Comparison of wingbeat amplitudes derived at different frame rates for three species flying at low speeds in the observation chamber
| . | . | . | Wingbeat amplitude (degrees) . | . | . | . | . | . | . | . | . | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| . | Flight speed V (m s-1) . | Wingbeat frequency fw (Hz) . | Cine at 200 frames s-1 . | . | . | DigiBeta into VHS at 48 frames s-1 . | . | . | VHS at 24 frames s-1 . | . | . | ||||||||
| Species . | . | . | Range . | Maximum . | Minimum . | Range . | Maximum . | Minimum . | Range . | Maximum . | Minimum . | ||||||||
| Vespadelus regulus | 3.3 | 10.4 | 29.2 to -29 | 35 | -45 | 22 to -30 | 30 | -40 | 22.5 to -30 | 30 | -40 | ||||||||
| Chalinolobus gouldii | 2.9 | 10.7 | 38.3 to -22.5 | 40 | -25 | 41.7 to -20 | 45 | -20 | 41.7 to -16.7 | 45 | -20 | ||||||||
| Chalinolobus gouldii | 2.6 | 12.0 | 33.8 to -10 | 40 | -15 | 30 to -13.3 | 40 | -20 | 30 to -13.3 | 40 | -20 | ||||||||
| Tadarida australis | 5.4 | 8.9 | 44.2 to -80 | 50 | -90 | 35 to -61.7 | 45 | -80 | 33 to -55 | 40 | -70 | ||||||||
| Tadarida australis | 5.2 | 9.0 | 46 to -36.7 | 50 | -80 | 37 to -41.7 | 45 | -60 | 39 to -41.7 | 45 | -60 | ||||||||
| . | . | . | Wingbeat amplitude (degrees) . | . | . | . | . | . | . | . | . | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| . | Flight speed V (m s-1) . | Wingbeat frequency fw (Hz) . | Cine at 200 frames s-1 . | . | . | DigiBeta into VHS at 48 frames s-1 . | . | . | VHS at 24 frames s-1 . | . | . | ||||||||
| Species . | . | . | Range . | Maximum . | Minimum . | Range . | Maximum . | Minimum . | Range . | Maximum . | Minimum . | ||||||||
| Vespadelus regulus | 3.3 | 10.4 | 29.2 to -29 | 35 | -45 | 22 to -30 | 30 | -40 | 22.5 to -30 | 30 | -40 | ||||||||
| Chalinolobus gouldii | 2.9 | 10.7 | 38.3 to -22.5 | 40 | -25 | 41.7 to -20 | 45 | -20 | 41.7 to -16.7 | 45 | -20 | ||||||||
| Chalinolobus gouldii | 2.6 | 12.0 | 33.8 to -10 | 40 | -15 | 30 to -13.3 | 40 | -20 | 30 to -13.3 | 40 | -20 | ||||||||
| Tadarida australis | 5.4 | 8.9 | 44.2 to -80 | 50 | -90 | 35 to -61.7 | 45 | -80 | 33 to -55 | 40 | -70 | ||||||||
| Tadarida australis | 5.2 | 9.0 | 46 to -36.7 | 50 | -80 | 37 to -41.7 | 45 | -60 | 39 to -41.7 | 45 | -60 | ||||||||
There is good correlation between amplitude values derived at high wingbeat frequencies (>9.5 Hz). The mid-range represented by Tadarida australis shows that frame rates significantly faster than 48 frames s-1 are required to capture the full range and maxima used by the bat.