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Apr 06. Successful maiden flight of a bearingless Advanced Technology Rotor. Eurocopter has celebrated another milestone in the development of the rotor technology of the future at its Donauwörth plant. Following the first successful flight of a BK117 helicopter with an adaptive rotor system in September 2005, today saw the maiden flight of the newly developed 5-blade “Advanced Technology Rotor” fitted on an EC145 test helicopter. This rotor is designed to be ideally suited for 4-ton class helicopters. The development of advanced technology rotor systems goes back a long way at Eurocopter. It began with the hingeless main rotor with composite blades, used by the BO105 and BK117 models, followed by the bearingless four-blade rotors used by the EC135, and now sees its latest development, the ATR 5-blade rotor. Key characteristics of the new bearingless ATR is its extremely compact and light-weight rotor hub and its use of modular components. These design innovations result in improved flight characteristics and a more comfortable ride in comparison to the existing EC145 rotor, while also yielding cost and weight benefits. Added comfort thanks to reduced vibration and improved flight characteristics. The design of the ATR as a 5-blade rotor results in reduced vibrations, which affect helicopter components and passengers alike. Due to the compact rotor hub the helicopter’s flight characteristics are also improved.
27 Apr 06. Insect eye inspires future vision. Bees eyes are made of thousands of lenses. An artificial insect eye that could be used in ultra-thin cameras has been developed by scientists in the US. The dimpled eye contains over 8,500 hexagonal lenses packed into an area the size of a pinhead. The dome-shaped structure, described in the journal Science, is similar to a bee’s eye. The researchers, from the University of California, Berkeley, say the work may also shed light on how insects developed such complex visual systems. As a result, the team of bioengineers came up with a relatively cheap and easy method for creating the artificial eyes that may in part mimic natural processes. Insect eyes, known as compound eyes, usually consist of hundreds of tiny lens-capped optical units, known as ommatidia. For example, a dragonfly has 30,000 of the structures in each eye. Individual ommatidia guide light through a lens and cone into a channel, known as a rhabdom, which contains light-sensitive cells. These are connected to optical, nerve cells to produce the image. As light passes through the micro lens of the artificial ommatidia, it is focused on a point where photo-chemical changes in the resin automatically generate the cone and the wave-guide. The ommatidia are crammed side by side into bulges that create a wide field of view for the insect. As each unit is orientated in a slightly different direction, the honeycombed eye creates a mosaic image which, although low in resolution, is excellent at detecting movement. The team created the artificial eye by first creating a tiny, reusable mould with 8,700 indentations. The pock-marked hemisphere was then filled with an epoxy resin that reacts when exposed to ultraviolet light to create a harder material with different chemical properties. After being baked at a low temperature to set the material it can be extracted from the mould. The result is a pin head sized dome with 8,700 raised humps arranged in a honeycomb pattern across its surface. Each raised hump acts like a lens, focusing any light into the material below. Over time the concentrated light reacts with the resin to form a cone that guides the light deeper into the structure. As the light continues to burn a path through the resin it creates a tiny channel, called a wave-guide, which is similar to the rhabdom in an insect’s eye. The reaction of the polymer with the light changes the optical properties of the material meaning that a