1Dk4eXg

megative-g valve
tude) and pilot can experience ‘red-out’. This condition is
intermittently inevitable in severe turbulence but is
normally prohibited for non-aerobatic aircraft.
negative-g valve Inverted-flight valve.
negative image Apart from photographic meaning,
transposition of blacks and whites in TV, EO or IR
picture.
negative pole Cathode, or S-seeking pole of magnet.
negative pressure relief valve Prevents dP in pressurized
aircraft becoming negative.
negative rolling moment Tending to rotate aircraft anticlockwise,
seen from rear.
negative stability See instability.
negative stagger Backwards stagger; lower plane in
advance of upper.
negative stall Stall under negative g; this regime provides
lower left boundary of basic manoeuvre envelope.
negative sweep See forward sweep.
negative terminal That from which electrons flow; thus
towards which ‘current’ flows.
negative-torque signal Indication of fault characterized
by driven member (eg propeller) tending to drive driving
input (eg turboprop).
negative yaw Rotating aircraft anticlockwise about
z-axis seen from above.
NEGL Negligible.
negotiation Commercial discussion preceding contract.
negotiation threshold Point in escalating conflict at
which either participant is likely to draw back and initiate
negotiation.
NEH Code: ‘I am connecting you to a station accepting
traffic for station you request’ (ICAO).
N18 Powder metallurgy nickel alloy, MPt
1,225–1,323°C.
NEIA Net-enabled information access.
NEL National Engineering Laboratory (UK).
NEMA National Electrical Manufacturers Association
(US).
nematic See liquid crystal.
NEMO, Nemo Navy [or Naval] Earth Map Observer.
NEMP Nuclear electromagnetic pulse.
Nems, NEMS Nano-electromechanical system[s].
Nemspa National EMS Pilots’ Association [offices,
Alexandria, VA22314] (US).
NEO 1 National energy outlook (US).
2 Near-Earth object[s].
3 Non-combatant evacuation, or extraction, operation.
4 Network-enabled operations.
neodymium Nd, silver metal, density 7.0, MPt 1,021°C,
used in lasers and in permanent magnets of highest known
energy level [see next].
Neomax Magnetic material Nd 15 Fe 77 B 8 .
neon Ne, inert gas, density 0.9×10 –3 , BPt –246°C.
Neoprene Family of synthetic rubbers (polymerized
chloroprenes) resistant to hydrocarbon fluids.
NEP 1 Noise equivalent power.
2 Nuclear-electric propulsion.
3 Night enhancement program, or package.
4 Nuclear explosive package (ICBM).
Nepal drop Low-level airdrop of cargo, usually food, in
which about 20 sacks are attached to strong plywood
sheets by cords which break on impact.
neper Unit (Napier) expressing scalar ratio of two
net height
currents, N = nat log (I 1 /I 2 ) nepers, = 8.686 dB. Applicable
to all scalar ratios of like quantities.
nephelometer Measures light scattering by fine particles
in suspension.
nepheloscope Measures temperature changes in gases
rapidly compressed or expanded.
nephometer Convex mirror divided into one central and
five radial parts for estimating cloud cover.
nephoscope Optical instrument for measuring direction
and angular velocity of cloud motion.
NEPP Normal and emergency preflight procedures.
Neptco Process for manufacturing soft-skin composite
in which main fibres are pultruded rods.
Nerc, NERC 1 New EnRoute Centre (Swanwick,
NATS, UK).
2 Natural Environment Research Council (UK).
3 National Environmental Research Centre (EPA).
NERO 1 National Energy Resources Organization
(US).
2 Nederlanse Vereniging voor Raketonderzoek.
Nerva Nuclear energy, or engine, for rocket-vehicle
applications; May 1961.
NES 1 Netcentric Enterprise Services, moves nets such
as GCCS and GLCS into web-based environment.
2 National Estimating Society [Huntsville, AL] (US).
Nesacc North, east and southern area control centres
(China).
NESC 1 Naval Electronics Systems Command (USN).
2 National Environmental Satellite Center (NOAA).
3 NASA Engineering & Safety Center (LaRC, 2003–).
NESDIS, Nesdis National environmental satellite data
and information service or system (NOAA).
NESN NATO English-speaking nations.
Nest Non-expendable space transport [S adds system].
Nesterov loop Flying 360° circle in horizontal plane
whilst rolling continuously (1913).
NET 1 Network entity title.
2 Network enabled technologies.
net 1 Tailored mesh forming structural link between
traditional gas balloon envelope and useful load.
2 Electronic, optical or other telecommunications
system(s) forming single service covering designated area
accessible at any point.
net area 1 Traditional gross area (normally of wing)
minus projected horizontal area of fuselages, booms,
nacelles, pods, etc.
net dimensions Those of final shape, thus a * moulded
core.
netcentricity Conduct of future warfare governed by an
integrated ISR network using aircraft and UAVs; hence
netcentric warfare, etc.
NETD Noise equivalent temperature difference., or
differential.
net dry weight Basic weight of engine or other device
calculated according to various rules but always excluding
fluids (fuel, lubricant, coolant, etc) and usually all accessories,
protective systems, instrumentation systems, etc,
not essential for device to function.
net flightpath That followed by aircraft, esp. aeroplane,
after application of factors (particularly for averageaircraft
performance and average pilot skill); ie gross
flightpath fully factored.
net height That at any point on net flightpath, esp.
during takeoff and climb-out.
443