Author Topic: WW&F No. 9 - Official Work Thread  (Read 495520 times)

Hansel Gordon

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Re: WW&F No. 9 - Official Work Thread
« Reply #465 on: April 07, 2015, 01:23:53 PM »
Since there seems to be confusion,

The wider the whistle, the louder it gets.

The longer the the whistle, the deeper it gets.

Short & chubby= high pitched (#9's whistle)
Long & skinny= deep pitched

Keith Taylor

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Re: WW&F No. 9 - Official Work Thread
« Reply #466 on: April 07, 2015, 01:40:36 PM »
Since there seems to be confusion,

The wider the whistle, the louder it gets.

The longer the the whistle, the deeper it gets.

Short & chubby= high pitched (#9's whistle)
Long & skinny= deep pitched
Not quite Hansel....width does not make it louder. It affects the timbre or "character" of the sound. The whistle's "loudness" is a function of pressure.
The length of the resonator determines the musical note played. The longer the bell the lower the note. Long and skinny will give a low pitch.....but a thin nasal sound. Long and a wide bell gives the deep resonant note. Short and wide gives a high pitched but resonant note.
But to return to your premise...the diameter of the bell doesn't affect how loud it is. The reason you can "quill" a whistle to change the volume is because you are changing the pressure admitted to the whistle by limiting the amount of steam entering the whistle.
Keith
« Last Edit: April 07, 2015, 01:47:31 PM by Keith Taylor »

Keith Taylor

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Re: WW&F No. 9 - Official Work Thread
« Reply #467 on: April 07, 2015, 01:52:20 PM »
Here is an example of a long bell small diameter whistle.
https://www.youtube.com/watch?v=Mfl3hAveRoE
You can hear it is playing a low musical note....but it has a thin nasal sound.
Not the deep rich sound you might hear in a steam boat.
Keith

Dwight Winkley

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Re: WW&F No. 9 - Official Work Thread
« Reply #468 on: April 07, 2015, 02:41:41 PM »
AHHH!  A old time trolley car whistle.

dwight

Keith Taylor

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Re: WW&F No. 9 - Official Work Thread
« Reply #469 on: April 07, 2015, 03:59:29 PM »
AHHH!  A old time trolley car whistle.

dwight
Yes...a Westinghouse "trombone" whistle. Interurbans and MU cars like the Pennsylvania RR's MP-54's used these whistles.

Keith

John McNamara

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Re: WW&F No. 9 - Official Work Thread
« Reply #470 on: April 07, 2015, 04:08:15 PM »
What I think has been missing so far is a discussion of harmonics, i.e. multiples of the fundamental frequency of the whistle. If the fundamental frequency is 1000 Hertz, there are also some other frequencies present, such as 2000, 4000, etc. These are all pressure waves that need some space to do their thing - i.e. resonate. A wider whistle will provide the space for more pressure waves of varying harmonic frequencies and hence a "richer" tone. A narrow whistle will only provide space for the fundamental frequency without any overtones - hence a shrill sound. The foregoing is a bit of a hand-wave, but I believe it is correct.

Indeed, as Hansel says short and stubby = high pitched, and long and skinny = deep pitched, but I'll add that wide = rich and skinny = shrill.

-John

Wayne Laepple

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Re: WW&F No. 9 - Official Work Thread
« Reply #471 on: April 07, 2015, 04:40:04 PM »
Here's a perfect example of what John is saying above. It's Norfolk & Western No. 1281. The N&W's standard freight "hooter" was made from a piece of superheater flue -- just a hunk of steel pipe. But check out the overtones and undertones demonstrated by the engineer's wrist action on the whistle lever. And as a bonus, listen for the Doppler Effect as the engine passes.
https://www.youtube.com/watch?v=zBm-ONvNhS4

Keith Taylor

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Re: WW&F No. 9 - Official Work Thread
« Reply #472 on: April 07, 2015, 05:09:41 PM »
Here's a perfect example of what John is saying above. It's Norfolk & Western No. 1281. The N&W's standard freight "hooter" was made from a piece of superheater flue -- just a hunk of steel pipe. But check out the overtones and undertones demonstrated by the engineer's wrist action on the whistle lever. And as a bonus, listen for the Doppler Effect as the engine passes.
https://www.youtube.com/watch?v=zBm-ONvNhS4
Wayne....you are not hearing overtones and undertones; you are hearing pitch modulation when the engineer quills the whistle. There certainly are a LOT of harmonics in that whistle and that comes from the steam sheet hitting the mouth of the resonator. A smoother surface would reduce the harmonics. In organ pipes when you want to eliminate the harmonics they glue leather to the lip of the pipe to eliminate the "bite."
 Again my area is pipe organs and having a bigger cross section doesn't necessarily mean more harmonics. A 6" diameter diapason is full of harmonics, yet the same 6" diameter in a Tibia Clausa has virtually no harmonics.
Keith
P.S. I think we are getting a little far afield of the topic No.9! I suggest that Ed move the whistle topic elsewhere. It is a very interesting topic....but not really on topic here.

Ira Schreiber

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Re: WW&F No. 9 - Official Work Thread
« Reply #473 on: April 07, 2015, 05:52:47 PM »
Besides, who gives a hoot...........(ducks again)

Hansel Gordon

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Re: WW&F No. 9 - Official Work Thread
« Reply #474 on: April 07, 2015, 07:32:35 PM »
Hey Keith,
I was just trying to dumb it down for those who aren't into whistles.

Jason M Lamontagne

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Re: WW&F No. 9 - Official Work Thread
« Reply #475 on: April 07, 2015, 07:37:52 PM »
There is a topic in work and events called new whistles for 9 and 10... Perhaps it should move there. 

I look forward to hearing no 9's whistle- Eric basically finished it up today.  Really, with the work that went into it and the fact that it reproduces the historical sound (as much as we know how anyway), it'll have to be REALLY bad to deserve any drastic changes.

See ya
Jason

Stephen Piwowarski

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Re: WW&F No. 9 - Official Work Thread
« Reply #476 on: April 07, 2015, 11:46:40 PM »
I'm looking forward to hearing this historic sound recreated in all its glory. I've been enjoying this topic from afar and love all of the good information that has gone into it. One thing that I believe has yet to be mentioned is the height of the cut up- that is the distance of the bottom of the bell away from the windway. The higher this cut up is the lower the fundamental frequency or pitch of the whistle. This whistle appears to have a fairly high cut up. That, paired with a relatively short, stout bell should produce a sound rich in overtones, that can be feathered with great variation in pitch. I can't wait.

Stephen Hussar

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Re: WW&F No. 9 - Official Work Thread
« Reply #477 on: April 09, 2015, 09:10:10 AM »
Not meaning to derail the whistle conversation, these are just a few shop pictures around No 9.




Dave Crow

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Re: WW&F No. 9 - Official Work Thread
« Reply #478 on: April 09, 2015, 10:53:55 AM »
Forgive my ignorance, but what holds the tapered wedges in place?

Keith Taylor

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Re: WW&F No. 9 - Official Work Thread
« Reply #479 on: April 09, 2015, 11:01:48 AM »
Forgive my ignorance, but what holds the tapered wedges in place?
Friction....just like a Morse Taper holds a drill chuck onto a drill press or a Jacobs taper holds the drill chuck in place on a portable electric drill.

Keith