HELIN SLSAT
| HELIN SLSAT | |
| |
| Company | HELIN |
|---|---|
| Produced | 1952-1962/3? (SLSAT 52)
1962/3?-1965 (SLSAT 62) |
| Type | Omnidirectional Engine-Driven Electromechanical |
| Horsepower | 7 hp |
The Siren Loudspeaker Single Axle Trailer (SLSAT) refers to 2 omnidirectional mobile gas-powered mechanical sirens produced by HELIN from 1952 to 1965. These were intended for use in the event power would not be available or reliable. Several units can still be found today, with a very small amount still in service as fire sirens or in the hands of private owners.
Design
SLSAT 52
The SLSAT 52, at its core, consists of a HELIN DS55 (which seemed to have been made specifically for the SLSAT but could be ordered separately if desired), a small omnidirectional 1.4 kW (~1.8 hp) siren with a near identical design compared to the E57, minus the smaller size and rain shield. Also included are 2 speakers mounted on each side of the siren unit. These are mounted above a large trailer with a viewing window. A door is located on the side of the trailer, allowing for access to the internals. The assembly is attached to a chassis with 2 wheels attached to it. The speaker units were manufactured by Siemens and Halske, while the trailer is a product of Westfalia and Wiedenbrück. Inside the trailer are the controls for the siren and speakers and a generator, powered by a 2-stroke, 5.2 kW (7 hp) ILO L 250 engine, which drives the siren. Also included inside the trailer are storage compartments under the roof for cables and spare parts, a spare wheel and a drawbar. On the door is a compartment for the remote control and several other tools. The engine has a fuel tank capacity of around 6.5 l. This engine could also be used for other purposes when the siren/speakers were not in use. The speakers' controls would be housed inside the vehicle towing the unit as well as a microphone, allowing for the driver to deliver voice announcements.
SLSAT 62
The SLSAT 62 was introduced in 1963 as an improved version of the SLSAT 52 with minor changes. The most notable visual changes include the door on the side of the trailer being removed and replaced by 2 doors on the front and rear of the trailer, the addition of an angled viewing window also on the trailer's rear, and the inclusion of a large fan on the trailer's front end to provide sufficient ventilation to the inside and prevent any of the components from overheating, as the SLSAT 52 was known to have ventilation issues. The fan is protected by a circular cover, bolted on to the trailer. 2 extendable support legs located at the trailer's rear are also included. Some of the parts used for the unit's internals were replaced with different ones, manufactured by Kaiser. Several compartments inside the trailer are also rearranged. The speakers manufactured by Siemens were switched out for plastic ones made by Telefunken, as HELIN wanted to make the unit lighter, and the metal Siemens speakers only hindered their efforts. A few largely un-notable changes in the trailer's construction are also apparent. Aside from these changes, the SLSAT 62 and SLSAT 52 are relatively identical.