TL;DR: In this paper , the authors highlight the bio-mimicable traits of an eagle which can be incorporated into bionic UAVs to improve roll and yaw control of a UAV along with drag reduction.
Abstract: Abstract: This review tends to shed light on the eagle’s aerodynamic attributes along with its inbuilt structural control surfaces that facilitate its high maneuverability. Apart from this, few aspects of the eagle’s wing morphing techniques, its aerofoil, and its aerodynamic stability are also being highlighted. The aim is to highlight the bio-mimicable traits of an eagle which can be incorporated into bionic UAVs. This work acts as a base for current and future works involving slotted wingtips and bionic control surfaces. The traits discussed are being used to design mechanical control surfaces and wingtips that resemble the eagle’s slotted wings and control surfaces. These works when combined with compliant mechanisms can help improve roll and yaw control of a UAV along with drag reduction. This review also highlights the aerodynamics of flapping; specifically of the hummingbird. From the hummingbird’s aerodynamics to its hovering techniques; all of its main features are being highlighted. These birds have demonstrated a wide range of aerodynamic traits which if mimicked to near perfection could pave the way for new-age drones. Maneuverability and enhanced aerodynamic optimality could be the outset of extreme sustainability measures with these birds paving the way with their evolutionary flight measures. Apart from their aerodynamic traits, a few aspects of their wing morphing techniques and their evolutionary hereditary traits are also being highlighted.
TL;DR: In this article , a flat delta wing with and without winglets at different angles of attack under low Reynolds numbers is analyzed and simulations are carried out to draw comparisons between the winglets on the basis of span-wise flow velocity vectors.
Abstract: Delta wing has numerous applications across aerospace vehicles. Highly inclined and variable swept back wings have a lot of added advantages in maneuverable fighter airplanes, supersonic cruise airliner; and modern unmanned aerial vehicles that have been equipped with and have deployed low swept back delta wings. Vortex flow across these delta wings is dominant for micro aerial vehicles and mini unmanned aerial vehicles flying at a low speed Reynolds number regime. Many experiments were carried out to study and analyze the aerodynamic flow parameters of delta wings wherein vortex sheet flow patterns were observed and studied at different angles of attack and flow parameters. In this paper we are plotting lift co-efficient and drag coefficient for a flat delta wing with and without winglets at different angles of attack under low Reynolds numbers. Furthermore, simulations are carried out to draw comparisons between the winglets on the basis of span-wise flow velocity vectors.
TL;DR: A mechanism is designed that aims at using morphing techniques to mimic a bird’s tail to achieve yaw control and directional stability in absence of a rudder and with the aid of the horizontal stabilizer solely.
Abstract: Abstract: Mimicking birds to enhance aerodynamic efficiencies of modern day aircrafts is a method that has seen major applications in the aerospace industry. Birds, due to their feathers, muscles and distinct morphologies tend to utilize methods that are otherwise impractical to incorporate in aircrafts due to limitations in terms of structure and materials. Yet, major influences are seen in many aircrafts that are inspired by the aerodynamic features of avian beings. Morphing is a major method that helps aircrafts make changes to their components, such as their wings to adapt or adjust to their varying flight conditions for efficient control and performance. In this paper, a mechanism is designed that aims at using morphing techniques to mimic a bird’s tail. The main purpose of this design is to achieve yaw control and directional stability in absence of a rudder and with the aid of the horizontal stabilizer solely. Keywords: Morphing, yaw stability, compliant mechanism, biomimetics, tail, twist morphing
TL;DR: In this article , a winglet design inspired by birds with slotted wings is presented to improve the maneuverability and aerodynamic characteristics of a bionic UAV with better endurance and roll control.
TL;DR: In this article , the authors have discussed the aerodynamic soaring capabilities of the albatross and eagle in detail along with the eagle's control surface aerodynamics and highlighted the different control surfaces and their actuations along with wing morphing techniques.
Abstract: Abstract: The optimal aerodynamic traits of the natural flyers have always been a foundation for the designing of bionic drones. In this paper, the aerodynamic soaring capabilities of the albatross and eagle are discussed in detail along with the eagle’s control surface aerodynamics. The bell shaped lift distribution characteristics exhibited by the albatross are also discussed along with its subsequent sub traits such as proverse yaw, wing-tip vortices and so on. The main soaring dynamics discussed are the dynamic soaring exhibited by the albatross and the utilization of thermal updrafts for thermal soaring by the eagle. Apart from these, the different control surfaces and their actuations along with wing morphing techniques are also highlighted. A proper and near perfect manifestation of the traits of natural flyers could be a harbinger to near perpetual modern aircrafts. Aerodynamics and propulsion system are the areas of research that are of concern in this manuscript.