Editing Ramjet (section)

===Soviet Union===
[[File:MAKS2015part7-44.jpg|thumb|Kh-31 missile ramjet exhaust]]

In the Soviet Union, a theory of supersonic ramjet engines was presented in 1928 by [[Boris Stechkin]]. Yuri Pobedonostsev, chief of [[GIRD]]'s 3rd Brigade, carried out research. The first engine, the GIRD-04, was designed by I.A. Merkulov and tested in April 1933. To simulate supersonic flight, it was fed by air compressed to 200 [[bar (unit)|bar]], and was fueled with hydrogen. The GIRD-08 phosphorus-fueled ramjet was tested by firing it from an artillery cannon. These shells may have been the first jet-powered projectiles to break the [[speed of sound]].

In 1939, Merkulov did further ramjet tests using a [[two-stage rocket]], the R-3. He developed the first ramjet engine for use as an auxiliary motor of an aircraft, the DM-1. The world's first ramjet-powered airplane flight took place in December 1940, using two DM-2 engines on a modified [[Polikarpov I-15]]. Merkulov designed a ramjet fighter "Samolet D" in 1941, which was never completed. Two of his DM-4 engines were installed on the [[Yak-7]] PVRD fighter during World War II. In 1940, the Kostikov-302 experimental plane was designed, powered by a liquid fuel rocket for take-off and ramjet engines for flight. That project was cancelled in 1944.

In 1947, [[Mstislav Keldysh]] proposed a [[Keldysh bomber|long-range antipodal bomber]], similar to the [[Silbervogel|Sänger-Bredt bomber]], but powered by ramjet instead of rocket. In 1954, NPO Lavochkin and the Keldysh Institute began development of a Mach 3 ramjet-powered cruise missile, ''[[Burya]]''. This project competed with the [[R-7 Semyorka|R-7 ICBM]] developed by [[Sergei Korolev]], but was cancelled in 1957.