Whistle

[sabin]

Some questions around the track about how to modulate a steam whistle like the full size locos. Most of our models seem to be on or off. Is it the whistle or the valve? If the valve can it be modified? Any ideas?
JIm

[Miserlou57]

I second this question.

I'm dealing with the final touches on my LE American, and the whistle is uhh, ... okay. I've noticed some locomotive whistles in the hobby that sound fantastic, and others just sound awful. Considering I'm just a hardcore foamer and a picky SOB, I really want something that sounds great and his highly 'playable'. I've got Nelson's book, Kozo's A3 book, and an article by Richard B. Bagley from 1953 entitled 'Fools Dive in where the Angels Know Better ..!!" about steam whistle construction.

Some of you probably have a bunch of experience with what works and what doesn't. Have any of you had success with what these books/articles recommend? Does anything work better?

Thanks,
Derek

[Bill Wilkins]

Some whistles simply have to be "tuned". My experience is with the Coles whistle I have on the Mogul. I tuned it by screwing the tube out to change the width of the opening. Worked great on air, then when I tried it on 100lbs of steam it sounded terrible. So I adjusted it little by little and brought it to a very shrill whistle like it should be.
The tube is threaded so it can be screwed clear off if needed. Anyhow with the tube threaded and the ability to adjust it up or down fine tunes the whistle. If you miss adjust, it will sound terrible. I think a lot of whistles suffer from a lack of necessary adjustment.

Bill W

[sabin]

Thanks guys
What I'm talking about is to modulate, or alter the volume of......As in ooOOO-ooOOO-OO- oooOOOOooO
This should probably be in the Live Steam post but I don't know how to change it.
Jim

[Fender]

Hi,
What you're speaking of is called "quilling" the whistle. Varying the pressure to the whistle changes both the pitch (frequency) and loudness of the whistle. This ability is what a "whistle artist" is using to advantage.
Unfortunately, physics of whistles is working against the live steamer. The pitch of a whistle is a function of it's length, with lower notes requiring a longer whistle. But the ability of a whistle to be quilled depends on the ratio of its length to it's diameter. The long, skinny whistles like we commonly use don't have as much ability to be quilled as a fatter whistle of the same length. This ratio of length to diameter is called the "scale" of the whistle. The Yahoo Steam Whistles group has a lot of technical information on their design and properties.
Since there is no room on our locos for a six-inch diameter whistle, my only suggestion is to go with a higher-pitched whistle, one with a smaller length-to-diameter ratio, if you want to be able to quill it.

[Bill Shields]

The somewhat 'standard' whistle valve sold by man vendors will allow you to change VOLUME if you are careful pulling on the actuating arm.

The trick is that when you first start pulling, the whiste is frequently cold and gurgles a lot.

I find that I need to pull on the arm just enough to let steam through to heat things up, BEFORE opening just a little bit more to make it sound.

I have drainage weep holes and self-draining pipe, but still, a COLD whistle tends to condense at first.

As suggested by others, it is somewhat of an art as much as a science.

[STRR]

Fender, your comments on quilling and the scale ratios are right on the money. I believe there is another major factor and that is the valves. Larger valves tend to be easier to quill with than the smaller valves used in most live steam applications. I believe this to be mostly due to the ratio of valve to seat size related to steam pressure.

In terms that I can understand: Larger valves are easier to open/close (throttle) slowly whereas smaller valves tend to "pop" open and closed without much throttling ability. Just my angle on the problem.

The answer: Find someone with a whistle you like and ASK. Most of us are happy to share all the details of manufacturers, vendors, installation, and many more details.

Good Luck,
Terry

[FLSTEAM]

Any easy solution to quilling is to use a ballanced valve. A ballanced valve has a pilot valve with a small port thru the center of the main valve. This tends to equallize the pressure on both sides of the main valve. The main valve can be gently opened and closed ( quilled ).

Here is a pic of a ballanced valve on a 15" ga. Cagney.
John

[Fred_V]

i have found 2 major issues with live steam whistles.
1. Nelson's book is wrong. the OD of the steam slit must be no larger than the ID of the whistle bell.
2. the outlet of the valve is usually too big allowing the whistle overblow. this sends the sound to the second octave and it shrieks.

i have a good sized whistle with a 1 1/2" bell and a 1/4" ball valve to control it but i have reduced the outlet of the valve to 1/8" pipe thread. i can quill the stew out of the whistle. on my Chloe i have a 1" dia. bell that has a 1/4" copper tube feeding it (may be 3/16" tube). it quills nicely too.

in Live Steam recently there is a very good article on whistle making and he has a formula for calculating who wide to make the steam slit. i haven't had a chance to play with that yet but i suspect that is also a factor in quilling ability of our whistles. it is some what of a black art to make a good whistle and requires a bit of fussing to get it right but it can be done on any size hooter.

[Greg_Lewis]

I had a chat with Jack Bodenmann about this once and he said one factor is the valve. The head, or the part that moves up and down away from the seat, needs to be tapered more than a standard valve. Try making a new one of those.

[Bill Shields]

AGREED with Jack and Gregg.

The 'whistle valves' being sold as such have nice, tapered seat lifting plugs that make such quite doable - as long as you are not 'heavy handed' when pulling the cord.

[Fender]

I agree completely with Fred_V's point about the location of the slit. However, the overblowing problem can be cured by making the slit width narrower for higher pressures. Lower steam pressures require a wider slit. There is a formula for calculating the slit width from the steam pressure on the Steam Whistles site.