These have probably been asked & answered,but I could not locate them.
1)... What is the advantage of tilting and putting the Bulbs in an off~centered position on a Roto-Ray? Thanks Travis!!
2)... On Mechanical Q~2s, I've noticed some recessed in the bumper or the front of the cab.Also included is the "Directional Cone" available from Federal.Wouldn't that create a "loss of air"? It seems,to me, that the "loss of air" intake would lower the efficiency of the unit
TIA!!
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Assuming question 1 was referring to a Roto Ray, the advantage is beams of light shooting in all directions, instead of just forward, especially in the fog. The disadvantage (which weighs heavier in my opinion) is that the thing is spinning with weight going 3 different directions because it's not equally centered anymore, you can tear it up doing that. I yell at my guys for messing with it at all, even spinning it without being on, I'm 1 step away from yelling at them for even looking at it!
Trav!
Travis- Mill Twp. Fire Dept. Marion, IN.
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On #2 by recessed are you talking about only the forward 4" or so sticking out vs a pedestal mount?
That front part is the bit that creates the sound, the rest of the Q behind that is just an electric motor. I've worked on engines with both set ups and have never noticed a difference in sound quality.
Aaron Woods
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I think he's talking flush mount on the front of the bumper vs recessed mount, still on the front of the bumper, but set inward with the bumper on either side of it. I didn't answer that part of the question because I really wasn't sure how those work...
Trav!
Travis- Mill Twp. Fire Dept. Marion, IN.
The Q2s mounted Without ANY protrusion .I guess some would actually call it "Internal Mount". Except where the "Directional Cone" is mounted.Either Pedestal or the 4" or so sticking out the front sheet metal where it could be attached.
I thought the side grille(??) was the air intake and the front grille(10-12 inches front ) was where the sound was projected from.
I apologize if I'm stating incorrectly. Please understand I am an old man...LOL...
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For #2, you mean like on Boston's new KME Predator engines? I've had the same question in mind...
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Interesting, I have not seen a mechanical siren completely flush mounted before.
Aaron Woods
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05-03-2014, 01:53 AM
(This post was last modified: 05-03-2014, 01:09 PM by YeOldeEnjine.)
1- Off-setting or "rotating" the bulbs in a Roto-Ray are an effort to create a different / wider light pattern that makes the warning light more noticeable. Depending on the amount of "rotation / off-setting" there can be more light visible when viewed from the side.
As long there is no change in the weight of each light fixture there should be no concerns about throwing the Roto-Ray out of balance by off-setting / "rotating" the lights. I'm sure there is "some" change in the amount of air resistance by rotating a light fixture but I doubt there is enough to cause an "out of balance" rotation concern.
I have seen a Roto-Ray light "out of balance" vibrating wildly during operation but that was caused by a customer modifying the unit on their own with a PAR halogen light bulb in one head and LED arrays in the other two heads. The different in weight between PAR bulb and the LED's caused enough vibration to crack the Roto-Ray mounting plate.
2- "Flush" mounting a Federal Q2B were the grille face of the siren is flush with the face of the bumper has a couple of advantages. First it helps in reducing the overall length of an apparatus, secondly it protects the siren more from damage. As long as there is sufficient air-flow into the front grille of the Federal Q2B there should be no reduction of sound output or quality. Behind the bumper is typically wide open under the deck plate. Manufacturers take great pains to ensure things like bumper boxes or the like are not in close proximity to the side grilles of the siren. Again we're not talking about a large airflow here. As for the Projector / Director Cones... I have no data that supports either way if they cause any diminished sound output from the siren.
My comments are from my observations....Your mileage may vary!
Tim W.
Mechanical engineers build weapons, whereas civil engineers build targets.
When the man at the door said," Alcohol, Tobacco and Firearms", I, naturally assumed it was a delivery!
Quote:For #2, you mean like on Boston's new KME Predator engines? I've had the same question in mind...
Yes Sir. [url=http://www.firepics.net/groupboards/index.php?showtopic=47&page=77%C2][/url] I have also seen a limited number in the front sheet metal.
Tim W., Thank You for the detailed explanation. Makes sense now. And also,Thanks to the other replies.
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A mechanical siren works by drawing air in from the front, compressing it, and forcing it out then side slots. The idea of the directional cone is to redirect the sound to the front of the siren and not the side. As for recessing a Q, I would think that there is some decrease in the effectiveness if it is mounted like it is on Boston's new rigs, but I doubt that it is really noticeable.
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Quote:A mechanical siren works by drawing air in from the front, compressing it, and forcing it out then side slots. The idea of the directional cone is to redirect the sound to the front of the siren and not the side. As for recessing a Q, I would think that there is some decrease in the effectiveness if it is mounted like it is on Boston's new rigs, but I doubt that it is really noticeable.
Thank you... I knew that and I probably shouldn't answer a post after midnight......... on a Friday, after a couple of beers.........
Mechanical engineers build weapons, whereas civil engineers build targets.
When the man at the door said," Alcohol, Tobacco and Firearms", I, naturally assumed it was a delivery!
So I had it going the other way.
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I guess I didn't realize Boston's new KMEs had mechanical Q sirens, I thought it was just a cover for an Electric Q.
Trav!
Travis- Mill Twp. Fire Dept. Marion, IN.
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Quote:I guess I didn't realize Boston's new KMEs had mechanical Q sirens, I thought it was just a cover for an Electric Q.
Trav!
That's what I was thinking - keeping Chicago as my benchmark. I had always thought that the flush-mount Qs were just covers for EQ2Bs - kinda scared me that more departments were going away from the screamers to electronic sirens. Glad I saw this thread!
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