DARPA的飛行運輸戰車

????幾年前，五角大樓的高級研究計劃局（DARPA）公開征集一種飛行汽車的設計方案，同時特別指出美軍需要的是一種像悍馬越野車一樣的運兵車，而且要能夠垂直起飛和降落，可以運載四名士兵及其裝備高速航行。這個概念聽起來似乎太牽強了，但是洛克希德馬丁公司卻真的給出了這樣一份設計方案。它在車子的頂部安了兩個碩大無比的螺旋槳，這種聽起來頗為合理的方案也通過了DARPA的兩輪設計審查。

????去年，DARPA放棄了對飛行汽車的興趣，但并沒有完全拋棄這個計劃，只是要求洛克希德馬丁的工程師繼續改進螺旋槳系統的設計，因為DARPA現在希望這套系統能夠適應一系列不同的負載。

????DARPA最終希望看到的是一套多功能的直升機式的飛行系統。它可以搭載一套情報傳感器，或是在軍艦、軍事基地或部隊之間吊運物資（不包括人員）。這種運輸系統甚至可以演變成一種自動的、無人駕駛的“戰地救護直升機”，深入戰區自動將傷員運至后方，以免有人的醫療直升機遭遇被擊落的風險。這個被戲稱為“變形金剛”的概念現在還停留在概念階段。但是美國軍方已經給了洛克希德馬丁公司一份合同，讓該公司在2015年前開發一款能吊升起3000磅（約合1.36噸）貨物的原型機用于驗證。

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.