On October 5, 1933 Trenn patented a design for a VTOL flying platform resembling the postwar "flying Jeeps" of Piasecki or the more complex Hiller Platforms - only a quarter century earlier!
Trenn originally envisioned two models, one with the cockpit in the annular disc ring, the other with the cockpit in a central position. Trenn later concentrated on the version with central cockpit for practical reasons.
From a technical point of view, the realization of this machine would be extremely difficult, especially with the placement of the engine. From the design plan, it would be installed directly under the pilot in the central body, but even there, the diameter of this section seems insufficient to accommodate a 140 hp Siemens-Halske SH14 motor from the Fw-44 Stieglitz (Goldfinch).
Drawing from the patent : http://rec.aviation.military.narkive.com/owaulNM3/1933-trenn-flying-platform:i.1.1.full
A closer look at the model : https://cdn1.imggmi.com/uploads/2018/5/28/23dc567ddf51885ce239fa521e8a28ee-full.jpg