A Federal Signal precursor to a Thunderbolt? 1946

[Robert Gift]

A friend told me that, as a US soldier in Osaka, Japan, during the U.S. Military occupation after WWII, they had a device on base which sounded at 12:00 and 16:00, SIR! (That's Noon and 4 p.m. to all of you.)

The master clock's swinging pendulum had a sharp point on the end which dipped into a small pool of mercury.
Each pass would close a circuit and relays would count the swings.

The siren had three horizontal exponential horns 120 degrees apart.
10 hp three-phase motor. Sounded at 400 Hz. (About G4)

At 02:00, he heard the compressor start.
He ran to the building to disarm the alarm, but knew he could not get to it in time. His partner, also involved with the timekeeping device, also showed up out of breath.

Fortunately, the prankster did not know how to set the other timer to open the valve.

I would have figured it out and HAD A BLAST!

[500AT]

This sounds like it might have been a Toshiba siren, possibly a pneumatic model with an air compressor. Toshiba's sirens tended to be ultra loud and were low-pitched, so they would penetrate hilly and mountainous areas much better than a higher pitched siren. In fact, if you watch the 1956 sci-fi classic "Rodan," you can see one of these sirens in action when the monster is flying over Sasebo-shi.

Interestingly enough, the prototype Thunderbolt was created in 1945, and was designed for the Alamagordo, New Mexico atomic bomb test site. When I visited with Art Johannes at Federal Signal back in 1989, he showed my several historical photographs of the prototype Thunderbolt, which were from the company archives. Hopefully, these photos still exist and were not tossed into the trash, when Federal decided they needed more room to expand.

The projection horn was almost identical to what was common in the later production models of the 1950s, likewise, the compressor was smaller, but the rotor box had a more "streamlined" appearance. That said, the prototype Thunderbolt performed flawlessly, just as intended, but did not escape the bomb blast unscathed. Moreover, two significant problems that plagued this unit, was the gears were getting stripped in the rotor box, and blower motor would overheat.

The only major failures to the siren was compressor, and rotor box, the latter of which, prevented the projection horn from rotating, and the former caused the siren to sound at limited intensity. Nonetheless, the first T-bolt was able to run after the blast, but it needed a lot of work, including later refinement of the entire siren itself. Furthermore, it would be three years before Federal could really inspect the siren components up close due to contamination, and then a lot of research and development was needed to make it successful. However, a star was born, and got better with few more test models being constructed, before the Thunderbolt went into regular production in 1952.

[Robert Gift]

Interesting.
Thanks, Ron.
I'll ask him if he remembers Toshiba.

I hope Federal would not have discarded any of that historic stuff.
Give it to a library or someone interested.

Have you toured the U of M bell tower near Hill Auditorium?
Can't remember the Coach's name. Begins with B.

[Daniel]

The siren had three horizontal exponential horns 120 degrees apart.
10 hp three-phase motor. Sounded at 400 Hz. (About G4)

Did it look something like this?

[JasonC]

That siren has to have the record of "world's crappiest siren".

[holler]

I just have to ask, what the hell is that and how much alcohol was involved?

[pyramid head]

I would buy it. That siren is very unique, and that is something i admire.

[AllSafe]

The siren in that pic is a Sterling. The sirens he's talking about used to be all around the San Onofre nuclear power plant.

[Daniel]

Most have agreed that ithe Tangent, Oregon, siren is a Sterling, but some think the horns were added on by the owner. It is a 1940's model, and my theory is that it was a prototype and factory made with these horns. Sadly, it has little to do with Japanese sirens and is not connected to a compressor.

[loudmouth]

every time i see the picture of the poor siren im allways like now that is the world sadest looking siren. Just due to the way the horn is drooping down lookes so depressed.. o well i would be too if i had that rusty look to me.