Aerospace Toolbox

correctairspeed - Calculate equivalent airspeed (EAS), calibrated airspeed (CAS), or true airspeed (TAS) from one of other two airspeeds

Syntax

as = correctairspeed(v, a, p0, ai, ao)

Description

as = correctairspeed(v, a, p0, ai, ao) computes the conversion factor from specified input airspeed, ai, to specified output airspeed, ao, using speed of sound, a, and static pressure p0. The conversion factor is applied to the input airspeed, v, to produce the output, as, in the desired airspeed. v, as, a, and p0 are floating-point arrays of size m. All of the values in v must have the same airspeed conversions from ai to ao. ai and ao are strings.

Input required by correctairspeed is:

`v`	Airspeed in meters per second
`a`	Speed of sound in meters per second
`p0`	Static air pressure in pascal
`ai`	Input airspeed string
`ao`	Output airspeed string

Supported airspeed strings are:

`'TAS'`	True airspeed
`'CAS'`	Calibrated airspeed
`'EAS'`	Equivalent airspeed

Output, as, is calculated as airspeed in meters per second.

Examples

Convert three airspeeds from true airspeed to equivalent airspeed at 1000 meters:

as = correctairspeed([25.7222; 10.2889; 3.0867], 336.4, 89874.6,'TAS','EAS')

as =

   24.5057
    9.8023
    2.9407

Convert airspeeds from true airspeed to equivalent airspeed at 1000 and 0 meters:

ain = [25.7222; 10.2889; 3.0867];
sos = [336.4; 340.3; 340.3];
P0 = [89874.6; 101325; 101325];
as = correctairspeed(ain, sos, P0,'TAS','EAS')

as =

   24.5057
   10.2887
    3.0866

Assumptions and Limitations

Based on assumption of compressible, isentropic (subsonic flow), dry air with constant specific heat ratio (gamma).

References

Lowry, J.T., Performance of Light Aircraft, AIAA Education Series, Washington, D.C., 1999