The R-7 missile was designed and specifications written in 1953, serving as the basis for the most famous family of boosters ever developed.[1] By 1954, engine development was underway at the GDL. In 1955, the testing launch site at Baykonur was selected.[2] The booster was built at the Kuznetsov factories at Kuybyshev.[3] In April 1956 the first R-7 rockets were finished and ready for testing and engine testing began.[4] From August, until Dec. 1956, launch equipment for the R-7, was installed at Baykonur.[5] After this, an R-7 test article was used to test the ground support equipment.[6] The first flight version R-7 was rolled out to the launch pad after two months of checkout, on May 5, 1957. The rocket was launched on May 15, only to fail after 50 seconds of flight. After three more failures, the first successful flight of the R-7 occurred on August 3. The rocket test flight terminated at the Kamchatka peninsula. The second successful flight was on Sept. 7, with Premier Nikita Khrushchev viewing the launch.

The R-7 was originally built as the Soviets first ICBM, but it was never deployed in significant numbers. The missile was found to take too long to fuel and launch to be an effective weapon. It also required large above ground launch facilities that were very vulnerable to attack. It could also only stand by fueled for 24 hours before the propellant line seals and valves began to degrade dangerously. Test flights of the missile continued in April 1958 then stopped until April 1959 and continued through January, 1960 with tests at full range, some with accuracy of 2 km. in the target region of the Pacific where 3 Soviet ships and US intelligence forces observed the reentry. There were less than 20 test flights, of which more than half failed. The U.S. achieved a slightly better failure rate during testing of the first 35 Air Force Atlas ICBM's. By Aug. 1961, there were only four R-7 ICBM's in operational service. This included two missiles in storage to reload the two operational launch pads at Plesetsk.

The R-7's were taken out of service by 1967 and new launch facilities with an enclosed service structure buildings were built to serve as space launch pads for the R-7 booster. The R-7 rocket consisted of five parts, a core stage 2.95 meters in diameter and 28 meters long, which was surrounded by four strap-on boosters, each 19 meters long and three meters in diameter. The booster was 10.3 meters diameter at the base, from tail fin to tail fin. The basic R-7 was used to launch early Sputniks which were light enough to achieve orbit using only the core of the booster as a final stage. After several launches, the test flights stopped in July, 1958, for a year of redesign to perfect the booster for operational use. The R-7 used an RD-107 rocket engine in each strap-on booster.

Development of the RD-107 and RD-108 engines started in 1954 at the Gas Dynamics Laboratory in Leningrad. The RD-107 had four main nozzles with two steering vernier engines which gimballed on one axis, the main engines did not gimbal. Each RD-107 engine consisted of four combustion chambers, feed by a single turbo-pump mounted above the chambers. The chambers were the same basic technology as the German V-2 engine chamber. Each had the same thrust as a V-2 engine, but the chamber pressure was four times higher. The core stage used a RD-108 engine, which was the same as the RD-107, but with four steering verniers.

To start the RD-107 and RD-108 type engines, propellant valves open and propellant flows through the pumps under force of gravity. The propellant is ignited by pyrotechnics and the engine burns at what is called intermediate thrust. As the pumps are turned by the propellant flow, they also drive two small pumps that feed hydrogen peroxide into a gas or steam generator. The gas generator (also called an APU or Auxiliary Power Unit) produced a large amount of steam that drives the propellant pumps. This creates an increased pump speed and feeds more propellant into the combustion chamber. The engine then runs at full thrust. The gas generator exhaust also flows through a heat exchanger to warm nitrogen that pressurizes the booster's propellant tanks. The exhaust is then expelled into the engine exhaust. The engines also use regenerative cooling, circulating the cool Kerosene fuel around the nozzle in order to cool it. Many of the RD-107 and RD-108 engine parts were made of Bronze alloys to conduct heat away from engine parts.

This kit is one of the latest offerings in Cutting Edge's new "Lift Off" series of real space subjects. As expected from Cutting Edge, the resin castings are very nearly flawless with no mis-aligned mold seams, air bubbles, or other typical resin casting faux pas sometimes found among today's resin kit manufacturers. All of the parts are still attached to their casting sprues or plugs, which will certainly make an impressive pile of scrap after they are removed. My kit came in two bags, large parts in one, small parts in the other. My only complaint about the kit is the lack of packing material. I found several broken pieces from the kit parts banging into each other, the strap-on booster fins and small details around the 3rd stage booster.
 

Various internet sites

 Rockets of the World - Third Edition

http://members.aol.com/Satrnpress/products.htm

October 2003