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Unlike conventional aircraft, birds can glide without a vertical tail. The purpose of this paper is to analyse the influence of dihedral angle spanwise distribution on lateral-directional dynamic stability by the simulation, calculation in the development of the bird-inspired aircraft and the flight testing.

The gliding magnificent frigatebird (Fregata magnificens) was selected as the study object. The geometric and mass model of the study object were developed. Stability derivatives and moments of inertia were obtained. The lateral-directional stability was assessed under different spanwise distributions of dihedral angle. A bird-inspired aircraft was developed, and a flight test was carried out to verify the analysed results.

The results show that spanwise distribution changing of dihedral angle has influence on the lateral-directional mode stability. All of the analysed configurations have convergent Dutch roll mode and rolling mode. The key role of dihedral angle changing is to achieve a convergent spiral mode. Flight test results show that the bird-inspired aircraft has a well-convergent Dutch roll mode.

The theory that birds can achieve its lateral-directional stability by changing its dihedral angle spanwise distribution may explain the stability mechanism of gliding birds.

This paper helps to improve the understanding of bird gliding stability mechanism and provides bio-inspired solutions in aircraft designing.

The purpose of this paper is to create a conceptual design a bird-inspired unmanned aerial vehicle (UAV) that can stay in the air for a long time while this design influences the species near the airport with predator appearance. To achieve that goal, reverse engineering methods took into account to find out optimal parameter, and effective bird species were examined to be taken as an example.

Design parameters were determined according to the behaviour of bird species in the region and their natural enemies. Dalaman airport where is located near the fresh water supplies and sea, was chosen as the area to run. To keep such birds away from the airport and to prevent potential incidents, information from animal behaviour studies is enormously important. According to Tinbergen, chicken and gees reacted to all short-necked birds because they thought they were predators. The entire method is based on information from these data, along with reverse engineering principles.

UAV can remain in the air for more than 5 min when the engine stops at an altitude of 200 m. Also, when the UAV loses altitude of 100 m, it can cover a distance of about 2 m with the 19.8-glide ratio. Moreover, 380 KV brushless electric motor can provide 5.2 kg thrust force with 17 × 8-inch folding propeller which means 1.3 thrust to weight ratio (T/W). This engine and propeller combination work up to 12 min at maximum power with 7000 mAh lipo-battery. The UAV can climb more than 40 min at 0.2 T/W ratio.

While bird-inspired UAV trials have just begun, general ornithopter studies have taken smaller birds as their source because this is the limit of the flapping wing, one of the largest birds modelled in this study. Thus, it is inevitable the UAV influences other birds in the area. In addition, this bird’s inherent flight behaviour, such as soaring, ridge lifting and gliding, will increase its credibility. Owing to size similarity with UAV systems, reverse engineering methods worked well in the design.

Some of the specialist try to fly trained falcon in airport as an alternative method. This study focussed on the design of a bird-inspired UAV by optimizing the glide performance, both for scare the other birds around the airport and for the observation of birds in the vicinity and for the identification of bird species.

As this type of work has been proven to reduce the risk of bird strikes, the sense of flight safety on society will increase.

Researchers and companies generally work on flapping wing models for related subjects. However, these products are kind of model of the Falconiformes species which don’t have too much influence on big birds. For this reason, the authors took account of Imperial eagle’s specifications. These birds perform long soaring flights while seeking for prey like the glider design. So, the authors think it is a new approach for designing UAV for preventing bird-strike.

Increasing endurance was a very appropriate subject for the biomimetic approach. The study aims to design and manufacture a long-lasting mini unmanned aerial vehicle (UAV) using active gliding and soaring.

The endurance of mini UAVs is limited by battery or fuel capacity, and it is not always possible to increase these energy sources due to the fuselage size. Long endurance aircraft are required in various areas such as silent environment and traffic monitoring or search and rescue. Literature research on bird flight performance conducted to determine design parameters. These parameters are used in the theoretical design of the UAV for optimization. Computational fluid dynamics simulation and flight tests of the UAV performed to figure out the success of the design.

For a mini UAV to be produced in this class, it has been observed that it is more accurate to examine birds instead of gliders due to the size similarity. The UAV design reaches a 27.5 L/D (Glide ratio) ratio in the theoretical approach. However, flight results approved max L/D ratio is around 25 at the sea level. This flight performance is enough to outperform in glide ratio of Wandering albatrosses.

Sailplanes are known as sport aircraft. However, recent projects focus on glider designs due to fuel efficiency and silent tracking. Stemme S-14 that carries a high-resolution camera is one of the examples of these projects. The unmanned glider design can lead to these implications in the UAVs at least during the stand-by period in the air. Thanks to low weight, UAVs do not require strong thermals, which allows flying almost all over the world.

Researchers generally focus on increasing the battery capacity or the performance of the UAV. However, this study’s concentration is to increase the flight duration of the UAV by using geographical currents. For this purpose, taking advantage of bird morphology is quite a new topic. Also, glider type designs are rarely found in the field.

Ground effect is one of the important factors in the enhancement of wing aerodynamic performance. This study aims to investigate the aerodynamic forces and performance of a flapping wing with the bending deflection angel under the ground effect.

In this study, the wing and flapping mechanism were designed and manufactured based on the seagull flight and then assembled. It is worth noting that this mechanism is capable of wing bending in the upstroke flight as big birds. Finally, the model was examined at bending deflection angles of 0° and 107° and different distances from the surface, flapping frequencies and velocities in forward flight in a wind tunnel.

The results revealed that the aerodynamic performance of flapping wings in forward flight improved due to the ground effect. The effect of the bending deflection mechanism on lift generation was escalated when the flapping wing was close to the surface, where the maximum power loading occurred.

Flapping wings have many different applications, such as maintenance, traffic control, pollution monitoring, meteorology and high-risk operations. Unlike fixed-wing micro aerial vehicles, flapping wings are capable of operating in very-low Reynolds-number flow regimes. On the other hand, ground effect poses positive impacts on the provision of aerodynamic forces in the take-off process.

Bending deflection in the flapping motion and ground effect are two influential factors in the enhancement of the aerodynamic performance of flapping wings. The combined effects of these two factors have not been studied yet, which is addressed in this study.