My next model project is a 1/24th scale calliope truck, and I’ve been poking around on the web to see what a calliope actually looks like. It’s just a row of steam whistles with their valves hooked to a keyboard. No biggie, except for the tedium of making twenty-five valves–but I’ll make one and then cast 24 copies.
But it occurs to me: Both whistles and pipe organs use a compressed gas to create sound. But how does the operating principle of a whistle differ from that of an organ pipe?
size of the toot.
steam calliope is big whistles.
There’s also the physical difference between, say, a policeman’s whistle, where all the air comes out the fipple, and a steam whistle/calliope/recorder, where some of it also goes up the tube and out the top. That’s going to give a larger resonating chamber for vibrating air, but that’s about all I’ve got for an explanation.
There are a number of different categories of organ pipe - some of them are just big whistles, others have reeds or other voicing mechanisms.
I once made a few organ pipes (very small ones) It is usual to vary the length to get notes, but an organ pipe can be half the length if it is closed at the top. Whistles etc usually have an open end like the higher notes of organ pipes.
steam would be at higher pressure than pumped air. also the steam would need to be vented and/or condensed.
i think that reed pipe organs used in air pipe organs might corrode and not work long. closed pipes might not vent enough pressure.
If you blow on an organ, it doesn’t necessarily make a sound. 