History of Ramjet Design
Rene Lorin, a French inventor designed the first plans for the ramjet in 1913. After being awarded a patent, he attempted to build a prototype. However, materials were unavailable at the time to build the ramjet. In 1915, inventor Albert Fono in Hungary attempted to utilize ramjet technology to provide additional range for artillery. After the First World War, he proposed an idea for German military to use ramjets on planes.
Boris S. Stechkin and Yuri Pobedonostsev began researching ramjets for projectiles and planes in the late 1920s in the Soviet Union. Using this technology, I.A. Merkulov developed a two-stage rocket in 1939. The same year he further adapted this concept into the first plane to use ramjets. Attaching two of his DM-2 ramjet engines to a Polikarpov I-15, the plane was used as a fighter. With the onset of World War II, he designed a experimental plane that used liquid fuel rockets in conjunction with ramjet engines. Although the airplane's potential was understood, the project ultimately was canceled with the end of the war.
In 1949, French inventor Rene Leduc successfully constructed the first successful ramjet-powered aircraft, the Leduc 0.10. Using a single ramjet, Leduc conducted the first flights and nearly reached Mach 1.
Later, the French government continued experiments with ramjet technology. The Nord 1500 Griffon was launched in the mid-1950s. Designed to be a fighter for the French Air Force, the plane reached speeds in excess of Mach 2.
Facts on ramjet technology show that they are useful for supersonic speed attainment. However, they are limited in range. Overall, the fact that they require only one moving part, they are reliable and represent one of the earliest forms of aviation engine design.