Introduction & mass launch / drag race question

Hello TRF

Let me briefly introduce myself, I'm Pyroplegic from PyroUniverse.com. I'm a certified professional pyrotechnician from Virginia, I had a motorcycle accident in '05 & now use a chair to get around.

I searched briefly but couldn't find what I was looking for. If you'd rather link me to the answers in other threads, than type out reply's that's fine.

Our client wants to do a fundraiser with a high school as shooting a mass of model rockets. 100's 1000's if they sell enough even more than 3130 the GWR. If I may as a NOOB ask some questions.

I'm well versed in State and NFPA codes and the many AHJ restrictions for fireworks, are there any regulation codes I need to know about?

We're planing on using A8-3 motors are these unregulated?

We'll be using commercial (MJG) firework style ematch, rather than the estes igniters, for more fire & reliability. In testing I was having ignition failures. Is there a sealant on the propellant of these motors preventing easy or accidental ignition? It was suggested to use a non-sparking tool (brass awl AKA Pyro-poke) to scrape any sealant off & expose the propellant to fire. Is this safe why / why not?

How do ya'll fire off mass launches or drag races? Wire in one series all the matches & throw some type of cap discharge system on it? For 100's even? We're planning on using a professional firework firing system to disperse the electricity.

They're also creating launch pads to hold 100 or so at a time, aside from bulk are there any design do's & don'ts we should be aware of?

Anything else I should be aware of?

Thanks for any assistance you can point me towards

Jake

Hi Jake,

Welcome to the forum. I can't give you enough definitive info and a small, partial response would only add noise to the thread.

One thing that would help is letting us know your location.

I wish you well.
Kenn

Full disclosure: I have no personal experience with mass launches.

The National Association of Rocketry has some recommended stand-off distances built into the safety code when flying at NAR sactioned events: https://www.nar.org/safety-information/model-rocket-safety-code/ specifically #5.

A8-3 motors are un-regulated. You may want to contact Estes for a bulk order: https://www.estesrockets.com/

I've never used a firework style ematch but the majority of failures with Estes style nichrome wire igniters involve shorts due to installation error or the tip not in contact with the propellant (again install error).

I might suggest contacting the NAR leadership. Maybe they can put you on to local folks with some experience with this kind of thing.

Virginia Fredericksburg & Richmond area

Midwest Power 11 did a mass launch of about 25 rockets. I think Tim from Wildman Rockets pushed the button... You can reach him via his online store or reach the club via QCRS.us... There's a great YouTube video of it, just search for Midwest Power 11

I don't have any advice on how to do this mass launch, but I would like to go on record saying I want to see the video!

There is no coating or sealant on the propellant. if you had problems with ignition, then you either shorted the igniter leads before they reached the tip bridge wire or you did not have the tip in contact with the propellant. When installed with the plugs that the motors come with, they are extremely reliable, but he older "igniters" have a black pyrogen tip and the newer "starters" have a clear/whitish looking covering on the tip that is not a pyrogen, so firm contact is very important for "starters" as the bridge wire must touch the propellant.

Legal safe distances for mass launches are covered in the NFPA 1122.

For some first hand experience handling hundreds of rockets simultaneously launched, you may want to look up the guys who did the Mt. Dew commercial a few months back...

[video=youtube;U13gJA0kQRQ]https://www.youtube.com/watch?v=U13gJA0kQRQ[/video]

In the behind the scenes video, they talk about the film makers, and they seem to know what they were doing.

Pointy Side Up!
Jim

ThirstyBarbarian said:

I don't have any advice on how to do this mass launch, but I would like to go on record saying I want to see the video!

Click to expand...

here's a 2010 attempt at 3200
[video=youtube;YykV9Xjxj3c]https://www.youtube.com/watch?v=YykV9Xjxj3c[/video]
[video=youtube_share;7qpQMvCAhGs]https://youtu.be/7qpQMvCAhGs[/video]

pyroplegic said:

here's a 2010 attempt at 3200
[video=youtube;YykV9Xjxj3c]https://www.youtube.com/watch?v=YykV9Xjxj3c[/video]
[video=youtube_share;7qpQMvCAhGs]https://youtu.be/7qpQMvCAhGs[/video]

Click to expand...

Wow! That was pretty cool!

shreadvector said:

There is no coating or sealant on the propellant. if you had problems with ignition, then you either shorted the igniter leads before they reached the tip bridge wire or you did not have the tip in contact with the propellant. When installed with the plugs that the motors come with, they are extremely reliable, but he older "igniters" have a black pyrogen tip and the newer "starters" have a clear/whitish looking covering on the tip that is not a pyrogen, so firm contact is very important for "starters" as the bridge wire must touch the propellant.

Legal safe distances for mass launches are covered in the NFPA 1122.

Click to expand...

I have an ATF license so can I can purchase and I'm planning on using true electric match. they take less current and provide more fire than a standard starter. But I'm sure the HPR guys use ematch. Our other thought is the fire too quick? I fit the match head inside the nozzle, 2 with the plugs in & one without, didn't short out any of them, they popped in the test but the motors didn't ignite. hence why we thought there was a sealant on the fuel, and if the fire was too quick.
Anybody here use actual commercial electric match? what's your technique?

[video=youtube_share;AwIsIaTYOuI]https://youtu.be/AwIsIaTYOuI[/video]

Jake-pm sent

Did not watch the video, but Model Rocket Motors do not require a blastic cap type of shock to detonate them. They need a heat source to start them buring. If your lectric matches "POP", then they simply pop themselves out of the motor nozzle before heat can be transferred to the bare propellant face.

You want heat. For a cluster or mass lauch you want all motors to get that heat fast. You want low current igniters that generate heat energy and not a lot of gas and "POP" and you want the igniters to stay in the nozzle as the heat is quickly transferred. Again - if the igniter generates an explosive blassting cap-like shock it will just blow itself out of the nozzle and the motor will not ignite. BUT you will get to waste lots and lots of money on very expensive igniters that do not work.

Find someone who has a large number of the classic pyrogen tipped Estes Solar Igniters as opposed to the newer "Starters". Those will work fine with a relatively low current requirement for each. THey are fired fast with 4 AA batteries, so a largerr power supply should be able to power lots of igniters wires in parallel. Series is a bad idea for these - they are NOT 'electric matches'.

pyroplegic said:

I have an ATF license so can I can purchase and I'm planning on using true electric match. they take less current and provide more fire than a standard starter. But I'm sure the HPR guys use ematch. Our other thought is the fire too quick? I fit the match head inside the nozzle, 2 with the plugs in & one without, didn't short out any of them, they popped in the test but the motors didn't ignite. hence why we thought there was a sealant on the fuel, and if the fire was too quick.
Anybody here use actual commercial electric match? what's your technique?

[video=youtube_share;AwIsIaTYOuI]https://youtu.be/AwIsIaTYOuI[/video]

Click to expand...

Fred, thanks for this explanation this sounds like what's happening. so rocket fuel propellant is not nearly as susceptible to fire as a BP based firework? I thought I'd seen a Mythbusters rocket show where some HPR guys were usung e-match to light off those. What motor/ignition combo are they using in the dew commercial? look very closely at (01:41/01:43)

"I keep thinking of motors as a gerb (fountain) in reverse. I’ve been trying over & over & every time a failure to ignite. I come from a close prox background & this is just like matching a gerb yeah? I put the head in the nozzle all the way in (as far as possible) secure wire so after ignition the match is blown out but not sent flying (also tried the yellow plug that comes with the motors, tried a piece of gaff tape to seal it & one without anything over the nozzle) Nothing… I tried scraping some sealant if any, off the fuel with a nonsparking pyropoke, no luck, then a tiny piece of black match inside the nozzle first then the match head to propagate the fire, nada…lastly a length of visco fuse shoved in & hand lit… still nothing! WTF!!! I’ve not seen any ignite. The match heads pop every time, not shorted, plenty of fire. Are my test motors bunk? I nearly want to tell these guys to get firework rockets or missels from a 1.4 dealer… "

Asked this on pyro-U

[video=youtube_share;U13gJA0kQRQ]https://youtu.be/U13gJA0kQRQ?t=1m43s[/video]

pyroplegic said:

Fred, thanks for this explanation this sounds like what's happening. so rocket fuel propellant is not nearly as susceptible to fire as a BP based firework? I thought I'd seen a Mythbusters rocket show where some HPR guys were usung e-match to light off those. What motor/ignition combo are they using in the dew commercial? look very closely at (01:41/01:43)

"I keep thinking of motors as a gerb (fountain) in reverse. I’ve been trying over & over & every time a failure to ignite. I come from a close prox background & this is just like matching a gerb yeah? I put the head in the nozzle all the way in (as far as possible) secure wire so after ignition the match is blown out but not sent flying (also tried the yellow plug that comes with the motors, tried a piece of gaff tape to seal it & one without anything over the nozzle) Nothing… I tried scraping some sealant if any, off the fuel with a nonsparking pyropoke, no luck, then a tiny piece of black match inside the nozzle first then the match head to propagate the fire, nada…lastly a length of visco fuse shoved in & hand lit… still nothing! WTF!!! I’ve not seen any ignite. The match heads pop every time, not shorted, plenty of fire. Are my test motors bunk? I nearly want to tell these guys to get firework rockets or missels from a 1.4 dealer… "

Asked this on pyro-U

[video=youtube_share;U13gJA0kQRQ]https://youtu.be/U13gJA0kQRQ?t=1m43s[/video]

Click to expand...

The simple thing to do is just use one of the igniters packaged with the motors and see if the motor lights. If the motor lights, then the problem is your non-standard igniter or ematch or whatever you are using. If the motor does not light using the igniter designed for it, then maybe you do have a bad batch of motors, but that its pretty unlikely. As far as I know, there is no "sealant." Sometimes (rarely) a motor is manufactured with a defect in which some of the clay that forms the nozzle covers what is supposed to be the exposed end of the fuel grain. In that case, you cannot light the motor. It doesn't happen that often.

Basically, try following the instructions and use the motors and igniters as designed. If that fails, then there is probably a defect. To me, that makes a lot more sense thatn to try a lot of non-standard igniters and conclude the motors are bad when it doesn't work.

Myth busters probably used composite propellant motors, not black powder motors. Composite motors have a large slot or central hole and the igniter is inserted AT&T the way inside to the top of the motor. When a composite igniter fires it must create heat for a decent amount of time and project or radiate that heat across a good portion of the inner exposed face of the solid rubbery propellant grain. Extra pressure can flow out of the nozzle as the igniter gets the composite propellant burning. As it comes up to pressure, the igniter wires are spit out and the entire inner surface is burning resulting in supersonic glow at the narrow point if the nozzle (it is "choked").

A normal Estes black powder model rocket motor is easy to ignite. Children can do it, but the actually follow the instructions and read the instructions. The black powder is not a loose powder - it had been pressed onto a solid grain. If you look into the nozzle with a bright flashlight you should see black or very dark grey propellant beyond the outer light gray clay nozzle.

I do this all the time when I cluster BP motors. I wrap tape around the nozzle end, dump a bit of 4F BP into the nozzle hole, put the ematch into the powder and close the tape around everything. Low current and works every time!!