Lockheed CL-945 stowed rotor aircraft CARR 3D model

In the mid-60’s, VTOL in all its forms was all the rage. In 1965, Lockheed answered a US Army Request For Proposals with the CL-945 concept, a stowed-rotor helicopter design. At low speeds and hover, it would operate as a helicopter; at higher speeds, aircraft-style propulsion systems would power it forward; and at much higher speeds than helicopters normally attain, the rotors would stop rotating and would fold back and be stowed for minimum drag. It was a great idea that had the little problem of being horribly complex, heavy and expensive.