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Stingers - how do you start them?


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#1 mabuse00

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Posted 08 January 2022 - 04:45 PM

I did a few experiments with stingers in 1lb over the last years and I love them. Not a serious firework but a plaything ;)

But it seems to me most of us like playthings.

My experience is that a nail type launch pad does not work (for me). Things will always go sideways.
I use 1lb tubes cut in half.
The last one had 73g, with a little header full of some 20g sand.

The header does not seem to be the problem, even considering it is of slightly greater diameter than the motor, the thing is stable once it spins.

The critical moment is at the very beginning, the sidevent pushes the tube to the side before it spins up.
I had to bolt the launch pad to the ground, otherwise the thrust would push it over.

Also the core starts too early. But I cannot prevent that.
When it starts to stabilise, it's likely in a horizontal path...

 

Another sidevent on the other side would cancel that out but together with the required simultaneous ignition adds a lot of workload. 

Has anybody here ever tried to shoot stingers out of tubes?
Or what is your preferred method of shooting upright?

 

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#2 Carbon796

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Posted 09 January 2022 - 11:22 AM

Yes you can use tubes to launch them. Ben S. from firesmith tools prefer's this method, iirc.

#3 Bourbon

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Posted 09 January 2022 - 05:08 PM

I love Stingers. I use Caleb's tools (longer skinnier spindle) I found them to be a little finicky at first. Like Mabuse said "cores would lite too quick" not allowing enough spin up time. I ended up having to be particular about the tangential hole. After my first 25 or so, I started drilling my holes first and just put a piece of tape over it before ramming a nozzle and grain. I did this to clean the frayed paper from the Inside after drilling. After finishing the motor, I'd remove the tape and just tap out that tiny bit of loose powder. (No hole in the grain at all) Slice my fuse at a 45° and just push it right up against the grain. Super glue and tape it 90° to the motor. That right there gave it an extra second of spin up time, and 1 second is all it took. No fray of paper to disfigure the grain worked like magic. I then built a small stand with 2 different size  launch spindles to test which would work better. Every three stingers I give the launch spindle a quick steel wool. I found that a spindle that takes up at least 3/4 of the core worked best. Less wobble as she spun up before take off. I rarely ever get a stinger that goes off more then 15°. They fly beautiful.


Edited by Bourbon, 09 January 2022 - 05:12 PM.


#4 6afraidof7

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Posted 09 January 2022 - 09:25 PM

Good to hear these experiences and recommendation's. Looking to make some soon, just received Caleb's tool set for 1#. Bourbon, in the Skylighter construction article for stingers they recommend to drill the hole first also, but they are assembling the fuse in the tube prior to pressing. Similar method you described with the fuse end flush to inner wall of tube then super glue and tape at 90 degree angle.

 

Excited to try them. Was thinking of a tube as a holder, didn't think of a spimdle. You're just placing them on a spindle? Any fear of the core being damaged?



#5 Bourbon

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Posted 09 January 2022 - 10:11 PM

Dang I didn't know Skylighter had that stuff posted. Would have saved me some time lol. Oh well, it was fun trial and error.

 

The grain should be pretty tough. I haven't had any problem just sliding them on a spindle, course I've never done it hard. I did preglue many fuses but it doesn't work well with a tube support.  ;) I hand ram them so I quit using a support, waste of time. I personally like a bit of nozzle and plug bulge. I don't know why I never went back to pregluing them. Nice with the fuse out of the way I guess.

 

Edit in: There's an old small book out called "Spin Stabilized Rockets" like 10 bucks or something (free if ya look around) If ya haven't read it, it's not to shabby. Good stuff!


Edited by Bourbon, 09 January 2022 - 10:17 PM.


#6 mabuse00

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Posted 10 January 2022 - 06:44 AM

I'd like to state that my sidevents are usually perfectly aligned and barely scratch the fuel.

There's no spin up time to be won here...

 

 

longer skinnier spindle

What length and diameter is that?

I found that most toolmakers produce (i my opinion) very large nozzles, same as with endburners, same as the popular Rocket Tool Scetcher delivers.

 

For 1lb I'm using a 4,8mm spindle with a 2mm sidevent. That still survives the best BP I can make.

My objective was to make use of non ideal fuels, because I only have a very small ballmill. Like greenmix, or one of the candy propellants for daylight flights.

With the typical six-comma-something spindles this wont work.

 

 

Well, I guess I prepare a little mortar for next time...



#7 Bourbon

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Posted 10 January 2022 - 01:00 PM

Spindle approximately: 9mm bottom x 5mm top x 48mm long. 3/4ID x 3.75" tube.

 

Caleb says to use good hot fuel "75/15/10" but I couldn't. CATOs, however, I hand ram. If I pressed I could most likely do this. So I use milled 65/25/10 of good stuff and/or 70/20/10 of milled stuff with commercial AF.

 

Hope you get it the way you like it. They sure are fun. Well I think so anyway.



#8 Carbon796

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Posted 10 January 2022 - 04:52 PM

Typical 1# stinger's use a spindle with .19" at the top, and .25" at the nozzle. Both of your spindles are larger than this, at the nozzle. Which will contribute to lower thrusts/velocitys and reduced spin up times. Your spindle specs are more in line with what would be used for 3# stinger's. Typically stinger's wouldn't use ballmilled BP, but a good scratch mixed and riced RF. Which would be cheaper and have a much nicer tail.

#9 Bourbon

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Posted 10 January 2022 - 06:34 PM

Interesting. That makes the spindle less then 2mm difference either way. I agree about the tail, but I generally don't worry about that. I use mine to lift pay. I also use these tools without a tangential hole for a regular short motor. Works great, no thrust issues either way. 150 gram header as a stinger before it gets squirrely, and/or I can put up a 280 gram header as a regular motor. Not bad for a 3.75 tube with a small fuel grain. Scratch mix is ok, but to pukey for me.


Edited by Bourbon, 10 January 2022 - 11:53 PM.


#10 mabuse00

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Posted 11 January 2022 - 11:48 AM

Wait a minute - 48mm? Wow, now that is long. I dont have my notes right now, but mine is something like 31mm.
But a 9mm nozzle is like a standard coreburner size, that is not a very hot setup.

I cant see how it should be possible to pop that, except
-when the production method is faulty
-or the burning sidevent at ignition causes overpressure...

How large is your sidevent for that setup?
Did you wax the tubes?

 

 

150 gram header as a stinger before it gets squirrely

For 1lb size? Wow, that's much more than I expected.

 

 

Both of your spindles are larger than this, at the nozzle. Which will contribute to lower thrusts/velocitys and reduced spin up times.

Mine is 0,19inch at the nozzle. But spin up is still too short for my taste. Can't be helped...


Edited by mabuse00, 11 January 2022 - 11:52 AM.


#11 Bourbon

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Posted 11 January 2022 - 01:59 PM

Nope, nothing hot about this setup. I think the longer core gives a bit more poop.

 

My hot fuel "75/15/10" pops these, but, as I said, I hand ram. I believe if I were to press or wax the tubes they would work just fine. Or, even the 2% moisture alone might work. I Dunno? The side vent "tangential hole" is right at 2mm also. I also use a nozzle. Some folks don't. I'd say that would let you use any fuel with no nozzle.

 

Tool Set: https://www.woodysro...R_/_ZIPS.html#/

 

I also believe that my slightly slower fuel "milled 65/25/10" gives it time to ramp/spin up, before that long core kicks in. The shape of that header means everything on the Stinger to get 150 grams up. Conical cones or domes of coarse. Nothing fat or bulky; she might fly, but look out!


Edited by Bourbon, 12 January 2022 - 10:08 AM.


#12 Bensmith

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Posted 12 January 2022 - 09:34 AM

The trick with Stingers is to make sure they don't carry too much header weight. Though they have the lifting power, the heavier the header, the more the center of gravity shifts and the more erratic the flight. I prefer to launch mine out of a simple fiberglass tube (the 1.75" 1.4 stuff works a-ok). This method allows the Stinger to spin up and stabilize a bit before flying, producing a "mostly" vertical flight... for a Stinger, anyhow. Use the hottest 75:15:10 BP you can make, add a bit of titanium, charcoal or micro-stars to the fuel above the spindle for a nice tail. Here's a tutorial I wrote quite a while ago that details my technique. BP stingers tutorial.qxd (wsimg.com)


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#13 Mumbles

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Posted 19 January 2022 - 11:35 AM

Have any of you guys experimented with any tape or thin reinforcement at the bottom over the main nozzle?  I've never tried it personally, but I know a few guys that would swear by those reinforcing stickers you use on 3-hole punched paper or paper tags. (

 

My experience is rather limited and without much success.  I had a lot of the same issues as many of you have had at one point I'm sure.  They love to go every direction except up, with a particular heat seeking affinity for people.  A lot of the descriptions and advice in this thread ring true.  I'd often see a kind of poor or incomplete spin up, wobbling rocket on the launch spindle, and then it'd take off before totally spin stabilized in whatever direction it felt like.  I was just thinking about this reading the thread, and was wondering if a little extra stabilization or reinforcement might help keep the stingers spinning a little more true or stay pointed upwards.


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