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SUAVS
2 Strategic UAV experiment (UK).
SUAVS Small unmanned aerial vehicle system (USA).
sub Smaller contractor, partner chosen in teaming down;
can be thought of as short for subordinate or subcontractor.
subassembly Assembly (eg structural, electronic or for
some other system) forming part of a larger item.
subcarrier Subsidiary modulated carrier which in turn
modulates primary RF.
subchannel Intermittent fraction of telemetry channel
conveying one repeatedly sensed measurement.
sub-cloud car Car suspended below above-cloud aerostat
giving view of ground.
subcommutation Commutation of additional telemetry
channels, output of which is fed to primary commutator;
called synchronous if commutation frequency is multiple of
that of primary (which it usually is).
subcontract Agreement other than prime contract to
perform work on same programme. Normally between
subcontractor and prime contractor for work assisting
latter to complete task. Does not necessarily confer design
authority or responsibility.
subcritical mass Mass of fissile material inadequate in
magnitude or configuration to sustain chain reaction.
subcritical rotor Rotor, esp. main lifting rotor of helicopter,
whose fundamental flapping, lag-plane or other
resonant frequency is less than normal operating
frequency, latter being frequency with which one blade
passes given angular position.
subcritical wing Wing designed not to exceed M crit at any
point.
subgrade Soil underlying airport pavement.
subgrade code ICAO coding for strength of subgrade: A,
150 MN m –3 ; B, 80; C, 40; D, 20.
subgravity Condition in which apparent vertical acceleration
is between zero and + 1 g.
subharmonic SHM or other sinusoidal waveform whose
frequency is exact multiple of related fundamental waveform.
sub-idle Operating speed or control selection below
idling, occasionally provided with main engines for ground
operation.
SUBJ Subject [to ...].
subjective Dependent upon personal opinion; in such
fields as aircraft noise and visible smoke unquantified *
measures play a major role, usually as the result of seeking
views of statistically significant population.
sub-kiloton weapon NW whose yield is below 1 kT.
sublimation Direct transition, in either direction, between
solid and vapour state.
sublimator Solid material designed to reject waste heat by
sublimation to space environment, usually a porous plate
and in some cases not a true * but medium for evaporating
liquid heat-transfer medium.
submarine Verb, to slide down out of seat harness in
violent deceleration [impossible with 5-point harness].
submarine missile Missile launched by submarine, eg
against distant city target.
submarine rocket Submarine-launched rocket (Subroc)
weapon for use against other submarines.
submarine striking force Force of submarines having
guided or ballistic missile capabilities and formed to launch
offensive nuclear strike (DoD).
suck-out
submodulator AF power amplifier preceding main RF
modulator.
submunition Self-contained warhead carried in multiple
(tens or hundreds) inside single delivery vehicle, eg
air/ground store.
subprogram See subroutine.
Subroc Submarine-launched [guided, nuclear-warhead]
rocket.
subroutine Set of instructions necessary to enable EDP (1)
computer to carry out well defined mathematical or logical
operation, forming part of complete program; unit of
routine for specific sub-task, usually written in relative or
symbolic coding even if full routine is not, and in closed *
entered by jump path from main routine and reverting to
main routine at completion (one sequence of instructions
can be * and at same time a main routine with respect to its
own *).
subsatellite Satellite of Moon.
subsatellite point Point on Earth’s surface directly below
Earth satellite, ie on local vertical through satellite at any
time.
subscale prototyping Not defined. The A380 conceivably
might be assisted by a balsa chuck-glider.
subsidence 1 Extensive sinking of air mass, eg in polar
high, in which air forced to descend is warmed by compression,
increasing stability.
2 Disturbance to aircraft flight which dies away without
oscillation (UK usage only and unusual).
subsidy US term for an interest-bearing loan to a
competitor.
subsonic Slower than speed of sound in surrounding
medium. According to one lexicographer, Mach numbers
less than 0.7.
subsonic flow Flow whose velocity is less than speed of
sound within it; in contracting duct accelerates and rarefies
slightly and in expanding duct decelerates and compresses
slightly.
substantiation Formal demonstration of compliance, eg
with design fatigue-life requirement.
substrate In various kinds of planar technology, structural
layer upon which operative layers and/or devices are
formed; in most microelectronics has low resistance, while
in solid-state circuitry and solar cells * is normally an
insulator.
substratosphere Imprecise, generally taken to mean upper
layer of troposphere.
subsystem There is no clear demarcation between system
and * though it is simple to give examples of dynamic organized
groupings of devices that can be seen to be one or
other. It could be argued, eg, that because it is part of a
flight-control system a stability-augmentation system is a
subsystem. Again, a BITE can be considerd an integral part
of a system or as a *.
suckdown Downwards pull on jet-lift aircraft when
hovering in ground effect, usually caused by upward flow
around fuselage from fountain.
suck-in Traditional verbal command in hand-starting
piston engine, meaning ‘Do not energize ignition (cylinders
are being filled with mixture)’.
suck-out Deliberate or undesired characteristic of some
vertically translating airbrakes, esp. on sailplanes, of being
pulled open by local depression under certain flight conditions.
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