Abstract
This paper reports on direct measurement of differential pressure on a butterfly wing during free flight. Differential pressure was measured using a micro-fabricated sensor. A piezo-resistive cantilever was used as a differential pressure sensor. The sensor was 1.0 mm × 1.0 mm × 0.3 mm in size and 0.7 mg in weight so that it did not interfere with wing motion. By attaching the sensor to the center of a butterfly forewing with a flexible wiring, the differential pressure on the wing was measured during free flight. We revealed that the maximum pressure value was 11.7 Pa at the end of stroke. The maximum aerodynamic force in free-flight is 10 times as large as the gravity acting on the body.
