<<There is another interesting approach to calibrating the ASI using a GPS.
One flies 3 GPS ground tracks which are 90 degrees apart (e.g. 0, 90, 180) at
the same indicated airspeed on each track, noting the GPS speed on each. The
wind need not be known although it is assumed to be constant for the duration
of the measurements. The density altitude is assumed constant since TAS
(rather than CAS or IAS) is found by this method. Error is introduced if the
density altitude or indicated airspeed differs between readings.>>
there is an excel spreadsheet using exactly this method, also including
density altitude calcs at:-
ftp://avnet.co.uk/pub/europa
files are IAS_UTIL and IAS_UTI2, first is for Psion 3 and the other is for
excel, v4 I think. The PFA were quite happy with a spreadsheet showing a page
full of figures derived from these from my final test flight.
Unfortunately, cant seem to connect to the ftp site ATM....... but I have
copies if another server can be made available.
chus,
dave
g-bxum
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