Marquardt Corporation  Marquardt Corporation was an aeronautical engineering firm started in 1944 as ‘’’Marquardt Aircraft Company’’’ and initially dedicated almost entirely to the development of the ramjet engine. Marquardt designs were developed from the mid-1940s into the early 1960s, but as the ramjet disappeared from military usage, the company turned to other fields. In 1968 Marquardt was merged with CCI Inc. of Tulsa, OK. Throughout the 1970s and 1980s pieces of Marquardt were sold off or merged with other firms. By the 1990s, one of the remnants of the company, called "Marquardt Manufacturing Inc." (MMI) was embroiled in a legal suit with its predecessor organization, which had become principally a landlord who owned the buildings and land where MMI was located, and part of Ferranti in England – itself in bankruptcy. MMI subsequently declared bankruptcy and sank into oblivion. The remaining piece, "Marquardt Jet Laboratories" was sold to Kaiser Aerospace. Kaiser-Marquardt was later sold to Primex in Florida. Roy Edward Marquardt was a 1940 aeronautical engineering graduate of The California Institute of Technology (Caltech) who had worked at Northrop during World War II on the YB-35 flying-wing bomber project. While working on problems cooling the engines, which were buried in the wings, he found that the heat generated by the engines could be used to provide useful thrust. This created an interest in the ramjet principle, and in November 1944 he started Marquardt Aircraft in Venice, California to develop and sell ramjet engines. In the late 1940s, the company relocated to Van Nuys, California, adjacent to the Van Nuys Airport. Marquardt's initial products were wind tunnels, but by the end of their first year they had delivered an experimental 20 inch (0.51 m) ramjet to the United States Navy for testing. The United States Army Air Forces purchased two of the same design early in 1946, and fitted them to the wingtips of a P-51 Mustang fighter for in-flight testing. By this time the Navy had installed theirs on an F7F Tigercat; flight tests commenced in late 1946. Later, the Navy tested the same engines on an XP-83 and F-82 Twin Mustang. In 1947 Martin built the Gorgon IV missile testbed, powered by the 20" engine.