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two words, or one as adjective, hence spooldown time.
Also called rundown.
spool duct Joins engine to augmentor and UAA nozzle.
spool up To accelerate engine rpm, esp. to TO power or
at least to much higher level than previously; normally
turbofan or turbojet.
spool valve Fluid-flow control in which an external pressure-difference
force moves an axially sliding valve in
which two or more pistons close or open wall apertures [as
in steam locomotive].
sporadic E Irregular radio-reception and disturbance
caused by abnormal variation in E-layer.
sportplane No definition, but genreally taken to mean
small GA aircraft in which flight performance dominates
other qualities.
SPOT 1 Spot wind (ICAO).
2 Speed, position, track.
3 Smart position-only tag.
spot 1 To form up aircraft in close ranks on carrier deck
ready for free or catapult takeoffs.
2 Designated place on airfield where landing is to be
made.
3 Bright region where electrons strike fluorescent tube
face in CRT and many other displays or image converters.
4 To determine, by observation, deviations of ordnance
from target for purpose of supplying necessary information
for adjustment of fire (DoD).
5 To search from ground for hostile aircraft in own
airspace (UK civilian usage, WW2; hence spotter, spotting).
6 Code, spot wind.
7 A hydraulic or pneumatic cylinder in a disc or platetype
wheel brake [thus, a nine- * brake].
spot annealing Annealing local area of hard steel, eg to
drill and tap fixing hole.
spot beam Electromagnetic beam made as parallel as
possible to maximize power at great distance.
spot elevation See spot height (US usage).
spot facing Local surface-machining round hole or other
point, to improve surface finish, adjust dimensions or
provide square-on surface for bolt head.
spot fuel Uplifted and paid for on the spot, as distinct
from part of ongoing contract.
spot height Height of point, esp. mountain peak or other
high point, marked on map or chart.
spot hover Helicopter training manoeuvre in which
machine is hovered at low level over point, turning
through four successive headings 90° apart.
spot jamming Jamming of specific frequency or channel.
spot landing Aeroplane landing made from specified
position and height AGL on to spot (2); form of accuracy
landing.
spotlight 1 A DBS radar operating mode using very
narrow beam with highest possible resolution, steered to
dwell on targets of high interest so that numerous echoes
can be integrated.
2 Strongly directional light aimed at area of interest,
e.g. part of airframe susceptible to icing.
spot net Com net used for spot (4) information.
spot report Sent from attack or reconnaissance aircraft
stating passage overhead specific target.
spot size Diameter of spot (3).
spotter 1 Person assigned to task of watching for and
identifying hostile aircraft; hence raid *, official responspoiler/elevator
computer
control, while others use * only at low speeds or high
speeds. * operation on commercial transports is invariably
linked with position of speed brakes, response
depending on whether differential or not. DLC * is
primary flight control, esp. during landing. Many * used
as lift-dumpers after touchdown.
2 Movable deflector used to kill most if not all residual
thrust from engine or from turbofan core; much simpler
and lighter than reverser.
3 Comb, flap or other device extended on command to
break up local airstream, eg ahead of open weapons bay.
spoiler/elevator computer Multiplexes input control
signals to provide roll and speedbrake control and, if
fitted, gust-alleviation; following failure of pitch
computer also provides back-up main and trim control in
pitch.
spoiler initiation angle Rotary deflection of pilot’s roll
control (spectacles, handwheel, etc) at which spoiler(s)
start to open (from wings-level flight with speedbrake
fully closed).
spoiler-mode control system Governs spoilers as DLC in
flight and auto dumper and speedbrake on touchdown.
spoileron Small spoiler either augmenting ailerons with
large input, or serving as primary control in roll.
spoking 1 Regular or erratic flashing of rotating timebase
on PPI or other radial display.
2 Any PPI display which radiates out from a central
origin.
SPOL Solar-powered obstruction light[s].
sponginess, spongy Descriptive but vague term for flight
controls where response appears unduly delayed or uncertain,
usually due to cable stretch, play in pully supports
and mechanical wear.
sponsons 1 Symmetric projections low on each side of
flying-boat hull in form of short thick wings to provide
stability on water in place of outer-wing floats.
2 Projections from helicopter fuselage in form of short
thick wings to provide attachment for main landing gear
(and in some cases retraction stowage space).
3 Short, thin wing-like structures projecting from aeroplane
or helicopter fuselage to carry weapons, external
tanks, guns and possibly other devices.
spontaneous ignition point Lowest temperature at which
vapour spontaneously ignites without external ignition
source [see auto-ignition].
spoof 1 To copy hostile IFF reply code.
2 See spoofing.
spoofer Air-intercept code: contact is employing electronic
or tactical deception measures (DoD).
spoofing Acting the part of hostile forces, especially in
EW.
spook Adjective or noun: aircraft, manned or
unmanned, flying EW missions, especially clandestine.
spool 1 One complete axial compressor rotor, in case of
multi-shaft engine forming LP, IP or HP portion of
complete compressor. Some authorities include the driveshaft
and turbine.
2 Attachment anchor, usually one of L/R pair, for
catapult bridle of carrier aircraft.
3 To open throttles (colloq.). Increasingly, spooling =
ground running.
spool down To allow gas-turbine engine rpm to decay to
zero, eg after closing shut-off valve or HP cocks; normally
spotter
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