As compared with propulsion and, especially, with guidance and control, the contributions of university research after the start of the war were less important, in part because virtually all aerodynamicists were already working for the Air Ministry. But academic contractors to Peenemünde made a couple of valuable theoretical innovations, and they built or refined measurement technology for the tunnels. Corporate research, in the form of Schirmer’s work at Zeppelin, was of more significance, although still modest. The end of the airship era, resulting from the Hindenburg accident and Hitler’s and Göring’s dislike for those fragile vehicles, must have created an opening for the rocket program in the company’s aerodynamic facility.35
Among the most important contributions of Zeppelin—in conjunction with supersonic work at Peenemünde—was new research into winged missiles. In June 1939 a member of Riedel’s design bureau, Kurt Patt, proposed that the high energy of an A-4-type missile as it approached impact be employed instead to generate aerodynamic lift. Through the use of wings, the A-4’s range could thereby be doubled to 550 kilometers. That idea—later called the A-9—was taken up enthusiastically by von Braun’s group because it seemed a relatively cheap way to extract extra range from a missile powered by the 25-ton engine. Patt’s design, essentially a fuselage-less flying wing, was too radical, but affixing aircraft-type wings to an A-4 appeared to be a feasible alternative. That idea would require basic research into the configuration of a supersonic airplane that could ascend as a missile and descend as a glider. By 1941 a workable design emerged: a simple sweptback wing. More radical airfoil shapes were also tried, but producing a compromise that worked at all velocities proved to be anything but simple. A-9 research continued into 1942 before it was halted altogether by higher-priority projects. In the last months of the war it was revived and given the designation A-4b.36
A prominent feature of the glider missile project, as in the case of the A-5/A-4, was the repetitive, systematic wind-tunnel work required to evaluate different designs at different Mach numbers and different angles of attack (the angle of the missile’s nose to the direction of airflow). Doing comprehensive pressure measurements on a half-model, to take an extreme example, entailed more than 100,000 gauge readings recorded by hand by twenty people for two weeks in two shifts. As the war went on at Peenemünde, the inherent character of aerodynamic research, combined with intense political pressure to finish the A-4, made the work process increasingly stressful, routinized, and factory-like. A second 40-by-40-centimeter test section was built so that one would be available while changes were being made on the other. The aerodynamics group went to multishift operation nearly around the clock. In addition to all the missile work, extensive research was also done for Army Ordnance on artillery shells, including the fin-stabilized “Peenemünde Arrow Projectiles” designed in-house.37
This mass production of research reinforces a basic point about the revolutionary breakthroughs in key technologies that Peenemünde achieved between 1936 and 1941. In aerodynamics as in propulsion, brilliant ideas and excellent management were not by themselves sufficient. Only the existence of a massive and well-funded organization allowed the rocket group to create working technology in a short period of time. The case of guidance and control—the most difficult challenge in the whole A-4 project—illustrates this point even more clearly.
VON BRAUN, STEINHOFF, AND MISSILE GUIDANCE
Unlike the other two key technologies, the transformation of research in guidance and control did not begin around the turn of the year 1936–37. Until just before the disturbing failures of the A-3s in December 1937, Ordnance remained dependent on Kreiselgeräte as its sole contractor in this area. Those failures then greatly accelerated a twofold shift in philosophy: toward competitive development by a number of firms in the gyroscope and autopilot sector, and toward a buildup of in-house expertise at Peenemünde. Although those two processes overlapped, it was not until 1939 that Wernher von Braun began in earnest to put together a large guidance laboratory. He did so because he was increasingly dissatisfied with the corporations. The extreme and specialized demands of ballistic missile guidance, combined with Ordnance’s pressure to produce results quickly, strained the research and development capability of contractors already overburdened with Luftwaffe and Navy work. Rather than accept delays, von Braun used his rapidly expanding budget to construct a new laboratory at the center.
Competition for Kreiselgeräte was first formally discussed on November 9, 1937, when Dornberger and von Braun went to a meeting at the aviation instruments division of Siemens, the giant electrical concern. Among those attending was Siemens’s Dr. Karl Fieber, who remembers the “unusual declarations of secrecy with threats of the death penalty.” Also present were Karl Otto Altvater, director of the aviation instruments division, and Klaus Riedel, who had worked for the company for three or four years after the collapse of the Raketenflugplatz. Altvater, a retired U-boat captain and Naval Ordnance section chief in the 1920s, was Riedel’s uncle. He had given his nephew and two or three other rocket enthusiasts jobs when the amateur group fell apart. After the settlement of the Nebel–Riedel patent in July 1937, Klaus Riedel went with his friends to Peenemünde, where he in all likelihood suggested Siemens as an alternative source of gyroscope expertise. The firm had become increasingly involved in aircraft autopilots and navigation instruments since the 1920s and had purchased Boykow’s patents in this area in 1931.38
During the November 9 meeting von Braun lectured on the A-3 guidance system, giving no indication that the rocket group had anything but confidence in it, and the Siemens people made no comment. Nevertheless, Dornberger indicated that Ordnance had “the conscious intent… to create a competitive line of development to Kreisegeräte Ltd.” Nothing came of the discussions right away. For the next two months the preparations for the launches on the Oie and the postmortems on the failures completely absorbed the attention of Dornberger and his assistants. Only toward the end of January 1938 was it possible to meet again. Now the tone was completely different. With hindsight provided by the A-3 launches, the Siemens representatives expressed their reservations about the Sg 33’s inadequate control forces and its inability to stop a rapid rolling of the vehicle.39
Meanwhile, the discussions between the rocket group and Kreiselgeräte had produced some basic decisions. There was a need for systematic launch testing, a dramatic increase in the forces exerted by the jet vanes, and a refinement of the aerodynamic stability of the new vehicle. Kreiselgeräte must also make its control system simpler in most aspects, while more complicated in others. The company would remain with Boykow’s basic concept, one fundamental to most inertial guidance systems: a stabilized platform that remains fixed in space regardless of the movements of the rocket. Such a platform provides a reference for measuring the position or acceleration of the vehicle. But for the A-5 it was imperative to add the third gyro for the roll axis, which had been omitted from the Sg 33 for reasons of simplification. To reduce complexity, Peenemünde and Kreiselgeräte decided to eliminate the nitrogen jets that stabilized the platform, as well as the electricity supply that powered the gyros after liftoff. The A-5 would be equipped with gyros large and heavy enough to hold the platform steady by themselves, even though they would be slowed down by friction during the forty-five seconds of engine firing. That solution was clearly a temporary stopgap and was inadequate to the much more demanding requirements of the A-4.