Indian Rock Thunderbolt (Berkely, CA)

[oliveoil22]

Hey ya'll, today I visited the Indian Rock Park Thunderbolt in Berkely, California. It appears to be a jailbar. I did some photo touchups in Adobe Lightroom CC to make them look a little more professional.

Edit: I see now how atrocious my "color correcting" was. I apologize for the eye strain lol.

[fire_freak_57]

Hey ya'll, today I visited the Indian Rock Park Thunderbolt in Berkely, California. It appears to be a jailbar. I did some photo touchups in Adobe Lightroom CC to make them look a little more professional.



This one is out of focus.. oops.:


Horn closeup:


This one looks creepy:




Horn closeup 2.0 (if you zoom in you can see the jailbar!):


And finally bonus - The view of the San Francisco skyline at Indian Rock Park:

That’s definitely a jailbar. The screen is consistent with that. I’ve seen and heard two before. That’s a 1000 (single toned model); these were never made dual tone. They were made from 1952 (first year the Thunderbolt was produced) till about 1955 when the jailbar was dropped and a simple mesh screen was added as the horn didn’t need the structural support of having the grids there. They’re in a 3x3 configuration. One set of grids on the front, another inside, and another inside that. Here is one from a picture of one active in my area:

03B754B6-E273-4479-9620-CF01B227BED8.jpeg (389 KiB) Viewed 6953 times

[Tyler]

That’s definitely a jailbar. The screen is consistent with that. I’ve seen and heard two before. That’s a 1000 (single toned model); these were never made dual tone. They were made from 1952 (first year the Thunderbolt was produced) till about 1955 when the jailbar was dropped and a simple mesh screen was added as the horn didn’t need the structural support of having the grids there. They’re in a 3x3 configuration. One set of grids on the front, another inside, and another inside that. Here is one from a picture of one active in my area:

Allow me to quote the Wiki to correct some information:

A notable feature of some Thunderbolts is their projector, or "horn". The earliest thunderbolts had metal cross support bars, now referred to as "Jailbars", throughout the horn making a 3x3 grid in the front, 2x2 in the middle, and 2x2 in the back. This acted like reinforcements. Since the Thunderbolt was new at the time, Federal wanted to make sure the horn did not warp or bend as this would ruin the sound output. After 1952, Federal started testing to see if there really was any benefit from having these "supports" in the projector, this caused some models to have them, and some to lack them. After 1955, it became obvious that the thick metal panels used for the projector were strong enough to not compromise the projector itself. Federal decided to drop the reinforced projectors and continue making the models with nothing more than a mesh screen used to keep various animals, insects, and debris out so the rotor wouldn't lock up leading to a burnt motor.

[coastalsyrolover]

That’s super cool. Wouldn’t it be interesting if it was once a bumblebolt? (I don’t think it was I’m just saying it’d be kinda cool...)

Either way I didn’t know that one was a jailbar but it’s cool to have a close up of it.

[fire_freak_57]

That’s definitely a jailbar. The screen is consistent with that. I’ve seen and heard two before. That’s a 1000 (single toned model); these were never made dual tone. They were made from 1952 (first year the Thunderbolt was produced) till about 1955 when the jailbar was dropped and a simple mesh screen was added as the horn didn’t need the structural support of having the grids there. They’re in a 3x3 configuration. One set of grids on the front, another inside, and another inside that. Here is one from a picture of one active in my area:

Allow me to quote the Wiki to correct some information:

A notable feature of some Thunderbolts is their projector, or "horn". The earliest thunderbolts had metal cross support bars, now referred to as "Jailbars", throughout the horn making a 3x3 grid in the front, 2x2 in the middle, and 2x2 in the back. This acted like reinforcements. Since the Thunderbolt was new at the time, Federal wanted to make sure the horn did not warp or bend as this would ruin the sound output. After 1952, Federal started testing to see if there really was any benefit from having these "supports" in the projector, this caused some models to have them, and some to lack them. After 1955, it became obvious that the thick metal panels used for the projector were strong enough to not compromise the projector itself. Federal decided to drop the reinforced projectors and continue making the models with nothing more than a mesh screen used to keep various animals, insects, and debris out so the rotor wouldn't lock up leading to a burnt motor.

Either way it’s pretty self explanatory by looking at the picture. . . .

[Duderocks5539]

There's another one on a building on Ashby Ave and College Ave.

[dispatcherman]

Nice find!!

[oliveoil22]

There's another one on a building on Ashby Ave and College Ave.

Yeah I know about that one. Couldn't get to it that day.

[Jake_7367]

Where at the park is it located?

[coastalsyrolover]

Where at the park is it located?

If you want a possible quicker answer may I point you at the “thunderbolts in existence” siren map? Or the Cali ones? You should find you answer there.