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This paper aims to propose a novel design concept for a biomimetic dolphin-like underwater glider, which can offer the advantages of both robotic dolphins and underwater gliders to achieve high-maneuverability, high-speed and long-distance motions.

To testify the gliding capability of dolphin-like robot without traditional internal movable masses, the authors first developed a skilled and simple dolphin-like prototype with only gliding capability. The hydrodynamic coefficients, including lift, drag and pitching moment, are obtained through computational fluid dynamics method, and the hydrodynamic analysis in the steady gliding motion is also executed.

Experimental results have shown that the dolphin-like glider could successfully glide depending on the pitching torques only from buoyancy-driven system and controllable fins without traditional internal moveable masses.

A hybrid underwater glider scheme that combines robotic dolphin and glider is firstly proposed, shedding light on the creation of innovation gliders with maneuverability and durability.

AT the start of a new era of civil air transport the possibilities offered by the numerous new developments in the operation as well as in the design of aircraft should be analysed in order to exploit them to the full extent in building up an efficient transport system. One of the new appearances in the field of air transportation is the towed glider, which reaped many laurels in the last war. Names like Crete, Sicily, Arnheim recall heroic battles in which glider troops played a prominent part. These military successes have given rise to many articles in which the transport glider is announced as an important discovery for economical air transport. Aerial trains consisting of one tug and a number of gliders have been proclaimed to be a new and valuable contribution to the future of civil aviation. On economic as well as safety considerations the author advises the advocates of the transport glider to restrain their enthusiasm and not to overestimate the future possibilities of this type of air transport.

WHEN considering the dynamics of a combination of a tug and a glider one is apt to neglect the interference effects between the two aircraft, especially when the towing cable has a length of several hundred feet. That the disturbances caused by the tug have an appreciable influence on the forces acting on the glider was demonstrated by the results of flight tests recently carried out by the Nationaal Luchtvaartlaboratorium (National Aeronautical Research Institute), Amsterdam, Holland.

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 glider presents a simpler problem to the performance calculator than does the engine‐driven aeroplane: a problem free from the variables that are inevitably introduced when propulsion is derived from a complicated system of engine and airscrew. Nevertheless, the process of determining the performance to be expected of any projected glider design is usually quite a lengthy one; and if, in addition, an investigation is to be made into the effects of varying all the factors concerned, with a view to finding their optimum values, the process becomes so lengthy that in practice it is sometimes neglected. Glider development then tends to proceed along what may be described as Darwinian lines, and progress becomes unnecessarily slow: the evolution of gliders to fit new operational requirements as they arise takes longer than it need.

THE production of a glider presents problems that are similar in many respects to those found in the production of any other type of aircraft. The position in the case of the glider is simplified by the absence of such parts as the engine and the various equipment associated with it, and also the elaborate undercarriage installation. It is, however, complicated by the relatively large overall size of the aircraft as compared with an equivalent power machine.

ON September 21st and 22nd, 1934, a conference was held in Munich by the V.L.F. (Vereinigung für Luftfahrtforschung) Committee for soaring flight. The aim of the V.L.F. is to maintain a close co‐operation between the various aeronautical research institutions and individual research workers and the aircraft industry. A number of papers on the various problems connected with the development of soaring flight were read at the conference and, with a few exceptions, they are published in this number of Luftwissen.

The purpose of this paper is to present the concept of the author’s method of fatigue properties assessment of polymer composite structures, especially structures having nodes of concentrated force introduction (NCFI) using fatigue test data of coupons of similar composites and the ratio of their structural stress rate factors.

Basing on fatigue properties of pure composite shells coupons subjected to cyclic loads, and basing on the static strength difference between pure composite shells and shells having the structure affected by NCFI – (considered here as not only a manner of load introduction but also a kind of structural discontinuity), a method of relative fatigue properties reduction (RFPR) was developed. In the RFPR evaluation process, the author used the results of experiments on a special type of an NCFI named “a labyrinth non-adhesive node of concentrated force introduction” (LNA-NCFI) applied in certain composite gliders for fitting glider wings with the fuselage and also referred to design directives relating to primary structure of composite gliders, which are presented in the form of lightness factors linking stress with a structural mass.

The result of RFPR method application matched well with the results of fatigue tests of the LNA-NCFI type of a NCFI. The RFPR method may significantly facilitate the estimation of fatigue life of a structure with a structural discontinuity or an NCFI.

The RFPR method may significantly facilitate the estimation of fatigue life of a structure with a structural discontinuity or an NCFI.

The paper presents a proposal of a novel simplified method for fatigue life estimation of composite structures having a kind of structural discontinuity or an NCFI.

DURING the past 40‐odd years or so, a number of experimental aeroplane types have been invented, visualized, designed, constructed and even flown which, in a quite unorthodox manner, had neither behind the wing nor in front of it any sort of stabilizing and/or controlling surfaces.