The Steamboating Forum

Hello,

i have built a steam whistle for my steam boat project. With a diameter of 30 mm and a overall length of 275 mm it is the biggest of my ring split whistles.

The bell is made from a brass tube and a cap of gunmetal.

The base is made from four parts.

Two parts of the base form a chamber in which the steam settles and the first condensate is separated.

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Dietrich

Neat! Did you bore the holes w/ a ball end mill? I've had problems w/ grabbing with partial holes like that.

- Bart

Hi Bart,

first i have drilled the six holes upside, then drilled a pilot hole downside. Then it was turned out to the final dimensions on the late.

The steam delivery disc has a bit different design, it is much thicker and has a 30° slope on the outside. So the steams Speed increases four times and the flow is laminar. So the whistles tone is clear.

The base and the bell are silver soldered.

The slot is very small, only 0,1 mm so the steam consumption is very moderate, so it is possible to test the whistle with my little test boiler.

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Dietrich

Hello,

last weekend i have tested the whistle with steam and adjusted the distance between the base and the bell to get a clear tone.

How it can sounds you can hear in this video.

https://youtu.be/6jP3eD-3tC8

https://www.youtube.com/watch?v=6jP3eD-3tC8


Hope it enjoys
Dietrich

Of course; this is silver soldered togther ! I don't know why I didn't see that immediately.

Very nice sound on the video, and amazing for so little steam consumption. The whistle on our Otter was made by Cedric Witham back east; it can be blown by mouth (~0.2 bar). The one on Rainbow consumes 10x the steam and is being replaced during the replumb.

- Bart

Very good work. The sound is clear.

Anyone thinking of making a whistle and need brass tube, search eBay for ''bar rail''

My limited experience with whistle making shows that they have a pressure range they will operate, the antique whistle on my steamcar can be operated on breath, but just squeals at pressures above 60 pounds, I had to mount a needle valve on it to try to limit the flow. It only operates at favorable pressures and it's nearly impossible to adjust. The gap between the languid plate and the outer shell is what determined the pressure on the whistle I made for the tug, it cannot be sounded on pressure below 30 psi. Higher pressure = narrower gap.They are a science unto themselves.

In Dietrichs picture showing the opening with the languid plate, one can see the gap. It is also important that the top of the plate is flush even with the shell to direct the curtain of gas straight up into the sharp bevel edge of the bell. His looks perfect.

It operates by filling the bell chamber with gas at pressure above atmospheric. As the gas tries to escape over the sharp edge it cracks. The length and volume of the chamber determines how many times per second this happens, larger chamber means lower frequency and a lower note. The larger the chamber, the longer it takes for the whistle tone properly as it takes longer to pressurize.

Hello,

this sketch shows the dimensions of the whistle.

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Dietrich

Hello,

i have tested the tone with soundcorset. The program is easy to handle and the screen is clear.

The whistle produces a tone of 493 Hz (B4). That is a bit higher than the planned 440 Hz and is due to the somewhat shorter inner bell length (180 mm instead of 190 mm).

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Dietrich

Dietrich,

Thanks for sharing your drawing.

Hi Ron,

I liked doing it. If someone would like to have the complete set of drawings, please write me a PM.

I have changed the title of the blog because another steam whistle is being built in my workshop, which I would like to show here. It is a single tube three tone one. The basic design is based on an article by D.A.G. Brown. I increased the diameter to 40 mm.

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Dietrich