Flight performance of rotary seeds

doi:10.1016/S0022-5193(89)80176-6

Journal of Theoretical Biology

Volume 138, Issue 1, 7 May 1989, Pages 23-53

https://doi.org/10.1016/S0022-5193(89)80176-6 Get rights and content

Many samaras or winged seeds make autorotational flight during their fall. Twenty samples to each of ten species are tested in a vertical wind tunnel, and filmed by a still camera and a cinecamera with stroboscope flash and by smoked flow observation technique. Mean values of their flight characteristics as well as their geometrical configurations are listed in tables and shown in figures along with the variance in the data.

Generally the seeds of simple configuration, such as those of maple and black pine, have good performance: there is a low rate of descent in spite of high wing loading (or small wing area but large seed weight) because of high rotational speed and thus a low coning angle.

It becomes clear from a simple analysis that the rate of descent, spinning rate of autorotation, pitch angle and coning angle of the rotating seeds are dependent on their geometrical characteristics such as span and area of the wing, mass of the seed, airfoil configuration, position of center of mass, center of moment, and radius of gyration or moment of inertia. Important parameters that relate to the performance are also pointed out and their effects on the flight characteristics are discussed.

The precise aerodynamic characteristics of rotary seeds are clarified by applying the local circulation method. Most of the lifting force is generated near the tip or outside terminal of the wing whereas the horizontal force, which is comprised of a driving force and a resistant force, is negative at the wing tip and is positive near the root. Thus the driving torque is obtained near the mid-point of the wing span.

Two-dimensional aerofoil or section characteristics of the respective species are also presented. Specifically, for the seed of maple, the results obtained from the gliding flight of a swept wing formed by two seeds and from the autorotational flight of a single seed are compared and found to be in good agreement.

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There are more references available in the full text version of this article.

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Journal of Theoretical Biology

References (12)

Flight of a Samara, Alsomitra macrocarpa

J. theor. Biol.

Local Momentum Theory and Its Application to the Rotary Wing

J. Aircraft

An extension of the Local Momentum Theory to the Rotor Operating in Twisted Flow Field. Paper No. 5

Aerodynamics of the Helicopter

The Wake Geometry of a Hovering Helicopter Rotor and Its Influence on Rotor Performance

J. Am. Helicopter Soc.

Mechanics of Fluids

Cited by (75)

Bioinspired airwings: Design and additive manufacturing of a geometrically graded microscale maple seed

Wind variability limits the potential influence of propagule morphology and descent rate on dispersal in the winged fruits of Carpinus (Betulaceae)

The load-bearing mechanism of plant wings: A multiscale structural and mechanical analysis of the T. tipu samara

Thresholds of nature: How understanding one of nature's penultimate laws led to the PowerCone, a biomimetic energy source

Model for sectional leading-edge vortex lift for the prediction of rotating samara seeds performance

Maple samara flight is robust to morphological perturbation and united by a classic drag model