17/48 7.1.3 Velocity Direction from Yaw Tube,Pivoted Vane,and Servoed Sphere Determination of angles of attack and yaw aboard flight vehicles is often accomplished with vane-type probes. These devices are essentially one-or two-axis weather vanes with suitable damping to reduce oscillation and with motion pickups to provide electrical angle signals. Limitation of this type of device for certain high-speed,high-altitude applications have led to the development of the servoed-sphere type of sensor. Rotary motion transducer 0n6 Pivot point Boom-mounted Flush-mounted transducer Angle-of-attack,angle-of-yow probe transducers Single-oxis probe Flow Figure 7.11 Vane-Type Probes 18/48 7.1.3 Velocity Direction from Yaw Tube,Pivoted Vane,and Servoed Sphere A servo-driven sphere is continuously and automatically aligned with the velocity vector by means of two independent servosystems using the differential-pressure signals P,-P2 and P3-P as error signals. A fifth tap measures the stagnation pressure. Angle of sideslip-Taps 1.2 |会lf db 0 Angle of attack -Taps 3,4 1.0 10 Stognation pressureTop 5 100 Frequency,cps /告ul Taps 1,2,3.4-0.188 in.dia each42°from stagnation point System frequency Tap 5-0.5 in.dia Nose of vehicl response 6.5-in.-dia sphere -90+ Flow Flow angle P3-P Amplifier Servo Rotary m Motion angle volve hydroulic actuator pickup signal Sphere Differential taps pressure tronsducer Sphere rotation ongle Angle-of-attack servo system Angle-of-sideslip system functionally identical Figure 7.12 Servoed-sphere Probes7.1.3 Velocity Direction from Yaw Tube, Pivoted Vane, and Servoed Sphere Figure 7.11 Vane-Type Probes ‹ Determination of angles of attack and yaw aboard flight vehicles is often accomplished with vane-type probes. ‹ These devices are essentially one- or two-axis weather vanes with suitable damping to reduce oscillation and with motion pickups to provide electrical angle signals. ‹ Limitation of this type of device for certain high-speed, high-altitude applications have led to the development of the servoed-sphere type of sensor. 17/48 7.1.3 Velocity Direction from Yaw Tube, Pivoted Vane, and Servoed Sphere Figure 7.12 Servoed-sphere Probes ‹ A servo-driven sphere is continuously and automatically aligned with the velocity vector by means of two independent servosystems using the differential-pressure signals P1-P2 and P3-P4 as error signals. ‹ A fifth tap measures the stagnation pressure. 18/48