Труды сотрудников ИЛ им. В.Н. Сукачева СО РАН

[Текст] / D. L. GRODNITSKY // Zool. Zhurnal. - 1993. - Vol. 72, Is. 7. - С. 84-94. - Cited References: 48 . - 11. - ISSN 0044-5134РУБ Zoology

Аннотация: Vertical and horizontal periodic movements of the body following each wing stroke were investigated in three butterfly species during their free flight in a transparent cage. Distribution of the movements along the stroke cycle shows that specimens climb during downstroke, supination, and upstroke. Pronation of the wings in the top of their trajectory (Weis-Fogh's clap-and-fling mechanisms) is followed by height reduction. The horizontal distance that insects cover during pronation and downstroke exceeded mean value and it was less than the mean value during supination and upstroke. The data acquired suggest that distributions in lift and thrust along a stroke cycle are characterized by sinusoid-like curves as a first approximation. Maximal lift is generated during the end of each downstroke, while the maximal thrust coincides in time with the end of the upstroke and the clap of the wings. A new non-steady mechanism of aerodynamic force generation is proposed. The mechanism is connected with air throwing off the flapping planes during their pronation and supination. Horizontal flight speed is negatively correlated with the angle between the body and the horizon, but does not depend on wing beat frequency. A hypothesis is suggested that insect flapping flight power regulation system includes a finite number of stable kinematic patterns each corresponding to a particular flight mode and characterized by specific values of intimately correlated stroke parameters.


Доп.точки доступа:
GRODNITSKY, D.L.

[Текст] / D. L. GRODNITSKY // Zool. Zhurnal. - 1992. - Vol. 71, Is. 4. - С. 21-28. - Cited References: 27 . - 8. - ISSN 0044-5134РУБ Zoology

Аннотация: Several kinematic parameters of wings and linked with them vertical oscillations of the body were studied analyzing cinema films of 3 butterfly species flying free and being tethered. Tethered insects demonstrated prolonged near harmonic strokes. Contrary to that in free flight downstroke lasts more than the upstroke. Butterflies change relationship between lift and thrust changing the angle between longitudinal body axis and the horizon. Absolute value of aerodynamic force is regulated with stroke amplitude. Lift may be enhanced by increasing relative duration of downstroke. interrelationship between wing kinematics and periodical vertical body movements shows that almost no sustaining force is generated during Weis-Fogh's clap-and-fling. Maximal lift values have place in the lower part of downstroke. New data do not support the hypothesis on the role of reactive force in insect flight.


Доп.точки доступа:
GRODNITSKY, D.L.