Missile, Surface-to-Air, Rheinmetall-Borsig Rheintochter R I

The Rheintochter (Rhine Maiden) R I was an experimental German two-stage, anti-aircraft missile tested in the last years of World War II. Initiated by the German Air Ministry in 1942, as part of its program to respond to increasingly effective Allied bomber raids, the RI was also one of the largest solid-fuel rockets of the war and its first stage produced the largest thrust, although for a very short duration. Eight-two test missiles were fired in 1943-1944, but due to its inadequate altitude ceiling the RI was to be supplanted by the R III model, a liquid-fuel missile with two side-mounted, solid-fuel boosters. Only six of those were ever launched.

The U.S. Air Force transferred this Rheintochter R I to the National Air and Space Museum in 1966. It has been on loan to the Deutsches Museum in Munich, Germany, since 1983 and was refurbished for exhibit there.

The Rheintochter (Rhine Maiden) R I was an experimental German two-stage anti-aircraft missile tested in the last years of World War II. Initiated by the German Air Ministry in 1942, as part of its program to respond to increasingly effective Allied bomber raids, the RI was also one of the largest solid-fuel rockets of the war and its first stage produced the largest thrust, although for a very short duration. Eight-two test missiles were fired in 1943-44, but due to its inadequate altitude ceiling, the RI was to be supplanted by the R III model, a liquid-fuel missile with two side-mounted solid-fuel boosters. Only six of those were ever launched.

The U.S. Air Force transferred this Rheintochter R I to the National Air and Space Museum in 1966. It has been on loan to the Deutsches Museum in Munich, Germany, since 1983, and was refurbished for exhibit there.

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, 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. It was behind the solid-propellant of the sustainer stage, in front of the first-stage fins.

References

Karl-Heinz Ludwig, "Die deutschen Flakraketen im Zweiten Weltkrieg," Militaergeschichtliche Mitteilungen (1969), no. 1, pp. 87-100.

J. R. Smith and Antony L. Kay, German Aircraft of the Second World War (Putnam: London, 1972), pp. 709-712.

Frederick I. Ordway, III and Ronald C. Wakeford, International Missile and Spacecraft Guide (McGraw-Hill Book Co., Inc.: New York, 1960), pp. 94-95.

Bill Gunston, The Illustrated Encyclopedia of the World's Rockets & Missiles (Crescent Books: New York, 1979), p. 149.