They had rotating-systems. There looks to be a system of speed-reducing gears in the area between the rotor and engine. Did they have a clutch for that too?
Anyway, I remember a video of Jielong shooting a video of a Chrysler that was off. I cannot find it, though. You asked for footage.
There's a half-hour long video called "The Day Called X," which was made in 1955 and has footage of Chrysler sirens rotating. I think the sound is dubbed over though.
The video shows what it would be like if an H-bomb attack on Portland, Oregon was about to take place. There is a shot of a siren rotating at the beginning, somewhere in the second half, and at the end.
The sound is most likely dudded. It sounds more like a Sterling M but it could be speeded up footage of the Chrysler. There's also just after they show the guy roll back under the truck he's working on a few good shots of an IBM double projector 4030 fire alarm horn. The sound you hear while the horn is shown and while that office is evacuated is the actual horn sounding.
China has the only two that we know of. One has been converted to use an electric motor, and I think the other has a different engine in it than what it originally used. Not sure on that one though.
Nothing but a low-down, double-dealing, backstabbing, larcenous perverted worm!