21 replies to this topic

[Pretty green flames]

I want to make some insert shells, for the first one I'd like to make a whistling serpent with report shell.
I trully have no idea on how to construct these whistling serpents with report, well I have a general idea but I don't know what the dimension of the serpent casing should be.

I was thinking along the lines of 10mm ID, 60mm long (could I shorten it to 50mm, having a little shorter "nozzle"?), 15mm of whistle mix pressed into the casing (leaving 30mm of the tube to act as the nozzle and the last 15mm will be filled with a small ammount of report composition and capped. Would this dance around the sky (and make some noise) or just fall to the ground with no sound?

PGF

Edited by Pretty green flames, 12 July 2008 - 04:34 PM.

[pyroduck7]

have you made insert shells before, dont run before walking

[Pretty green flames]

If I wanted to run before I could walk I would not be here, I'd be in my workshop pressing serpents with no general idea if they will work.

[Frozentech]

PGF, I've not made serpents with a flash bounce at the end, but I have had good luck with whistle inserts in general. I followed the instructions from Ofca's Techniques in Fire - Color/Whistle/Report shell booklet. I'd be interested in how you end up doing whistling report serpents though. Contact me off list for more info on the C/W/R shells if you are interested.

Oh, and pyroduck, PGF is an accomplished shell builder, if you did not know.

[pyrotrev]

If my limited experience is anything to go by, you don't want a nozzle in your whistles - it seems to stop the whistling and just give you a small rocket (which may sometimes go bang)

Edited by pyrotrev, 14 July 2008 - 12:25 PM.

[digger]

If my limited experience is anything to go by, you don't want a nozzle in your whistles - it seems to stop the whistling and just give you a small rocket (which may sometimes go bang)

Yep been there, tried that. As you say it stops the whistle effect. Mine did not cato, but they they did have a strange almost strobing quality to them pop pop pop pop pop as they disappeared into the distance.

[Mortartube]

Why don't you make a couple to do a static test with, just to make sure they don't blow up before they should? I have no doubt that they will be energetic enough to give the effect that you want once in the air. Will they be silver tailed or "Straight" whistle mix?

[Pretty green flames]

Why don't you make a couple to do a static test with, just to make sure they don't blow up before they should? I have no doubt that they will be energetic enough to give the effect that you want once in the air. Will they be silver tailed or "Straight" whistle mix?

I will ofcourse do some static tests before loading them in a shell, I just needed a reference point to know where to start.
The whistles will be silver tailed, either with Aluminium or Titanium, personally I favour Aluminium but if it doesn't work out during static testing I'll use Titanium.

[BrightStar]

PGF: I haven't made whistle serpents yet but it's high on my 'to do' list so I've done a few ground tests.

I don't think you'll have too much difficulty making these work. As they are falling through the sky the thrust / weight ratio isn't particularly critical - whistle produces plenty of gas so they'll fly about regardless. There's no need for a core in the whistle mix and any reasonably hot comp +10% Ti should do.

I'd probably start with standard 1/2" rocket tubes, cut down to 3" length and no more than 1.5" whistle. The main question in my mind is whether you'll need a clay bulkhead between the whistle and the flash report.

Good luck - let us know how it goes!

Edited by BrightStar, 15 July 2008 - 04:47 AM.

[Mortartube]

The dimensions that you originally suggested are very near to the Nico-Moog made inserts that have been used by countless manufacturers in mines etc. I would suggest 50mm long but you are not far off otherwise. Try those for testing. Roll a few tubes of those dimensions and give them a go. I reckon you will probably get it right first or second time.

Edited by Mortartube, 14 July 2008 - 11:49 PM.

[cooperman435]

Brightstar I wouldnt see the need for a clay bulkhead between the Whistle and report powder but certainly ending the whistle with an indented end will aid the ignition to the flash.

If however you notice premature ignition of the flash it may be due to the whistle cracking during thrust and bursting its top in to the flash early. In that case a clay bulkhead would be needed.

[portfire]

PGF-I don't know how your tests have gone, but if it helps I just happen to have some spent whistling serpent cases that I found in the garden from last year. I can take some measurements if you want? (thats the reason i kept them, forgot I had them) There non report though.

[MDH]

Typically whistling serpent inserts are just small rocket payloads with a tiny bit of titanium in them. They are often found in consumer fireworks. The tube will be about 1" long and 2/4" wide. Flash powder is in another compartment in the tube, and yes, clay can be used to seperate it. They are most often not plugged or nozzeled.

Edited by MDH, 05 August 2008 - 01:45 AM.

[Pretty green flames]

Portfire, go ahead and post the measurements if it's no trouble, every bit of information is welcome.

Thanks

[Bonny]

I'm just curious as to if the burst may CATO the whistle inserts? I once tried to fire a 1" whistle from a mortar and the lift charge blew it apart...VERY loud BTW.