<DOC>
<DOCNO>
1004
</DOCNO>
<TITLE>
free-flight measurements of the static and dynamic
</TITLE>
<AUTHOR>
</AUTHOR>
<BIBLIO>
</BIBLIO>
<TEXT>
  the effects of contamination of helium by air upon static-pressure,
total-pressure, heat-transfer, and temperature measurements have been
investigated in the 2-inch helium tunnel at the langley research
center .  within the scope of the tests, even a small amount of air is
shown to affect these measurements .  the heat-transfer and temperature
measurements were made on a 26.6 half-angle cone and demonstrated the
effects of contamination qualitatively .  the wall static and centerline
pitot pressures show that if the contaminating air is held to less
than about 0.2 percent by volume, the error in indicated mach number is
less than 1 percent as calculated from the rayleigh pitot equation .
the corresponding errors in wall static and center-line pitot pressures
are about 1.7 and 0.4 percent, respectively .
</TEXT>
</DOC>
