B.The C-2 was designed to be launched vertically from the ground, and traveling at a supersonic speed to be guided into bombe formations where it would be exploded.

C. The Wasserfall resembles a half size V-2 with small wings. It has a similar motor and is launched in much the same manner. Its control gear is also similar. (See fig. 198.)

It could reach a maximum speed of about 770 meters per second in about 45 seconds after which time the speed would decrease as the fuel would be exhausted. It could still chase targtes until its speed had dropped to about 350 meters per second. Its maximum fighting ranges were: 18 kilometers in height and 26 kilometers in horizontal range. It was designed to withstand maneuvers to up to 4.4 g. The missile was guided by radio signals from the ground until approaching the target at which time a self-contained homing sys-tem was to lead it in. It was planned to incorproate a proximity fuze to explode the wea-pon close to the bombers.

With these properties the Germans expected every other missile to bring down a bomber making 2 g evasive maneuvers at a speed of 250 meters per second.

A. The Warhead was planned for use from the ground against air targets, specifically bombers. Suggested locations for launching sites were along the French coast and ap-proches to major targets of bombers.

B. The launching site requires much equipment and, although mobile, would thus be sub-ject to attack. Lack of maneuverability against relatively slow airplans would have inhibi-ted its effective use.

C. The Wasserfall was expected to be both cheaper and more effective than ordinary flak for the results obtained. Only operational use could prove this point.

Conclusions. The Wasserfall was not completed and thus offers no immediate possibili-tes  as a weapon without much further work on the control system.

Recommendations. It is believed that an intensive study of the Wasserfall will yield much informations on the principles and the use of a supersonic guided missile.

AIRFRAME. A. Type and Description. In over-all appearance the Wasserfall resembles a half-size V-2 with small wings. The approximate dimensions are:

Length: 7,800 mm.
Caliber: 880 mm.
Wing span: 1,890 mm.
Tail span: 2,500 mm.

There are four small biconvex dorsal wings at the center of gravity to assist in making turns. In line with these wings are four stabilizing fins at the tail. Control surfaces are fit-ted on the stabilizing fins both in the air stream and in the gas stream of the jet motor.

B. Aerodynamic Characteristics. The Wasserfall is designed to catch, while traveling at a supersonic speed, a target havin a velocity of 250 meters per second doing 2 g maneu-vers.

Essentially the missile travels at and is designed for supersonic speeds. However, the transition from zero speed at launching to the supersonic range is not instantaneous and some additional control is desirable during this interval. This is supplied by the gas stream fins which are present for the first 5 - 15 seconds of flight. Once the supersonic range is reached the air stream fins supply sufficient control while the jet stream fins add a drag. Consequently they are jettisoned at that time.

The missile is designed to stand maneuvers up to 4.4 g. The wings will support a lift of 8,000 kg per pair to which the body, tail, etc., add about another 4,000 kg making a to-tal lift of 12,000 kg.

The missile weighs about 3,500 kg at take-off, but the weight drops continually to about 1,500 kg by the time the fuel exhausted. Thus at take-off the lateral acceleration should not exceed 3 g, increasing to 4.4 g as the fuel is consumed. To allow for this the control applied to the servo is made weak at first and is gradually brought up to its full power.

Wind tunnel tests of models made may be found in report No. UM 6013 dated February 1945 in the Göttingen documents. Evidence obtained at the wind tunnels at Kochel shows that at least six different shapes have been tried out to get the best aerodynamic results.

C. Design Data. The missile is fabricated from mild steel to the shape in Figure 198. It may be broken down into the following parts:

1. Nose: Contains the homin device (Zielsuchendes Gerät) fuzes (Zünder) and explosive (Sprengstoff).

2. Nitrogen tank: (Druckluftbehälter).

3. Visol tank: (Brennstoffbehälter).

4. Wings: (Flügel).

5. Salbei tank: (Salbeibehälter).

6. Control system: Mounted to rear of Salbei Tank.

7. Tail: Supports motor (Brennkammer), tails (Flosse), air rudders (Luftruder), and jet rudders (Strahlruder).

D. Productions Data. The following remarks apply to all parts of the missile. The only pro-duction was by the Electromechanische Werke at Peenemünde for the developmental testing. Estimates of this production range from 40 to 275 units.

Estimates were drawn up for the men, material and space needed for the mass produc-tion of 5,000 monthly.

PROPULSION SYSTEM.  A. Type and Description. A liquit jet motor drive is used which de-velops an 8,000 kg thrust for 45-seconds. The motor burns a self-igniting mixture of Sal-bei (nitric acid) and Visol (a hydro-carbon mixture) in a cham-ber with a venturi nozzle.

Thrust: 8,000 kg.
Total impuls: 360,000 kg.
Launching acceleration: 1.2 to 2.6 g.
Final acceleration: Ca. 4 g.
Fuel consumption: 41 kg/sec.
Specific impulse: 180 to 195 sec.

C. Design Data. The general arrangement is indicated in figure 198. The fore-most flask contains nitrogen at a pressure of 200 - 300 atmos. This flask is 8 to 13 mm thick and is not wire wound. The compressed gas passes through a reducing valve to 30 atmos and is used to force the liquids out of their storage tanks. This flask and the two storage tanks are made of rolled and welded steel.

The forward storage tank contains about 400 kg or 430 liters of Visol. Visol is a rather variable fuel according to the ingredients available or the intended use. A typical Visol mixture is: 40 percent isoprophyl alcohol; 40 percent vinyl ether; 2 percent water; 18 percent of four other ingredients including 1 percent of a dope to control the ignition de-lay time.

Visol is a contracted code name for vinylisobutylether. A Diesel oil may also be used in place of Visol.

The rear tank contains about 1,500 kg or 1,100 liters of the oxidant Salbei. Salbei is a mixture of 90 percent nitric acid (including 3 percent water) and 10 percent sulfuric acid. No attempt is made to make the acid water free as it would be reasorbed from the air before it was ever used. The sulfuric acid was added to prevent corrosion by the nitric acid of the steel available for the tanks.

As already mentioned, the fuel and oxidant were forced out by pressure. The fuel is re-moved through a swinging pipe hanging down in the tanks. As this pipe is subjected to the same acceleration as the fuel, its end is always covered by liquid. This design gives a light-weight removal system which removes practically the last drop of liquid although the liquids are being swished around, in the tanks. It is said this system increased the maximum altitude obtainable by 4 kilometers over a pump arrangement that was tried.

Both fuel and oxidant are passed through a valving arrangement which introduces both liquids into the motor at the same time under full flow. Valves in the various pipe lines are opened simultaneously by explosive charges. Just before each liquid enters the motor there is a diaphragm. These diaphragms stop the liquid until it has built up to practically full pressure at which time the diaphragm bursts and allows a full flow of liquid, from the start, to enter the motor.

The ratio of liquids by weight is Salbei to Visol from 5 to 1 up to 8 to 1 depending upon the actual Visol mixture being used.

The Visol is fed directly to the nozzle head. The Salbei first passes through the cooling jacket of the motor before going to the nozzle head. In some cases some of the Salbei is also injected through cooling holes into the combustion chamber. The two liquids ignite within 0.01 to 0.1 second after contact. An expansion ratio of 2.5 to 1 up to 3.8 to 1 is obtained in the motor. The gas exit velocity is approximately 1,850 meters per second.

Brennschluss (turning off of the motor) had not been settled. Provious were made for se-veral methods, which were:

1. Letting the motor use up all of the fuel

2. Turning off the motor by radio signal

3. Turning off the motor at a predetermined velocity by means of an integrating ac-celerometer.

A. Type and Description. Many systems were tried or proposed which, although radically different in details, are very similar in function. Three gyros are used to prevent oscilla-tions about the three axis. Remote radio control is used to guide the missile toward the target. A homing device is to be used in the final part of the chase to guide the missile to within killing distance of the target. Finally a proximity fuze is to explode the missile. In addition there is a relay transmitter in the missile to enable the personnel on the ground to follow it.

B. Characteristics. The control system must be capable of guiding the missile very close to a target which is making 2 g curves at a velocity of 250 meters per second.

C. Design Data. 1. Rudders and Rudder Machines. In each of the four tail fins there is a pair of rudders in the air stream and the jet stream. Each pair of rudders is driven by one all-electric servo motor. The amature of the servo motor oscillates at 50 cycles a second to reduce the back lash to almost zero. Roll control is applied to all rudders.

2. Gyros. Three course gyros are used to prevent the missile from oscillating. The take-off cards on the gyros are positioned by the remote radio control to keep the gyros oriented with respect to the desired path.

3. Remote Control Radio Receiver. This unit receives command signal from the ground control station to direct the missile towards the target. The "Strassburg" E230V is em-ployed as the receiver.

4. Relay Transmitter. A transponder triggered from the ground radar to indicate the angle of roll of the missile by measurement of the polarization of the wave transmitted is known under the code name "Reuse".

5. "Mischgerät". An electrical computing device which receives signal from the control ra-dio and the gyro, mixes these signals, and sorts them out for the various rudder motors.

6. Homing Device. A device to make the missile home in very close to target. None had been sufficiently developed to test in the missile. It is a prerequisite as the ground con-trol is not sufficiently accurate to guide the missile close enough to the target to do da-mage.

7. Power Supply. Batteries, invertors, regulator, etc., to power the control system.

8. Warhead, Fuze, Firing Circuit. About 305 kilograms of explosive were to be used. Of this about 100 to 150 kg would be concentrated in the nose. The remainder would be distributed throughout the body much in the form of primercord. This distributed charge was necessary to destroy the missile in mid-air as it would be used over friendly terri-tory. The warhead was expected to have a destructive range of 40 meters.

9. Auxiliary Equipment. The Wasserfall required considerable ground equipment for the re-mote control. Equipment is required not only for the transmittal of control signals to the missile, but also to track both the missile and the target. The missile is guided so that it is always on the line between the target and the ground observer.

Preferably the tracking is done optically. In this case, the operator has only to keep the missile and the target lined up in the optical field. However, radar tracking mut be provi-ded for the many times that optical tracking will be inadequate. The radar tracking sys-tem and control system known as the "Elsass" consists of the following functional parts:

Mannheim radar. – Radar set to track the target. It also measured the distance between the target and the missile.

Rheingold. – The Rheingold follows the missile and measures the roll position of the missile by determination of the angle of polarization of the signal sent out by the "Riese" relay transmitter in the missile.

Indicator. – The indicator displays information obtained from the Mannheim and the Rheingold:

Azimuth and elevation of target and missile,
Distance to target and missile,
Roll position of missile.

Kehl control transmitter. – An operator sits before the indicator and by means of a joy stick control keeps the missile in line with the target. This joy stick controls the com-mand signals sent out by the "Kehl" control transmitter to the "Strassburg" receiver in the missile. By this transmitter the operator may also fire a fuze in the missile when his indicator shows the missile is at the target.

Figure 198 – Wasserfall