Gingrich was skeptical. He asked for a demonstration. Antheil, nothing if not bold, “analyzed the next fifty girls that came down the Plaza staircase.” Gingrich happened to know one of them. Evidently, the composer called her correctly. “I went home that morning with exactly five thousand six hundred dollars’ worth of ordered articles,” Antheil concludes. Gingrich had even offered to pay in advance.
[FIVE]
Leaving Fritz
Hedy never specified in detail which German technological advances she heard discussed over luncheons and dinners in the Mandl mansions, but there was much to hear. In 1935, the monocoque-bodied Messerschmitt Bf 109 fighter and the dual-use Heinkel He 111 bomber both saw their first flight tests. The small, heavily armed cruisers that the British called pocket battleships began entering service in the German navy. In 1936, the first of the new Type VII diesel-electric attack submarines was commissioned, and Adolf Hitler began planning his Westwall of defensive fortifications opposite France’s Maginot Line.
Certainly Hedy listened closely to discussions of submarine and aerial torpedoes, weapon systems for which Hirtenberger was supplying components. The genius of German torpedo development at that time was a northern German mechanical engineer named Hellmuth Walter. Born with the century and educated at the Hamburg Technical Institute, Walter was particularly interested in submarine propulsion, which was limited by the problem of supplying oxygen underwater to sustain combustion.
The standard submarine of the day (and throughout World War II) used diesel engines for surface operation, where it could draw in air from outside the vessel. Underwater, with no available air supply, it had to switch to battery-powered electric motors, which limited its speed and the time it could remain submerged before its batteries had to be recharged. On the surface such a submarine might make 17 knots (“knots” is a phonetic abbreviation of “nautical miles per hour”; 1 knot equals 1.15 miles per hour). Underwater it could make half that speed at best, while the ships it might be stalking could pull away (or hunt it down) at surface speeds of up to 35 knots. Walter wanted to find a means, he wrote, “to drive a submarine at much higher speeds than the conventional 6 or 8 knots, submerged.”
In the 1920s, while employed as a marine engineer at Stettiner Maschinenbau AG Vulcan in Stettin, on the Baltic, Walter worked out his ideas: Instead of carrying fuel for engines that needed air to sustain combustion, preventing their operation underwater, why not identify an oxygen-rich fuel that could be chemically decomposed to supply its own oxygen, and use that reaction to drive a turbine directly? There were such fuels. Pure oxygen was obviously one, but storage in a small space such as a submarine would require that it be cooled to a liquid and maintained there, below its boiling point of −297.33°F. Nitric acid was another, with 63.5 percent oxygen available when decomposed, but it was highly corrosive and difficult to store and handle.
A little research led Walter to hydrogen peroxide, H2O2, a liquid slightly denser than water first isolated by the French chemist Louis Jacques Thénard in 1818. Used in low concentrations, up to 30 percent, as a bleaching agent and a disinfectant, hydrogen peroxide at high concentrations could be decomposed by contact with an appropriate catalyst into steam and oxygen—H2O + O—in the process generating intense heat: 80 percent H2O2 when it decomposed would generate a temperature of 869°F, superheating the steam sufficiently to drive a power plant without adding any additional fuel. Fuel could be added, however, drawing on the oxygen released from the H2O2 for combustion and further superheating the steam, increasing its propulsive energy. In the first case, the purity of the H2O2 would determine the rate of energy release; in the second, the injection of a fuel such as alcohol or kerosene into a combustion chamber to mix with the decomposing H2O2 could be throttled to vary the output on demand. In either case, the energy would be generated without the need for additional air.
Walter found very little available research on the use of hydrogen peroxide for energy production, he recalled, “only isolated suggestions which have never been developed beyond the stage of theoretical discussion.” Nor was there much interest at Vulcan in H2O2 research. Frustrated, Walter took his ideas to the German naval command in Berlin. “Years later,” a biographer writes, “colleagues remembered him carrying around papers for his Unterwasser Schnellboot [underwater fast boat], so that he could lobby for his proposals at any opportunity.”
The naval command was interested, but before Walter could proceed with research and development, he had to prove to its officials that H2O2 was safe for transportation and storage. Higher concentrations were commonly believed to be dangerously explosive, a prejudice that had seriously retarded research. Tests at the Chemical State Institute in Berlin—exploding lead azide, a strong detonator, with H2O2, decomposing it under pressure—established its non-detonability up to 80 percent strength. “After the encouraging results of this period of predevelopment and research,” Walter writes, “I founded my own engineering firm on July 1, 1935. The real development of engines and rockets started after this date.”
From his new Walterwerke (Walter Works) in Kiel, Walter proposed to the German naval command a two-thousand-horsepower hydrogen-peroxide-driven four-man mini-sub designed for underwater speeds of up to thirty knots. With support from Captain Karl Dönitz, already an influential submarine flotilla commander, naval command encouraged Walter’s project, which would be awarded a construction contract in 1939. By late 1936, Walter had achieved one thousand kilograms of thrust in a hydrogen-peroxide-fueled turbine. A four-thousand-horsepower system followed not long after.
While exploring development of his new submarine, a potentially devastating weapon, Walter also describes working on missile engines and assisted-takeoff devices (ATOs, temporarily adding thrust, enable aircraft to take off from shorter runways or boost heavily loaded aircraft into the air) for the German air force, the Luftwaffe:
The first flight with a liquid propellant took place in February 1937, with 100-kg thrust. Later in that year and during 1938, a great number of flight tests were made with ATO’s at 300 to 500-kg thrust with land and sea planes…. All of these were mono-fuel devices working with 80 percent hydrogen peroxide. A number of unguided missiles were tested, among them a midget prototype of the V-2 [rocket] which climbed up to 18-kilometer height and broke through the sound barrier. Rocket-propelled depth charges were thrown over 200-meter distances, and sea mines, dropped from an airplane, were decelerated so that they fell gently into the sea. During the summer of 1939, the first airplane took off (Heinkel 178) propelled solely by a controllable rocket. The first torpedoes were launched just at the outbreak of the war. In this case, the propulsion engine was used with a dual fuel system [of] kerosene and hydrogen peroxide.