The RP-318-1

Another organization involved in rocket research in the Soviet Union was the Gas Dynamics Laboratory (GDL) in Leningrad. Established in 1921, it was mainly engaged in developing solid-fuel rockets for arming aircraft or assisting aircraft during take-off. In 1929 a small subdivision was added, headed by 20-year-old Valentin P. Glushko, to conduct research on electric and liquid-propellant engines. While the GIRD members were mainly driven by utopian visions of space travel, the GDL team primarily consisted of military-oriented rocketeers and received its modest funding directly from the military.

In 1932 the Red Army Chief of Staff Marshal Mikhail Tukhachevskiy, convinced that the Soviet Union needed modern technology to arm itself against the forces of capitalism, proposed to unite GIRD and GDL into a single institute to develop both solid and liquid-fuel rockets for the military. After many months of negotiations, the new organization, called the Reactive Scientific Research Institute (RNII) was founded in September 1933. Placed in charge of RNII was GDL’s Ivan Kleymyonov, with GIRD’s Sergey Korolyov acting as his deputy.

The different backgrounds of the two organizations soon led to internal conflicts about the future direction of the new institute. Many of these centered around the types of propellants to be used. While the GDL faction favored solid propellants or storable liquid propellants, the former GIRD team promoted engines burning liquid oxygen. Also, Korolyov was hoping to continue work on rocket planes capable of reaching the stratosphere, but this was of little interest to Kleymyonov, who saw the development of military missiles as the institute’s main objective. These and other disagreements caused Korolyov to be demoted to work as a chief engineer in the section for winged missiles in early 1934.

Winged missiles offered several advantages over ballistic missiles in destroying both mobile and stationary targets. Their flight path could be controlled after shut­down of the engines and they could cover much larger distances thanks to the extra lift provided by the wings, thereby compensating for the absence of powerful rocket engines in those days [3]. However, for Korolyov they also provided an opportunity to covertly pursue his dream of achieving manned stratospheric flight.

Ever since the work on the RP-1 rocket plane, Korolyov had become increasingly convinced that it would be difficult to turn existing aircraft or gliders into efficient rocket planes. Neither was the time ripe to put men aboard ballistic missiles. What was needed instead was a new type of winged machine capable of withstanding higher acceleration forces and fitted with low-aspect-ratio wings, a tail section, and a long fuselage to house the propellant tanks. Although the winged missiles tested at RNII in the 1930s were officially seen as precursors to surface-to-air and air-to-surface missiles, Korolyov developed many of them with the goal of manned stratospheric flight in the back of his mind.

At a conference on the use of rockets to explore the stratosphere in March 1935, Korolyov went public with his ideas to build manned winged missiles that could reach altitudes of up to 20-30 km, emphasizing the need to build “flying laboratories” that would pave the way for such vehicles. Apparently, by late 1935 Kleymyonov was impressed enough to include studies of rocket planes in the RNII’s plans for 1936. By early 1936 Korolyov had drawn up a step-by-step plan calling for the development of ever more capable piloted rocket planes. The first of these (218, later renamed 318), powered by either a solid-fuel or liquid-fuel rocket engine, would reach an altitude of 25 km and be flown by two pilots wearing pressure suits. The ultimate goal was to push the ceiling to a phenomenal 53 km [4].

The rocket engines needed for such planes were not yet available, but Korolyov got approval to build an experimental rocket plane based on his SK-9 glider, which he had probably built with that idea in mind. The rocket plane was initially called RP-218-1 and later renamed RP-318-1 after a reorganization within RNII. The engine selected to power the plane was Glushko’s ORM-65, a nitric acid/kerosene engine capable of generating between 50 and 175 kg of thrust and already under development for the 212 winged missile.

The goals formulated by Korolyov for the rocket plane program in early 1936 were “to achieve a record altitude and speed’’ and “to obtain the first practical experience in solving the problem of piloted rocket flight’’ [5]. To him personally, it was probably the first step on the long road to manned space travel, but Korolyov

was well aware that this would not be enough to receive continued support for the program. As he would have to do more than once in his later rocket and space career, he had to justify his efforts by coming up with military applications. In a study requested by Korolyov, the Zhukovskiy Air Force Academy concluded in 1937 that, despite the limited operating time of the rocket engine, rocket planes could play a vital role as fighters [6]. Their main task would be to intercept enemy bombers. With the development of jet engines in an embryonic stage, rocket engines would be the only practical way of significantly increasing speed in the near future.

After an exhaustive series of tests, the ORM-65 was installed in the SK-9 in September 1937 and began a series of integrated test firings in December 1937. Korolyov was intent on piloting the RP-318-1 himself, going down in history as the first man to fly a rocket plane. However, by this time Stalin’s purges were beginning to sweep through the ranks of RNII (renamed NII-3 in 1937). Tukhachevskiy, Kleymyonov, and his deputy Langemak were executed in January 1938, and Glushko and Korolyov were arrested on trumped-up charges in March and June 1938, disappearing into the Soviet prison system for the following six years.

Work on the RP-318-1 was not resumed until the end of the year under the leadership of A. Shcherbakov. The ORM-65 was replaced by a somewhat simplified but more reliable version called the RDA-1-150 with a thrust of between 50 and 146 kg, developed by Glushko’s successor Leonid Dushkin. After being installed in the plane, it underwent a series of more than 100 test firings between February and October 1939.

In November 1939 the RP-318-1 was transported to an aerodrome in the out­skirts of Moscow, where after several more test firings of the rocket engine it made its first historic flight on 28 February 1940. Piloted by Vladimir Fyodorov, the 675 kg and 7.9 m long rocket plane was towed into the air by an R-5 airplane and released at an altitude of 2.8 km. After gliding down to an altitude of 2.6 km, Fyodorov ignited

the RDA-1-150 engine, which burned for 110 seconds, accelerating the plane from 80 to 140 km/h and taking it to an altitude of 2.9 km. There were two more flights on 10 and 19 March 1940. If it hadn’t been for the delays caused by the repression in the late 1930s, the RP-318-1 might very well have become the world’s first aircraft propelled by a liquid-fuel rocket engine. In the event that distinction went to the German Heinkel He-176, which made its maiden flight on 20 June 1939 using a rocket engine fueled by hydrogen peroxide.