Monday 20 January 2020

German Explosive Ordnance - Rockets (Part 10)







German Explosives







Feuerlilie Model F-55




Description

The F-55 is another of the Feuerlilie series of rocket-propelled guided missiles which the LFA (Luftahrtforschungsanstalt Hermann Goering E.V.) located at Volkenrode/Braunschweig, Germany was developing in order to obtain aerodynamic data in the transonic region.  Although the primary purpose of the Feuerlilie series development work was to obtain aerodynamic test data, there is evidence that a certain amount of thought was being given to the possibility of using the F-55 as a weapon.

The Feuerlilie F-55 has a fuselage 4.8 meters in length and a diameter of 55 cm.  The wing span of the two main fins which are attached to the afterbody of the fuselage is 2.6 meters.  The first F-55 had a solid propellant rocket drive, but later models used a liquid rocket motor with a dry powder assisted take-off unit.

The F-55 was to be ground launched and it was expected to reach an altitude of 4,800 meters with a maximum horizontal range of 7,500 meters.  Elaborate plans were also being made to install telemetering and to follow the flight path of the missile by cine-theodolites.




History of Development

Development work on the F-55 was started about May 1944 by Dr. Gerhard Braun of LFA.  The body for the F-55 was built by Ardelt Werke, Eberswalde, Breslau.

The production scheduled for experimental models of F-55 for the year 1945 called for a total of 35 with deliveries of at least 3 per month for the first 10 months of the year.  These were to be tested with various stabilizing systems and the later models were also to be equipped with telemetering and remote control equipment.

The first model of F-55 with solid propulsion was tested at Leba, Pomerania in May 1944, with satisfactory results, a Mach number of 1.25 being attained.  The second model with a liquid fuel system and take-off unit was tested at Poenemunde on 11 December 1944; this model went into a spin about its pitch axis shortly after leaving the launching track.  The third model had been sent out to Poenemunde for testing, but had not yet been tested.


Conclusions

Since the Feuerlilie F-55 was primarily a research project, it is of interest largely from the standpoint of the methods tried and the techniques of flight observations used.

As the F-55 like the F-25 was a manifestation of the Velkenrode research groups' ideas, it undoubtedly represents a high order of an aerodynamic development and requires treatment as such.  The Braunschweig documents, duplicated by the United States Army Air Forces and evacuated to Wright Field, Dayton, Ohio, include comprehensive reports on the Feuerlilie series.


Details

Airframe

The airframe of the Feuerlilie F-55 consists of a fuselage 4.8 meters long, and having a maximum diameter of 55 cm.  There are two sharply swept back wings having a span of 2.6 meters.  Two vertical fins are mounted at the extremities of the wings, this position being chosen to keep them out of the wake of the body.

The outer halves of the training edges of the wings are movable so as to give aileron control.  No rudder is provided, yaw control being obtained from aileron action.


Power Plant

The power plant used for the first model of F-55 was the RI 503 solid propellant type built by Rheinmetall-Borsig.  For the second and third propulsion unit designed by Dr. Contrad of DVX (Deutsche Versuchsanstalt fur Kraftfahrzeug und Fahrtzeugmotoren) located in Berlin.  In addition, an assisted take-off unit.  "Pirat," a solid propellant rocket was used.




Design Data

SG 20
Thrust: 6,400 kilograms
Time of burning: 7 seconds
Weight of fuel: 210 kilograms
Impulse: 45,000 kg/sec


Pirat ATO
Thrust: 10,000 kilograms
Time of burning: 2.7 seconds
Weight of fuel: 150 kilograms

Impulse: 27,000 kg/sec



Control System

On the first model of F-55, no roll stabilization was used.  On the second and third models, gyro equipment developed by Fischl of DFS (Deutsche Forschungsanstalt fur Segelflug) was tried.  This system used a single gyro with Askania pneumatic rubber servos.

It was expected that the rubber would provide the necessary mechanical damping, but due to the fact that the only test flight on which this system was used failed, it was impossible to determine whether or not this was the case.  On subsequent models, it was proposed to use a Horn gyro system consisting of two gyros, one of which was used for damping only.  This system was also to be used with the Askania pneumatic servo systems of remote control.

In connection with the Feuerlilie program, a new telemetering system "Stuttgart" had been developed which had 12 channels and gave 20 values per second with an accuracy of plus/minus 5 percent.  This system was designed by the Forschungsanstalt Graf Zeppelin, located at Stuttgart/Ruit.


Warhead and Fuzing

Since the F-55 was primarily a research missile in the early stages of its development, there was no provision made for a warhead.  Like the F-25, a Rheinmetall-Borsig time fuze was used to ignite the flares mounted on the wing tips to insure satisfactory tracking of the missile in flight by means of cine-theodolites.


Launching

The F-55 was launched from an inclined ramp built by Ardelt Werke, Breslay.  The launching angle was 20 degrees to the vertical.












Rheintochter




General Description


The Rheintochter is a radio-controlled anti-aircraft rocket designed for ground launching against bomber formations.  The first model Rheintochter 1, is a two-stage rocket having a total launching weight of 1,750 kg.  The starting rocket has a burning time of only 0.6 seconds, after which it drops off, the main stage then being automatically ignited.  Stabilization was achieved by six fins attached to the rear of the main body of the rocket and four fins attached to the starting unit.  The rocket was to be remote radio controlled with the possibility of using an infra-red homing device together with a proximity fuze to detonate the missile in the midst of the bomber formation.  The control surfaces were located at the nose of the missile.  It attained a final velocity of 360 meters per second, and could reach a height of 6 kilometers with a maximum horizontal range of 12 kilometers.

The Rheintochter 1 was replaced by the development of the Rheintochter 3.  The remainder of this discussion will be on the second model and will go into considerable detail.

In the Rheintochter 3, the rear take-off unit was dispensed with and replaced by two auxiliary take-off units mounted on the sides of the body of the rocket.  The main rocket stage could be either a liquid or a solid propulsion unit, depending on the availability of fuels.  The Rheintochter 3 is designated as R-3f when a liquid propulsion unit is used and R-3p when a solid propellant is employed in the main rocket stage.  The control and steering mechanism are identical in both Rheintochter 1 and Rheintochter 3.  The Rheintochter 3, however, is allowed to rotate about its axis in flight and instead of six stabilizing fins, it is provided with only four.




Details

Airframe

The Rheintochter 3 consists of a main fuselage 500 cm long and 54 cm in diameter, having four large swept-back main fins and two auxiliary take-off units mounted on the sides of the body between the two pairs of fins.  As in the Rheintochter 1, the control surfaces are mounted in the nose section but are of a somewhat different aerodynamic design. 

The main fin span is 220 cm, the four fins being attached to the body so that the angle between successive fins is 90 degrees.

As in Rheintochter 1, the main fuselage is constructed partly of aluminum plate, partly of steel alloy plate and partly of a material called ELEKTRON.  The fins were to be constructed of LIGNOFOL, a highly compressed laminated wood, but for mass production purposes, plywood could have been used.



Design Data


Length: 500 centimeters
Span: 220 centimeters
Diameter: 54 centimeters

Weight (Empty): 525 kilograms
Take-off Units: 440 kilograms
Main Stage Fuel: 88 kilograms
Main Stage Oxydizer: 336 kilograms
Main Stage Compressed Air: 18 kilograms

Explosive (Weight): 160 kilograms
Launching Weight: 1,570 kilograms
Weight at Target: 685 kilograms



Power Plant

A. R-3f Liquid Propulsion Unit: The R-3f liquid propulsion unit requires fuel tanks carrying 336 kg of Salbei, 88 kg of Visol and 18 kg of compressed air at a pressure of 250 atmos to provide pressure feed to the combustion chamber.



B. R-3p Solid Propellant Unit: The R-3p solid propellant unit utilizes 5 rods of diglucol dinitrate weighing 90 kg each, making a total weight of 450 kg.



Design Data (R-3f)

Launching Altitude: Angle

Total launching impulse: 105,000 kg/sec
Velocity at end of combustion: 410 m/sec
Velocity at target: 400-200 m/sec

Take-off units: 2 dry powder rockets
Take-off unit impulse: 25,000 kg/sec
Take-off unit thrust: 28,000 kg/sec

Main stage rocket impulse: 80,000 kg/sec
Main stage burning time: 45 sec
Main stage thrust: 1,700 to 2,300 kg



Control System

Since remote control radio roll stabilization was found to be unsatisfactory, it was decided that Rheintochter 3 would be allowed to rotate at the rate of one revolution per second about its longitudinal axis, just as X-4 rotates.  Since the X-4 gyrocommutator system for converting control impulses to the proper control surfaces in turn was available, it was thought that this system could also be used for Rheintochter 3.

The combination radar tracking and remote control system "Elsass" or possibly "Brabant", the decimeter version, was to be used for guiding the flight of the Rheintochter 3, just as proposed for Rheintochter 1.  However, the "Elsass" development was not far enough along to permit field tests to determine whether it was satisfactory.



Warhead and Fuzing

In the liquid propulsion version R-3f, the warhead is carried between the Salbei and Visol fuel tanks in that section of the main fuselage to which the main fins are attached.

In the solid propellant version R-3p, the warhead is located farther forward between the control compartment and the propelling charge.  The warhead consists of 150 kg of high explosive.

The fuzing system for Rheintochter 3 had not been finally decided upon.  Several plans were under consideration, all of which contemplated the use of a complicated fuzing system, which would not only serve to detonate the missile, but also take care of detaching the ATO units after one second and igniting the main jet.  In addition, of course, a time feature would be embodied to detonated the missile after 50 seconds in the air so that it would not fall and explode on friendly territory.  The Rheintochter 3 was also to be fitted with an impact fuze and a proximity fuze of some sort, either acoustic, infra-red, or radio.  Among the proximity fuzes considered were "Kranich", "Kakadu", "Marabu", "Fox", and several others.

As pointed out, plans were also under way to utilize some sort of homing device in Rheintochter, but these plans were still in a very nebulous state.


Auxiliary Equipment


Like Rheintochter 1, Wasserfall, and the other guided AA rockets, Rheintochter 3 requires a great deal of auxiliary ground equipment, such as computers, optical gear, range finders, etc, for remote control purposes.



Launching Equipment

The launching equipment for the Rheintochter 3 is identical to that used by the Rheintochter 1.




Next Time: Rockets (Part 11)


Source: German Explosive Ordnance Vol. 1: Bombs, Rockets, Grenades, Mines, Fuzes & Igniters

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