Collaboration with JAXA
Kaijo Sonic Corporation has developed in collaboration with the Japan Aerospace Exploration Agency (JAXA) an UltaSonic Velocimeter (USV) for aviation (Matayoshi et al 2005). The USV is based on a conventional ultrasonic anemometer that consists of two main components: (1) A probe, which senses the three-dimensional aircraft-relative airflow vector and ambient temperature by measuring ultrasonic pulse transit time between three mounts (see figure at right); And (2) a control box and a junction box, which control ultrasonic pulse emissions, and output the measured data via RS-232C. The main advantage of the USV as compared to a pitot-static system is that it can provide accurate measurements at low speed. This is obviously important for helicopters. Unlike conventional ultrasonic anemometers, the USV uses high-frequency (200 kHz) ultrasonic pulses to reduce acoustic noise, and its probe shape minimizes airflow disturbance at high airspeeds. These modifications allow a broad range of airflow measurements, from 0 to 70 m/s, which covers the entire flight envelope of most commercial helicopters.
As part of a collaboration agreement that we developed with JAXA, we mounted a prototype version of the USV on the nose of the HOP, next to the AIMMS-20. We are exploring the performance of the USV (as compared to the AIMMS-20) in flights at different altitudes and under different meteorological conditions.
References
- Matayoshi, N., H. Inokuchi, K. Yazawa, and Y. Okuno, 2005. Development of an airborne ultrasonic velocimeter and its application to helicopters. AIAA 2005-6118.
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