The Siren Board

Well, what if they made a thunderbolt tripple toned? Could that effect the output?

to an extent, yes.
more air would be able to escape at once, so the blower would not be able to build as much pressure, sacrificing the high decibel level of thunderbolts

i know im starting this fourm again, but i still want to know more about the choppers/rotors staeting with the Codewell siren

I believe that the choppers with the curved inner vanes have better sound output for the energy that goes into it. In HVAC, such centrifugal fans with forward-curved vanes or blades have excellent performance characteristics.

I have a feeling the performance increase is so small it's not worth the cost to engineer a new rotor like that. I mean, look at ACA. They made a 135 decibel siren using knife edge ports on their stators and directional rotors. Having straight vanes must be efficient enough for producing a lot of sound.

Model L wrote: ↑

Thu Mar 14, 2019 2:36 pm

to an extent, yes.
more air would be able to escape at once, so the blower would not be able to build as much pressure, sacrificing the high decibel level of thunderbolts

The 1000 has only 5 wide openings and can reach up to 130dB. I think the factor here is the width of the chopper holes.

If you see closely on American Dual Tones (aka Single chopper & stator sirens) especially those with a single tone variant in the line, the chopper & stator openings on the dualtones are narrower than singletone counterparts.

However when it comes to British designs which implemented a dual rotor design, the sound output isn't that lod due to the lacking of directional horns. Most directional sirens are louder that their omnis since the sound beam is focused at one spot, hence the phrase unidirectional.

the most effient design would be a francis turbine type of rotor! this pushes alot of air but at the same time it compresses the air aswell

or
The chopper is designed in the same way as the impeller of a turbo pump. lots of pressure and volume.