Aviation-related units

__NOTOC__ Units used in aircraft specifications, with approximate SI equivalents:

Linear measures (measures of length)

• m - metre, SI unit
• km - kilometre
• ft - foot, 0.3048 metres
• in - inch, 0.0254 metres
• mi - mile, 1609 metres
• nm - nautical mile, 1,852 metres, equal to one minute of arc of latitude

Measures of area

• m² - square metre, SI unit
• ft² - square foot, 0.0929 square metres

Measures of mass

• kg - kilogram, SI unit
• lb - pound, 0.4536 kg

Measures of force

• kN - kilonewton, SI unit with multiplier
• kgf - kilogram-force, 0.0098 kN
• lbf - pound-force, 0.00445 kN

Measures of power

• kW - kilowatt, SI unit with multiplier
• PS - Pferdestärke (metric horsepower), 0.7355 kW
• hp - horsepower, 0.7457 kW

Measures of speed

• Mach - Mach number, the ratio of the aircraft's flight speed to the speed of sound there - strictly not a unit, but a dimensionless number. Depends on temperature only, equaling approximately 340 m/s (660 kt) at standard conditions for temperature and pressure at sea level and lowering with altitude.
• m/min - metres per minute, 0.0166... m/s
• m/s - metres per second, SI unit, equals 1.944 kt
• km/h - kilometres per hour, 0.2778 m/s
• ft/min - feet per minute, 0.0057 m/s
• mph - miles per hour, 0.4470 m/s
• kt - knot, nautical miles per hour, 0.5144 m/s

bg:Мерни единици в авиацията