H.O.R. Siro-Drone

The infamous "Hula-HOR" Siro-Drone in Toledo, OH, known for its rapidly spinning loose housing. It was permanently taken out of service in 2023.

### Type of siren

Omnidirectional Electromechanical

The **Siro-Drone** was a series of small to mid-size vertical omnidirectional sirens designed and produced by H.O.R.'s founder and designer, Harry O. Ricci, out of Staten Island, NY. These were H.O.R.'s first large sized sirens, and proved quite successful over the roughly 30 years it was produced. Ranging from tiny pole toppers to medium sized weatherproof sirens, these sirens were very versatile and several continue to serve to this day.

## History and Design

The Siro-Drone began production by as early as 1942, and were H.O.R.'s first successful attempt at making an outdoor warning siren larger than a vehicular siren. The Siro-Drone was advertised as a "roaring" siren, and was intended to be a competitor to the Fedelcode (and later Model series) sirens produced by Federal Electric. The sirens were available in a variety of different horsepower ratings and housing styles, and it is unknown exactly how many different variations there were. The Siro-Drone was available in 1/8HP, 2HP, 3HP, 5HP, and 7.5HP. These sirens were available in single or three-phase AC, and could use 7, 9, 10, or 12-port single tone rotors and stators.

   Most Siro-Drones use a rotor-over-motor configuration, with the intake being located on top. All Siro-Drones use housings with a single skirt to direct the sound from the rotor outwards, while the rainshield on top serves to both protect the siren from the elements and project the siren's intake sound downwards and outwards. Most Siro-Drones are not completely weatherproof, using bare motors exposed to the elements, and the rotor and stator are also often exposed to the elements. Despite this, Siro-Drones were marketed as weatherproof, even in salt air. Some were designed with special weatherproof housings, before switching to a housing design reminiscent of the Model Series sirens.

The most common style used on Siro-Drones is the original style advertised in 1942. The siren uses a bare 5HP motor, which drives a 10-port rotor and stator. The siren uses a large skirt attached to the top of the stator, which directs all of the rotor's output downwards, and a large rainshield is attached to the skirt by 4 thin metal rods. The rainshield protects the rotor from the elements, while also directing the sound from the siren's cylindrical intake outwards and downwards. This made the siren ideal for both roof and pole mounting. The motor has a stand attached to it for mounting purposes.

The most peculiar housing design is used on the smaller 3HP models. This design uses a wide, flat skirt mounted below the 9 or 10-port rotor and stator, with the rainshield being its own separate piece held up by a support attached to the top of the stator. The skirt and rainshield work together to project the siren's intake and rotor sounds outwards evenly, however this design has a critical flaw. The rainshield is held on by only a single screw, which can come loose over time due to wear and tear, and the jolt of the siren starting and stopping. Eventually, the rainshield can come loose and begin spinning violently as the siren operates. This will damage the siren and its mount over time, eventually resulting in either the siren being jolted off of its mount, or the rainshield flying off. One such example of this problem is an infamous "Hula-HOR" Siro-Drone in Toledo, OH.

The Siro-Drone, along with its larger cousins the Sirex and Super Sirex, ended production sometime in the late 1960s, as Ricci retired from the siren business. Several Siro-Drones continue to operate today, despite being discontinued over 60 years ago. Its simple design allows it to be incredibly low-maintenance, which allows them to keep roaring. While their time as civil defense sirens has passed, they continue to be used for fire calls, noon blasts, and severe weather warnings.

#### Type 93

Other housing styles also exist, including an early weatherproof design that was named the Type 93, which was 3HP by default but could be upgraded to 5 or 7.5HP through special order. This design used a large cylindrical housing around the motor, rotor and stator, with a rounded skirt directing the siren's output downwards, and a small opening on the top where the siren intakes. A gong-shaped rainshield protects the siren and projects the intake sound outwards. Later in the siren's life, the weatherproof design would be changed to a design extremely similar to Federal's Model Series, although the Siro-Drones are able to be told apart visually by their smaller (or sometimes larger) skirt, and flatter rainshields than Federals.

#### Type 925

One of the smallest of the Siro-Drones is the 2HP Type 925, which uses a small 12-port rotor and stator, driven by a 2HP AC motor. These sirens were designed as pole toppers, filling in small coverage gaps or for short range use. These tiny sirens are comparable to a Federal Model 2 or Sterling 2V8 in size, albeit with an omnidirectional design instead of directional. The siren heavily resembles a downsized version of the 1942 design, with the addition of finger guards on the stator ports to prevent personal injury. These 2HP Type 925 Siro-Drones are very rare, with 4 known surviving units, including one still in service in Hettick, IL.

#### Type 87

The smallest Siro-Drone was a small electric siren designed for industrial use known as the Type 87. Very similar in appearance to Federal's Model A and D, as well as the Sterling Type F, this model of Siro-Drone uses a 7-port rotor and stator, driven by a high speed 1/8HP AC/DC universal motor. The Type 87's internals are housed inside of a rounded motor cover, which is attached to a metal stand by a swivel. The design of this stand is nearly identical to that of Federal's industrial sirens, albeit with a slightly shallower angle at the swivel due to the differing width of the motor cover. The siren's intake is different than any other H.O.R. siren, heavily resembling those used by Sterling's sirens. The intake is conical to a certain point where it then flares back out to the full width of the stator. This pressurizes the air, increasing performance. A large conical projector surrounds the rotor and stator to direct the full output in a single direction. The Type 87 is designed to be mounted on any flat surface, with four mounting screw holes included on the stand. Interestingly, despite being a small siren, the Type 87 lacks any sort of protection for the user, with no finger guards or intake screens.