Colerain, OH siren

[Trey]

I don't think this video has been posted (that I know of), but take a look...a mystery siren...

http://youtube.com/watch?v=7J3DHqeEBOQ& ... ed&search=

[Thunderbolt 612]

I think this is some kind of ACA prototype siren, with a 10/14 ratio, producing a 600/840 hertz sound output at 3600 RPM.

[Robert Gift]

How does that work?

Two rotors and stators on two motors because both tones do not wind-up simultaneously as though on one motor shaft.

Where is air pulled in?

Thank you,

[Elliott]

The guys at Messer Bros. (shop where it is located) built it, according to Clayton Werden, but I dont know of it being a ACA derivative. I believe there to be two sirens; the one in the photo, and then another in a yellow box nearby. I will try to get my own video from a different angle next month.

[Robert Gift]

Thanks, Elliott.
I wondered how we heard the two sounds.
Where is air pulled in?
Thank you,

[Daniel]

This has been on this board several times before. The big yellow siren is the high pitched sound. It was built by the machine shop whose roof it sits on. I don't know what's inside, but my guess is a Q2B type siren head and an AC motor. The low-toned siren is on another building nearby. I believe it is a bench-grinder type inside a box, but it has a weird tone that I can't figure out. Either it is a single-toned siren with about three ports (like an Elektror S3) or it's a dual tone and all we're hearing is the resultant pitch.