from a depth of 30 to 50 feet, "A staggering sight it was when those twenty heavy powder rockets suddenly rose, with a rush and a roar, from the calm waters of the Baltic." Aerodynamic Institute The supersonic wind tunnel at Peenemünde's "Aerodynamic Institute" eventually had nozzles for speeds up to the record speed of Mach 4.4 (in 1942 or 1943), as well as an innovative desiccant system to reduce the condensation clouding caused by the use of liquid oxygen, in 1940. Led by Rudolph Hermann, who arrived in April 1937 from the University of Aachen, the number of technical staff members reached two hundred in 1943, and it also included Hermann Kurzweg of the (University of Leipzig) and Walter Haeussermann. Heimat-Artillerie-Park 11 Initially set up under the HVP as a rocket training battery (Number 444), Heimat-Artillerie-Park 11 Karlshagen/Pomerania (HAP 11) also contained the A-A Research Command North for the testing of anti-aircraft rockets. The chemist Magnus von Braun, the youngest brother of Wernher von Braun, was employed in the attempted development at Peenemünde of anti-aircraft rockets. These were never very successful as weapons during World War II. Their development as practical weapons took another decade of development in the United States and in the U.S.S.R. Peenemünde V-2 production plant In November 1938, Walther von Brauchitsch ordered construction of an A-4 production plant at Peenemünde, and in January 1939, Walter Dornberger created a subsection of Wa Pruf 11 for planning the Peenemünde Production Plant project, headed by G. Schubert, a senior Army civil servant. By midsummer 1943, the first trial runs of the assembly-line in the Production Works at Werke Süd were made, but after the end of July 1943 when the enormous hangar Fertigungshalle 1 (F-1, "Mass Production Plant No. 1") was just about to go into operation, Operation Hydra bombed Peenemünde. On August 26, 1943, Albert Speer called a meeting with Hans Kammler, Dornberger, Gerhard Degenkolb, and Karl Otto Saur to negotiate the move of A-4 main production to an underground factory in the Harz mountains. In early September, Peenemünde machinery and personnel for production (including Alban Sawatzki, Arthur Rudolph, and about ten engineers) were moved to the Mittelwerk, which also received machinery and personnel from the two other planned A-4 assembly sites. On October 13, 1943, the Peenemünde prisoners from the small F-1 concentration camp boarded rail cars bound for Kohnstein mountain. Operation Crossbow Two Polish janitors