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modulated waves
flow continuously variable to give smooth increase in
thrust from max. cold to max. augmented.
modulated waves Electromagnetic waves on which is
impressed information in form of variation in amplitude
(AM) or frequency (FM).
module 1 One of assemblies of modular system, easily
replaced but seldom itself torn down except at major base
or by manufacturer; eg spacecraft command *, engine
fan *.
2 Single box of electronic equipment replaceable as
plug-in unit.
3 Any standard dimensions or standard size of
container.
4 Standard-capacity building block of computer
memory.
modulus of elasticity Ratio of unit stress to unit
deformation of structural material stressed below elastic
limit (limit of proportionality), symbol K.
modulus of rigidity Shearing modulus of elasticity,
proportional to angle of distortion but measured in stress
per unit area, symbol C or N.
modulus of rupture In beam loaded in bending to failing
point S M = Mc/I [M bending moment, c distance from
neutral axis]; in shaft or tube failing in torsion S S = T c /J.
MoE, MOE 1 Measure of effectivness.
2 Maintenance organization exposition.
MOET More open electrical technologies (Hispano-
Suiza).
Moffett Moffett Field, CA, home of NACA lab., now
known as NASA Ames Research Center, and an NAS.
Mofle Mid and outer fixed leading edge.
MOG Maximum on ground, areas suitable for large
number of airlift transports in front-line LZ at time of
peak delivery of, or resupply of, ground force.
Mogas Motor gasoline, ie ordinary automotive petrol.
Usually 91 or 93 octane.
Mogr Moderate or greater.
MOG spots Unloading spots for STOVL transports in
battle area, typically along short length of highway.
MOH Major overhaul.
Mohol Mix of Mogas and alcohol.
MoHS Ministry of Home Security [against air attack,
1940–46], (UK).
MOI Mars orbit insertion.
MOKA Methodology of knowledge acquisition.
MOL Manned orbital laboratory.
mol See mole (2).
MOLA Mars orbiter laser altimeter.
mold Mould (US spelling).
Mole Molecular electronics, many suffixes, not listed.
mole 1 Self-contained intelligence sensor air-dropped
over hostile territory.
2 SI unit for amount of substance containing as many
units [eg, atom, ion, molecule] as in 0.012 kg of C 12 , abb.
mol.
molecular sieve Filter designed continuously to remove
particles of a selected size from an airflow [water, or gases
other than oxygen].
mole dropper Usually a UAV, see previous.
moleskin strip Soft strip around bonedome to eliminate
scratching canopy.
Molle Modular lightweight load-lifting equipment.
Mollier diagram Plot of enthalpy (ordinate) against
entropy.
momentum wheel
Molochite Precision casting mould material, a
Ca-Mg-Al silicate.
moly Colloquial for molybdenum disulphide lubricant.
molybdenum Mo, hard white metal, density 10.2, MPt
2,620°C, important alloying element in steels and in
‘moly’.
moly bolt Patented bolt which can be inserted or
removed with access from one side only.
MOM 1 Metal-oxide-metal.
2 Methanol/oxygen mix.
3 Moment.
moment Turning effect about an axis: force multiplied
by perpendicular distance from axis to force; for conversion
factors, see torque..
moment arm Distance from axis to force, eg from c.g. to
aerodynamic centre of tailplane.
moment coefficient 1 Any moment reduced to nondimensional
form, usually by dividing by dynamic
pressure.
2 Particular values such as C m (section *), C mo (pitching
*), C mac (about aerodynamic centre) and C mcg (about
c.g.).
moment distribution Analytical method for frameworks
based on bending moments at rigidly attached joints
between members.
moment index Divisor, typically 10 4 , to reduce numerical
values in balance calculations of heavy or large
aircraft.
moment of area Not normally used, though term ‘second
***’ synonymous with moment of inertia.
moment of inertia Symbol I, sum of all values of mr 2
where m is elementary particle and r its distance from axis
about which I is measured, or Mk 2 where M is total mass
and k is radius of gyration; SI unit usually kg-m 2 = 23.73
lb-ft 2 = 0.73756 slug-ft 2 .
moment of momentum See angular momentum.
momentum Mass multiplied by velocity, symbol p = mv,
units kg ms –1 .
momentum coefficient For CC/BLC System in Vj/qS,
symbol Cµ.
momentum drag Drag due to change in momentum of
air entering lateral or other non-ram inlet; major factor
in design of ACVs and small high-power jet-lift
V/STOLs; =
WV
–––
g
where W is mass flow and V vehicle
speed.
momentum separation Flow separation from convex
duct wall or other surface where Coanda effect is inadequate.
momentum theory Idealized Froude treatment for
propellers and other driven rotors by calculating
momentum ahead of and behind disc exerting uniform
pressure on uniform flow through a stream tube exactly
containing the propeller.
Momentum thickness Measure of reduction in
momentum of flow due to viscous forces in boundary
layer.
momentum thrust Component of jet-engine thrust due to
acceleration of jet = ––––
WVj
where W is mass flow and V j is
g
jet velocity. See thrust.
momentum transfer method Drag measurement by pitot
traverse of wake.
momentum wheel Flywheel, eg in attitude stabilization.
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