Aircraft speed: Difference between revisions

Aircraft speed (view source)

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 *[http://en.wikipedia.org/wiki/Indicated_airspeed '''Indicated''' airspeed (IAS)] is the number displayed on the [http://en.wikipedia.org/wiki/Airspeed_indicator airspeed indicator].
-Airspeed is usually measured with a [[#Pitot tube]] at the front of the aircraft. The ram pressure measured with the [[#Pitot tube]] is not the TAS since the pressure differs greatly with [[altitude]] (more specific the density of the air). The higher the [[altitude]] the lower the IAS while flying the same TAS.
+Airspeed is usually measured with a [[#Pitot tube]] at the front of the aircraft. The IAS is not the TAS since the pressure differs greatly with [[altitude]] (more specific the density of the air). The higher the [[altitude]] the lower the IAS while flying the same TAS.
 In spite of this dependence on [[altitude]], IAS is a very useful quantity in flight. Many aerodynamical properties, for example drag, the stress on the airframe, stall speed or the forces on control surfaces depend on the dynamic pressure generated by the airstream, not on the actual aircraft speed. The stall speed of an aircraft at sea level is very different from the stall speed (in TAS) at 30.000 ft - but they correspond to the same IAS reading.