The whistle consists of the following main parts, as seen on the drawing: the whistle bell (1), the steam orifice or aperture (2), and the valve (9). Ommundsen, Peter (2004). "Whistle mouth area and lip height in relation to manifold pressure". Horn and Whistle (103): 7–8. Beginning in 1869, [17] steam whistles began being installed at lighthouse stations as a way of warning mariners in periods of fog, when the lighthouse is not visible. 10" diameter whistles were used as fog signals throughout the United States for many years, [17] until they were later replaced by other compressed air diaphragm or diaphone horns. Steam quality – The dryness of steam provided to a whistles is variable and will affect whistle tone frequency. Steam quality determines the velocity of sound, which declines with decreasing dryness due to the inertia of the liquid phase. The speed of sound in steam is predictable if steam dryness is known. [45] Also, the specific volume of steam for a given temperature decreases with decreasing dryness. [46] [47] Two examples of estimates of speed of sound in steam calculated from whistles blown under field conditions are 1,326 and 1,352 feet per second. [48] Chime whistle – two or more resonant bells or chambers that sound simultaneously. In America, railway steam whistles were typically compact chime whistles with more than one whistle contained within, creating a chord. In Australia the New South Wales Government Railways after the 1924 re-classification many steam locomotives either had 5 chimes whistles fitted (this include many locomotives from the pre 1924 re-classification, or were built new with 5 chime whistles. [19] 3-chimes (3 compact whistles within one) were very popular, as well as 5-chimes, and 6-chimes. In some cases chime whistles were used in Europe. Ships such as the Titanic were equipped with chimes consisting of three separate whistles (in the case of the Titanic the whistles measured 9, 12, and 15inches diameter). The Japanese National Railways used a chime whistle that sounds like a very deep single-note plain whistle, because the chords where just accessed in a simple parallel circuit if the whistle trigger is pulled down. [20]

Steam whistle - Wikipedia

A multi-bell chime whistle installed at the Standard Sanitary Manufacturing Company in 1926 was composed of five separate whistle bells measuring 5 x15, 7 x 21, 8x 24, 10 x 30, and 12 x36 inches, all plumbed to a five-inch steam pipe. [94] Ommundsen, Peter (2005). "Effect of mouth size on frequency of a single bell chime whistle". Horn and Whistle (110): 29–30. Frequency and distance – Sound pressure level decreases by half (six decibels) with each doubling of distance due to divergence from the source, an inversely proportional relationship. (Distinct from the inverse square law, applicable to sound intensity, rather than pressure.) Sound pressure level also decreases due to atmospheric absorption, which is strongly dependent upon frequency, lower frequencies traveling farthest. For example, a 1000Hz whistle has an atmospheric attenuation coefficient one half that of a 2000Hz whistle (calculated for 50 percent relative humidity at 20 degrees Celsius). This means that in addition to divergent sound dampening, there would be a loss of 0.5 decibel per 100 meters from the 1000Hz whistle and 1.0 decibel per 100 meters for the 2000Hz whistle. Additional factors affecting sound propagation include barriers, atmospheric temperature gradients, and "ground effects.” [73] [74] [75] Acoustic length [76] or effective length [77] is the quarter wavelength generated by the whistle. It is calculated as one quarter the ratio of speed of sound to the whistle's frequency. Acoustic length may differ from the whistle's physical length, [78] also termed geometric length. [79] depending upon mouth configuration, etc. [30] The end correction is the difference between the acoustic length and the physical length above the mouth. The end correction is a function of diameter whereas the ratio of acoustic length to physical length is a function of scale. These calculations are useful in whistle design to obtain a desired sounding frequency. Working length in early usage meant whistle acoustic length, i.e., the effective length of the working whistle, [80] but recently has been used for physical length including the mouth. [81] Loudest and largest whistles [ edit ]

A whistle has a characteristic natural resonant frequency [30] that can be detected by gently blowing human breath across the whistle rim, much as one might blow over the mouth of a bottle. The active sounding frequency (when the whistle is blown on steam) may differ from the natural frequency as discussed below. These comments apply to whistles with a mouth area at least equal to the cross-sectional area of the whistle. Serway, Raymond A. (1990). Physics for Scientists and Engineers. Philadelphia: Saunders College Publishing. ISBN 0-03-005922-4. Turbines engraved in the laser - rather than sanding them down, I placed a circle of engraving over the blades (watch your laser settings, make sure it's set to engrave). Elliott, Brian S. (2006). Compressed Air Operations Manual. New York: McGraw-Hill. ISBN 0-07-147526-5. The sounding chamber of a whistle installed at the 1924 Long-Bell Lumber Company, Longview, Washington measured 16inches diameter x 49inches in length. [90]

Acme Siren – Thomann UK

Each siren has to have a spinning wheel or paddle to work. We find there are 4.5.6 angled holes in the wheel ( or rotor ), each acting like an individual whistle, the force behind the wheel ( blowing ) accelerating the wheel in turn driving the pitch higher and higher. After a lot of use, the original version suddenly jammed solid and wouldn't do more than hiss. A lot of shaking and poking things through holes eventually dislodged a single turbine blade - it had snapped off. Once the snapped blade was gone, though, the turbine continued to work as before, with very little difference in the sound. Ross, David (2004). The Willing Servant: A History of the Steam Locomotive. Tempus. p.42. ISBN 0-7524-2986-8.

Siren horn with 7" bell

Außerlechner, Hubert J.; Trommer, Thomas; Angster, Judit; Miklós, András (2009-08-01). "Experimental jet velocity and edge tone investigations on a foot model of an organ pipe". The Journal of the Acoustical Society of America. Acoustical Society of America (ASA). 126 (2): 878–886. Bibcode: 2009ASAJ..126..878A. doi: 10.1121/1.3158935. ISSN 0001-4966. PMID 19640052. Atchison, Topeka, and Santa Fe Railway 1925 engineering drawing, published 1984, Horn and Whistle 13:12-13. a b Ommundsen, Peter (2003). "Effects of pressure on whistle frequency". Horn and Whistle (101): 18. Lerner, L.S. (1996). Physics for Scientists and Engineers. Physics Series. Vol.1. Jones and Bartlett. ISBN 978-0-86720-479-7. Helmholtz whistle – a whistle with a cross-sectional area exceeding that of the whistle bell opening, often shaped like a bottle or incandescent light bulb. The frequency of this whistle relative to its size is lower than that of a conventional whistle and therefore these whistles have found application in small gauge steam locomotives. Also termed a Bangham whistle. [28] [29]

Acme Siren 147 - ACME Whistles

Chanaud, Robert (1970). "Aerodynamic whistles". Scientific American. 222 (223): 40–46. Bibcode: 1970SciAm.222a..40C. doi: 10.1038/scientificamerican0170-40. Steam whistle player's hospitalization won't stop concert". ydr.com. Archived from the original on 2010-12-19 . Retrieved 2010-12-25. A fire-warning whistle supplied to a Canadian saw mill by the Eaton, Cole, and Burnham Company in 1882 measured 20inches in diameter, four feet nine inches from bowl to ornament, and weighed 400 pounds. The spindle supporting the whistle bell measured 3.5inches diameter and the whistle was supplied by a four-inch feed pipe. [86] [87] Stuart, Robert (1829). Historical and Descriptive Anecdotes of Steam Engines and of their Inventors and Improvers. London: Wightman and Cramp. p.301.Dampflokpfeifen / The Whistles of Steamtrains. Archived from the original on 2021-12-13 – via YouTube. a b Ommundsen, Peter (2007). "Observations on whistle cut-up and frequency". Horn and Whistle (116): 4–7. a b Gilbert, T.M. (1897). "A test of the steam consumption of a locomotive whistle". Sibley Journal of Engineering (11): 108–110. Steam warning devices have been used on trains since 1833, [8] when George Stephenson invented and patented a steam trumpet for use on the Leicester and Swannington Railway. [9]

Siren Whistle. the Most Annoying Toy Ever! - Instructables Siren Whistle. the Most Annoying Toy Ever! - Instructables

Interestingly, the siren itself with forced air driven through air lines, came almost 100 years before the need to have mouth blown designs originate. Fletcher, N. H. (1974-08-01). "Nonlinear interactions in organ flue pipes". The Journal of the Acoustical Society of America. Acoustical Society of America (ASA). 56 (2): 645–652. Bibcode: 1974ASAJ...56..645F. doi: 10.1121/1.1903303. ISSN 0001-4966. Blowing pressure – Sound level increases as blowing pressure is raised, [60] [61] although there may be an optimum pressure at which sound level peaks. [49]Axle cut from the acrylic sheet - there's a small circle in the middle layer - save it, and glue it to the engraved dot on the base layer. This is very fiddly! a b c Ommundsen, Peter (2005). "Effect of slot width on whistle performance". Horn and Whistle (109): 31–32. As part of my schools recruitment drive for new students, we have a day that grade 6 kids can come to high school for a few hours and try different subjects. I was asked to motivate kids to choose engineering, which sounds all good, but, then you read the fine print...... 138 kids,... two and a half hours........ Oh crap!