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The purpose of this paper is to present an approach to a polar graph measurement by a flight testing technique and to propose a baseline research method for future tests of UAV polar graphs. The method presented can be used to demonstrate a conceptual and preliminary design process using a scaled, unmanned configuration. This shows how results of experimental flight tests using a scaled flying airframe may be described and analysed before manufacturing the full scale aircraft.

During the research, the flight tests were conducted for two aerodynamic configurations of a small UAV. This allowed the investigation of the influence of winglets and classic vertical stabilizers on the platform stability, performance and therefore polar graphs of a small unmanned aircraft.

A methodology of flight tests for the assessment of a small UAV’s polar graph has been proposed, performed and assessed. Two aerodynamic configurations were tested, and it was found that directional stability had a large influence on the UAV’s performance. A correlation between the speed and inclination of the altitude graph was found – i.e. the higher the flight speed, the steeper the altitude graph (higher descent speed, steeper flight path angle). This could be considered as a basic verification that the recorded data have a physical sense.

The polar graph and therefore glide ratio of the aircraft is a major factor for determining its performance and power required for flight. Using the right flight test procedure can speed-up the process of measuring glide ratio, making it easier, faster, robust, more effective and accurate in future research of novel, especially unorthodox configurations. This paper also can be useful for the proper selection of requirements and preliminary design parameters for making the design process more economically effective.

This paper presents a very efficient method of assessing the design parameters of UAVs, especially the polar graph, in an early stage of the design process. Aircraft designers and producers have been widely performing flight testing for years. However, these procedures and practical customs are usually not wide spread and very often are treated as the company’s “know how”. Results presented in this paper are original, relatively easily be repeated and checked. They may be used either by professionals, highly motivated individuals and representatives of small companies or also by ambitious amateurs.

The aim of this article is to determine the simplest and clearest relations existing between the principal characteristics of aeroplanes and their performances.

IN the early stages of design, when the general conception of the aeroplane is discussed, it is important for designers to realize the numerical influence of changes in the design parameters (characteristics) upon the performances.

Aerodynamics of paragliders is very complicated aeroelastic phenomena. The purpose of this work is to quantify the amount of aerodynamic drag related to the flexible nature of a paraglider wing.

The laboratory testing on scaled models can be very difficult because of problems in the elastic similitude of such a structure. Testing of full-scale models in a large facility with a large full-scale test section is very expensive. The degradation of aerodynamic characteristics is evaluated from flight tests of the paraglider speed polar. All aspects of the identification such as pilot and suspension lines drag and aerodynamics of spanwise chambered wings are discussed. The drag of a pilot in a harness was estimated by means of wind tunnel testing, computational fluid dynamics (CFD) solver was used to estimating smooth wing lift and drag characteristics.

The drag related to the flexible nature of the modern paraglider wing is within the range of 4-30 per cent of the total aerodynamic drag depending on the flight speed. From the results, it is evident that considering only the cell opening effect is sufficient at a low-speed flight. The stagnation point moves forwards towards the nose during the high speed flight. This causes more pronounced deformation of the leading edge and thus increased drag.

This paper deals with a detailed analysis of specific paraglider wing. Although the results are limited to the specific geometry, the findings help in the better understanding of the paraglider aerodynamics generally.

The data obtained in this paper are not affected by any scaling problems. There are only few experimental results in the field of paragliders on scaled models. Those results were made on simplified models at very low Reynolds number. The aerodynamic drag characteristics of the pilot in the harness with variable angles of incidence and Reynolds numbers have not yet been published.

Expanded polystyrene (EPS) is a low‐density and cheap material, which has been widely used in commercial areas. As the demand for small‐batch, flexible and quick production increases, producing EPS products with metals moulds has become unaffordable. The purpose of this paper is to describe the development of an EPS rapid prototyping (ERP) process, with an electric heating tool.

Two new cutting strategies for the ERP process, constant angle mode and constant thickness mode, are proposed. The methods to generate tool path of those models are also discussed. In order to improve accuracy and cutting effectiveness, experiments have been carried out to investigate the thermal characteristics in the ERP process. Consequently, the relationships between the size of material removal area and process parameters are obtained. Suitable processing parameters for the ERP system are also conducted.

It is found that the ERP process can rapidly produce complex three‐dimensional parts in one‐off clamping without post‐processing procedures as in traditional rapid prototyping, such as, extra support removing, step texture finishing and distortion regulating.

The paper provides several examples to explain and illustrate the applicability and workflow of the ERP system.

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Committee, Reports and Technical Notes of the U.S. National Advisory Committee for Aeronautics, and publications of other similar research bodies as issued

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.

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.

The purpose of this study is to identify the crack in the shaft at incipient stage. Transverse crack is the most common type of crack found on the periphery of the shaft. The changes in dynamic behaviour of the rotor at high speed are enormous. The reliable operation of the machinery is paramount for the safety of individual and plant. Condition-based maintenance monitors the mechanical and operational condition of the machine. During such inspection, if any unhealthy symptoms are detected, then affected part is identified and taken out for the maintenance at most appropriate time.

Simulating the transverse crack of different depth and location is the most challenging part of the experimental analysis. To optimize the total experimental cost for simulation of crack in the shaft, inverted crack is proposed to be produced in shaft and investigation shall be carried out for of early crack detection in shaft using vibration analysis. The set of experiments has been conducted on healthy shaft, inverted cracked shaft and actual cracked shaft. Inverted crack methodology provides flexibility of simulating crack of any size and at any location, and it can be reconfigured for several times to obtain various set of results.

To derive objective of the study, steady state response analysis and transient response analysis are performed on the experiment test rig. Vibration signals are acquired from the bearing locations to detect the crack. The paper addresses the influence of the inverted crack on critical speed of the shaft and deviation of first and second harmonic component of the shaft because of introduction of inverted crack. The resultant Nyquist plots, orbit plots and frequency plots are compared with the baseline data (obtained with the healthy shaft) to identify the crack.

The present study focuses on methodology by which inverted crack is developed in the healthy shaft, which resembles the behaviour of actual crack, and it shall be used to study the changes in rotor stiffness caused by transverse crack. The experimental results obtained using the inverted crack shaft have same vibration characteristics but in reverse direction as it would have occurred with the cracked shaft.

D‐TRAK — the self‐assembly kit form conveyoring system launched last year, now has another new dimension. Not only is the tracking completely adjustable, but now the framework has been re‐designed to accommodate any changes in a production line.