Elytra boost lift, but reduce aerodynamic efficiency in flying beetles

L. Christoffer Johansson; Sophia Engel; Emily Baird; Marie Dacke; Florian T. Muijres; Anders Hedenström

doi:10.1098/rsif.2012.0053

Elytra boost lift, but reduce aerodynamic efficiency in flying beetles

Journal of The Royal Society Interface ◽

10.1098/rsif.2012.0053 ◽

2012 ◽

Vol 9 (75) ◽

pp. 2745-2748 ◽

Cited By ~ 32

Author(s):

L. Christoffer Johansson ◽

Sophia Engel ◽

Emily Baird ◽

Marie Dacke ◽

Florian T. Muijres ◽

...

Keyword(s):

Force Production ◽

Aerodynamic Performance ◽

Vertical Force ◽

Negative Interaction ◽

Aerodynamic Efficiency ◽

Wing Span ◽

Quantitative Measurements ◽

Flying Insects ◽

Weight Support ◽

Extra Weight

Flying insects typically possess two pairs of wings. In beetles, the front pair has evolved into short, hardened structures, the elytra, which protect the second pair of wings and the abdomen. This allows beetles to exploit habitats that would otherwise cause damage to the wings and body. Many beetles fly with the elytra extended, suggesting that they influence aerodynamic performance, but little is known about their role in flight. Using quantitative measurements of the beetle's wake, we show that the presence of the elytra increases vertical force production by approximately 40 per cent, indicating that they contribute to weight support. The wing-elytra combination creates a complex wake compared with previously studied animal wakes. At mid-downstroke, multiple vortices are visible behind each wing. These include a wingtip and an elytron vortex with the same sense of rotation, a body vortex and an additional vortex of the opposite sense of rotation. This latter vortex reflects a negative interaction between the wing and the elytron, resulting in a single wing span efficiency of approximately 0.77 at mid downstroke. This is lower than that found in birds and bats, suggesting that the extra weight support of the elytra comes at the price of reduced efficiency.

Download Full-text

Investigation into Reynolds number effects on a biomimetic flapping wing

International Journal of Micro Air Vehicles ◽

10.1177/1756829317745319 ◽

2018 ◽

Vol 10 (1) ◽

pp. 106-122 ◽

Cited By ~ 2

Author(s):

Daniel K Hope ◽

Anthony M DeLuca ◽

Ryan P O’Hara

Keyword(s):

Reynolds Number ◽

Natural Frequency ◽

Air Force ◽

High Speed ◽

Force Production ◽

Vertical Force ◽

Linkage Mechanism ◽

Wing Span ◽

Institute Of Technology ◽

Wing Stroke

This research investigated the behavior of a Manduca sexta inspired biomimetic wing as a function of Reynolds number by measuring the aerodynamic forces produced by varying the characteristic wing length and testing at air densities from atmospheric to near vacuum. A six degree of freedom balance was used to measure forces and moments, while high speed cameras were used to measure wing stroke angle. An in-house created graphical user interface was used to vary the voltage of the drive signal sent to the piezoelectric actuator which determined the wing stroke angle. The Air Force Institute of Technology baseline 50 mm wing was compared to wings manufactured with 55, 60, 65, and 70 mm spans, while maintaining a constant aspect ratio. Tests were conducted in a vacuum chamber at air densities between 0.5% and 100% of atmospheric pressure. Increasing the wingspan increased the wing’s weight, which reduced the first natural frequency; and did not result in an increase in vertical force over the baseline 50 mm wing. However, if the decrease in natural frequency corresponding to the increased wing span was counteracted by increasing the thickness of the joint material in the linkage mechanism, vertical force production increased over the baseline wing planform. Of the wings built with the more robust flapping mechanism, the 55 mm wing span produced 95% more vertical force at a 26% higher flapping frequency, while the 70 mm wing span produced 165% more vertical force at a 10% lower frequency than the Air Force Institute of Technology baseline wing. Negligible forces and moments were measured at vacuum, where the wing exhibited predominantly inertial motion, revealing flight forces measured in atmosphere are almost wholly limited to interaction with the surrounding air. Lastly, there was a rough correlation between Reynolds number and vertical force, indicating Reynolds number is a useful modelling parameter to predict lift and corresponding aerodynamic coefficients for a specific wing design.

Download Full-text

Lift vs. drag based mechanisms for vertical force production in the smallest flying insects

Journal of Theoretical Biology ◽

10.1016/j.jtbi.2015.07.035 ◽

2015 ◽

Vol 384 ◽

pp. 105-120 ◽

Cited By ~ 28

Author(s):

S.K. Jones ◽

R. Laurenza ◽

T.L. Hedrick ◽

B.E. Griffith ◽

L.A. Miller

Keyword(s):

Force Production ◽

Vertical Force ◽

Flying Insects

Download Full-text

Ontogeny of aerial righting and wing flapping in juvenile birds

Biology Letters ◽

10.1098/rsbl.2014.0497 ◽

2014 ◽

Vol 10 (8) ◽

pp. 20140497 ◽

Cited By ~ 9

Author(s):

Dennis Evangelista ◽

Sharlene Cam ◽

Tony Huynh ◽

Igor Krivitskiy ◽

Robert Dudley

Keyword(s):

Force Production ◽

Vertical Force ◽

Alectoris Chukar ◽

Avian Flight ◽

Body Roll ◽

Chukar Partridge

Mechanisms of aerial righting in juvenile chukar partridge ( Alectoris chukar ) were studied from hatching to 14 days-post-hatching (dph). Asymmetric movements of the wings were used from 1 to 8 dph to effect progressively more successful righting behaviour via body roll. Following 8 dph, wing motions transitioned to bilaterally symmetric flapping that yielded aerial righting via nose-down pitch, along with substantial increases in vertical force production during descent. Ontogenetically, the use of such wing motions to effect aerial righting precedes both symmetric flapping and a previously documented behaviour in chukar (i.e. wing-assisted incline running) hypothesized to be relevant to incipient flight evolution in birds. These findings highlight the importance of asymmetric wing activation and controlled aerial manoeuvres during bird development and are potentially relevant to understanding the origins of avian flight.

Download Full-text

Biomechanics of the unique pterosaur pteroid

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2009.1899 ◽

2009 ◽

Vol 277 (1684) ◽

pp. 1121-1127 ◽

Cited By ~ 9

Author(s):

Colin Palmer ◽

Gareth J. Dyke

Keyword(s):

Leading Edge ◽

Aerodynamic Performance ◽

Biomechanical Analysis ◽

Aerodynamic Efficiency ◽

Fourth Finger ◽

Forward Part ◽

The Way

Pterosaurs, flying reptiles from the Mesozoic, had wing membranes that were supported by their arm bones and a super-elongate fourth finger. Associated with the wing, pterosaurs also possessed a unique wrist bone—the pteroid—that functioned to support the forward part of the membrane in front of the leading edge, the propatagium. Pteroid shape varies across pterosaurs and reconstructions of its orientation vary (projecting anteriorly to the wing leading edge or medially, lying alongside it) and imply differences in the way that pterosaurs controlled their wings. Here we show, using biomechanical analysis and considerations of aerodynamic efficiency of a representative ornithocheirid pterosaur, that an anteriorly orientated pteroid is highly unlikely. Unless these pterosaurs only flew steadily and had very low body masses, their pteroids would have been likely to break if orientated anteriorly; the degree of movement required for a forward orientation would have introduced extreme membrane strains and required impractical tensioning in the propatagium membrane. This result can be generalized for other pterodactyloid pterosaurs because the resultant geometry of an anteriorly orientated pteroid would have reduced the aerodynamic performance of all wings and required the same impractical properties in the propatagium membrane. We demonstrate quantitatively that the more traditional reconstruction of a medially orientated pteroid was much more stable both structurally and aerodynamically, reflecting likely life position.

Download Full-text

Mechanics of six-legged runners

Journal of Experimental Biology ◽

10.1242/jeb.148.1.129 ◽

1990 ◽

Vol 148 (1) ◽

pp. 129-146 ◽

Cited By ~ 28

Author(s):

R. J. Full ◽

M. S. Tu

Keyword(s):

Mechanical Energy ◽

Center Of Mass ◽

Force Production ◽

Stride Frequency ◽

Gravitational Potential Energy ◽

Vertical Force ◽

Body Form ◽

Blaberus Discoidalis ◽

Ghost Crabs ◽

Reaction Forces

Six-legged pedestrians, cockroaches, use a running gait during locomotion. The gait was defined by measuring ground reaction forces and mechanical energy fluctuations of the center of mass in Blaberus discoidalis (Serville) as they travelled over a miniature force platform. These six-legged animals produce horizontal and vertical ground-reaction patterns of force similar to those found in two-, four- and eight-legged runners. Lateral forces were less than half the vertical force fluctuations. At speeds between 0.08 and 0.66 ms-1, horizontal kinetic and gravitational potential energy changes were in phase. This pattern of energy fluctuation characterizes the bouncing gaits used by other animals that run. Blaberus discoidalis attained a maximum sustainable stride frequency of 13 Hz at 0.35 ms-1, the same speed and frequency predicted for a mammal of the same mass. Despite differences in body form, the mass-specific energy used to move the center of mass a given distance (0.9 J kg-1m-1) was the same for cockroaches, ghost crabs, mammals, and birds. Similarities in force production, stride frequency and mechanical energy production during locomotion suggest that there may be common design constraints in terrestrial locomotion which scale with body mass and are relatively independent of body form, leg number and skeletal type.

Download Full-text

Aerodynamic Investigation of Double Surface Airfoil

ACS Journal for Science and Engineering ◽

10.34293/acsjse.v1i2.13 ◽

2021 ◽

Vol 1 (2) ◽

pp. 41-46

Author(s):

Siva J ◽

Suresh C ◽

Paramaguru V

Keyword(s):

Experimental Investigation ◽

Flow Separation ◽

Research Work ◽

Aerodynamic Performance ◽

Aircraft Industry ◽

Aerodynamic Efficiency ◽

Flight Vehicles ◽

Double Surface ◽

Naca 0012 ◽

Aerodynamic Investigation

Aircraft industry has been deeply concerned about reduction of drag by reducing flow separation and improving the aerodynamic efficiency of flight vehicles, particularly in commercial and military market by adopting various methods. Reduction of flow separation is a concept by which we can increase aerodynamic efficiency. The purpose of the project is to perform an experimental investigation on aerodynamic performance of NACA 0012 airfoil model with and without splits. It is evident from this research work that the airfoil model with split possesses greater aerodynamic performance by producing lesser overall drag. This is due to the delay in flow separation from the surface.

Download Full-text

Experimental analysis of cell pattern on grid fin aerodynamics in subsonic flow

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410019872349 ◽

2019 ◽

Vol 234 (3) ◽

pp. 537-562

Author(s):

Manish Tripathi ◽

Mahesh M Sucheendran ◽

Ajay Misra

Keyword(s):

Subsonic Flow ◽

Lift Coefficient ◽

Aerodynamic Performance ◽

Aerodynamic Efficiency ◽

Grid Fin ◽

Stall Angle ◽

The Individual ◽

The Impact ◽

Control Surfaces

Grid fins consisting of a lattice of high aspect ratio planar members encompassed by an outer frame are unconventional control surfaces used on numerous missiles and bombs due to their enhanced lifting characteristics at high angles of attack and across wider Mach number regimes. The current paper accomplishes and compares the effect of different grid fin patterns on subsonic flow aerodynamics of grid fins by virtue of the determination of their respective aerodynamic forces. Furthermore, this study deliberates the impact of gap variation on aerodynamics of different patterns. Results enunciate enhanced aerodynamic efficiency, and lift slope for web-fin cells and single diamond patterns compared to the baseline model. Moreover, the study indicates improved aerodynamic performance for diamond patterns with higher gaps by providing elevated maximum lift coefficient, delayed stall angle, and comparable drag at lower angles. The study established the presence of an additional effect termed as the inclination effect alongside the cascade effect leading to deviations with respect to lift, stall, and aerodynamic efficiency amongst different gap variants of the individual patterns. Thus, optimization based on the aerodynamic efficiency, stall angle requirements, and construction cost by optimum pattern and gap selection can be carried out through this analysis, which can lead to elevated aerodynamic performance for grid fins.

Download Full-text

Vertical Force Production in Soccer

Strength and Conditioning Journal ◽

10.1519/ssc.0000000000000513 ◽

2019 ◽

pp. 1 ◽

Cited By ~ 1

Author(s):

Irineu Loturco ◽

Chris Bishop ◽

Tomás T. Freitas ◽

Lucas A. Pereira ◽

Ian Jeffreys

Keyword(s):

Force Production ◽

Vertical Force

Download Full-text

Experimental Study of the Aerodynamic Interaction between the Forewing and Hindwing of a Beetle-Type Ornithopter

Aerospace ◽

10.3390/aerospace5030083 ◽

2018 ◽

Vol 5 (3) ◽

pp. 83 ◽

Cited By ~ 2

Author(s):

Hidetoshi Takahashi ◽

Kosuke Abe ◽

Tomoyuki Takahata ◽

Isao Shimoyama

Keyword(s):

Pressure Sensors ◽

Aerodynamic Performance ◽

Flapping Wing ◽

Differential Pressure ◽

Vertical Force ◽

Unique Combination ◽

Force Enhancement ◽

Forward Flight ◽

Micro Electro Mechanical Systems ◽

Aerodynamic Interaction

Beetles have attracted attention from researchers due to their unique combination of a passively flapping forewing and an actively flapping hindwing during flight. Because the wing loads of beetles are larger than the wing loads of other insects, the mechanism of beetle flight is potentially useful for modeling a small aircraft with a large weight. In this paper, we present a beetle-type ornithopter in which the wings are geometrically and kinematically modeled after an actual beetle. Furthermore, the forewing is designed to be changeable between no-wing, flapping-wing, or fixed-wing configurations. Micro-electro-mechanical systems (MEMS) differential pressure sensors were attached to both the forewing and the hindwing to evaluate the aerodynamic performance during flight. Whether the forewing is configured as a flapping wing or a fixed wing, it generated constant positive differential pressure during forward flight, whereas the differential pressure on the hindwing varied with the flapping motion during forward flight. The experimental results suggest that beetles utilize the forewing for effective vertical force enhancement.

Download Full-text