GB820062A - Airflow directional indicator - Google Patents

Abstract

820,062. Fluid flow direction indicators. BOEING AIRPLANE CO. April 9, 1957, No. 11589/57. Class 97(2) [Also in Group XXXIII] Apparatus for determining a local direction of airflow comprises (for a wind tunnel) a pillar 8 movable transversely through the tunnel 9 by means of a screw mechanism 80, 81 which slides the pillar axially within a mounting 82. The mounting 82 is pivoted at 85 for rotation by a drive 86, transversely to the axis of pillar 8. A non-rotative member 3 is pivoted at 30 to pillar 8 for pitching movement under the control of a screw mechanism 31, 32, the shafts 31 and 81 being driven by a motor 40 through a differential 4 for simultaneous or differential rotation to adjust the vertical position and inclination of member 3. Member 3, Fig. 2, carries an extension 33 provided with bearings 10 for a rotatable probe 1 which encloses forwardly opening conduits 21', 22 respectively connected through rotary seals 27, 28 with further conduits 23, 24 in turn connected to a pressure comparing device which generates an electric signal to operate through lead 41 an indicator (not shown). The exterior of the probe is provided with helical vanes 13 to create continuous rotation of the probe and the rear face of the probe carries notches (not shown) which co-operate with spring loaded plungers 5. The plungers are withdrawn in succession from engagement by the notches by means of solenoids 53, 54 in order that step-by-step rotation of the probe is permitted to indicate the angular position, about the axis of the probe, of the open ends of conduits 21, 22 at which a pressure difference occurs. By adjusting the position of the probe until no pressure difference is indicated, a means is provided whereby the angular position of the probe indicates the exact direction of local airflow. Specification 820,061 [Group XXXIII] is referred to.