A4B Credit - © Mark Wade

Intermediate range boost-glide missile. Family:

Winged boost-glide version of the V-2 missile. The A4b designation was used to disguise work on the prohibited A9 program.

Two prototypes were flown; a manned version was planned. The A4b had an empty mass 1350 kg greater than the basic V-2, with wings of 52 degree sweep. Another variation was conceived and under construction at the end of the war - a boosted version. This would use a ring of 10 solid propellant rockets to achieve Mach 6 cruise at 20,000 m altitude, extending the range by a further 400 km.

Manufacturer: Von Braun. Launches: 2. Failures: 1. Success Rate: 50.00%. First Launch Date: 1944-12-27. Last Launch Date: 1945-01-24. Launch data is: complete. Apogee: 85 km (52 mi). Associated Spacecraft: A9. Liftoff Thrust: 312.000 kN (70,140 lbf). Total Mass: 12,800 kg (28,200 lb). Core Diameter: 1.65 m (5.41 ft). Total Length: 13.60 m (44.60 ft).

• Stage1: 1 x A-4. Gross Mass: 12,805 kg (28,230 lb). Empty Mass: 4,008 kg (8,836 lb). Motor: 1 x A-4. Thrust (vac): 311.800 kN (70,095 lbf). Isp: 239 sec. Burn time: 68 sec. Length: 12.00 m (39.00 ft). Diameter: 1.65 m (5.41 ft). Propellants: Lox/Alcohol.

November 1939 - Peenemuende -. Peenemuende wind tunnel goes into operation. The tunnel was used an average of 500 hours per month. 1000 cubic metres of vacuum vessels were pumped to a 98% vacuum in three to five minutes by three banks of double vacuum pumps. When vented, they provided the tunnel with 20 seconds of run time at velocities from Mach 1.2 to Mach 4.0, or 1500 m/s. Models 4 to 5 cm in diameter x 30-40 cm long could be accommodated in the tunnel, instrumented at 110 data points. These tests showed that drag increased 70% at the sound barrier and that the centre of pressure on the missile moved back one-half calibre. The wind tunnel runs showed that the basic A4 shape was all right, but that it needed load-carrying wings and a new rudder for the higher-speed A9 glider version. Huge trial and error was required to develop an A9 configuration that was stable, but not so stable that the control surfaces were too large. An arrow wing was the best performing, but the control surfaces were then in the turbulent flow of the wing and inadequate. Swept wings provided 12% less glide ratio than the arrow wing, resulting in a 60 km loss of range. Trapezoidal wings were the final solution, the end of a long iterative process.

Peenemuende-developed delta wings were adapted to Army artillery rounds of the 105 mm flak gun and K5 280 mm cannon, decreasing drag by 35%. The result was an increase of 6 kg in the explosive load, a 6 kg increase in the iron mass of the round, but with a range increase from 59 to 90 km. Equipped with a new, lighter warhead, and a sabot boosting a slimmer round, the gun could shoot projectiles to a range of 135 to 150 km, with an accuracy of 2 per mill.

Late 1939-1943 - Peenemuende -. A9 basic research and design By adding wings to the A4, the 800 m/s of kinetic energy the rocket had at cut-off could be exploited in a glide attack, extending the range of the missile from 250 km to 550 km. Such a supersonic aircraft had never been flown and presented many aerodynamic and engineering problems in 1943. Various tests of the A4's with wings began in early 1940. These were successful, and the configuration was dubbed the A9. The trajectory for such a missile involved a boost to an apogee of 29 km, then a stable glide at 20 km altitude at a speed of 1250 m/s. At the end of the glide, the missile would have descended to 5 km altitude, then make a vertical dive on the target in the fashion of the Fi-103/V-1. The A9 would be equipped with wings with a total area of 13.5 sq m. A manned version of this boost-glide rocketplane was also designed. This could reach a conventional airfield 600 km from the launch point in only 17 minutes, landing at a speed of 160 kph. Another possibility to further extend range would be a catapult-launched A9, using the technology developed for the V-1. This would provide an extra velocity of 350 m/s, further extending the missile's potential range.

1944 October 24 - Construction of 5 prototype A4b winged V-2's completed The A-4b was a winged V-2. This resurrected work on the A-9, abandoned in 1943 to concentrate on V-2 production. The A9 was to be the second stage of an ICBM designed to reach North America. By this time in the war the intent was to extend the range of the V-2 once Allied forces pushed the German lines so far back that Britain could no longer be targeted.

1944 December 9 - Peenemuende -. Boosted A4b test planned. 10 solid propellant rockets were delivered from the Wehrmacht to Pruefstand XII. Work was to be completed by the end of March to begin flight test of an extended-range using solid rocket boost. However Peenemuende was evacuated before the first flight test could be undertaken.

1944 December 27 - Peenemuende -. V-2 18484 FAILURE: Failure. A-4b #1 Work on a winged version of the A4 had been stopped in early 1943. Now, with the Allies overrunning launch sites in Belgium and Holland, Kammler ordered it resumed in order to have a long-range version of the weapon that could reach England and Allied continental rear areas from Germany. Within weeks the wind tunnel results generated since 1940 were reviewed, and a prototype winged version of the missile built. On the first launch, the steering failed at 30 m, and the missile crashed a short distance from the pad. Several more test articles were on hand, but testing could not resume immediately due to a shortage of alcohol fuel.

1944 December 31 - Peenemuende -. Peenemuende rocket team faces the New Year It was for them a depressing time. The V-2 came too late to affect the outcome of the war. The years 1939-1942, when Hitler had blocked development and production of the V-2, were lost years. By this time, the Peenemuende staff was allocated as follows: 135 were working on Taifun anti-aircraft barrage rocket; 1940 were working on the V-2; 1220 were working on the Wasserfall surface-to-air missile; 270 were working on the A4b winged V-2; and 660 were in administrative positions. Meanwhile Kammler was constantly underway, trying to deploy the wonder weapons he believed would save the Reich. He could only be met at one-hour meetings at autobahn intersections, on his way from one place to another.

1945 January 24 - Peenemuende P10. V-2 18543 A-4b #2 The first successful launch, this reached 80 km altitude and 1200 m/s. It then flew stably in supersonic flight using its 13.5 sq. m. wing. The automatic guidance system was designed to keep the missile on course in both supersonic and subsonic flight regimes. However the wing broke off shortly after the beginning of the glide. This concluded work on the A4b/A9; the increasingly chaotic situation in Germany prevented further flight tests.