Doak Aircraft Co Inc
Incorporated in 1940 in Los Angeles, California, developing the Model 16 VZ-4Da, with ducted propellers rotating at wingtips, under contract to the U.S. Army Transportation Research and Engineering Command, 1958. This was transferred to NASA for further evaluation. Doak sold out to Douglas Aircraft Company in early 1960s. Doak finally closed its doors early in 1961.