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Marquardt Corporation was one of the few aeronautical engineering firms that was dedicated almost solely to the development of the ramjet engine. Marquardt designs were developed through the 1940s into the 1960s, but the ramjet never became a major design and the company turned to other fields in the 1970s. They suffered a particularly bad financial crisis with the ending of the Cold War, and went bankrupt in the 1990s.
Roy Marquardt was an aeronautical engineering graduate from 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 produced useful thrust. This started his 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 first 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 fitted theirs to a F7F Tigercat and started flight tests in late 1946. Later Navy tests fitted the same engine to a XP-83 and F-82 Twin Mustang.
In 1947 Martin built the Gorgon IV missile testbed, powered by the 20" engine. Four Gorgon flights with the new engines were made that year at Mach 0.85 at 10,000 feet (3,000 m) altitude, and in 1948 a newer engine pushed the speeds to Mach 0.9. Martin eventually won a contract to convert the Gorgon design into a target drone, becoming the KDM-1 Plover, and delivering Marquardt a contract for 600 more 20" engines.
In 1948 the newly created United States Air Force took delivery of several larger 30" (0.76 m) designs and fitted them to the wingtips of a P-80 Shooting Star, which became the first manned aircraft to be powered by ramjets alone. An even larger 48" (1.22 m) design was built as a booster for a new interceptor design, but not put into production.
The same year the company also started conversion of the existing engine designs to operate at supersonic speeds. This requires the airflow to be slowed to subsonic speeds for combustion, which is accomplished with a series of shock waves created by a carefully designed inlet. Starting with the existing 20" design from 1947, work progressed until the new engine was ready for use in 1949.
By this point the company had outgrown its Venice plant, but was unable to fund a larger factory. Marquardt sold a controlling interest in the company to General Tire and Rubber Company in 1949, and used the funds to move to a new site in Van Nuys, the former Timm Aircraft factories. The purchase wasn't a happy one for General Tire due to management differences, after making "only" 25% return in one year, they agreed to sell their share of the company to another investor. Eventually such an investor was found, and General Tire sold their stake to Laurance Rockefeller in 1950 for $250,000.
In the early 1950s supersonic cruise missile and target drone projects for various roles were quite common. Many of them were designs to be shot down as target drones, or simply crash or explode at the end of their mission, so simplicity and low cost was as important as high-speed performance. This made the ramjet ideally suited to these roles. By 1952 Marquardt was involved in a number of projects, including the Navy's Rigel missile, and the Air Force's CIM-10 Bomarc anti-aircraft missile. To test the new engine design for the Bomarc, the X-7 high-speed radio control test aircraft was built.
Over the next few years the X-7 missile broke many records, and led the Air Force to award Marquardt the contract for the BOMARC missile engines. Originally they had intended to award the production to a larger company with better manufacturing abilities, as the Van Nuys plant wouldn't be able to build the 1,500 engines quickly enough. Instead, the Air Force and Marquardt collaborated on a new plant on the shores of Great Salt Lake just outside of Ogden, Utah. The plant opened in June 1957, and delivered their first engines a month ahead of schedule. By 1958 the engine was in full production, leading to an additional engine contract from the Air Force for an equally large run of a more advanced version for the IM-99B "Super BOMARC". Meanwhile the X-7 continued to break records, eventually setting the speed record for air-breathing vehicles at Mach 4.31.
By 1959 the company had sales of $70 million, and had purchased several smaller aerospace firms. One of these purchases, Power Systems, led to a number of designs for small rocket motors used as positioning thrusters. This would eventually become one of Marquardt biggest product lines in the 1960s. Meanwhile the main Van Nuys plant was also involved in research into new systems, including a nuclear-powered ramjet for Project Pluto and a liquid air cycle engine (LACE) for the Air Force's Aerospaceplane efforts. Another new product line started with the introduction of their first ram-air turbine, small air-powered generators for providing aircraft with electric power if the main engine failed. With this diversification came a name change, to Marquardt Corporation.
By 1970 Marquardt was known primarily as "the" company for small rocket engines and thrusters. Practically all US space vehicles and satellites used their designs, eventually including a major win for the Space Shuttle program. The company developed and provided the 25 and 870 lb. trusters for the space shuttle.
The market for ramjet engines had largely disappeared by this point due to increased performance from turbojet engines, but Marquardt continued low-level development on advanced designs. One system, developed in partnership with Morton Thiokol, placed a solid fuel booster inside the ramjet core. When the solid fuel burned out the ramjet would ignite as normal. The idea was to combine the booster and ramjet into a single airframe, thereby reducing cost, size, and range safety requirements, as nothing would be jettisoned in flight.
In 1983 the company was purchased by the ISC Defense and Space Group International Signal and Control. In 1987, ISC was purchased by British-based Ferranti. Ferranti declared bankruptcy in 1991, and Marquardt was split in two. The Marquardt Jet Laboratory, building rocket thrusters, was sold to Kaiser Aerospace, while the Marquardt Manufacturing Company disappeared. Kaiser reportedly picked up Marquardt for a mere $1 million, with about $50 million in outstanding Space Shuttle contracts. Kaiser closed the Van Nuys plant in 2001.
- Marquardt RJ30
- Marquardt RJ31
- Marquardt RJ34
- Marquardt RJ39
- Marquardt RJ43
- Marquardt RJ57
- Marquardt RJ59
- Marquardt Space Sled
- Marquardt R-4D 100 lbf (440 N) thrust reaction control engines were used on both the Apollo Lunar Module and the Command Service Module on all the manned moon flights.
- Jon Wallace Jacobsmeyer, The Marquardt Story, n.d. (retrieved February 9, 2009).