sentences:  Two piston engines buried in the body drove propellers located on the leading edge at the wingtips.In the 1930s, Charles H. Zimmerman was a noted aeronautical engineer who advocated the concept of "discoidal" aircraft, the so-called "Zimmer Skimmer" and worked on a variety of projects on his own and with the Vought company.After testing using scale models, including a remotely controlled, electrically powered large-scale model, designated the Vought V-162, the US Navy approached Zimmerman and offered to fund further development.