kb/data/en.wikipedia.org/wiki/Aggregat-2.md

title	chunk	source	category	tags	date_saved	instance
Aggregat	3/5	https://en.wikipedia.org/wiki/Aggregat	reference	science, encyclopedia	2026-05-05T13:25:58.892208+00:00	kb-cron

== A5 (1938–1942) == The A5 played a vital role in testing the aerodynamics and technology of the A4. Its rocket motor was identical to the A3, but with a new control system provided by Siemens, was 5.825 m (19.11 ft) long, with a diameter of 0.78 m (2.6 ft) and a takeoff weight of 900 kg (2,000 lb). The A5 was fitted with a Brennschluss receiving set, a parachute recovery system, could stay afloat in water for up to two hours, and was painted yellow and red, aiding recovery. New tail surfaces were tested in the Zeppelin Aircraft Works subsonic tunnel and the supersonic tunnel in Aachen. The internal vanes were now made of graphite instead of molybdenum. Uncontrolled A5s were launched from Griefswalder Oie in late 1938. Models that were 1.5 meters (5 ft) long and 20 centimeters (8 in) in diameter were dropped from Heinkel He 111s starting in September 1938, testing supersonic speeds in the absence of a supersonic wind tunnel. Hellmuth Walter also made models of the A5m which included a hydrogen peroxide motor, with potassium permanganate as a catalyst, and were test launched in March 1939. The final fin configuration was wider, curved outward to accommodate the expanding exhaust gases, included external air vanes, but no ring antenna. The A5, like the A3, was fueled with ethanol with liquid oxygen as an oxidant. The first successful guided flights were made in October 1939, with three of the first four flights using a Kreiselgeräte complete guidance and control system called SG-52. This used a 3-gyro stabilized platform for attitude control and a tilt program, whose signals were mixed with rate gyros, and fed to a control system connected to the jet vanes by aluminium rods. The Siemens Vertikant control system first flew on 24 April 1940. The Siemens system used three gyros, particularly 3 rate gyros providing stabilization, and hydraulic servomotors to move the jet vanes to correct pitch and yaw, and control roll. The Möller Askania, or Rechlin system, first flew on 30 April 1940, and used position gyros, a mixing system and a servo system. A5 testing included a guide plane system for lateral control, and a radio system for propulsion cutoff at a preselected speed, after which the rocket followed a ballistic trajectory. The A5s reached a height of 12 km (7.5 mi) and a range of 18 kilometres (11 miles). Up to 80 launches by October 1943 developed an understanding of the rocket's aerodynamics, and tests of a better guidance system. The aerodynamic data resulted in a fin and rudder design that was basically the same one used for the A4. At the conclusion of the A5 testing, Dornberger stated, "I now knew that we should succeed in creating a weapon with far greater range than any artillery. What we had successfully done with the A5 must be equally valid, in improved form, for the A4."

== A4/V-2 rocket (1942–1945) ==

In the late 1920s, Karl Becker realised that a loophole in the Treaty of Versailles allowed Germany to develop rocket weapons. General Becker was very influential during the development of the A4 until he committed suicide on 8 April 1940 following criticism from Adolf Hitler. The A4 was a full-sized design with a range of about 320 kilometres (200 mi), an initial peak altitude of 89 kilometers (55 mi) and a payload of about 1,000 kg (2,200 lb). Versions of the A4 were used in warfare. They included the first ballistic missile and the first projectile to reach outer space. The propellants of choice continued to be liquid oxygen, with a 75% ethanol and 25% water mixture. The water reduced the flame temperature, acted as a coolant, and reduced thermal stress. This increase in capability came from a redesign of the A3 engine, now known as the A5, by Walter Thiel. It became clearer that von Braun's designs were turning into useful weapons, and Dornberger moved the team from the artillery testing grounds at Kummersdorf (near Berlin) to Peenemünde, on the island of Usedom on Germany's Baltic coast, to provide more room for testing and greater secrecy. This version was reliable, and by 1941 the team had fired about 70 A5 rockets. The first A4 flew in March 1942, flying about 1.6 kilometers (1 mi) and crashing into the water. The second launch reached an altitude of 11 kilometers (7 mi) before exploding. The third rocket, launched on 3 October 1942, followed its trajectory perfectly. It landed 193 kilometers (120 mi) away, and reached a height of 83 kilometers (52 mi). The highest altitude reached during the war was 174.6 kilometres (108.5 miles) on 20 June 1944. Production started in 1943 on the rocket. The missile testing ground at Blizna was quickly located by the Polish resistance movement, the Home Army (Armia Krajowa), thanks to reports from local farmers. Armia Krajowa field agents managed to obtain pieces of the fired rockets by arriving on the scene before German patrols. In early March 1944, British Intelligence Headquarters received a report of an Armia Krajowa agent (code name: "Makary") who had covertly surveyed the Blizna railway line and observed a freight car heavily guarded by SS troops containing "an object which, though covered by a tarpaulin, bore every resemblance to a monstrous torpedo". Subsequently, a plan was formed to make an attempt to capture a complete unexploded V-2 rocket and transport it to Britain. Around 20 May 1944, a relatively undamaged V-2 rocket fell on the swampy bank of the Bug River near the village of Sarnaki, and local Poles concealed it before German arrival. The rocket was then dismantled and smuggled across Poland. In late July 1944, the Polish resistance secretly transported parts of the rocket out of Poland in Operation Most III (Bridge III) for analysis by British intelligence.