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shear rate
hull, showing half-sections as numerous transverse
planes.
shear rate Vertical wind gradient, often measured in kt
per 1,000 feet.
shear slide Free-sliding piston moved by pressurant
along length of propellant tank to force liquid propellant
into (usually rocket) engine.
shear spinning Method of forming solid rocket case from
preformed thick tubular billet by rolling against rotating
mandrel, using two rollers 180° apart, normally
performed at room temperature.
shear strength Stress required to produce fracture in
plane of cross-section by two opposed forces with small
offset.
shear stress Component of any stress lying in plane
of area where stress is measured; for fluid, equal to
du
τ,µ –– (see Newton’s laws). Existence of ** in fluid is
dy
evidence of viscosity. Integrated over an area = skin friction.
shear wave Wave in elastic medium causing any element
of medium to change shape but not volume; in isotropic
medium a transverse wave, mathematically one whose
velocity field has zero divergence.
sheath 1 Metal tip, and often leading edge, to soft-blade
propeller; also called tipping.
2 Envelope of plasma surrounding re-entry body.
sheathing See sheath (1).
SHEB Solid hydrogen, embedded boron.
shed Traditional term for shelter (hangar) for aerostats,
esp. airship.
shedding 1 Action for removal of ice from aircraft in
flight, rain from windshield (windscreen) and non-vaporised
material separated from ablating surface on re-entry.
2 Rapidly repeated generation and release of vortices
from alternate sides of an object in a fluid flow.
sheep dipping Process whereby CIA pilots were given
fully documented false professional backgrounds.
sheer lines Outlines of vertical sections of fuselage [or,
especially, hull or float] parallel to longitudinal axis.
sheet Standard form of raw material; in case of metal,
uniform sheet not over ⅛ in (0.125 in, 3.175 mm) thick;
thicker metal = plate.
sheet moulding compound 2-D fibre-reinforced plastics
not needing complex laying-up procedure.
SHEL Surrogate high-energy laser (ABL).
Shelf Super-hard, extremely low frequency; military
communications system.
shelf 1 Figurative location where items are stored before
use; thus * life, published maximum period during which
item will not deteriorate in suitable storage; off-the-*,
standard commercial product already available.
2 Spanwise strip[s] hinged to leading edge of movable
surface and to trailing edge of fixed structure [eg
elevator/tailplane]; see compound *.
3 Longitudinal beams outboard of fighter engine[s]
carrying tailplanes.
shell 1 Bare monocoque structure, eg fuselage or
nacelle; shade of meaning includes thin-skinned and
deformable, thus engine carcase excluded. Some
definitions state ‘curved’.
2 Ordnance projectile launched from gun or other tube,
with or without own propulsion, and containing explosive,
incendiary or other active filling; calibre normally
shift
greater than 20 mm. Word also applicable to AP projectiles
of such calibres.
3 Supposed hollow spheres at different radii from
atomic nucleus occupied by electrons, 2 in innermost *, 8
in next, 18 in next etc, all electrons in each * sharing
similar energy level.
shellac Naturally derived resinous varnish.
shell curve Plot of control effectiveness [X-axis] against
control damping [Y].
Shelldyne Family of related synthetic fuels developed by
Shell for USAF expendable turbojets, mainly characterized
by high energy per unit volume.
shelter 1 Unhardened (generally recessed or underground)
accommodation for civilians faced with air
attack, in some cases attempting to offer some protection
against nuclear attack (fallout *).
2 Unhardened reinforced-concrete structure accommodating
(usually single) combat aircraft at dispersal and
offering protection against conventional attack, eg Tab-
Vee.
shelter marshal Officer in charge of security and movements
within HAS, HPS or PBF.
Sheradizing Anti-corrosion treatment similar to case
hardening but employing Zn dust.
Sheridan tool Family of large stretch-presses often able
to apply double curvature to thick plate.
SHF Support helicopter force.
s.h.f., SHF Super-high frequency (see Appendix 2).
SHFE 1 Sustained hypersonic flight experiment (UK).
2 Small heavy-fuel engine.
SHFT Shift.
SHGR Hail shower.
SHGS Small hail or snow pellets.
SHI Standby horizon indicator.
Shi Experimental number, with numerical prefix for
year of Emperor’s reign; thus 16-* = 1941 (Japanese Navy,
1931-45).
shield See shielding (1).
shielded bearing Ball/roller/needle race with metal ring
on each side to reduce ingress of dirt.
shielded cable See screened.
shielded configuration Aircraft deliberately designed so
that parts of major structure, eg wing, are often interposed
between sources (of noise or IR radiation) and ground
observers or defences.
shielding 1 Material of suitable thickness and physical
characteristics used to protect personnel from radiation
during manufacture, handling and transport of radioactive
and fissionable materials (DoD, NATO).
2 Obstructions which tend to protect personnel or
materials from effects of NW (DoD).
3 Design philosophy of installing crucial parts of
primary structure, whether damage-tolerant or otherwise,
as far as possible behind others or in some other way
geometrically protected from in-service damage.
4 See screen (4) (US usage).
5 Structural and other methods used to protect spacecraft
from serious consequences of micrometeorite
impact. Hence * factor, the raio of shielded to unshielded
construction.
shift 1 Ability to move origin of radar P-type display
away from centre of display; limit of * usually to
periphery.
2 See fuel *.
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