Modifications
Bachem's design caught the eye of Heinrich Himmler. The Reichsführer-SS granted Bachem an interview and fully supported the project. In the middle of September 1944 the Technical Office of the Waffen-SS made an order for Bachem to develop and manufacture the Natter at his Waldsee factory. In December 1944 the project came largely under the control of the SS and Hans Kammler. This decision is said to have been the only time the SS significantly interfered with aircraft design and air fighting strategy. Early in the project the Reichsluftfahrtministerium (RLM) undertook an engineering assessment of the Natter, which it reported on 28 October 1944. Various stringent economies were imposed on an already frugal design.
The Natter had no landing gear, which saved weight, expense and construction time. Consequently one of the most unusual features of the machine was the escape of the pilot and recovery of the machine. The proposed sequence of these events was as follows: After the attack, the Natter dives to a lower altitude and flattens out into level flight. The pilot then proceeds with a well-practised escape sequence. He opens the cockpit canopy latch; the canopy flicks backwards on its hinge in the airstream; he undoes his seat belt and removes his feet from the rudder pedal stirrups. By squeezing a lever mounted on the control column, he releases a lock at the base of the column, which allows him to tilt the column forwards where it engages in and undoes a safety latch for the nose release mechanism. He then leans a little further forward and pulls a lever hinged near the floor at the front of the cockpit. This action frees the nose section, which flies off as a result of the reduced aerodynamic pressure at the front of the fuselage. As the nose section separates, it pulls briefly on two cables that release a small ribbon parachute stored on the starboard side of the rear fuselage. The parachute opens and decelerates the Natter. The pilot is ejected from the cockpit by his own inertia and as soon as he is clear of the fuselage, he opens his personal parachute and descends to the ground.
Although it was originally planned to recover the Walter liquid propulsion unit, which was probably the most expensive single component of the machine, using two salvage parachutes, associated problems were still not fully resolved prior to the war's end.
Professor Wilhelm Fuchs reportedly calculated the Natter's aerodynamics at the Technische Hochschule, Aachen using a large analog computer. Wind tunnel testing on a wooden model, scaled at 40% of full size, was performed at the Deutsche Versuchsanstalt für Luftfahrt (DVL), Institute for Aerodynamics at Berlin-Aldershof in September 1944 at speeds up to 504 km/h. Results from these tests were reported in January 1945 to the Bachem-Werk. Further model tests were carried out at Luftfahrtforchungsanstalt Hermann Göring (LFA), Braunschweig at speeds close to Mach 1. In March the Bachem-Werk simply received a statement that satisfactory flying qualities should be expected with speeds up to 1,100 km/h.
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