“飞碟”无人机

日前，英国的GFS项目公司向英国防部演示了其根据附壁作用设计的无人机。

它包括直径0.91米、重5.45千克的GFS-6a和更小的GFS-7无人机。演示是在彼德伯勒市的室内飞行区进行的。这种电池驱动的垂直起降无人机盘旋并机动飞行了大约3分钟，这是该机目前的续航水平。

尽管续航时间短，但该无人机携带的载荷重量目前已达到了0.75千克。前气垫飞行器工程师杰弗・哈顿说：“我们预计无人机采用改进型涵道风扇设计后，性能将明显提升。”

该无人机能在指定点垂直起飞、全控飞行、盘旋和着陆。由于利用附壁作用产生升力，因而它的下洗气流很小，气动性非常稳定。哈顿领导的试验小组已经发现，除了涵道风扇的几何结构之外，舱盖上的定子位置对稳定性和升力至关重要。

霍尔格・巴宾斯基博士是一名航空学高级讲师，他对该飞行器能够稳定飞行充满信心，他强调说，实际情况比预期还要好。霍尼韦尔公司和美国国防部位于阿拉巴马州亨茨维尔市的战术无人机办公室也希望加入项目合作。

该无人机应用领域非常广泛，其中包括战场和城区监视、智能指示目标、灾区侦察、通信中继和干扰、传感器布撤、探雷、大气质量取样、监听以及搜救。该无人机在城区环境中最为有用，它能够盘旋、飞近建筑物和飞入建筑物内，实施近距监视与收集情报。由于旋转部件没有暴露在外面，无人机与墙壁等发生碰撞摩擦不会危及其飞行安全。

[注]附壁作用：

又称康达效应[Coanda-effect)，它是以罗马尼亚发明家亨利・康达为名的。简单的表达就是水流或气流离开本来的流动方向，改为随着凸出的物体流动的倾向。在日常生活中，当我们把小汤匙凸面放在水龙头下的小水流边时，水流会被吸引，流到汤匙的背上，而争水流一直在汤匙上的凸出表面流动就是附壁作用的结果。附壁作用是大部分飞机机翼的主要运作原理。

UK―based Geoff's Flying Saueer(GFS) Projects has demonstrated its coanda-effect unmanned air vehicle to the Ministry of Defense

The 0.91m―diameter,5．45kg GFS-6a and smaller-7 prototypes were demonstrated at an indoor flying area in Peterborough.The battery-powered vertical take-off and landing vehicles hovered and maneuvered for about 3min． which is their current endurance.

“We expect substantial improvements With improved fan design,”says inventor and former hovercraft engineer Geoff Hatton．Despite the short endurance，a 0.75kg payload has been carried so far .

The UAV is capable of vertical take off,fully controlled flight，hovering and landing on a specified point By using the Coanda principle to create lift，it has very little downwash and is aerodynamically stable As well as fan geometry，Hatton’s team has found that the location of stators on the canopy is important to stability and lift．

Dr Holger Babinsky， a reader in aeronautics，was confident the vehicle would be stable， but says it was better than expected． Honeywell and the US Department of Defense’s Huntsville，Alabama tactical UAV office have visited GFS ．

Numerous applications have been identified．including battlefield ＆ urban surveillance，intelligent targeting，dlsaster area reconnaissance．communications relay and jammling，sensor distribution，land mine detection，air quality sampling，listenIng and search ＆ rescue. The UAV will be most useful in urban environments．where its ability to hover and fly close to and within buildings will enable close quarter surveillance and intelligence gathering.Having no exposed rotating parts，brushes with walls etc，do not compromise the craft’s night