tube launched rockets *edited title*

have an idea to build a rocket powered tube launching system and am having a bit of design trouble. The concept is to build a tube with a positive powered plate and a negative powered plate at the bottom which are always connected to a battery. When you drop the rocket down the tube the moment the igniter contacts hit the plates it launches. I want to use low power so it really doesn't travel far and acts like flare style mortars floating down by parachute.
The design issues I'm having are:
how to make the mortar slide nicely inside the tube and not bind,
how to make sure the igniter tabs contact the plates,
what shape should the mortar be.

i would like to here some ideas and opinions, thanks.

i have edited the thread title because people have thought i was building a weapon system powered by model rockets, this is not the case.

mbecks said:

I have an idea to build a rocket powered mortar tube and am having a bit of design trouble. The concept is to build a tube with a positive powered plate and a negative powered plate at the bottom which are always connected to a battery. When you drop the rocket(mortar) down the tube the moment the igniter contacts hit the plates it launches. I want to use low power so it really doesn't travel far and acts like flare style mortars floating down by parachute.
The design issues I'm having are:
how to make the mortar slide nicely inside the tube and not bind,
how to make sure the igniter tabs contact the plates,
what shape should the mortar be.

i would like to here some ideas and opinions, thanks.

Click to expand...

You said you want opinions. Here’s mine.
It’s a violation of NFPA 1122, 1127, and the Safety Codes of NAR, TRA, and CAR. It’s also dangerous. Once you drop the rocket you have no way to prevent ignition and you’re in violation of the safe distances.

Thanks for the opinion.

Steve Shannon said:

You said you want opinions. Here’s mine.
It’s a violation of NFPA 1122, 1127, and the Safety Codes of NAR, TRA, and CAR. It’s also dangerous. Once you drop the rocket you have no way to prevent ignition and you’re in violation of the safe distances.

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^ this

Try a flip fin, ring gap tail, or any other thing that might safely fit in a tube tower. Just be safe and maybe please don't call it a mortar?

I'm with Steve Shannon here. Lots of stuff could go wrong ans create a dangerous situation...what if the rocket gets stuck in the tube or misfires? Then you have the dangerous task of extracting it from the tube without having it go off in your face.

Misfires will be frequent...they occur often enough when you can take your time wiring the igniter with alligator clips.

If you really want a rigid launcher, maybe you should build a competition-style tower...lots of folks have made that work. But don't try to get fancy with ignition.

I've done tube launched folding fin rockets but always with an igniter lead and safe distance.

I would have thought this was a troll reaction post if I hadn't seen the previous "Rocket Train" thread.

So let's spell this out clearly: using model rocket components in any way to construct something that looks and acts like a hand held weapon is an outrageously ill-considered idea. Don't you realize how close our hobby is to being regulated away? Not only would your idea fly in the face of all of the regulations already cited, and whatever other Canadian rules haven't been cited, the optics are terrible. One well publicized accident could easily start a round of "oh, maybe those things shouldn't be available in stores for kids to buy" and POOF our hobby dies.

Use model rocket engines to fly rockets.

You guys should see what kids are up to with rockets on YouTube! I will probably carry on. Thanks for the concerns. Anyone have any build ideas for this project?
Heres an example of what popular youtubers are up to: https://youtu.be/DUmIDz5L0O8

YouTube children are probably not the best examples for anyone ever?

But they are, they are what the other kids are watching and getting ideas from, not my channel.

I think I’ve learned my lesson. Do my project, make my video let everyone yell at me after.

Your project is ill conceived. It is dangerous. It is against various rules cited by others. Yet you persist in doing it, and the you are going to post it to YouTube for all the world to see? That is not smart, and referencing the idiots on YouTube to justify your actions shows that you are also not the brightest bulb.

mbecks said:

But they are, they are what the other kids are watching and getting ideas from, not my channel.

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Hold my energy drink and watch this…

Whatever we as adults do, we set examples. We can either set good examples or we can set poor examples. It’s up to you.

markkoelsch said:

Your project is ill conceived. It is dangerous. It is against various rules cited by others. Yet you persist in doing it, and the you are going to post it to YouTube for all the world to see? That is not smart, and referencing the idiots on YouTube to justify your actions shows that you are also not the brightest bulb.

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yea I’d say I’m about a 40 watt,

I'm going to be a differing voice...in a way. I think the idea is interesting and with some change of ideas and some out of the box thinking, it *might* be possible to do something like this and not run afoul of the NAT/TRA/CAR rules.

I don't think your idea of a straight drop and ignite is going to fly in any way as it violates 2 major rules that I can think of; the safe stand-off distance and the standard electrical ignition. The first issue you could work around by doing something that would allow you to drop it in the mortar tube remotely. Either a pull string or a solenoid jump to mind but there might be other ways. The second issue is the ignition process. Your idea could work if it can be disabled remotely like a standard launch controller. My idea is something along the lines of:

1) ensure controller is safe with interlock removed.
2) go to "pad" and load rocket
3) return to controller and reinstall the interlock
4) verify controller has igniter enabled
5) release rocket to drop into mortar
6) rocket launches from mortar -or- it doesn't and you disable controller and remove interlock. You could then approach the "pad" just like anyone else.

There may be other ways of doing it but this is what I came up with after a few minutes of thinking.

Everyone - besides safety distance and odd motor ignition, what else is he running afoul of?

heada said:

I'm going to be a differing voice...in a way. I think the idea is interesting and with some change of ideas and some out of the box thinking, it *might* be possible to do something like this and not run afoul of the NAT/TRA/CAR rules.

I don't think your idea of a straight drop and ignite is going to fly in any way as it violates 2 major rules that I can think of; the safe stand-off distance and the standard electrical ignition. The first issue you could work around by doing something that would allow you to drop it in the mortar tube remotely. Either a pull string or a solenoid jump to mind but there might be other ways. The second issue is the ignition process. Your idea could work if it can be disabled remotely like a standard launch controller. My idea is something along the lines of:

1) ensure controller is safe with interlock removed.
2) go to "pad" and load rocket
3) return to controller and reinstall the interlock
4) verify controller has igniter enabled
5) release rocket to drop into mortar
6) rocket launches from mortar -or- it doesn't and you disable controller and remove interlock. You could then approach the "pad" just like anyone else.

There may be other ways of doing it but this is what I came up with after a few minutes of thinking.

Everyone - besides safety distance and odd motor ignition, what else is he running afoul of?

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Aaron,
Having a mechanical or electromechanical release like that would satisfy the safe distance requirement.
As far as the electric ignition requirement I would make sure that a launch switch must be held while dropping the rocket in the tube with the previously mentioned release. If the launch switch were not held ignition couldn’t happen. If the launch switch were released, ignition current would cease flowing.

mbecks said:

i would like to here some ideas and opinions, thanks.

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*IDEA* AND *OPINION*

Dont even attempt that.. Its not to smart..

Just sayin...

Unless you like being on the news for stupid idea of the day segment..

Steve Shannon said:

Aaron,
Having a mechanical or electromechanical release like that would satisfy the safe distance requirement.
As far as the electric ignition requirement I would make sure that a launch switch must be held while dropping the rocket in the tube with the previously mentioned release. If the launch switch were not held ignition couldn’t happen. If the launch switch were released, ignition current would cease flowing.

Click to expand...

Yes, that was my intent. Arm the controller, hold the "ignite" button, drop the rocket. Upon failure, release the ignite button and disarm the controller.

I think the idea of how to install and connect the igniter may need some work. Not sure I followed the original idea but if the base of the mortar tube had 2 concentric rings of copper or similar and those were the 2 leads from the controller, you could then install an igniter into the rocket motor and ensure the leads from the igniter are of differing lengths so that when the rocket reaches the bottom of the mortar tube, the leads from the igniter touch the rings in the base. The rings may have to be spring loaded to ensure solid connection and you don't get a bounce and disconnect.

I think it goes without saying but I'll say it anyway, this would only be suitable to LPR.

heada said:

Yes, that was my intent. Arm the controller, hold the "ignite" button, drop the rocket. Upon failure, release the ignite button and disarm the controller.

I think the idea of how to install and connect the igniter may need some work. Not sure I followed the original idea but if the base of the mortar tube had 2 concentric rings of copper or similar and those were the 2 leads from the controller, you could then install an igniter into the rocket motor and ensure the leads from the igniter are of differing lengths so that when the rocket reaches the bottom of the mortar tube, the leads from the igniter touch the rings in the base. The rings may have to be spring loaded to ensure solid connection and you don't get a bounce and disconnect.

I think it goes without saying but I'll say it anyway, this would only be suitable to LPR.

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You are still in violation of the minimum safe distances for launching. Not sure what CAR's distaces are but Model Rocketry Safety Code requires 15' minimum.

How about using water rockets? At least you wont get burned. Just dont try looking down the tube with one in there.

burkefj said:

I've done tube launched folding fin rockets but always with an igniter lead and safe distance.

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These are in a lot of commercial rocket assisted boating safety illumination flares using chute recovery. They are in self contained hand held tubes with a mechanical electronically ignition source. So a mechanical movement slider pull to ignite a match. I think these commercial boating rocket flare safety devices would be a direct violation of safety codes because of stand off distances. They appear to use sanitized MPR APCP motors in single use casings. The practical application is boating rescues and survival uses. I'm not okay with the mortar name. You need to call it a automatic boating rocket illumination safety flare device or some gibberish for peaceful intentions only. Make it a safety oriented device. It may be legal but not under any rocketry rules for commercial products. It needs to have parachute recovery. Arming and loading needs to be electronic to meet stand off distances by TRA. NAR. Or CAR. And the idea in general is likely ill advised.

Rocket boating safety flares aren't advertised as mortars. They don't use hobby motors. They do offer high performance. And somehow someone filed a bunch of paperwork to make it legal somehow. I'm not fully knowledgable about the topic. In the US you would need to make it not a destructive device because the ATF gets hyper critical. Basically make it survival lifesaving kind of system and not anything anybody could weaponize. I don't know how the commercial boating flare companies got around the legal definitions.

Now we are getting some decent discussion. Thanks for all the imput. I officially change the name to “safety rocket tube for helping starving animals”. Are the CAR and NAR rules in anyway law or are they the rules of an organization? I’m not apart of any club so if they are club rules they don’t really apply to me. I think some people’s idea of dangerous and my idea are a bit different. I jump dirt bikes, mountain climb and served in the infantry in Afghanistan, I barely see the danger in what I’m doing with rockets, but I’m ok with people being concerned and appreciate you voicing your opinions, if I disagree don’t take it persoanlly.

In the US I would be afraid of how the ATF a government firearm regulating agency would view the device. If it absolutely has a safety intention like boating flares then they avoid a bunch of crap on over certain milimeter tube sizes it's a destructive device (and a felony to own/make) without a whole bunch of government manufacturer approved forms in certain processes found on ATF website. But you may need to verify with the government to get approvals to make darn sure they are happy and it's not a weapon or easily convertible. The dangers I think you are in a legal mess. It's not a hobby rocket. It's not an explosive tipped mortar. But if government calls it easily convertible destructive device then ot oh.

The other idea is try the licensed pyrotechnic firework route, then it is no longer required to recovery and a firework mortar by definitions legally rather than any could be X or Y type device that could be labeled by lawyers in bad malicious ways. I hate to get all over blown about the legal definitions but you need to ensure its legal whatever your doing.

mbecks said:

Now we are getting some decent discussion. Thanks for all the imput. I officially change the name to “safety rocket tube for helping starving animals”. Are the CAR and NAR rules in anyway law or are they the rules of an organization? I’m not apart of any club so if they are club rules they don’t really apply to me. I think some people’s idea of dangerous and my idea are a bit different. I jump dirt bikes, mountain climb and served in the infantry in Afghanistan, I barely see the danger in what I’m doing with rockets, but I’m ok with people being concerned and appreciate you voicing your opinions, if I disagree don’t take it persoanlly.

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No, club rules are not law; however, in many cases they are based on laws. In the USA, the Federal Aviation Administration owns the airspace, and has laws in place to regulate what kinds of rockets they will allow into their airspace, and when, and where. Likewise, we have a thing called the National Fire Prevention Act. It is not law, but many fire departments and municipalities have accepted it as the standards for their local laws.

I am guessing that Canada has similar laws, and it is your responsibility to know them and obey them. The nice thing about the clubs is that they do know the law, and if you are following their safety codes, then you know you are obeying the law.

I’m not American but I get your point. What differentiates a model rocket launched using a rail or pole and one coming from a tube? Isn’t it still just a model rocket, especially since I have full intent of having a recovery system.

May I ask if any difference if anyone tried like an L-3 Arcas in a pressurized tube launcher as launch rail system instead of a tower using compressed air???? How would that go down with NAR?

mbecks said:

I’m not American but I get your point. What differentiates a model rocket launched using a rail or pole and one coming from a tube? Isn’t it still just a model rocket, especially since I have full intent of having a recovery system.

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You are correct. However, as others stated, there are minimum safe distance requirements (which may or may not be law where you fly), as well as a need to be able to disconnect the launch system for an emergency abort. I don't think anyone is saying that launching from a tube is a problem, but rather the above.

In the US, there are NFPA (National Fire Protection Association) rules that most locations have adopted as state laws/codes and thus they have the force of law. Not every location has adopted them though.(Indiana is still NFPA 1122/1127 free!) I'm not sure about Canada as I've never researched it but I'd suggest you should if you're located there. If you're not a member of any of the organizations, you're not held by their rules but there are benefits to joining such as being able to purchase commercial high power rocket motors, the insurance and club launches. If you decide to not join, you must be sure of the laws for your location and you should carry your own insurance.

As for just renaming something just to skirt the rules, it has been done in the past and the results were not good. I would highly recommend against it as it shows you knew it was wrong and tried to bypass the rules. Justice departments normally don't take too kindly to such things. I think the term is premeditated and it only makes things worse for you. You have clear intentions and there are legal methods to do what you want to do, even if they're much more difficult.

Back in the day a high school friend made a sabot type rocket for a class project. He made the boot out of two halves of Styrofoam shaped to enclose the rocket. The whole assembly fit in a cardboard tube. When the rocket launched, it exited the tube, the foam halves fell away and it had a typical safe flight. It looked just like a tank firing a sabot round, but straight up instead of horizontal. He launched per the safety codes with minimum safe distance and electronic ignition.

If I read your OP correctly, you’re not really interested in firing a rocket out of a tube. You’re interested in an ignition system that fires the motor as soon as it hits the bottom of the tube.

I think your rocket powered rail and snow sleds are interesting and don’t see any issues with them as long as it’s done safely. But I think your rocket powered mortar idea is absolutely unsafe and I ask that you don’t do it. If you want to fire a rocket out of a tube, please do it the safe way per codes with minimum distances. They may not be laws but they’re good guidelines.

TL, DR: You’ll burn your hands off, kid.

Tube launching rockets is A-OK and has been done for quite some time but...it always follows the rules. Electrically started from a safe distance. They're standard rockets and standard motors, just launched from a tube rather than from a rod/rail.

Heck, one of the coolest rockets I've seen was a scale Polaris missile launched from a tube that was submerged under water.