Photos: Howard Museum, Str. Natchez, and General Jackson to boot!

Jon,

What'd you and your father think of the little minature steam calliope aboard the GENERAL JACKSON? I played it once and heard it twice. It featured 44 minature scaled whistles (the smallest under one inch tall the tallest barely ten inches tall) and was scaled 2 octaves above middle "C" and ran 3 more octaves above.

It was built by Arthur Davis and originally was operated on steam aboard the boat (about 5 psi if I remember right). Rarely did it ever play and Opryland USA (the owners) lost interest in it after several mechanical problems cropped up. David Morecraft at one time was in contact with the owners to build a steam calliope for them to replace it. Too bad they didn't agree on an instrument for the boat suffers with out a true calliope, in my humble opinion.

To say the calliope aboard her is a keyboard-operated dog whistle would be a compliment!

~Travis~

(Un)fortunately, we never heard the thing play, only catching a few glimpses of its minuteness. The whistles are, to say the least, of laughable proportion!

What website, Jon? What web site, Jon? What web site, Jon? Is that enough words?

Alan Bates;6158 wrote: What website, Jon? What web site, Jon? What web site, Jon? Is that enough words?

Jon had it "hyperlinked"...

Here it is...

http://personal.stthomas.edu/jdtschiggfri/steam/

That calliope is certainly smaller than I would like, but don't be fooled by its diminutive proportions and low pressure of 5 PSI. It could still have the output of a calliope on 50 PSI, but of course at about an octave or two higher than normal. I have designed whistles for operation at 15 PSI that actually outperform whistles blown at 150 PSI.

Jon Tschiggfrie;6152 wrote: (Un)fortunately, we never heard the thing play, only catching a few glimpses of its minuteness. The whistles are, to say the least, of laughable proportion!

Yes, the output is one thing...but if the tonal quality is less than the desired effect (screechier and less tolerable than a "normal" calliope) what is the advantage of better output at a lower pressure? For the end result is not at all desirable.

Output and operating pressure are independent of a whistle's working length and frequency. Yes, I would prefer a more traditional frequency range myself for an instrument as loud as a calliope.

The point I am making is that the whistles of a traditional sounding calliope can also be made to fully blow at a much lower pressure while maintaining the same output by widening the steam slit at the bowl with the inverse square of the pressure. This maintains the flow rate to the bell in CFM.

The output of a whistle is much more dependent on the flow rate rather than the actual operating pressure, as most people tend to believe. The cutup height of the bells above the bowls would remain the same. Reducing the operating pressure of a whistle while maintaining the flow rate makes the conversion of steam flow to acoustical energy much more efficient (without changing the sound).

I have observed that a number of calliope whistles use paper thin slits and flattened bowls. This only reduces their output for a given pressure, as it limits the flow rate. By using slits of three times the width and deeper bowls, they would produce the same quantity of sound using only 1/9 the pressure.

What's the point of all this? You could get the same amount of sound using only a fraction of the input power-a good point to consider on boats without a large boiler. The quality of the sound is also unaffected and you still have an all acoustical instrument.

Travis Vasconcelos;6164 wrote: Yes, the output is one thing...but if the tonal quality is less than the desired effect (screechier and less tolerable than a "normal" calliope) what is the advantage of better output at a lower pressure? For the end result is not at all desirable.