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plane
plane 1 Aeroplane or airplane (colloq., rarely used in
professional aerospace).
2 A wing, either left or right or complete tip-to-tip.
3 To move over water at speed sufficiently high for
hydrodynamic and aerodynamic lift to predominate over
buoyancy.
plane angle Angular measure in 2D, planar, unit rad
[radian] = 57.2958°; hence 1° = 0.0174533 rad, 1’ =
2.90888 × 10 -4 rad, 1” = 4.81814 × 10 -6 rad.
plane-change engine Small rocket, usually MHR, whose
thrust alters orbital plane of satellite.
plane flying Navigation without electronic aids over
short distances such that curvature of Earth is neglectable
(in Editor’s view, nonsense).
plane-guard Routine duty of aircraft (today helicopter)
stationed off port (left) quarter (towards stern) of carrier
while flying operations are in progress; rescues ditched
aircrew and performs other tasks.
planemaker Aircraft manufacturer (colloq.).
plane of reference That, perpendicular to plane of
symmetry and in front of [or possibly touching] the nose,
from which all nose-to-tail stations are measured.
plane of rotation That in which tips of blades of rotating
object travel; in case of helicopter main rotor synonymous
with tip-path plane, and thus seldom perpendicular to
shaft axis.
plane of symmetry That containing OX and OZ axes,
dividing aircraft into (usually mirror-image) left/right
halves.
plane-polarized EM radiation, eg light, in which electric
force and direction of propagation remain in one plane.
planer Machine tool, often large, whose workpiece is cut
by linear motion past fixed tool. Skin mill has revolving
cutter(s).
planetary boundary layer From planet surface to
geostrophic wind level, including Ekman layer.
planetary gear Reduction gear in which driven sunwheel
turns planet-wheels engaging with fixed outer
annulus; any gearwheel whose centre describes circular
path around another.
planetary lander Spacecraft designed to (usually soft-)
land on planet.
planetocentric Related to planet’s centre, eg * orbit.
plane wave One whose front is normal to propagation
direction.
planform Geometric shape in plan, esp. of wings and
other aerofoils.
planimeter Instrument for mechanically measuring area
on plane surface.
planing bottom Faired smooth surface on underside of
float or hull (BSI); this omits to note need for deadrise,
chine, step etc, needed to plane (3).
plank Loosely used to mean a principal spanwise wingskin
member, especially if integrally stiffened.
plank antenna Antenna formed from planar assembly of
waveguides in vertical plane, fixed parallel to aircraft
longitudinal axis [usually on struts above fuselage].
plank wing Traditional wing, as distinct from swept or
other modern planform (colloq.).
plan-label display Radar display on which SSR alphanumeric
information can be written in association with
positional echo or symbol; usually fast synthetic, or
mixed-phosphor (hard for high-refresh alphanumerics
and soft for raw position symbol).
plastic flow
planned flight One for which flightplan is filed and which
has specific purpose, ie not air experience or joyride.
planned load One made up in advance and tailored to
cargo-aircraft type and mission.
planning-programming-budgeting Integrated system for
management of DOD budget and Five-Year Defense
Program (USAF).
planometer Surface plate.
plan-position indicator P-type display in which scene
appears in plan with observer, radar or other sensor at
centre; objects at radial distance giving range (usually
linear scale, often selectable to several values) and with
correct bearing (000° usually at top or 12 o’clock
position); offset PPI moves sensor to position away from
centre, typically to 6 o’clock margin. Expanded-centre
PPI has zero range at ring surrounding centre.
plan range In air reconnaissance, horizontal distance
from sub-aircraft point (that where local vertical through
aircraft intersects surface) and ground object.
PLAP, Plap Power-lever angle prime, throttle in UFC
(1) to which engine responds irrespective of pilot demand.
PLASI, Plasi Pulse-light approach slope indicator.
plasma Assembly of neutral atoms, ions, electrons and
possibly molecules in which particle motion is determined
by EM interactions; electrically conductive, hence
responds to magnetic field. Study called MHD or hydromagnetics.
plasma antenna Glass or ceramic container of ionized
gas.
plasma-based stealth Making aircraft morwe or less
invisible to hostile radars by enveloping them in an intense
EM field.
plasma engine See plasma rocket.
plasma flame stabilization Use of nanosecond pulses of
high-voltage current to stabilize very lean combustion.
plasma ignition Source of 1,000 J/s at 5,000K for solids,
liquids or gases.
plasma jet Jet of plasma produced by MHD.
plasma panel Electronic display of gas-discharge type,
usually AC, usually orange (Ne), but many other colours
with different gases.
plasma plating Deposition of refractory, abrasion-resistant
or anti-corrosive coating by means of intensely hot
(c16,600°C) plasma jet moving at supersonic speed into
which coat material is introduced as powder.
plasma rocket One whose working fluid is a plasma,
accelerated by intense EM field (ie, plasma jet).
plasma sheath That surrounding re-entry vehicle or
spacecraft, serving as barrier to radio communications.
plasma torch See next.
plasma welding Process similar to TIG welding except
that the current is carried by the plasma itself, not by a
pulsed arc.
plasma wind tunnel One capable of simulating spacecraft
re-entry to Earth atmosphere.
plastic Not elastic, tending to remain in deformed shape
or position (see plastics).
plastic effect Electronic display shows relief but little
tonal value.
Plasticele Transparent plastic which, unlike Pyralin, is
non-inflammable and does not discolour with age.
plastic flow That caused by stress beyond elastic limit
and remaining when stress is removed.
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