1Dk4eXg

spark erosion
resulting in very large electron flow linking points of high
potential difference along narrow and brilliantly luminous
path.
spark erosion See spark machining.
spark-ignition engine Piston engine, eg of Otto type, in
which hot electrical spark is used to ignite mixture before
each power stroke; thus, not diesel.
sparking plug Term (spark plug in N America) reserved
for plugs for spark-ignition engine and those few jet
engines where ordinary commercial plug is used; term for
gas turbines generally is igniter plug.
spark machining Precision machining of extremely hard
or otherwise difficult material by minute stream of HF
sparks struck between anode tool (often of particular
shape) and cathode workpiece; usually action is purely
thermal.
spark photography 1 Simplest and oldest method of
high-speed photography, in which shutter is left open and
scene is illuminated by single point-source brilliant spark
at exact time.
2 Various techniques, eg in tunnels, in which hot spark
is used to create local airstream of contrasting refractive
index.
sparks Wireless operator (UK traditional colloq.).
SPARP SPAR(2) program.
Spars Women’s arm of USCG (from semper paratus).
Sparta Special anti-missile research tests, Australia (US
programme).
SPAS 1 Shuttle pallet satellite.
2 Safety performance analysis system (ATOS).
SPASC System planning and system control.
Spasm Self-propelled air-to-surface missile.
Spasur Space-surveillance system with mission of
detecting and establishing orbital parameters of every
man-made object in Earth orbit, using fan of CW, across
Conus; US Navy portion of Spadats.
Spasyn Space synchro.
spat See spats.
Spate Special-purpose automatic test equipment.
spatial Relating to space, not in sense of cosmonautics
but 3-D volume of any (possibly very small) size; thus,
concerned with geometric position. Normal dictionary
entries need revision.
spatial awareness Suggest same as situational awareness.
spatial disorientation Colloq.uially, not knowing which
way is up; eg after losing control of aircraft in cloud.
spatial light modulator Hybrid optoelectronic module
combining speed and parallelism of optics with integration
of electronic chips.
spatial resolution Ability of sensor to distinguish
between two very close distant objects; thus an angular
measure (see resolution).
spatiography Mapping (‘geography’) of space.
Spato Single-pilot air-taxi operator (US).
spats Aerodynamic fairings over fixed landing wheels,
but no other part of landing gear; purists do not allow
term to encompass trousers.
Spawar Space and Naval Warfare Systems Command
(USN).
Spawn Space protection and warning (Darpa).
SPB Seaplane base.
SPC 1 Synthetic particulate chaff.
2 Software productivity consortium.
3 Special-purpose company.
special summary drawing
4 Statistical process control.
5 Stored-program control.
SPCD Space Communications Division (USAF).
SPCV Special-purpose corporate vehicle.
SPD 1 Spectral power distribution.
2 Speed.
3 System programme director.
4 Spool positioning device (umbilical lock).
5 Surface-position display.
SPDA Secondary-power distribution assembly.
SPDM 1 Solid-propellant divert motor[s] (MKV).
2 Special-purpose dexterous manipulator.
SPDS System project definition study.
SPE 1 Solar-particle event.
2 Solid-polymer electrolyte.
3 Seller-purchased equipment.
Spear 1 Selectable precision effects at range (RAF).
2 Support programme for evaluation of activities in
research.
3 Spontaneous protection enabling accelerated
response.
4 Special emitter array.
Spears Screener performance evaluation and reporting
system (FAA).
SPEC Standard for professional engineering competence
(UK).
Spec Special meteorological report, pronounced speck.
spec Specification, pronounced speck.
SPECI Special, especially special Metar.
special access See SAO.
special air mission One conducted by 89 Military Airlift
Wing, whether or not President is aboard (USAF).
special-assignment airlift Airlift which for any reason
cannot be accommodated by channel airlift (DoD).
special cargo Item requiring unusual handling, eg
detonators, precision instruments.
special flight One set up to move a specific load.
special flying instruction Warning issued to pilots
regarding handling of particular aircraft type [usually
temporary].
specialized undergraduate pilot training After division
into FB or TTT (USAF).
special material Nuclear, esp. fissile, material not naturally
occurring, eg Pu-239, U-235 or enriched uranium.
Special-Operations parachute system Semi-rigid
lift/control system worn by Special-Operations personnel
enabling them to travel silently up to 200 km (124 miles)
after leaving high-altitude aircraft.
special pilot ratings Instrument rating and instructor
rating (US).
special qualification Required, after special training, by
pilots of US commercial aircraft on scheduled routes into
airports likely to experience unusual turbulence or other
hazards.
special reconnaissance Flight made covertly, ie without
hostile detection.
special rules zone Protected airspace surrounding minor
airfield which does not justify a control zone; extends
from surface to published (usually low) FL.
Special Security Agreement Allows a non-US owner of
a US company to employ security-cleared US citizens
named and approved by US Government in order to bid
for classified defense work.
special summary drawing Prepared for each production
636