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In reality, only one
experimental vertical takeoff interceptor was available in 1944. This
simple innovative project designated Bachem Projekt 20, which was
accepted by the Air Ministry and received the official RLM designation
Ba 349, was code-named Natter (Viper). It was manufactured in small
numbers prior to the end of the war. A second design with vertical
takeoff capability, the He P 1077 (see p. 152), failed to materialize
except for a few gliders that may have been completed prior to the
war's conclusion.
The Bachem Werke GmbH was founded on February 10, 1942, by Dipl.-Ing.
Erich Bachem, formerly the Technischer Direktor of the Fieseler firm.
The company manufactured spare parts for piston-engine fighters and
other aircraft equipment before the Natter project was created.
The BP 20 was projected
as a small lightweight expendable interceptor, capable of destroying
any enemy bomber using the least possible weapon expenditure. To achive
this objective, this ambitious project employed a vertical
rocket-assisted takeoff followed by separate descent and landing of
pilot and aircraft by separate parachutes. It was believed that pilots
having little or no experience would need only rudimentary flight and
gunnery instruction, rather than spending valuable training resources
on the finer points of flight training. Erich Bachem reasoned that, a
reasonable number of such interceptors and launch sites could be
installed around key industrial targets, to make attacking Allied
bombers pay a prohibitively high price. Other attributes of Natter
included savings in the amount of steel and aviation fuel and the
ability to be quickly transported from small, camouflaged sites. The
ability to recover the rocket motor for reuse was considered an
important feature of this aircraft, which was essentially a manned
missile.. There were even plans to launch the interceptor from ships if
the need arose.
The BP 20 was of wood
construction and was to be built without the use of gluing presses.
Most of the parts could be made in small woodworking shops through
Germany, without interfering with the existing needs of the aircraft
industry. According to Erich Bachem, ) only 600 man-hours were required
for the production of one airframe, excluding the HWK 509 A-2 rocket
motor, which was a relatively simple to manufacture when compared to
sophisticated turbojet.
The fuel capacity was
to consist of 119 US gallons (450 litres) T-Stoff and 66 US gallons
(250 litres) C-Stoff, carried in separate tanks. The available fuel was
sufficient for 80 seconds at full power, developing a thrust of about
3,750 lb (1,700 kg). Takeoff assistance was provided by four solid-fuel
rockets SR 34 which produced an additional thrust of 2,200 lb (1,000
kg) for twelve seconds.
Natter's weapon systems
were simple and potentially devastating. They comprised either a
honeycomb 24 electrically fired 73 mm F6hn air-to-air rockets, or 32
R40 air-to-air missiles located behind a jettisonable cover in nose
section. The alternative, the Rheinmetall SG 119 consisted of six
clusters, each cluster containing seven MK108 barrels grouped together
in a cylinder with the clusters arranged about the Viper's nose as in a
revolver.
Bachem submitted his
Natter project to the OKL and simultaneously to the SS-F6hrungshaptamt
(SS Planning Office), in August 1944. One month later, a contract for
fifteen experimental BP 20 aircraft was awarded, and a few weeks later,
Natter was included in the J5gerNotprogramm (Emergency Fighter
Program). The first experimental aircraft, the Ba 349 M1 and M2, were
under construction in October 1944, at a time when the RLM believed the
Natter could be successfully employed against Allied heavy bombers,
including the anticipated American Boeing B-29.30 The first batch of
fifty Ba 349s was ordered for delivery between October 1944, and
January 1945. A measure of the importance attached to the program is in
the substantial order of 200 Vipers at the start of mass production.
The installation of
parachutes delayed flight testing of the first target defence
prototype, the Ba 349 M1, until November 1944. The Ba 349 M2 was
completed soon thereafter and the first takeoff under air-tow of the
third prototype, Ba 349 M3, was made at Neuburg on the Danube on
December 14, 1944. A second flight behind a He 111 by the DFS, followed
eight days later. After successful completion of ground tests near Bad
Waldsee on December 18, 1944, the first vertical launch from a ramp was
scheduled. This event was marred when the Viper caught fire as a result
of a technical fault. The next attempt was made four days later at
Heuberg Hill near Stetten am kalten Markt. The aircraft was towed to an
altitude of 2,460 ft (750 m) and parachutes were deployed to carry the
Viper and its simulated pilot safely to ground. The second takeoff
occurred on December 29, 1944, without serious incident while
simultaneously, other Vipers were towed into the air for further
testing.
French armor advanced
into Waldsee on April 1945 and a great number of spare parts was
captured- Only a few days before the French arrived, fifteen rocket
engines destined for Vipers had been thrown into Lake Waldsee to
prevent their capture. The secret was not well kept however and all
were later recovered.
Plans for mass production of the Ba 349 A-1 were authorized on March 1,
1945, but only a few Natters were actually completed. These were
followed by the improved Ba 349 B-1 (Entwurf 2) interceptors whkb were
to be produced at Waldsee, but few were actually completed.
On of the models were powered by a solid-fuel rocket to evaluate
takeoff characteristics. Practical tests carried out at Peenemunde,
where a first test conducted during February 1945, proved unsuccessful.
Willy A. Fiedler, a testing engineer working for the RLM, was sent to
the Heuberg Hills to oversee the program Erich Bachem is quoted after
the war as having said that about twenty Vipers had been used for
practical tests. Fifteen were of the A-series, and four B-series
aircraft. All were constructed at Waldsee. Still others were assembled
by the Wolf Hirth glider factory. Four additional Ba 349s, possibly of
the B-series, were captured at the end of the war by Allied forces near
St. Leonhard, Austria
.
Origin: Bachem-Werke GmbH,
Waldsee
Type: part-expendable target-defence interceptor
Engine: 2,000kg thrust Walter HWK 109-509C-1 bi-propellant rocket
(vertical launch boosted by four 500kg or two 1,000kg solid motors
Armament: 24 Föhn 73mm spin-stabilized rockets, or 33 R4M 55mm
spin-stabilized rockets, or (projected) two 30mm MK 108 cannon each
with 30 rounds
Speed: maximum speed (sea level) 800km/h, (at high altitude) 1,000km/h
Climb: 11,100m/minute
Range: 32-48km
Weight: empty 880kg, loaded 2,232kg
Wingspan: 3.6m
Length: 6.02m
Height: 2.25m
Crew: one |
