Ba 349 Natter | |
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A replica of the Bachem Ba349 at the Deutsches Museum in Munich, Germany | |
Role | Rocket-powered interceptor |
Manufacturer | Bachem Werke GmbH |
Designer | Erich Bachem |
First flight | 1 March 1945 |
Primary users |
Luftwaffe Schutzstaffel |
Number built | 36 |
The Bachem Ba 349 Natter (English: Colubrid, grass-snake) was a World War II German point-defence rocket-powered interceptor, which was to be used in a very similar way to a manned surface-to-air missile. After a vertical take-off, which eliminated the need for airfields, most of the flight to the Allied bombers was to be controlled by an autopilot. The primary role of the relatively untrained pilot was to aim the aircraft at its target bomber and fire its armament of rockets. The pilot and the fuselage containing the rocket-motor would then land using separate parachutes, while the nose section was disposable. The only manned vertical take-off flight on 1 March 1945 ended in the death of the test pilot, Lothar Sieber.
In 1943 Luftwaffe air superiority was being challenged by the Allies over the Reich and radical innovations were required to overcome the crisis. Surface-to-air missiles appeared to be a promising approach to counter the Allied strategic bombing offensive; a variety of projects were started, but invariably problems with the guidance and homing systems prevented any of these from attaining operational status. Providing the missile with a pilot, who could operate a weapon during the brief terminal approach phase, offered a solution. Submissions for a simple target defence interceptor were requested by the Luftwaffe in early 1944 under the umbrella of the "Emergency Fighter Program". A number of simple designs were proposed, including the Heinkel P.1077 Julia, in which the pilot lay prone (on his stomach), to reduce the frontal area. The Julia was the front-runner for the contract. The initial plan was to launch the aircraft vertically, but this concept was later changed to a conventional horizontal take-off from a tricycle-wheeled trolley, similar to that used by the first eight prototypes of the Arado Ar 234 jet reconnaissance bomber.
Erich Bachem's BP-20 ("Natter") was a development from a design he had worked on at Fieseler, the Fi 166 concept, but considerably more radical than the other submissions. It was built using glued and nailed wooden parts with an armour-plated bulkhead and bulletproof glass windshield at the front of the cockpit. The initial plan was to power the machine with a Walter HWK 109-509A-2 rocket motor; however, only the 109-509A-1, as used in the Me 163, was available. It had a sea level thrust variable between 100 kg (220 lb) at "idle" to 1,600 kg (3,500 lb) at full power, with the Natter's intended quartet of Schmidding SG34 solid fuel rocket boosters used in its vertical launch to provide an additional 4,800 kg (10,600 lb) thrust for 10 seconds before they burned out and were jettisoned. The experimental prototypes slid up a 20 m (66 ft)-tall vertical steel launch tower for a maximum sliding length of 17 m (56 ft) in three guideways, one for each wing tip and one for the lower tip of the ventral tail fin. By the time the aircraft left the tower it was hoped that it would have achieved sufficient speed to allow its aerodynamic surfaces to provide stable flight.