Poor Whistle Sound

[Daniel]

Hello all,

I'm looking for some ideas as my whistle is a bit of a limp noodle and I'm not sure why. I have a 5" polly 1.
It has always been a bit of a poor sound and never really makes a "toot" or clear whistle but makes the sound of a safety release valve lifting!
Other engines make a very impressive "toot toot" with a clear and definitive sound!
The whistle is underneath the running board just behind my ashpan so it is hidden. It is horizontal with the hle facing down to have any water escape, could it be this? My other thought was that the valve may not be letting enough steam through to make a good sound?

What do you think?

Kind Regards

Daniel

[Nigel Bennett]

It could well be the whistle itself. I'd borrow one that does work from somebody and try that.

[jma1009]

i have spent some time investigating miniature steam loco whistles, and wrote a paper on the subject some years ago.

firstly, the steam line and size of valve is as important as with injectors. the 'speed' of the steam as it passes the 'languid' or disc is critical. some whistle valves have ridiculously small passages, and some pipes to the whistle are ridiculously small, and the pipe should be as short as possible with a downward fall in all places.

your whistle with the mouth facing downwards is correct. the whistle should have a slight upwards tilt so no water collects at the 'stopped' end.

if the above is all ok, then the problem is with the whistle itself. this is quite a lengthy subject, but in short the whistle mouth may not be wide enough, and too long. try the whistle on compressed air and slide a piece of card wrapped round the whistle from the stopped end towards the disc slowly reducing the height of the mouth. the languid or disc should be level with the bottom opening of the mouth if not a few thou above. a small error here in silver soldering the disc is critical, but can be easily remedied by filing the bottom edge of the mouth if the disc is too low. if the disc is too high scrap the whistle. there is a relationship between the diameter of the whistle tube and its length with a given operating pressure (or more correctly the speed of the steam). the width of the gap between whistle tube and the cut out of the disc also has an effect (i have found about 5 thou to be ok for our miniatures).

LBSC's 'Shop Shed and Road' has a chapter on whistles and how to 'sound' them, and whilst LBSC doesnt go into the theory, he is spot on at how to achieve the correct result!

btw if the mouth is too high (avoid a 'V' slot, and a 'square' slot is quite ok), soft solder a piece of shim around the tube to reduce the height of the mouth.

2 days ago i altered a bell mouth whistle which is for a 7 1/4"g loco and was a commercial item. the whistle produced a sound like you have described...awful! i raised the height of the disc and lowered the 'bell' (easy on this type of whistle) and the whistle is now loud and clear!!

getting the 'right' note for a certain prototype is another matter entirely!

hope this is of some help and happy experimenting!

[daveburrage]

I made some hissing (rather than whistling) type whisles. Got a big improvement when I followed the drawing exactly and used the very thin wall tube specified rather than a bit the right OD I had lying around.

As usual - if all else fails - read the drawing!

regards

Dave Burrage

[Tony K]

Daniel, have sent you a personal message which should help.

[3.5inch]

I had the same problem with the crappy whistle on my new 3.5" Maisie Atlantic. The whistle was in the same position yours is. When I moved the whistles position so the hole wasn't facing down it produced a clear note.