Jim,
If my memory is correct speeds are defined as follows:
Indicated Airspeed (IAS) = Instrument reading corrected for instrument
(mechanical) error.
Rectified Airspeed (RAS) is the 1940's British equivalent of the
American Calibrated Airspeed (CAS). They both equal Instrument reading
corrected for instrument error and position (pressure) error( I think
there is some difference between the two at high speeds and altitudes).
If you are lucky, on our kind of aeroplane there won't be too much
difference between IAS and RAS or CAS.
Both RAS and CAS are close to the scientifically pure Equivalent
Airspeed (EAS).
EAS = True Airspeed (TAS) x the square root of the relative air
density. On a Standard day (15 deg C at sealevel falling at a little
under 2 deg C per 1000ft up to 36000ft) EAS equals TAS at sealevel, but
at 10,000 ft an EAS of 150kts is equivalent to a TAS of 174.5kts.
I could be wrong but I thought design manoeuvring envelopes were
defined in EAS and cockpit placards showed IAS.
Gerry Cole , Classic 121
----- Original Message -----
From: h&jeuropa
I have recently become aware that Vne is normally expressed in True
Airspeed (TAS). ?
Jim Butcher
XS N241BW
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