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```NOMENCLATURE FOR AERONAUTICS
AERONAUTIC SYMBOLS

1. FUNDAMENTAL AND DERIVED UNITS

[[6 column table]]
| Symbol | Metric Unit | Metric Abbreviation | English Unit | English Abbreviation

Length | l | meter | m | foot (or mile) | ft. (or mi.)
Time | t | second | s | second (or hour) | sec. (or hr.)
Force | F | weight of 1 kilogram | kg | weight of 1 pound | lb.

Power | P | horsepower (metric) |   | horsepower | hp.
Speed | V | {kilometers per hour | k.p.h | miles per hour | m.p.h
Speed | V | {meters per second     m.p.s. |feet per second | f.p.s.

2. GENERAL SYMBOLS

W, Weight = mg

g, Standard acceleration of gravity = 9.80665 m/s^2 or 32.1740 ft./sec.^2

m, Mass = W/g

I, Moment of inertia = mk^2. (Indicate axis of radius of gyration k by proper subscript.)

μ, Coefficient of viscosity

v, Kinematic viscosity

ρ, Density (mass per unit volume)
Standard density of dry air, 0.12497 kg-m^-4 -S^2 at 15°C. and 760mm; or 0.002378 lb.-ft.^-4 sec^2.
Specific weight of "standard" air, 1.2255 kg/m^3 or 0.07651 lb./cu.ft.

3. AERODYNAMIC SYMBOLS

S, Area

S[[sub]] w, [[/sub]] Area of wing

G, Gap

b, Span

c, Chord

b[[sup]] 2 [[/sup]]/S' Aspect Ratio

V, True air speed

q, Dynamic pressure = 1/2 ρ V^2

L, Lift, absolute coefficient C[[sub]] L [[/sub]] = L/qS

D, Drag, absolute coefficient C[[sub]]D[[/sub]] = D/qS

D[[sub]] 0[[/sub]], Profile drag, absolute coefficient C[[sub]] D [[sub]] 0 [[/sub]] [[/sub]] = D[[sub]] 0 [[/sub]]/qS

D[[sub]] i [[/sub]], Induced drag, absolute coefficient C[[sub]] D [[sub]] i [[/sub]] [[/sub]] = D[[sub]] i [[/sub]]/qS

D[[sub]] p [[/sub]], Parasite drag, absolute coefficient C[[sub]] D [[sub]] p [[/sub]] [[/sub]] = D[[sub]] p [[/sub]]/qS

C, Cross-wind force, absolute coefficient C[[sub]] C [[/sub]] = C/qS

R, Resultant force
[[/column 1]]

[[column 2]]
i[[sub]] w [[/sub]], Angle of setting of wings (relative to thrust line)

i[[sub]] t [[/sub]] Angle of stabilizer setting (relative to thrust line)

Q, Resultant moment

Ω, Resultant angular velocity

ρ(Vl/μ), Reynolds Number, where l is a linear dimension (e.g., for a model airfoil 3 in. chord, 100 m.p.h. normal pressure at 15°C., the corresponding number is 234,000; or for a model of 10cm chord, 40 m.p.s. the corresponding number is 274,000)

C[[sub]] p [[/sub]], Center-of-pressure coefficient (Ratio of distance of c.p. from leading edge to chord length)

α, Angle of attack

ε, Angle of downwash

α[[sub]] 0 [[/sub]], Angle of attack, infinite aspect ratio

α[[sub]] i [[/sub]], Angle of attack, induced

α[[sub]] a [[/sub]], Angle of attack, absolute (measured from zero-lift position)

γ, Flight-path angle
[[/column 2]]```

Transcription Notes:
[[sup]] for superscript ρ(Vl/μ) [[sub]] for subscript