Chrysler-Bell Victory Siren article in Jan 1943 PopSci

[bigloudnoise]

I imagine many have already seen this, but for those who haven't, here's a one-page article my father found in an old issue (January 1943) of Popular Science talking about the Chrysler siren. Sorry for the poor image quality, I currently don't have a working scanner.



If you can't read it, here's what the article says:

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(PHOTO CAPTION) Testing the machine, engineers have to hold their ears as the siren blasts out its mighty roar over New York

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New York Air-Raid Siren Nears Top Limit on Noise

Scientists have estimated that the loudest sound that could be produced would not reach more than 190 decibels. New York's super air-raid siren atop the RCA Building, when operating at full throttle, reaches a horn volume of 170 decibels, and can be heard over 50 miles away. The revolving mammoth "howler" comprising the siren proper, a blower to supply compressed air, and a 140-hp. engine to drive both, creates an ear-shattering roar by a high-frequency air disturbance. A "chopper," 25 inches in diameter, revolves behind six "throats" leading to the horn. As compressed air is sent into the throats at the rate of 2,500 cubic feet a minute, it is sliced off by the blades of the chopper, which revolves at a rate of 4,400 r.p.m.

[ginbot86]

Cool. I think they were the loudest siren ever made.

[holler]

50 mile audible range, sounds like a slight overstatement to me.

[SirenMadness]

The blower-setup reminds me of my screw rotor concept! I never knew that someone else had done it before me, but that was back in the day when sirens were all about power and not allot of practicality!

50 mile audible range, sounds like a slight overstatement to me.

I heard a recording, somewhere, of a Chrysler five miles away and it was fairly quiet. I agree with the five, but that was truly a typo with the zero.

[bigloudnoise]

I heard a recording, somewhere, of a Chrysler five miles away and it was fairly quiet. I agree with the five, but that was truly a typo with the zero.

I've heard that recording too. If I remember correctly, though, that particular recording was made with a Chrysler that was sitting right at ground level. Were it mounted on top of a building or tower, I wouldn't doubt that you could hear it further than five miles, assuming ideal conditions of course.

However, I agree though that 50 miles is definitely an overstatement. Perhaps 10 miles absolute limit if the weather is perfectly still and the listener was standing someplace with little or no ambient sound, but even that's likely pushing it.

[SirenMadness]

I've heard that the HLS has a range of ten kilometers, about six miles, so the Chrysler could go allot further.

[Robert Gift]

Thank you, big, for the text. That was good of you.

I am surprised thathe 25 inch chopper spins at 4,400 rpm.

No, I do not believe the 50 mile maximum claim of audibility.

[SirenMadness]

I am surprised thathe 25 inch chopper spins at 4,400 rpm.

That's over a hundred horsepower. Why not?

[Adam Pollak]

The blower-setup reminds me of my screw rotor concept! I never knew that someone else had done it before me, but that was back in the day when sirens were all about power and not allot of practicality!

The patent for the screw blower was issued in 1895, #536925

From that photo, the blower on the Chrysler looks like a 2-stage centrifugal blower...essentially a large central vac motor.

[ginbot86]

Yeah. 100 HP is pretty good.