This beast is Lockheed Martin's new transport aircraft that's slated to take over for the C-130 Hercules sometime around 2020. They're calling it the "Speed Agile."
The Air Force is looking for a new transport aircraft that's fast, agile, easy to fly, and capable of operating from short, improvised airfields, all while carrying larger and heavier payloads than the current generation of cargo aircraft can. To make all of these things happen at the same time calls for a radically new aircraft design, which is exactly what we're seeing with this 23% scale demonstrator that Lockheed Martin has been testing out in a NASA wind tunnel.
It's all pretty hush-hush still, but we do know that both Boeing and Northrop Grumman are also working on Speed Agile concepts of their own, and we've got some pics of those in the gallery below.