1Dk4eXg

servo-assisted controls
whose output is amplified and used to drive motor geared
to display.
servo-assisted controls See servocontrols.
servocontrols Not defined, and not recommended. BSI
definition: a control devised to reinforce pilot’s effort by
a relay. A US definition: a * is practically identical to a
trimming tab. Appears to be general vague term for
primary flight controls (not mentioned in BSI) where
surface deflection is produced by force other than, or
additional to, that of muscles. Such added force may come
from PFCU or various types of tab (see servotab).
Servodyne Registered (Automotive Products/Lockheed
UK) family of pioneer PFCUs with mechanical signalling
and hydraulic output.
servoed Operated by servo.
servo link See servo loop.
servo loop Conrol system in which human input is
amplified by servomechanism provided with feedback so
that, as desired output is attained, demand is cancelled.
servomechanism Force-amplifying mechanism such that
output accurately follows input, even when rapidly
varying, but has much greater power. Motions can be
rotary but usually linear, and can be controlled by input
only (open-loop) or by follow-up feedback (closed-loop)
forming servo loop. Essential feature is that * constantly
compares demand with output, any difference generating
an error signal which drives output in required direction
to reduce error to zero.
servomotor Rotary-output machine providing power
locally; not necessarily part of servomechanism.
servo optical mechanical Modelling program for IR ray
tracing.
servo rudder Auxilliary rudder driven directly by pilot’s
pedals and moving main rudder by twin cantilever beams
attaching ** to trailing edge of main surface. Common
1922-38. Precursor of servo tab but not a servomechanism.
servo system Servomechanism with feedback.
servotab Tab in primary flight-control surface moved
directly by pilot to generate aerodynamic force moving
main surface.
SES 1 Surface-effect ship.
2 Shuttle engineering simulator.
3 Software exploitation segment (JSIPS).
4 Single-event signal.
5 Secure equipment system.
6 Stored-energy system.
7 Support-equipment summary.
8 Société Européenne des Satellites (Luxembourg).
9 Single-engine seaplane.
10 Single European Sky.
11 Space environment simulator.
12 Small-eddy simulation.
13 Space Exploration Squadron (USAF).
SESA Society for Experimental Stress Analysis [office,
Westport, CT] (US).
Sesame Pronounced sessamy [from “Aladdin”], the
initial Single European Sky initiative, which explored the
possibility of redefining the airspace of the existing 35
ANSPs into a seamless whole; see next (EU, 2000–05).
Sesar Single European Sky ATM [air-traffic management]
research; new initiative of national governments,
ATM service providers [especially Eurocontrol], air oper-
SEU
ators and industry, first meeting Brussels 17 November
2005, completion target 2020. (EU).
SESC Special environmental sample container.
SESMA Special-event search and master analysis.
SESP Space Experiment Support Program (USAF).
Sespo Support Equipment Systems Project Office.
sesquiplane Biplane whose lower wing has less than half
area of upper.
SESS 1 Space environmental support system.
2 Session.
Sessia Société d’Etudes de constructions de Souffleries,
Simulateurs et Instruments Aérodynamiques (F).
SET 1 Split engine transportation (fan and core travel
as two items).
2 The Space Education Trust (RAeS).
3 Science, engineering and technology.
set 1 Drift (US, suggest arch.).
2 To place storage device, binary cell or other bistable
switch or gate in particular state; condition thus obtained.
3 Complete kit of special tools and/or parts for particular
job, eg field modification; also called shop *.
4 Permanent deflection imparted by straining beyond
elastic limit, esp. lateral bending of saw teeth.
5 Hand tool/hammer for closing rivets (rare in aerospace).
SETA, SE/TA Systems [or scientific and] engineering
technical assistance.
Setac German augmented sector-Tacan system used as
precision approach aid.
setback Distance from mould line (edge) and bend
tangent line to allow for radius of bend in sheet metalwork.
SETD Scheduled ETD.
SETE Supersonic expendable turbine engine.
SETI Search for extraterrestrial intelligence.
SETL Single-event threshold level.
Setnet Science, Engineering, Technology, Mathematics
Network [office, London WC2R 3ER] (UK).
SETO Single-engine takeoff.
SETOLS Surface-effect takeoff and landing system.
set-on Assignment of offensive electronics, especially
ECM jammer, to counter a particular threat, specifying
frequency, signal modulation and, if possible, direction.
SETP Society of Experimental Test Pilots [1955–; office
Lancaster, CA93584–0986] (Int.).
SETR Specific Equipment Type Rating (NATS
engineers).
SETS 1 Seeker evaluation test system.
2 Severe-environment tape system.
setting Angle of incidence of wing, flap, tailplane (or
trimmer) or other surface.
setting hammer See peening.
setting the hook Preventing roll reversal in air combat by
centralizing stick and using rudder.
settling Sink of helicopter on takeoff (if pilot does not
increase collective) caused by lift ceasing to exceed weight
as rotor rises out of ground effect.
settling chamber Section of wind tunnel upstream of
working section in which large increase in cross-section
results in great reduction in flow velocity and allows
turbulence to die out before acceleration into workingsection
throat.
SEU 1 Sensor, or sight, or seat, or system, electronics
unit.
606