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spin motor
spin motor Rocket(s) imparting spin (rotation about
longitudinal axis) to missile or other vehicle.
spinner Streamlined fairing over propeller hub; not used
for similar fairing over helicopter rotor hub.
spinning 1 Sheet-metal shaping by forcing against spinning
die of desired profile (suitable only for bodies of
revolution).
2 To engage in spin (1).
spinning nose dive Flight manoeuvre in which aeroplane
or glider is rolled with ailerons while in steep unstalled
dive (US usage).
spinning test 1 To explore spin characteristics of
aircraft.
2 Basic strength test of propeller or helicopter rotor, or
(often at very high speed in low-drag environment) other
rotating assemblies, eg turbine or fan rotor.
spinning tunnel See spin tunnel.
spin-off 1 Predicted or unexpected advances in one technology
caused by transfer of technical solutions from
another. Also called fallout.
2 In particular, transfer from defence to civil.
spin-on Technology transfer from civil to defence.
spin parachute See anti-spin parachute.
spin-recovery parachute See anti-spin parachute.
spin rocket See spin motor.
spin stabilized Given gyroscopic directional pointing
stability by high-speed rotation about longitudinal axis.
spin table Large disc on which objects, including human
beings, can be rapidly rotated about vertical axis for
varous test and research purposes; ** in turn may be
mounted on arm of centrifuge to give additional sustained
unidirectional lateral acceleration.
Spintcom Special-intelligence communications.
spintronics Technology of devices whose operation
depends on electron or nuclear spin.
spin tunnel Wind tunnel in which flow through working
section is vertically upwards, thus free model supported
by airflow can be examined for spinning characteristics.
SPIO Signal processor input/output.
SPIP Transponder identification pulse.
SPIR Single-pilot instrument rating.
SP(IR) Satellite picture, IR.
spiral 1 One of the five basic modes of aeroplane
motion, slow divergence or convergence in level flight
with gentle banks L/R persisting long enough for large
heading changes.
2 Flight manoeuvre in which at least 360° change in
heading is effected while in glide or shallow dive (chiefly
US usage).
3 A new [2004] buzzword meaning subdivision or part
(USAF).
spiral aerial (antenna) Aerial in form of single conductor
wound as spiral on conical dielectric support; common as
passive RWR receiver.
spiral angle Angle between pitch cone generator of bevel
gear and tangent to tooth trace; positive for right-hand
gear.
spiral beval gear Crown gear has pitch curves inclined to
pitch element and usually circular arcs.
spiral dive Extremely dangerous flight manoeuvre in
which aircraft, invariably fixed-wing aerodyne, is unwittingly
in spiral descent with neither turn nor slip
indicating and in absence of external cues few indications
other than horizon instrument if fitted.
splashed
spiral divergence Spiral dive with vertical acceleration
±1g.
spiral glide Sustained gliding turn.
spiral instability Faulty aeroplane flight characteristic in
which there is an inherent tendency to depart from
straight and level flight into oscillating sideslip and bank,
latter always being too great for tendency to turn. (Longestablished
UK definition unrelated to Dutch roll, which
is a high-subsonic phenomenon; suggest arch.).
spiral mode An exponential manoeuvre mode involving
pronounced roll and yaw, in some aircraft marginally
unstable.
Spiralok Patented female thread in which base of
normal 60° profile changes to 30°, forming tight clamp on
all male crests.
spiral scan See scan types.
spiral stability Desired aeroplane characteristic in
which, in co-ordinated turn, it automatically resumes
straight and level flight on release of flight controls. Note
that no slip is present to assist recovery, and that large fin
(needed for other reasons) exerts adverse influence.
Spirit Spectral IR rocket-borne interferometer telescope.
Spiritt Spectral IR imaging technology testbed, also
translated as spectral IR remote-imaging transit testbed.
spiroid gear Patented gear in which conical worm
engages with many teeth simultaneously of face-type gear,
possibly with exceptionally large reduction ratio.
SPIT, Spit Smart procurement implementation team.
Spits See SSPTS.
spitting Air intercept code: “I am about to lay
sonobuoys and may be out of radio contact (because very
low) for few minutes” (DoD).
SPJ Self-protection jammer.
SPK Synthetic paraffinic kerosene.
SPKL Sprinkle (rain).
SPKR Speaker.
SPL 1 Sound pressure level, see noise.
2 Standard parts list(ing).
3 Supplementary flightplan message.
4 Sun-pumped laser.
5 Signature and Propagation Laboratory (USA).
6 Special.
7 Student Pilot’s Licence [in UK replaced by CAA
medical certificate].
splash 1 Code word sent to observer 5 s before estimated
impact of weapon(s).
2 Target destruction verified by visual or radar means.
3 Generalized term for action of destroying aerial
target.
splash code Letter/number identity of navigation
beacon (WW2).
splash cooling strip Welded around interior of flame
tube of annular chamber so that cooling air entering
through perforations is converted into thin sheet moving
acrosss inner surface.
splash-detection radar Pinpoints impact of vehicle with
ocean to facilitate positive scoring and vehicle recovery
(eg in Nike X ABM tests).
splashdown End of space mission in which spacecraft,
capsule or other recoverable object impacts ocean surface;
defined as either a time or a location.
splashed Air-intercept code: enemy aircraft shot down
(followed by number and type) (DoD).
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