DESCRIPTION. The F-25 is one of the "Feuerlilie" series of rocket-propelled guided mis-sile which the LFA (Luftfahrtforschungsanstalt Hermann Göring e.V.) located at Volkenro-de/Braunschweig, Germany, was developing in order to obtain aerodynamic data in the near sonic and supersonic regions. Although the primary purpose of the Feuerlilie series development was obtain aerodynamic data, some thought was also being given to the possibility of using certain models, such as the F-25, for actual production as a weapon of war. This model has a fuselage 2 meters in length and 25 cm maximum diameter with two wings attached to the midbody. The main wing span is 112 cm. The rocket drive is of the solid propellant type. The F-25 was a ground-launched rocket, which could reach on altitude of 3,000 meters with a horizontal range of 5,000 meters.

HISTORY OF DEVELOPMENT. Development work on F-25 was started in the spring of 1943 by Dr. Gerhard Braun of LFA. The fuselage was built by the Ardelt Werke, located in Breslau. About 20 models were built, of which 10 or more were tested sucessfully at Leba, near the Ostsee in Pomerania. However, the low maximum speed of 220 meters per second makes the results of no great significance. Development work was stopped in the fall of 1944.

CONCLUSIONS. Since the Feuerlilie F-25 was primarily a research project, it is of inter-est from an historical standpoint only.

DETAILS. Airframe. The airframe of the F-25 consists of a 2-meter fuselage to which two main wings are attached near the mid body. The wings are provided with ailerons to give roll stabilization in flight. (See fig. 200.)

POWER PLANT. The power plant used for F-25 is of the solid propellant type RI 502 and was built by Rheinmetall-Borsing.

Weight of propellant: 17.5 kg.
Burning time: 6 sec.
Thrust: 500 kg.
Total weight of missile: 115 kg.

To produce an even thrust for aerodynamic data purposes, a blowoff valve located bet-ween the two venturis is porvided. This valve opens at a pressure of 100 atmos.

CONTROL SYSTEM. The roll stabilization system used for F-25 was the same as that used for Hecht; i.e., one gyro was installed with its axis perpendicular to the missile axis in such a way as to increase the effective moment of inertia of the missile in roll. If a disturbance sets up a roll moment, the gyro would tend to precess, which would in turn cause the ailerons to reverse the roll of the missile. When no damping was provided with this system, excessive roll occured. A mechanical dashpot was added to remedy this condition.

The main reason for the choise of this type of gyro control was that the weight and space requirements were less than for the conventional available auto-pilot devices. The gyros were procured from Kreiselgerät, Berlin.

WARHEAD AND FUZING. Since the F-25 was only a test model, no warhead was provi-ded.

A Rheinmetall Borsig time fuze was used to ignite the flares mounted on the wing tips to insure satisfactory tracking of missile in flight.

LAUNCHING. The F-25 was launched from the ground at an angle of 10° - 30° to the vertical.

Figure 200 – Feuerlilie F-25; Feuerlilie F-55