Hormann HLS F-71
| Hormann HLS F-71 | |
| |
| Company | Hormann |
|---|---|
| Produced | late 1960s - 1970s? |
| Type | Pneumatic |
| Sound output | ? dBc at 100 feet |
| Frequency | 400 - 530 Hz |
The HLS F-71 is a pneumatic siren manufactured by Hormann gmbH. It was an improved design of the Pintsch Bamag and Rickmers Werft models. These sirens have a diesel engine that drove an air compressor and generator. The air compressor fills up a 6,000 liter air tank up bellow the sirens tower. Air is then piped up to the head that has a cast aluminum disc rotor with 4 slots in it powered by a 48 volt motor. These sirens actually had speed control of some sort on the chopper motor which is why they have such a linear wind up. Battery voltage would only affect how fast the chopper would ramp up. Most of them tended to be somewhere in the 400 Hz or 420 Hz area so long as the batteries were in good condition ,but some can peak as high as 530 Hz. If the voltage falls too far below 24 VDC it would have slow wind ups and peak lower than normal just like any typical DC powered siren. When that speed controller or whatever it is gives up the ghost, the chopper will spin up and run at any pitch. ,and the generator charged up accumulators for power.