Chopper Cap
Inside this cast cap is what is called the chopper. it is a drum with two sets of equally spaced rectangular holes around its circumference. When the chopper spins, the holes line up with the throat of the horn and air escapes creating the wailing sound. This chopper is dual tone which is to say that there are six equally spaced holes around one half of the chopper and five holes around the other. This creates two tones simultaneously which creates a very distinctive warning sound not likely to be confused with the sound of a fire truck or ambulance.
This Federal Signal Thunderbolt 1000AT air raid and tornado siren was part of the Norman, Oklahoma outdoor warning system. Norman elected to replace their mechanical sirens with electronic outdoor warning sirens and I acquired this siren from the installation vendor for the new system.
It was an exhausting and expensive ordeal. My objective is to strip off the existing paint, repaint it and apply new decals, and then reinstall it on a short pole as a static display.
Chopper Cap
Inside this cast cap is what is called the chopper. it is a drum with two sets of equally spaced rectangular holes around its circumference. When the chopper spins, the holes line up with the throat of the horn and air escapes creating the wailing sound. This chopper is dual tone which is to say that there are six equally spaced holes around one half of the chopper and five holes around the other. This creates two tones simultaneously which creates a very distinctive warning sound not likely to be confused with the sound of a fire truck or ambulance.
This Federal Signal Thunderbolt 1000AT air raid and tornado siren was part of the Norman, Oklahoma outdoor warning system. Norman elected to replace their mechanical sirens with electronic outdoor warning sirens and I acquired this siren from the installation vendor for the new system.
It was an exhausting and expensive ordeal. My objective is to strip off the existing paint, repaint it and apply new decals, and then reinstall it on a short pole as a static display.