A
1953 proposal from
Karl Stöckel, for a
mixed propulsion fighter that used both a rocket and a jet engine.
Source : "Ludwig Bölkow und sein Werk-Ottobrunner Innovationen;Die deutsche Luftfahrt Bd 12" by Kyrill von Gersdorff
3-view plan by Karl Stöckel : https://cdn1.imggmi.com/uploads/2018/5/26/f916c6bc0f03d8313f7ec89975ab6248-full.jpg