The Measurement of Position Error at High Speeds and Altitude by Means of a Trailing Static Head aY

The static pcsztion error of a service wing-tip leading edge pressure head installation has been measured on a Meteor VII by means of a tralliw static head, developed espccs.sUy for use at high speeds. These tests ccver an alts.tude range f'romsero to 38,000 ft, and u3clud.e measurements Ln 'g' turns. The maxmumldach number reached was 0.84. For comparative purposes the static error was also measured at ground level by the aneroid method. The results showthat:-(1) It is possible to develop a trailing static for use to at least M = 0.84, and that an accuracy to within ti.0025 Edach number can probably be reached. (ii) At small values of CL the measured position error agrees approximately with that predicted from the aneroid test results by the Glauert law as far as Me0.75. Above this Mach number Weaver's or Charnley's use of the Glauert two-dimensional linearised subsonic flow theory substantially underestimates the measured position error. 6 (iii) At large CL'S the Glauert theory appears to bre& down at comparatively low Mach numbers (NcO.5). (iv) The pressure calibration of the trailing static head agrees with'the value fqund in the wind tunnel tc,withm 0.3,% of &pV2 (at least as far as M = 0.6). The tunnel-pSbrat~on was made by comparing with the pressure on a long static tube, the holes of which were far from the nose.