Metal Tubing For A Body?

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Lone Rocketeer

Lone Rocketeer

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Has anybody used metal tubing such as coper or aluminum to build a small rocket body? I want to try building a metal body for a small engine rocket and I was wondering if anyone else has had any success with this.
 
It's specifically FORBIDDEN by the model rocketry safety code. No metal body tubes, fins, noses, etc. As far as I know, the only metallic parts you can use are engine hooks and electronic payloads, which are only partly metal anyway.
 
Originally posted by TWRackers
It's specifically FORBIDDEN by the model rocketry safety code. No metal body tubes, fins, noses, etc. As far as I know, the only metallic parts you can use are engine hooks and electronic payloads, which are only partly metal anyway.
Click to expand...

ooopppss.... My bad.
I guess I could see some safety issues with that if one misfired.
I know I don't want a metal dart coming after me. (Lawndart Flashback)

So is there something stronger than cardboard tubes on the small scale level that is legal?
 
Originally posted by Lone Rocketeer
So is there something stronger than cardboard tubes on the small scale level that is legal?
Click to expand...

Try carbon fiber. Or glass the cardboard.

Would are you thinking about?
 
Originally posted by Rocketmaniac
Try carbon fiber. Or glass the cardboard.

Would are you thinking about?
Click to expand...

I just think that the bodies should be stonger than cardboard tubes.
Of course, there is some pretty thick cardboard out there but If I build a rocket, I want it to last.
 
Under normal use a tube is pretty stiff for its mass and thickness because it's circular in cross-section. A sphere is about the only shape that's going to be stiffer per unit mass or thickness. That's one reason why most submarines and many aircraft (commercial, not combat) are more or less cylindrical.

As long as you don't step on your rockets, that is.
 
Originally posted by TWRackers
Under normal use a tube is pretty stiff for its mass and thickness because it's circular in cross-section. A sphere is about the only shape that's going to be stiffer per unit mass or thickness. That's one reason why most submarines and many aircraft (commercial, not combat) are more or less cylindrical.

As long as you don't step on your rockets, that is.
Click to expand...

Fair enough.
But what do they build the big boys out of?
 
That depends on who the big boys are. Do you mean NASA's rockets, or the ones built by high-power-rocketry folks?
 
If you're looking for heavier walled tubing, check out the Large body tubes at Semroc

The wall thickess is twice that of the standard body tubes. You can get the nose cones that fit the tubes there also.
 
Full scale rockets are almost always metal because of the greater aerodynamic stresses involved, and because a rocket that's twice as long as another doesn't require walls that are twice as thick; otherwise, mass would go up by 2 cubed, or 8x. If you scaled down a full size rocket exactly, including the thickness of the metal walls, pretty soon you'd have a rocket that was made of the equivalent of a single layer of aluminum foil.
 
Originally posted by TWRackers
That depends on who the big boys are. Do you mean NASA's rockets, or the ones built by high-power-rocketry folks?
Click to expand...

I'm talkin about the high powered rocketry people.

Of course, I'd like to build somthing that breaks the atmosphere one of these days too. Most likely a pipe dream, however.
 
The larger high power rocket airframes can built from a variety of materials

1) Spiral wound fiberglass tubing
2) carbon fiber tubing (expensive!!)
3) paper tubing laid up with fiberglass, carbon fiber or a combination

Fins are typically G-10 fiberglass or aircraft plywood in a variety of thicknesses depending on size of rocket and motor choice. The plywood fins can also be laid up with fiberglass or carbon fiber.

There are A LOT of high power rocketry sites on the net describing construction, etc. Why don't you try Google? It's probably how most of us first figured out all this high power stuff.
 
Originally posted by JRThro
Well, yeah, exactly. The model rocket safety code, which was specifically referred to in the post above, says this, which I've taken directly from the NAR website at https://nar.org/NARmrsc.html:

"Model Rocket Safety Code

1. Materials. I will use only lightweight, non-metal parts for the nose, body, and fins of my rocket."
Click to expand...

That's exactly the part I was thinking about. I know things are a little different for Tripoli/high-power, but I have no experience there. I just got back into rocketry this fall after a 21+ year hiatus, so I'm still planning out a strategy to get my Level 1.
 
Originally posted by JRThro
Well, yeah, exactly. The model rocket safety code, which was specifically referred to in the post above, says this, which I've taken directly from the NAR website at https://nar.org/NARmrsc.html:

"Model Rocket Safety Code

1. Materials. I will use only lightweight, non-metal parts for the nose, body, and fins of my rocket."
Click to expand...

It was not or is it my intention to argue or debate this subject; imho it has been beat to death. Neither do I wish to offend anyone.


I would point out that original poster did not specify if his intended use was for hpr or model rocketry, rather the assumption was made by others that the relevant safety code was the model rocket code. When folks start asking about metal body tubes it seems to me they are talking HPR and not model rockets.

Perhaps a more relevant code can be found at NAR’s site and is quoted below.


3. Materials. My high power rocket will be made of lightweight materials such as paper, wood, rubber, and plastic, or the minimum amount of ductile metal suitable for the power used and the performance of my rocket.


So it seems safe to say that the use of metal body tubes in model rocketry is a violation of the model rocket safety code. It also seems clear the both NAR and Tripoli's HP safety code allow minimal use of "ductile metal".

That said it seems to me that minimal is the optimal word here and it is best to avoid the use of metal when a suitable alternative is available.
 
Originally posted by Last Frontier
When folks start asking about metal body tubes it seems to me they are talking HPR and not model rockets.
Click to expand...


In this case, I was talking about model/Low Power rocketry and not HPR. I was wanting to build a sturdier model. Something that would survive whatever malfuncions may occur. (short of getting hung up in a tree or dunked in a pond)
 
Originally posted by Lone Rocketeer
In this case, I was talking about model/Low Power rocketry and not HPR. I was wanting to build a sturdier model. Something that would survive whatever malfuncions may occur. (short of getting hung up in a tree or dunked in a pond)
Click to expand...

In that case I would say that is overkill...


;)
 
Originally posted by JRThro
Well, yeah, exactly. The model rocket safety code, which was specifically referred to in the post above, says this, which I've taken directly from the NAR website at https://nar.org/NARmrsc.html:

"Model Rocket Safety Code

1. Materials. I will use only lightweight, non-metal parts for the nose, body, and fins of my rocket."
Click to expand...

Well, NO, exactly. Sort of.
The ORIGINAL post asking the question mentioned nothing about the Model Rocket Safety Code.
The reply did.
Nor did the original post make mention of any organizations, be they guvamint or private.
As there are two certifying organizations in addition to, as I understand it, independant groups that stive to conform to NFPA 1127 but not necessarily other standards held by either NAR or TRA or both, your assertation is correct in only some cases.
NAR members have that nasty business of THE "Model Rocket Safety Code" while TRA seems not to have a big problem with it as long as it's done safely and when necessary, and the RSO can be talked into it.
It would seem that if a person is a member of TRA or and independant group, they can build rocket up to and including entirely out of metal if it is deemed to be necessary.
AND they will not be in violation of any part of NFPA 1127.

As for the
I know I don't want a metal dart coming after me.
Click to expand...

Why? What difference does it make? I'll let ya in on a little physics secret....
It doesn't make one whit of difference if the rocket is steel, aluminum, depleted uranium, phenolic, plastic, resin soaked toilet paper or whatever.
The energy with which it is gonna thump you or the ground or your car or Wildman's RV is dependant upon velocity and mass, not material. For the most part.
A five pound phenolic and plastic rocket traveling at 800fps is gonna mess you up the same as a five pound aluminum rocket traveling at 800fps.
Basically.
There is the whole "elastic" versus "inelastic" collision stuff if you want to get really technical where the phenolic rocket will probably crumple more and absorb "some" of the energy itself resulting in a somewhat less completely nasty boo-boo, but not enough to make a difference.
In the above examples I'm betting you're kaput either way so the minutia is moot.
And Tim's RV will have a BIG hole in it.
'Cuz by my calculations, they both hit you with right around 49,734 ft# of smack down.
To compare, a .45ACP, 230 FMJ (full metal jacket) aka, hardball, traveling at the same 800fps is going to deliver a seemingly measly 327 ft#.
It would be interesting to get a cadaver (even private individuals can do that you know) and see what the above rocket configuration would do to it.
But, ewwww, I'll leave that to others.

Greg
 
Oops, I forgot this isn't the thread with all the bad puns

Originally posted by 11Bravo
The energy with which it is gonna thump you or the ground or your car or Wildman's RV is dependant upon velocity and mass, not material. For the most part.
Click to expand...

A very good point. Kinda like, when you hit water from a very great height, it hurts about the same as hitting plain ol' solid ground. Nevertheless, it is the intent of the safety codes that we should try to minimize the 'bulletproof' construction and build so that the rocket absorbs as much of the impact energy as possible. This applies to low-, mid-, and high-power (and whatever class they come up with for those crazies out there working on "X" impulse-class motors).

This is a great discussion because we all need to remember safety. As much fun as it is, it still ain't worth getting killed for.

And the cadaver research could make an interesting NARAM project, but I think it might be better to substitute some ballistic gelatin?
 
Hey Lone,
Do you feel like your question has been answered yet? Judging by your responses you may not be satisfied even though the answers are in this thread. I will try again just for redundancy. :)

Everyone I know who has done a lvl 3 has fiberglassed their "paper" tubes. You get sheets of fiberglass cloth, wrap and epoxy it around the paper. There are various threads on this forums that talk about various techniques.

If you are going for some serious stress like uber-high altitude or mega-mach speeds then you are gonna want carbon fiber. Again this can be in sheets epoxied to the tube. As mentioned earlier there are also tubes of just carbon fiber sold. But carbon fiber is expensive and doesn't make since on smaller, slower, lower rockets.

I myself used 2 wraps of 6 oz (I think it was 6oz) fiberglass cloth on my level 3. I've also used fiberglass on smaller rockets that I expected to launch with a larger motor than they should be launched with. Never saw those again. :)

Anyway, I hope we've helped.
 
Originally posted by powderburner
Oops, I forgot this isn't the thread with all the bad puns
Click to expand...

Is there a "good" pun?
I mean there are good ones, but is there a "good" one?

snip....and whatever class they come up with for those crazies out there working on "X" impulse-class motors....snip
Click to expand...

Just the thought of that makes me go all gooshy inside.
More power. TMG. TMG TMG.

And the cadaver research could make an interesting NARAM project, but I think it might be better to substitute some ballistic gelatin?
Click to expand...

Or go Mythbuster style and use a dead pig.
Anyone know where to get a dead pig?
Maybe someone from Iowa?
Anyone?
Oh. Wait....
Guess that'd be me.
I am NOT driving all the way to NARAM with a dead pig in my car; I just got it.
The car that is.

Greg

TMG=Tool Man Grunt
 
Originally posted by PGerringer
Hey Lone,
Do you feel like your question has been answered yet?
<snip>
Anyway, I hope we've helped.
Click to expand...

Actually, I've gained a lot of info from this thread. My orignal intent was to find out if metal tubing would fly, however. My intent was for building a LPR that can take some abuse without being utterly destroyed. (i.e.- ejection misfire's, landing on the pavement, repeated use, etc.)

Apparently it is frowned upon, however. But am I breaking any actual laws by doing this or just some arbitrary guidelines? I don't want arrested just for experimenting with different materials.
 
Unless Missouri has some law that forbids it, no.
If you fly with NAR it appears they will frown bigly on it.

At https://tripoli.org/documents/use_of_metal.shtml, TRA says-
-- Since the rocket is to be recovered and reused as stated in this Safety Code, the rocketeer may determine that a particular rocket will be flown more than once, i.e. several times. A particular rocket may fly well one time using materials other than ductile metal, but continued use and the resultant stresses after the first flight may prove to render a non- metallic rocket unsafe. Such circumstances may include, but not be limited to, continual flights using M motors. Therefore, a particular rocket, in order to conform "to the other requirements of this code," shall be so constructed using any materials specified as being approved for use in a HP rocket, and in what ever amounts are required for compliance. Keep in mind that this interpretation takes into account the "installed total impulse (continual use of M motors), and whose primary use is for purposes of education, recreation, and sporting activities."

-- Finally, note the use of the words "when necessary" [2-6]. This is subjective and really up to the interpretation of (a) the person building the rocket, weighing all the factors of the entire Safety Code, and (b) the RSO who will ultimately make the decision whether or not to allow the flight.
Click to expand...

The above specifically sites large impulse motors and HPR, but it reads to me that if you were able to articulate your case that for some reason your flying location/conditions/needs necessitated more than normally minimal use of metal, you should be fine.
And notice further that it does pretty much put the onus on you to decide if it is necessary.
That and being able to talk the RSO into it.
And if you're launching on your own and you can't talk the RSO into it, you got bigger problems. :D

Go for it.
Even if you never fly it, at the least you get the practice and experience of working with another material.
Just launch it towards the south and Arkansas.
Not north towards Iowa.

Greg
 
Originally posted by Lone Rocketeer
Apparently it is frowned upon, however. But am I breaking any actual laws by doing this or just some arbitrary guidelines? I don't want arrested just for experimenting with different materials.
Click to expand...

If your local authorities (state/city/town firecode) have adopted NFPA 1122 (as most have across the country) then a model rocket cannot have 'major metal components'. You may still be able to launch a metal rocket on private property with permission from your local fire marshall. This includes non-commercial motors. They may treat anything outside of NFPA 1122/1127 as fireworks and require a permit.

The FAA does not specify materials, just >1lb liftoff weight. The ATFE only cares about the propellant.

However, if you want to have insurance to fly on someone else's property (NAR/TRA), or secondary personal liability insurance (NAR), then you have to follow their safety codes which are based on NFPA 1122 (and 1127 for HPR).

An easier solution is to use a layer or two of fiberglass/epoxy over the cardboard tube. I had a LOC Aura made like that and flew it on D thru H for dozens of flights until I lost it (on an F with an altimeter in it!).

-John DeMar
NAR/TRA L2
 
Originally posted by 11Bravo
Just launch it towards the south and Arkansas.
Not north towards Iowa.
Click to expand...
No worries.
I'm originally from Iowa.
I have an uncle in Arkansas, though.
I'll split the difference and blow up Kansas.... wait... My guitarist lives there.
OK.... Illinois it is! :D


Originally posted by jsdemar
You may still be able to launch a metal rocket on private property with permission from your local fire marshall.
Click to expand...
That shouldn't be a problem

Originally posted by jsdemar
This includes non-commercial motors. They may treat anything outside of NFPA 1122/1127 as fireworks and require a permit.
Click to expand...
Even if they treated it as a fireworks, I still wouldn't need a permit.
You can buy fireworks all over the place in MO. As long as the display isn't in city limits, you can blow stuff up all you want. Part of why I like living here. :D
 
Originally posted by Lone Rocketeer
Apparently it is frowned upon, however. But am I breaking any actual laws by doing this or just some arbitrary guidelines? I don't want arrested just for experimenting with different materials.
Click to expand...
I don't think I would call the TRA and NAR guidelines arbitrary. They are designed for the safest and most enjoyable experience. Course that is very arguable. :)

Your best bet would be to find out what your local laws alow. I can tell you though, if you go to most TRA or NAR sanctioned events they probably will not let you launch a full metal rocket.

As a side note, when last I was visiting Ross from Magnum he showed me two interesting rockets. One being a metal fin can where the fins were on a spring and you collapsed them so they fit in a tube. Once the rocket left the tube, the fins popped out and gave stability. The other was a "kit" a company was hoping to offer to the public. It consisted of a metal tube, metal fin can and a metal nosecone. You basically slid the motor into the metal body, screwed on the fin can for a retainer and you had a metal rocket. It was cool til he said something like noone would buy it because you can't launch a metal rocket at sanctioned launches.
 
Originally posted by PGerringer
I don't think I would call the TRA and NAR guidelines arbitrary. They are designed for the safest and most enjoyable experience. Course that is very arguable. :)

Your best bet would be to find out what your local laws alow. I can tell you though, if you go to most TRA or NAR sanctioned events they probably will not let you launch a full metal rocket.

As a side note, when last I was visiting Ross from Magnum he showed me two interesting rockets. One being a metal fin can where the fins were on a spring and you collapsed them so they fit in a tube. Once the rocket left the tube, the fins popped out and gave stability. The other was a "kit" a company was hoping to offer to the public. It consisted of a metal tube, metal fin can and a metal nosecone. You basically slid the motor into the metal body, screwed on the fin can for a retainer and you had a metal rocket. It was cool til he said something like noone would buy it because you can't launch a metal rocket at sanctioned launches.
Click to expand...

Here's my arguement........

I don't plan on doing any sanctioned launches. My schedule down't allow for me to plan far enough ahead for scheduled launches unless I take vacation time from work. I just go when I have the time and the weather is right. It's just going to be me, my wife, and my daughter out in a field with rockets doing our own thing.

And Ross was wrong, I'd definately buy the kit if it had a decent price tag on it.
 
Originally posted by PGerringer
One being a metal fin can where the fins were on a spring and you collapsed them so they fit in a tube. Once the rocket left the tube, the fins popped out and gave stability.
Click to expand...

Isn't there something like this in the move "October Sky". The boys were accused of starting a fire with said rocket, turned out to be some type of flare as I recall...
 

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