Huge Federal siren found in photo

[500 AT fan]

Found this a few days ago. Since it is a photo, and I'd prefer to know more about the siren itself, I'll post the link here, for now.

http://cgi.ebay.com/Worlds-largest-air- ... 4cef53b5c9

I know the user 500AT told me some information about this siren, but I'll let him post that.

[Siren1000T]

It seems that it has a huge fan to amplify the sound from the chopper. I can't really see the picture very well but I guess it would look identical to an over sized 500-SH.

[Mantis]

That fan must do wonders then. That chopper doesn't look very large...

[Daniel]

It looks like an eight-port siren head about the size of a Model 5 attached to a huge projector. I don't see a fan, only a segmented T-128-like horn. Basically, it is a primitive 500 model.

[500 AT fan]

My initial idea was that the eight blade fan spins around with the siren rotor, somehow supercharging the sound.

If only we had better photos of this siren. Then it'd be easier to tell.

[500AT]

I was going to bid on this negative on e-bay, did someone else from here bid on it?

[Archon]

Yep I did

[500AT]

Yep I did

Very cool.

[500AT]

It looks like an eight-port siren head about the size of a Model 5 attached to a huge projector. I don't see a fan, only a segmented T-128-like horn. Basically, it is a primitive 500 model.

Its interesting that you should bring this point up. According to Art Johannes, who worked for over 30 years at Federal, the Model 500 made it's debut in 1949. However, he said that there were earlier variations of that siren model going back a decade earlier. Some of which did not rotate, and were designed to propagate their sound pattern only one direction if need be.

[500 AT fan]

It is too bad Federal never documentated each of those early 500 variants.