Michael Neufeld - The Rocket and the Reich

When Boykow was brought into the program, he outlined his scheme for carrying out the pitchover. After a period of vertical ascent, the missile would turn quickly to a 45-degree angle and stay rigidly on another straight trajectory. Immediately following the A-3 failures, the rocket group and Kreiselgeräte realized that the forces required from a control system by this scheme were highly unrealistic since the Sg 33 was too weak even hold the rocket on a vertical trajectory. During the ensuing discussions in early 1938 between Peenemünde and its two guidance contractors, von Braun and his assistants came to accept the need for a gradual pitching of the vehicle, at least for the A-5. 43

The question was how to command such a maneuver. Fieber’s patent is unavailable, so it is unclear how he proposed to do it, but a solution was soon found that could be employed on any rocket-fixed system. By using a clockwork mechanism to rotate slowly the pickoff (sensing mechanism) of the pitch gyro, it would essentially be fooled into thinking that the missile was pitching in the opposite direction to the desired trajectory. The correction sent by the gyro to the control system would push the vehicle’s nose over. The stabilized platform of Kreiselgeräte’s Sg 52 and successor systems required a more complicated mechanism that rotated the platform in pitch to get the same effect. 44

Fieber’s Vertikant guidance, particularly when it included this simple mechanism for carrying out the pitch program, was thus an imaginative and viable alternative to Kreiselgeräte’s platforms. Actually developing the system at Siemens proved impossible, however. One company manager—perhaps Altvater himself—called the project “charlatanry.” He was skeptical of the whole enterprise because of the rocket’s rugged environment, the specialized character of Fieber’s gyros, and Ordnance’s desire for an A-5 system in less than a year from early 1938, which reflected the Army’s belief in the urgency of the ballistic missile program. Additional opposition arose in Siemens because the aviation instruments division was strained to capacity producing for the Luftwaffe. Faced with resistance to the idea of producing even two dozen systems for the Army, Wernher von Braun seized on an “almost absurd” idea thrown out in desperation by Fieber. Von Braun asserted in a meeting that three ordinary aircraft “course gyros” could be used in the A-5 to indicate the position of the rocket, even though they lacked accuracy and were not normally exposed to such high accelerations. Afterward Fieber was furious, but von Braun slapped him on the shoulder and replied, “But, Dr. Fieber, boldly asserted is half proven!” It was one of his typically audacious moves to get around obstacles in his way. 45

The date of this meeting is unclear, but by the fall of 1938 Siemens had laid down plans for an A-5 guidance system it called D 13. It used three course gyros for position and three rate gyros for stability, all attached to the body of the rocket. In August 1938 Peenemünde and the company also decided on the layout for transmitting commands to the jet vanes. Siemens had developed hydraulic servomotors to move aircraft control surfaces in response to its autopilots. Those systems translated electrical signals into variations in oil pressure in hydraulic pistons. The resulting mechanical energy could be used to rotate the jet vanes one way or the other. Hydraulic servos would in fact become one of the critical technologies for the A-4. 46

By late 1938, then, Peenemünde had two A-5 guidance systems under way at two companies, and in Fieber’s concept had a third possibility for the future, once better and more accurate gyroscopes were developed. But the situation was not satisfactory. Both Kreiselgeräte and Siemens were lagging farther and farther behind schedule. Siemens had indicated in early 1938 that its system should be available for launch no later than March 1939, which was already too late for Dornberger. In the event, no A-5 with D 13 guidance was actually launched until April 1940. When Kreiselgeräte promised in October 1938 to have a flight-ready Sg 52 by July 1939, von Braun wrote on the margins of the letter: “First promised: February, then: April 1, now July!” The feverish arms buildup of those years was undoubtedly part of the problem. The Army rocket project was only a sideline for both companies, since Kreiselgeräte worked almost exclusively for the Navy, and Siemens’s aviation instruments division was completely tied to the Luftwaffe. In the circumstances, it is not surprising that Wernher von Braun, who was now devoting much of his time and energy to the guidance problem, should seek further ideas and corporate contractors. 47

Sometime before the end of November 1938, von Braun came across the independent development by the Luftwaffe of another autopilot system. The project, based at the main air force test center of Rechlin in northern Germany, was headed by diploma engineer Waldemar Möller. Möller was to be transferred to the venerable precision instruments firm of Askania, where the autopilot could be taken from the laboratory to industrial production. After getting clearance from the Air Ministry, von Braun contacted Askania. The company advocated instead its simple Navy torpedo system, which used only position gyros and compressed air to convey the steering commands. Peenemünde immediately had to explain that the torpedo system would have to be extensively modified, because air damps out oscillations much less effectively than relatively dense water. Later investigations showed that a pneumatic control system was also far inferior to Siemens’s oil-hydraulic one. In the end, the project was largely a waste of time and it was abandoned at the beginning of the war. 48

In April 1939 the restless von Braun revived interest in the Rechlin autopilot. Möller’s system had a special kind of rate gyro and a control system based on amplifiers and electric motors. Since Askania did not actually take over the project until the end of the year, Peenemünde received little help, other than consultation with Möller himself. The true significance of this, the third A-5 guidance system, was that it contributed further to the buildup of Peenemünde’s own development capability. There was no one else to do the work on the “Rechlin guidance system.” In any case, von Braun had to have the staff to supervise three or four parallel guidance developments at once, and there were many theoretical and technical problems about which the contractors knew nothing or were too busy to care. 49

One such problem was establishing the extraordinarily difficult stability equations upon which the success of the A-4 depended. With the basic layout of the A-5 finished, the actual design of the A-4 began in January 1939, but this activity, like the aerodynamic work, only showed how much was still unknown. In 1937 the rocket group had hired a talented mathematician, Dr. Paul Schröder, to carry out the calculations, but von Braun soon became exasperated with him. Schröder asserted that certain guidance problems were impossible to solve—not an attitude that the brilliant, optimistic, hard-driving von Braun was likely to tolerate. In 1939, Schröder was shunted to the side and replaced by the highly capable Dr. Hermann Steuding from the Technical University of Darmstadt. Steuding and his staff, in conjunction with the aerodynamicists, were to make fundamental contributions to guidance theory. 50

Steuding in turn recommended a friend from the university, Ernst Steinhoff, to be the head of a new guidance and control division that von Braun was building. Steinhoff, who started at Peenemünde on July 1, 1939, was a striking character. Only thirty-one years old, he held the world’s record for distance in a glider as well as the honorary Luftwaffe rank of “Flight Captain” for his flying achievements. Steinhoff had been closely involved with the Air Ministry’s German Research Establishment for Glider Flight, which was situated near Darmstadt, and was writing a doctoral dissertation on aviation instruments, which he completed in 1940. An enthusiastic Party member since May 1937, he acknowledged National Socialist doctrines as “ideals.” According to von Braun, Steinhoff’s task was to assemble a staff and to build a laboratory at a cost of at least a million marks. In addition to guidance and control, he took charge of on-board electrical equipment and Gerhard Reisig’s measurement group. Steinhoff was less brilliant than Thiel and Hermann and contributed few basic innovations to the A-4, but he proved a good administrator and a “tremendous pusher,” according to Fritz Müller, an engineer at Kreiselgeräte. Von Braun, meanwhile, continued to play a significant role in guidance and control. He not only exercised the management talent that was visible in all areas, such as his ability to cut through the discussion in a complicated meeting and seize on precisely what was critical, he also spurred intellectual productivity in the guidance group with his charismatic personality and his continual questioning. 51