改变一切：美国无人机展亮点大放送

DARPA的飞行运输战车

    几年前，五角大楼的高级研究计划局（DARPA）公开征集一种飞行汽车的设计方案，同时特别指出美军需要的是一种像悍马越野车一样的运兵车，而且要能够垂直起飞和降落，可以运载四名士兵及其装备高速航行。这个概念听起来似乎太牵强了，但是洛克希德马丁公司却真的给出了这样一份设计方案。它在车子的顶部安了两个硕大无比的螺旋桨，这种听起来颇为合理的方案也通过了DARPA的两轮设计审查。

    去年，DARPA放弃了对飞行汽车的兴趣，但并没有完全抛弃这个计划，只是要求洛克希德马丁的工程师继续改进螺旋桨系统的设计，因为DARPA现在希望这套系统能够适应一系列不同的负载。

    DARPA最终希望看到的是一套多功能的直升机式的飞行系统。它可以搭载一套情报传感器，或是在军舰、军事基地或部队之间吊运物资（不包括人员）。这种运输系统甚至可以演变成一种自动的、无人驾驶的“战地救护直升机”，深入战区自动将伤员运至后方，以免有人的医疗直升机遭遇被击落的风险。这个被戏称为“变形金刚”的概念现在还停留在概念阶段。但是美国军方已经给了洛克希德马丁公司一份合同，让该公司在2015年前开发一款能吊升起3000磅（约合1.36吨）货物的原型机用于验证。

DARPA's flying car now hauls cargo

    A few years ago, Pentagon blue-sky research arm DARPA put out a call for proposals for nothing short of a flying ca r-- specifically a Humvee-like troop carrier that could also take off and land vertically, hauling four soldiers and their gear through the air at speed. The idea was as far-fetched as it sounds, but Lockheed Martin came forward with a design for a vehicle packing two massive ducted fans on top that was plausible enough to pass two DARPA design reviews.

    In the last year, DARPA has lost interest in its flying car. But it hasn't abandoned the program altogether, instead asking Lockheed engineers to move forward with the design of the ducted fan lift system that would've provided lift to its flying Humvee design. The twist: DARPA now wants the lift system to be adaptable to a variety of different payloads.

    What DARPA ultimately envisions is an autonomous flying lift system that could carry intelligence sensor packages or pick up and deliver cargo pallets or even vehicles (but without people in them) between ships or military bases or to troops in the field. Such a transport system could even work as an autonomous, unmanned ambulance transport, dropping into combat zones to collect wounded soldiers and fly them back to safety without putting manned Medevac units at risk. Transformer, as the concept is known, is still just a concept. But Lockheed has been granted a contract to develop a prototype capable of lifting 3,000 pounds for demonstration by 2015.