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WH Hurricane advisory.
Wh 1 Watt-hour.
2 White.
WHCA White House Communications Agency.
Wheatstone bridge Circuit with known and variable
resistances with which unknown resistance can be
accurately measured.
wheel 1 Early aircraft commonly had such an input to
lateral control system (cf ships, road vehicles);
terminology is needed for all forms of stick/control
column/handwheel/yoke/spectacles. No modern captain
would say “take the *”.
2 Complete turbine rotor, esp. single-stage or small
size.
3 High-speed gyrostabilizing device (see reaction *,
internal *, gyro *.
4 Verb, change of heading by formation of aircraft.
5 Verb, to introduce 3-D curvature to sheet (see
wheeling).
6 Noun, a defensive formation of several aircraft
circling in horizontal plane.
7 Of column of marching men, to change direction
whilst remaining in column of route.
wheelbarrow 1 Manoeuvre for airshows in which
aircraft proceeds with nosewheel[s] in contact with
runway and tail high in air (only possible with certain
types of aircraft).
2 To reposition tailwheel-type light aeroplane by lifting
tail and walking.
wheelbarrowing Violent oscillation in pitch on ground,
either because of undulating surface or harsh brake
application and rebounds from nose gear (not applicable
to tailwheel aircraft).
wheelbase Distance in side elevation between wheel
centres of nose and main landing gears; where there are
two sets of MLGs (eg 747, C-5A) measure is to point midway
between mean points of contact of front and rear
MLGs.
wheelbrakes Brakes acting on landing-gear wheels.
wheelcase Compartment containing train of drive gears
to accessories which are usually mounted thereon, the
whole tailored to fit against or around prime mover, eg
turbofan. There is only a shade of difference between this
and accessory gearbox.
wheel door(s) Covers landing wheels when retracted.
wheeler Tail-high landing by tailwheel aeroplane, subsequently
sinking into three-point position, also called
wheely or wheelie.
wheeling Sheet-metal forming (on * machine) by locally
squeezing it between upper and lower rollers; workpiece
hand-positioned to achieve desired 3-D curvatures.
wheel landing See wheeler.
wheel load Vertical force exerted by each landing wheel
on ground; hence ** capacity, but this is imprecise in
comparison with various soil-mechanics and civilengineering
measures, eg CBR.
wheel mode Satellite or position thereof rotates, often
fairly slowly (5–30 rpm), for attitude stabilization.
wheel satellite Made in shape of wheel, normally
rotating either for attitude stabilization or to impart
artificial gravity to occupants.
wheel track See track (8).
whisker
wheel trimming By separate [usually small] wheel
inceptor[s], requiring pilot to remove hand from flight
control.
wheel well Compartment in which one unit of landing
gear is housed when retracted.
which transponder R/T code: please state type of
transponder fitted, IFF, SSR or ATCRBS (DoD).
Whidds War HQ information display and dissemination
system (USA).
whifferdil Nose up 30°–60°, bank 90°, change heading
180° ending in dive.
whiffletree 1 Also rendered whippletree, originally
horse-traction linkage, which equalized and distributed
pull of many horses at one point; now used to distribute
pull of one large hydraulic jack or other load applicator
over an area of airframe via array of beams pulled at intermediate
point (usually mid-point) and transmitting pull
from both ends to other such beams.
2 Also used loosely for any pivoted beam or bellcrank
(US).
whip One meaning is upward jump of carrier pendant or
runway arrester wire after being depressed by passage
across it of landing wheel.
whip aerial Flexible aerial (antenna), either quarterwave
or of arbitrary length and usually vertically
polarized, projecting at about 90° from skin.
whip stall US term which appears ill-defined; existing
definitions agree only on fact that * is complete, violent
and involves large positive change in pitch attitude; some
suggest it is entered with flick manoeuvre, others make
this impossible by suggesting possible tail-slide at outset.
One authority gives tail-slide as alternative meaning.
Recent authorities equate * with stall turn.
whirl 1 Rotational flow of fluid, esp. when in translational
motion in duct, in which case streamlines follow
spiral paths.
2 Distortion of a shaft from straight to curved caused
by centrifugal force, tending to be rapidly catastrophic.
See whirling mode.
whirling arm Large family of instruments or installations
in which object (usually under test) is whirled on end
of balanced beam rotated about vertical axis; originally
used for aerodynamic tests, eg of aerofoils, but now more
often used to apply sustained high-g acceleration to
human beings and devices, sometimes in evacuated
chamber.
whirling mode Vibratory mode of shaft in which elastic
bending is suffered, giving severe out-of-straightness
either at end or along length, pronounced only at certain
critical rpm (critical whirling speeds).
whirl-mode flutter Aeroelastic flutter, esp. of wing, in
which input energy is derived, at least initially, from
whirling of engine or propeller shaft (catastrophic on one
type of turboprop transport).
whirltower Installation for static testing of helicopter
main rotor, including overspeed conditions. Peripheral
net retains separated blades.
whirl velocity Peripheral or tangential velocity, eg of
flow in axial or centrifugal compressor.
whirlwind Small local tornado in dry air, without cloud
or rain.
whirlybird Helicopter (rarely, other rotorcraft)
(colloq.).
whisker 1 Small single crystal, usually lenticular, whose
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