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Old 31st October 2009 | 03:22
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selfin
 
Joined: Apr 2004
Posts: 734
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From: London, GB
...except that modern airspeed indicators are designed for compressible flow and the whole argument about 'compressibility corrections' is largely irrelevant here.* The solution derived from Euler's dynamic equations and the equation of state by Jean Claude Barré de Saint-Venant (used in modern FAA/EASA-approved ASIs) is valid below M 1.0, and reasonably accurate until about M 1.3, after which the Rayleigh 'supersonic' Pilot tube formula should be used.

* See Old Smokey's 2006-01-12 post on dynamic -v- impact pressure here: http://www.pprune.org/questions/2057...ml#post2318100

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See also NACA Technical Report 837 (Langley, 1946).
Last edited by selfin; 31st October 2009 at 15:51. Reason: Note on NACA-TR-837.
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