There's been a lot of development activity around flying vehicles recently, but the Air Force wants a shortcut to an unmanned electric vertical takeoff and landing (eVTOL) concept for urban transport.

Development of compact, efficient rotary internal-combustion engines able to run on jet fuel has been boosted by U.S. Army contracts to advance the technology for unmanned-aircraft propulsion and ...

A company that makes an innovative rotary internal combustion engine just received a Phase I research grant from the U.S. Army to develop hybrid-electric propulsion for UAVs. The development ...

Rotary engines such as the Wankel have strange shapes that can be difficult to machine (as evidenced by the specialized production machines and patents in the 70s), which means it lends itself well to ...