The Rheintochter (Rhine Maiden) R I was an experimental German two-stage antiaircraft missile tested in the last year of World War II. Built by the Rheinmetall-Borsig company for the Luftwaffe, it was one of the largest solid-fuel rockets of the war. The R I was to be supplanted by the R III, a liquid-fuel missile with two side-mounted solid-fuel boosters that enabled it reach a higher altitude. However, only six R IIIs were ever launched, as opposed to 82 R I missiles.
The Smithsonian acquired this Rheintochter R I from the U.S. Navy in 1969. It was displayed in the National Air and Space Museum from 1976 to the early 1980s. In 2002 it was restored to its original condition and paint scheme for exhibit at the Stephen F. Udvar-Hazy center.
History
The Rheinmetall-Borsig A.G. of Berlin-Marienfelde received a German Air Ministry contract in November 1942, for a multi-stage, high altitude guided flak rocket. A Dr. Hennies was the main designer. Progress was slow and by July 1944, only 34 test missiles had been fired. Altogether, by the end of the war 82 test rounds were launched at Leba, Pomerania, of which 22 contained full radio guidance equipment. Eighteen of these worked well. An 88-mm antiaircraft gun carriage was modified for use as a launching ramp.
A shortcoming in altitude performance led to the cancellation of the R I as an operational missile in July 1944. Instead an improved, longer-duration, 43 second, 3,900-lb thrust liquid-fuel sustainer motor using nitric acid was designed by a Dr. Konrad for the R III version of the missile, using two solid-fuel boosters in place of the single solid booster. The R III reached the hardware stage with six test rounds fired by December1944, probably all with substitute solid-fuel sustainer motors. In the meantime, the remaining R-I models were used to test guidance systems. SS General Hans Kammler cancelled the Rheintochter on 6 Feb. 1945, along with a number of other missile programs, shortly after he received control over Luftwaffe missiles.
Construction
Torpedo-shaped main body tapering to a pointed nose around which are projected four canard-type, small, rounded steering surfaces operated by servos. At the aft end of the main stage are six large swept-back fixed fins. The exhaust gases are directed outward from six equidistant heavy steel nozzles in the spaces between the fins. The booster, or first stage, is attached to the rounded base of the main body or sustainer stage by a ring and explosive bolts. Projecting from the booster are four long, swept-back, laminated and varnished wood fins. Inter-bracing struts further strengthen the booster structure. The exhaust gases for this stage exited from a central and six surrounding smaller nozzles. The fins are detachable.
Launching was accomplished either by a 25-ft inclined steel ramp or converted 88-mm anti-aircraft gun mount. Guidance was by line-of-sight and remote joystick system. Radar could also be used but was seldom tried. Flares in the wings tips aided the tracking. Stabilization was by a gyroscopic system.
The booster, generating some 75,000 kg (165,000 lbs.) of thrust for 0.6 seconds accelerated the missile close to Mach 1 within the first 1,000 ft of travel. At burnout, the booster was immediately detached by detonation of a magnesium-alloy connection. The sustainer stage then ignited, producing 4000 kg (8,800 lbs.) of thrust for 10 seconds.
Because the propellant was standard double-base (nitroglycerine-nitrocellulose) of the day that was made by the extrusion, or squeezing out process, it could not be made in bulk but came out as sticks or rods. The sticks were placed in bundles within the propellant tubes of each stage and secured by thick metal discs called powder traps. The sticks bundles therefore necessitated the several separate nozzles on each stage. The Germans called their double-base propellant digylcol dinitrate. This propellant, which had a low impulse compared to modern propellants, also required heavy metal casings for their motors. The casing for the booster weighed more than 400 kg (880 lbs.) while the propellant weighed 240 kg (530 lbs.).
The warhead was not placed in the nose but well back behind the solid-propellant of the sustainer stage, near the roots of the first-stage fins.
References
J. R. Smith and Antony L. Kay, German Aircraft of the Second World War (London: Putnam, 1972), pp. 709-712.
Frederick I. Ordway, III and Ronald C. Wakeford, International Missile and Spacecraft Guide (New York: McGraw-Hill Book Co., Inc., 1960), pp. 94-95.
Bill Gunston, The Illustrated Encyclopedia of the World's Rockets & Missiles (New York: Crescent Books, 1979), p. 149.
Karl-Heinz Ludwig, "Die deutschen Flakraketen im Zweiten Weltkrieg," Militaergeschichtliche Mitteilungen (1969), no. 1, pp. 87-100.
Heinrich Klein, Vom Geschoss zum Feuerpfeil: Der grosse Umbruch der Waffentechnik in Deutschland 1900-1970 (Neckargemuend: Kurt Vowinckel, 1977), pp. 173-181.
