Engineering challenge: new kind of steam siren.

[Daniel]

Here's something my anachronistic mind dreamed up the other day. A steam siren designed for compressed air. Instead of having a rotor driven directly by steam pressure, it would be turned by a high-speed air motor. The finless, HLS-style rotor would sit at the bottom of a projector horn, like a diaphone piston, but would rotate and chop a stream of compressed air from the main air supply, as well as exhaust air from the motor. By regulating the air supply to the motor, the pitch can be raised and lowered, unlike a steam siren.

You're welcome to build one and get rich off the idea (yeah, right!) if you make one for me.