Mamod spring whistles - and perhaps why they are so bad?

old_timer · Mamod spring whistles - and perhaps why they are so bad?

Having been reminded by RASDVs videos of just how bad the modern day Mamod spring whistle is, I thought I'd take a look as to what possibly is the cause of the bad sound quality, as they seem to be worse now than when they were first introduced.

I discovered that there was a design change.

The top whistle here is the original design from the early 1970s and seals via a conical shaped lower end without any rubber seal. This type of whistle in my experience gives a much better, louder whistle.

The lower end was modified in the early 1980s to a flat disc that seals with the aid of a rubber 'O' ring. This design still remains today I believe.

Not sure how that would affect the sound quality though - perhaps it's just that they changed the shape of the opening that makes the Mamod whistle so bad.

This photo is a little mis-leading due to the variation in orientation of the 2 whistles, but I checked dimensions of the whistle body, and whilst both are the same height, the early version (on the left) was 7.90mm outside diameter whilst the revised later version is 8.00mm.

Remembering my basic physics, this change in size of both the body housing diameter and aperture size probably is the reason for for degradation in sound quality.

Proof, if proof were needed, of the truth in the old adage:
"If it ain't broke, don't fix it!"

oldstuff

As you say OT, different opening might be the cause. That would be my guess, too.
If plunger and/or spring were different in size, it would take up a different amount of
volume inside the whistle body and could affect the sound, as well.

If I were to make my own, I'd probably go for the plunger type over the handle-valve ones.
Seems easier, to me.

Spokesmann

The turned brass ones look better - but get so hot when in operation - I used to have wooden sleeves fitted on one SE3 with them . . .