Feuerlilie (“Fire Lilly’) was actually not one, but two surface-to-air missiles – the F-25 and F-55 – developed by Rheinmetall-Borsig.
The F-25 was a single-stage, solid-fuel SAM that had a range of 4.8 km and the maximum altitude of 3km. The F-55 was a two-stage missile (first stage – solid-fuel, the second stage – liquid fuel) and had a range of 12km and the maximum altitude of about 10 km.
Although it was designed as if it was a SAM (with provisions for warheads and fusing), F-25 was actually a research project into supersonic speed rather than an operational weapon. F-55 – developed based on the results of F-25 research and testing, was a full-fledged anti-aircraft missile.
Carrying a 100kg fragmentation warhead, it was supposed to be manually guided to its target and detonated within 10m of the bomber using a proximity fuse.
However, it suffered the same problems as the Enzian did – with the guidance system and the rocket motor. And thus met the same end – in January of 1945 the project was discontinued in favor of other projects.