aca cyclon 120

thingiverse

The first version, the 1968 Cyclone 120, had both rows of ports angled downwards. Like some of the other 1968 ACA siren designs, it was changed shortly after to improve performance. These improvements included a new, simple intake, and most notably the top row of ports being straightened out, as to direct the low tone outwards for maximum range while projecting the high tone downwards to the immediate area. At some point afterwards we also saw the use of the long, curved intake as seen on their 3 signal sirens. This allowed for an optional coding damper to be added, which produced a pulsating "local code" tone.