The morphology, kinematics and stiffness properties of lifting surfaces play a key role in the aerodynamic performance of vertebrate flight. These surfaces, as a result of their flexible nature, may move both actively, owing to muscle contraction, and passively, in reaction to fluid forces. However, the nature and implications of this fluid-structure interaction are not well understood. Here, w...

A diversity of efficient solutions for flapping flight have evolved in nature; however, it is often difficult to isolate the key characteristics of efficient flapping flight from biological constraints. Rather than base micro aerial vehicle (MAV) design on natural flyers alone, we propose a multi-fidelity computational approach for analysis and design. At the lowest fidelity level, we use a wak...

Miniature flapping flight systems hold great promise in matching the agility of their natural counterparts, bees, flies, and hummingbirds. Characterized by reciprocating wing motion, unsteady aerodynamics, and the ability to hover, insect-like flapping flight presents an interesting locomotion strategy capable of functioning at small size scales and is still a current focus of research. A vehic...

Flying insects and robots that mimic them flap and rotate (or ‘pitch’) their wings with large angular amplitudes. The reciprocating nature of flapping requires rotation of the wing at the end of each stroke. Insects or flapping-wing robots could achieve this by directly exerting moments about the axis of rotation using auxiliary muscles or actuators. However, completely passive rotational dynam...

Most birds and many insects use periodic wing motion to propel themselves and maneuver. Most conventional flying machines are propelled by rotating machinery, achieve lift through rotating or fixed wings, and are controlled through the production of steady aerodynamic forces produced by rotors or movable wings. Many of the first powered flapping-wing micro air vehicles (MAVs) effectively replac...

Birds have to flap their wings to generate the needed thrust force, which powers them through the air. But how exactly do flapping wings create such force, and at what amplitude and frequency should they operate? These questions have been asked by many researchers. It turns out that much of the secret is hidden in the wake left behind the flapping wing. Exemplified by the study of Andersen et a...

Flexible flapping wings have garnered a large amount of attention within the micro aerial vehicle (MAV) community: a critical component of MAV flight is the coupling of aerodynamics and structural dynamics. This paper presents a computational framework for simulating shell-like wing structures flapping in incompressible flow at low Reynolds numbers in both hover and forward flight. The framewor...

Insects are a prime source of inspiration towards the development of small-scale, engineered, flapping wing flight systems. To help interpret the possible energy transformation strategies observed in Diptera as inspiration for mechanical flapping flight systems, we revisit the perspective of the dipteran wing motor as a bistable click mechanism and take a new, and more flexible, outlook to the ...

The development of flapping-wing micro air vehicles (MAVs) demands a systematic exploration of the available design space to identify ways in which the unsteady mechanisms governing flapping-wing flight can best be utilized for producing optimal thrust or maneuverability. Mimicking the wing kinematics of biological flight requires examining the potential effects of wing morphology on flight per...

Stability and control of rotors at high advance ratio are considered. Stability of teetering, articulated, and gimbaled hub types is considered with a simple flapping blade analysis. Rotor control in autorotation for teetering and articulated hub types is examined in more detail for a compound helicopter (rotor and fixed wing) using the comprehensive analysis CAMRAD II. Autorotation is found to...