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The loudest/most badass sounding spindle shape for whistle fuel


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#1 mabuse00

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Posted 30 July 2017 - 02:17 PM

Sometimes you dont need much power, but you want a whistle rocket just for the whistle and the amount of payload is not so important.

 

Personally i found that a short and rather skinny nozzle of an endburner tool (I used one with an additional divergent section) sounds better than the longer spindles.

 

Do you have some favorites for such tasks?


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#2 NeighborJ

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Posted 30 July 2017 - 02:58 PM

I agree, for salutes I don't need a big spindle so the endburner tooling works nicely.

When the spindle is between 1.5-2x the tube diameter it also gives a unique descending tone, just like a bomb dropping in a cartoon. I love it.

When the spindle is longer it gives a steady tone which is also nice, just not as dramatic as the short spindles.

#3 dagabu

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Posted 30 July 2017 - 05:36 PM

Not so much the spindle at all but the sounding chamber. Extend the chamber by X2 IDand see if you dont get the sound you are looking for. Also, change catalysts, they make some very interesting noises!  

 

http://www.wichitabu...istletests.html

Sometimes you dont need much power, but you want a whistle rocket just for the whistle and the amount of payload is not so important.

 

Personally i found that a short and rather skinny nozzle of an endburner tool (I used one with an additional divergent section) sounds better than the longer spindles.

 

Do you have some favorites for such tasks?


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#4 mabuse00

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Posted 31 July 2017 - 10:15 AM

Yes, the resonating chamber is also a factor. A typical nozzleless tool with almost no collar on the spindle starts screaming after most of the core section is consumed...

 

OK, so lets take a 2-3x id collar height and, well, some stinger-tooling-like spindle?

 

In most cases one would use something existing, but maybe I'll get an extra tool for this task. Just for the fun. Unfortunately I dont have no salicylate.

 

 

PS:

I know the fuel + catalyst is a factor too. I once made whistle fuel with vaseline, and I dont know what i made wrong but there was almost no power but the sound was sooo raspy B)

 

But this here is about the spindle geometry.



#5 mabuse00

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Posted 24 September 2022 - 02:44 PM

Meanwhile I got a stinger tool, I always wanted stingers and made some experiments in that direction.

But making experiments with whistle was always a second objective.

 

My second, slightly slimmed spindle (1lb) is 5,5mm x 28mm.

Set up as a normal rocket with WM and a 60g salute on top they are great fun.

 

But the salute is not the main effect - it's the liftoff scream. It's a real homemade Nebelwerfer.

The scream is so load that you can hear the echo from faraway tree lines :D

 

The salute is not really important...

 

 

When the spindle is between 1.5-2x the tube diameter it also gives a unique descending tone, just like a bomb dropping in a cartoon. I love it.

Indeed. But not like a bomb dropping, it's something else...

Unfortunately it's not very powerful and burns a lot of precious perchlorate for little payload.

 

 

Extend the chamber by X2

That's what I tried - and it had zero effect. The core geometry is the key, at least that's my current conclusion (any objections to this?).


Edited by mabuse00, 24 September 2022 - 02:46 PM.


#6 nordicwolf

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Posted 25 September 2022 - 06:09 PM

My second, slightly slimmed spindle (1lb) is 5,5mm x 28mm.

Set up as a normal rocket with WM and a 60g salute on top they are great fun.

 

"WM"  ?   What does that mean?

 

Thanks.



#7 SharkWhisperer

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Posted 28 September 2022 - 06:53 PM

 

"WM"  ?   What does that mean?

 

Thanks.

Whistle mix. Not an acronym that's used very often (and not well-understood except for whistle practitioners)...



#8 justvisiting

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Posted 28 September 2022 - 10:37 PM

Another way to say it is that the absolute loudest whistle sound comes from when the rocket is closest to the listener? In that case, the best spindle might be no spindle :) A consumer firework called American Orbiter is a whistling girandola with 6 or 8 drivers and flat-ended propellant grain (no core). That's by far the loudest whistle(s) I've heard. A guy copied it and showed it on FW. It was very good. He used a strong benz whistle with copper oxychloride. 

 

I think the raspiness of benz whistle comes from chunks blowing off the core as it whistles. I recorded it on video and looked at stills of the burn. 

 


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#9 Uarbor

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Posted 01 October 2022 - 12:14 PM

Here is what slow benzo whistle sounds like on one pound Universal tooling with a seven and a half inch tube. Kind of like a sad mournful lovesick elephant.

https://youtube.com/...0?feature=share

#10 Uarbor

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Posted 01 October 2022 - 12:25 PM

I'm no expert but isn't the spindle section of a whistle tool set very short? Most of the burn is probably taking place with no core.

#11 justvisiting

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Posted 01 October 2022 - 01:41 PM

So that's what sad mournful lovesick elephants sound like! lol

 

In the example I showed, it's all cored whistle burning since there is no whistle above the spindle tip, only clay. I wonder how much the burning surface of a cored whistle motor 'flattens out' when the delay section burns, and if the shape of that burning surface affects the sound produced. 'They' say that the cored section doesn't whistle, but it does. At least that's true for 'regular' benz whistle. Salicylate whistle generally burns way faster so the core burn sound is more like a chirp.



#12 mabuse00

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Posted 03 October 2022 - 04:09 AM

Uarbor, that rocket might have great power but sound-wise this is NOTHING.

Another way to say it is that the absolute loudest whistle sound comes from when the rocket is closest to the listener? In that case, the best spindle might be no spindle :) A consumer firework called American Orbiter is a whistling girandola with 6 or 8 drivers and flat-ended propellant grain (no core). That's by far the loudest whistle(s) I've heard

Of course, more area, more noise.
But that does not count ;) I would love to see that in reallife though...

'They' say that the cored section doesn't whistle, but it does.

I agree, but only very little. When I want no noise, for example to "stay under the radar" and not to attract attention, W39j above the spindle kills it but for a short chirp at liftoff.

I think the raspiness of benz whistle comes from chunks blowing off the core as it whistles

Thats's possible.
Another theory is that the whistling is overlayed by a second frequency, maybe one from top to end and one travelling radially?

Edited by mabuse00, 03 October 2022 - 04:27 AM.





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