG Hydraulic permanent-magnet generator.
HPOC High power offload to Cass (USN).
HPOT High-pressure oxidiser turbopump.
HPOX High-pressure oxygen.
HPPAG High-pressure pure-air generator [missile
cooling].
HPR 1 High-performance rescue (vehicle).
2 High-power relay.
HPres, HPRES Pressure altitude.
HPRF 1 High pulse-repetition frequency.
2 High-power radio frequency.
HPRL Human Performance Research Laboratory
(NASA, Ames).
HPRP High-power reporting point (radar).
HPS 1 Helmet pointing system.
2 Horizon and pitch scale.
3 Hardened personnel shelter.
4 High-pressure sodium.
HPSC House Permanent Select Committee; I adds on
Intelligence (US).
HPSM High-power switching mode.
HPSOV High-pressure shut-off valve.
HPSS High-pressure single-spool.
HPSSL High-power solid-state laser.
HPT 1 High-pressure turbine.
2 High-precision thermostat.
3 High-power transmission.
HPTC High-performance technical computing.
HPTE High-performance turbine engine[s], or engined.
HPTIC High-performance thermal-imaging committee
(DERA/industry).
HPTS High-power transmit[ter], or transmitting, set.
HPW High-pressure water (snow removal).
HPX HP-spool shaft-horsepower extraction.
HPZ Helicopter protected zone.
hpz Hectopièze[s], non-SI unit of pressure = 10 5 Pa.
HQ Headquarters; -C 2 adds Command and Control,
MSS mission-support system.
HQR Handling-qualities rating.
Hr Hour[s].
HR 1 Helicopter route.
2 Helicopter, transport (USN category 1944–62).
3 Radar altitude.
4 Hear, here or hours.
HRA Highlands [of Scotland] restricted area.
H RAD Radar altitude measured in landing phase, = wheel
height.
HRB Horizon reference bar.
HRC 1 Historical-records container.
2 Helmet-release connector.
HRD Home-routing domain.
HRDF High-resolution direction-finding, or finder.
HRE Hypersonic ramjet engine.
HRF High-Response Force, since 2005 also often called
High-Readiness Force (NATO).
HRG 1 High-resolution geometric.
2 Hemispherical resonator gyro.
H ρ Density altitude.
HRI High-resolution instrument.
HRGM High-resolution ground map.
HRIR High-resolution IR radiometer.
HRL Human Resources Laboratory (USAF).
HRN High-resolution navigation mode.
HROD High rate of descent.
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