A potential new aircraft design, the hybrid wing design, involves mounting the engines on top of the airplane, rather than traditionally under the wings. NASA has demonstrated that this kind of design, so called “Hybrid Wing” airplanes, only use half the fuel of a standard airplane. The blended wing body (BWB) is not the only reason they are so fuel-efficient. The super-efficient ultra-high bypass ratio engines, could use half as much fuel. The challenge is to build the new hybrid design in a way so that it’s strong, and light enough to be practical. Below is an image of an artist concept of one version of the blended wing body aircraft, and a photo of a scale model of an early blended wing body design that was tested in one of the NASA Langley wind tunnels.
Photos by NASA.
What's amazing is how little drag a flying wing design has. Cant understand why it is not used more often.