Whereas MX-774B was an army air forces/air force project, the navy sponsored the Viking, with Milton W. Rosen responsible for the development and firing of the rocket. Reaction Motors designed the engine, drawing on its own experience as well as data from the V-2, with the Glenn L. Martin Company designing and building the overall rocket. Viking’s pioneering development and use of gimballing were the responsibility of Martin engineers. Like the MX-774B powerplant, Viking drew on the V-2 technology, but Rosen and his engineers designed it specifically for upper-atmospheric research. Rosen’s specifications called for a thrust of 20,000 pounds compared with 56,000 for the V-2. Under a contract initiated in September 1946, RMI designed an engine (XLR-10-RM-2) with a single cylindrical thrust chamber.
As with the V-2, the U. S. rocket’s propellants were alcohol and liquid oxygen, pumped into the combustion chamber by turbines driven by decomposed hydrogen peroxide. Whereas the V-2 had used alcohol at 75 percent strength and hydrogen peroxide at 82 percent, the Viking used 95 percent ethyl alcohol and 90 percent hydrogen peroxide. Edward A. Neu did the detailed design work on the combustion chamber and injector. Tests caused parts to fail and be replaced. Burnthroughs of the steel combustion-chamber liner (inner
wall) led to the substitution of pure nickel, the first known use of this metal for such a purpose. Its superior thermal conductivity and higher melting point solved the cooling problem in conjunction with the regenerative cooling in the original design. One injector caused an explosion, so new designs were necessary. Valves were a problem until M. E. “Bud" Parker borrowed valve designs from the MX-774B engine, which thus did influence at least the Viking design.
After the first launch of a Viking rocket from White Sands, New Mexico, on May 3, 1949, the vehicle experienced component failure, leading to subsequent improvements. As a result, each of the dozen Viking rockets fired through the last launch on February 4, 1955, differed from its predecessor. Rosen thought this was the most important aspect of the program. One example was the growth of the thrust of the various Vikings from 20,450 pounds on the first launch to 21,400 on two others. Even though the engine itself was generally successful, it made no known contributions to engine technology per se other than the experience gained by RMI, Martin, and navy engineers. The real contribution of Viking lay in the gimballing system for steering, not pure propulsion.22