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National Advisory Committee for Aeronautics, Technical Notes - Wind Tunnel Calibration of a Combined Pitot Static Tube and Vane Type Flow Angularity Indicator at Mach Numbers of 1.61 and 2.01

A limited calibration of a combined pitot-static tube and vane—type
flowsangularity indicator has been made in the Langley h— by h-foot super-
sonic pressure tunnel at Mach numbers of 1.61 and 2.01. The results indi-
cate that the instrument registers too high an angle of attack and gives
an error of 0.70 at an angle of attack of 20° for a Mach number of 1.61
and an error of 1.60 at an angle of attack of 2&0 for a Mach number of
2.01. At zero angle of attack the flow field about the yaw vane was unsym—
metrical and caused an error of l.h° in yaw indication at zero angle of
yaw for a Mach number of 2.01. The installation of a dummy vane pedestal
to provide a more symmetrical flow field reduced this error to 0.250. The
probe gave static-pressure readings which were too low at angles of yaw.

A combined pitot—static tube and vane-type flow-angularity indicator
has been designed by the National Advisory Committee for Aeronautics for
use on research aircraft. This instrument is designed to measure impact
and static pressures by means of a pitot-static tube and to measure angles
of attack and yaw by means of two free—floating vanes. The purpose of
the present investigation in the Langley h- by h-foot supersonic pressure
tunnel was primarily to obtain an aerodynamic calibration of the angle-
of-attack vane at supersonic speeds, since this calibration was required
in order to evaluate the drag characteristics of supersonic research air-
craft. Tests were made at Mach numbers of 1.61 and 2.01 and at pressure
altitudes of 30,000 feet and 60,000 feet. A limited amount of calibra-
tion data were also obtained for the angle-of-yaw vane. The effect of
yaw on the indicated static pressure is also presented. The effective-
ness of a dummy vane pedestal in producing a more symmetrical flow field
about the angle-of-yaw vane was also investigated.