Gents' of Leicester Tangent

**Type of siren** | Omnidirectional Electromechanical

The **Tangent** series was a line of dual rotor electric sirens (also referred to as "syrens" by the company) that were produced by Gents' of Leicester during the Second World War, competing with the likes of Carter and Castle Castings to warn of Axis air raids in Britain. These sirens would also see limited service after the war.

Gents' of Leicester was originally an electric clock manufacturer that was formed in 1872, and mainly stuck to this throughout its existence. Gents' was one of many companies that was commissioned by the British government to produce sirens during the Second World War, to warn of incoming air raids on British cities by Nazi aircraft. Gents' opted to create an entire line of "Syrens", which they named the Tangent series. These sirens were widely used across Britain, and were produced until the 1950s.

Originally, Gents' was the only manufacturer that was legally allowed to create air raid sirens due to an administration error, before this was later corrected. Gents' made several innovations, including conical-shaped rotors and stators (similar to an E.D. Bullard) and sirens with three different ports, creating a tritone. Gents' of Leicester continued to build electric clocks until 1981, when the company was acquired by Chloride and ceased operations. The only siren produced today by Chloride is the Type 1500, an indoor fire siren.

The known models are as follows:

## Small sirens

#### Type 1479

The Type 1479 is the smallest siren in the Tangent lineup, being little more than an indoor industrial siren repurposed as an outdoor air raid siren. Intended to fill small coverage gaps, the Type 1479 is a single rotor electric siren that uses a 12-port rotor and stator, driven by a 1/10HP AC motor at 50hz, up to 250V. The Type 1479 is extremely simple in design, with the rotor and stator attached to one side of the motor. The motor itself is protected by a rounded motor cover, and a small stand is located below. Unlike all other Gents' sirens, the Type 1479 uses curved vanes on the rotor (similar to a B&M or Federal Q-Siren), which offers much better efficiency for the rotor's size.

#### Type 1468

The smallest dual rotor siren made by Gents', the Type 1468 is a small step up from the 1479. The Type 1468 makes use of two 8-port rotors and stators, making it an 8/8-port single tone siren, quite similar to W.S. Darley Super Champions. The siren is driven by a 1/4HP AC motor running at 50hz, likely on single phase power. Little else is known about this siren including its appearance, as the siren is extinct.

#### Type 1469

The Type 1469 (sometimes marked as Type "IND" on the tag) is a single rotor siren that was produced by Gents'. The Type 1469 makes use of a single 12-port rotor and stator attached to one side of a 1/2HP AC induction motor, running at 50hz on 220V single phase power. The siren's rotor is likely very similar to the 12-port side of the Type 1471, and is likely a single rotor variant of that siren. The Type 1469 is a horizontally mounted siren, with a large square base acting as a mount, with four screw holes. The motor is attached to the base by two thin strips of metal. The siren could come with a manual shutter, which swivels over the intake to block the intake of air and make the siren much quieter if desired. The Type 1469 is an extremely rare siren, with very few units known to still exist today. It has a distinctively thinner rotor and stator compared to many British sirens of the time, including Gent's other models.

#### Type 1471

The smallest dual tone siren in the Tangent lineup, the Type 1471 is a dual tone electric siren that makes use of two rotors and stators on either side of a 1HP AC motor, running at 50hz, single or three-phase. The Type 1471 has a 10-port rotor on one side, and a 12-port rotor on the other, making the siren 10/12-port dual tone. The siren's bare motor is attached to a small, square stand for mounting purposes. The 1471 is considered extinct, as no surviving units are known to exist.

## Large sirens

#### Type 1472

The Type 1472 is a unique quad rotor siren that was produced by Gents'. The siren resembles a regular dual tone siren, but with two additional rotors and stators driven by one rotor shaft. The siren is unique in that it is a tri-tone siren, with three different ports. The two middle rotors and stators are 10-port, while a 12-port rotor/stator is attached on one side, and a 15-port rotor/stator is attached on the other. This results in a 12/10/10/15 tri-port siren, which has a distinctive, nearly musical sound. The siren originally was configured as a 12/10/15/10 prior to 1936.

The siren is driven by a bare dual sided 2HP AC motor, running at 50hz in either single or three-phase. The siren resembles a dual rotor siren as each rotor and stator are thin enough to not require additional outer bearings. The siren includes a square-shaped stand below the siren for mounting purposes, which originally spanned the entire width of the siren, at least for single-phase units. Single phase units use an asymmetrical motor. A few of these sirens survive today in private possession and museums, with at least one in functional condition.

#### Type 1474

Also known as the Type A.R.P, it is one of the most well-known Gents' sirens. The Type 1474 is a medium sized dual rotor siren that closely matches Carter and Castle Castings sirens in sound. The Type 1474 was available in 10/12-port dual tone only as standard, driven by a dual sided 4HP AC motor running at 50hz, single or three phase. The Type 1474 is unique and distinctive in appearance, using conical shaped stators. The reason for this is unknown, but it is possibly an attempt to direct some of the sound towards the intakes. The Type 1474 was available with optional coding dampers similar to those used by the Klaxon CS8 and Federal 3T22, which would allow it to create a pulse or hi-lo signal. These dampers would be included with extended, pointed intakes, and the solenoid mechanism was located underneath each intake.

The stators are attached to the motor by four legs, with the rotor shaft in the middle. This is a similar configuration to the Sterling Model M. The siren has a rounded motor cover which shields the motor from the elements, and the siren includes a simple four-legged stand for mounting. The Type 1474 was the most successful model, and at least one remains in service today as an industrial fire alarm.

#### Type 1478

The Type 1478 is the most peculiar and unique siren that was sold by Gents'. This siren uses an extremely strange layout, somewhat similar to what Dillon Box did with their Denver sirens as well as Yamaha with their Music Sirens. The siren has 4 separate rotors and stators, all connected to a single, long shaft coupled to the motor. The two inner rotors/stators are 12-port, while the two outer rotor/stators are 10-port. This results in a siren that is 10/12/12/10-port dual tone. The Type 1478 uses the same rotors and stators as the Type 1474, and can be seen as a larger variant of one.

The siren's dual sided motor is located in the middle, and is an 8HP AC motor, running at 50hz, single or three phase. Due to the additional weight of the extra rotors/stators, the Type 1478 includes two additional bearings between each set of rotors/stators, held up by solid supports which also hold the stators. The motor and bearings are attached to a single long common frame, which makes the siren impossible to mount on a pole. Two eyebolts are attached to lift the siren onto a rooftop by a crane. Understandably, the Type 1478 was not very successful due to its large size and expense, and very few are known to exist today, none in working order.