Metal-tipped nose question

[BABAR]

Just an idea from a LPR guy.

if you epoxy it in, maybe do it with an eye bolt in it and have a loop of heavy duty Kevlar hanging toward the tail end of the cone. use that as an attachment point for shock cord, and makes it less likely, should the epoxy fail, that you will miss the point (sorry, pun intended.)

 

[Walter Longburn]

it's Argonia, I think.

It used to be but that rule is no longer. Unless they recently went back to it.

 

[Wayco]

Kloudbusters webpage:
Aluminum Rockets at Argonia
Rockets launched at Argonia may not be constructed of all aluminum or any other metals. Aluminum fin cans or nose cones will be permitted only if required to ensure structural integrity of the rocket during a high-performance launch. Absolutely no aluminum airframes or fins attached directly to motor cases will be permitted under any circumstances.

 

[mtnmanak]

The separate metal nosecone tip gives you a number of options.

For Head End Dual Deploy and smaller rockets, I like to replace the screw with an eye bolt to use as an attach point. This also aids in tightening the bolt - take an appropriate length of PVC pipe - maybe 1" or 1/2" diameter (or sized to your nosecone diameter/eyebolt size) and cut a slot on the end that the eye of the eye-bolt fits into and you have the perfect tool to tighten your bolt to the metal tip. I do not usually epoxy the tip to the bolt in these cases, but I do use blue Loctite.

Here is the one I use on my 5" WM Goblin:

For normal DD rockets where the nosecone is big enough that I want to use it as an AV bay (tracker, etc), I replace the screw/bolt and use a long piece of all-thread that goes through the NC AV Bay and use a threaded eye-nut to hold everything together. I use metal screws/PEM nuts to hold the AV Bay in place (just like holding the AV Bay to a payload bay) and the sheer pins go in the AV bay coupler. The AV bay is built out internally as normal. Here is the nosecone to my 4" Darkstar. I flew it 3 times this weekend at MDRA and used a Marco Polo in the nosecone all three times. One of the flights on a K400 landed way out by the highway and the Marco Polo worked perfectly to guide me in from the road.

For these setups, I use red Loctite on the threads of the metal tip. That way I can get them apart again if I really have to.

I plan to be at Red Glare - stop by and I can show you some of these setups.

 

[Rocketclar]

Some land owners are concerned about the metal tips (or other significant metal) causing problems in their harvesting equipment. I, too, had to paint on the spot my metal tipped NC at Argonia before being allowed to launch it as I didn't know this beforehand.

 

[dhbarr]

Argonia is the farthest east waiver of its magnitude AFAICT. If a landowner wanted me to put a shamrock in every flight and brush with cinnamon toothpaste I'd do it. They bring the land. I bring toys.

 

[Sluggo]

As for metal parts, read this from the NAR website under the sub-heading..... Understanding FAA Regulations.

Understanding FAA Regulations | National Association of Rocketry (nar.org)

 

[icyclops]

Regardless, minimal amounts of metal parts does not mean a metal tip nose cone as that structurally is not needed for a hobby rocket. Plenty of other strong options. But thanks for the physics lesson. Again you are missing the point....

You can interpret the use and amount of metal in the safety guidelines as you wish, but I am pretty sure it does not mean using metal nose cones.

 

[icyclops]

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

Direct from NAR web page of the safety code.....#1.

And HP SAFETY CODE...

Materials. I will use only lightweight materials such as paper, wood, rubber, plastic, fiberglass, or when necessary ductile metal, for the construction of my rocket.

You really think a metal tip nose cone is a “necessary” component for construction....

 

[MClark]

The model rocket safety code doesn’t apply to these nose cones as they are not intended to be used on model rockets.
The high power safety code does allow metal parts and these tips are considered acceptable. Airframes entirely of aluminum are also acceptable, there are situations, high velocity being one, where aluminum is safer than other materials.

 

[Conway Stevens]

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

Direct from NAR web page of the safety code.....#1.

And HP SAFETY CODE...

Materials. I will use only lightweight materials such as paper, wood, rubber, plastic, fiberglass, or when necessary ductile metal, for the construction of my rocket.

You really think a metal tip nose cone is a “necessary” component for construction....

So.... have you seen what a fiberglass nosecone will fo coming in ballistic? At that point there isnt any difference between metal and fiberglass or carbon fiber. Ive seen cardboard and plastic come in pretty hard core to.


As Mr Clark hss pointed out the NAR guideline you are quoting DO NOT apply as they are model aka low and midpower requirements. Not highpower. Even the high power states ductile metal can be used. Plus... this is just NAR guidelines not TRA.

 

[cerving]

I've seen a plastic model rocket coming in ballistic go right through the roof of an aluminum trailer. Instead of focusing on how dangerous one ballistic rocket is vs another, the focus should be on ensuring that our rockets don't come in ballistic in the first place.

 

[Tractionengines]

Regardless, minimal amounts of metal parts does not mean a metal tip nose cone as that structurally is not needed for a hobby rocket.

The issue is in manufacturing these nosecones. When making a filament wound (fiberglass, carbon fiber, etc), or even sheet material, nosecone; you can not get the material to "lay up" at the tip. You end up with uneven layers, or inconsistent placement as the filaments are placed. The solution is to cut off this imprecise area and replace it with something that can be precision formed, and as structurally strong as the rest of the nosecone.
So I would contest your statement, and say they ARE structurally needed to make a properly balanced and structurally sound tip to a fiberglass or carbon fiber nosecone.

(This is not an issue with a injection molded part.)

 

[Conway Stevens]

I've seen a plastic model rocket coming in ballistic go right through the roof of an aluminum trailer. Instead of focusing on how dangerous one ballistic rocket is vs another, the focus should be on ensuring that our rockets don't come in ballistic in the first place.

100% spot on Cris.

I remember seeing a picture of an Estes rocket.. like b or c motor powered that came in ballistic and actually stuck pretty far into the roof of a house.


I myself, and i think most understand the POTENTIAL INHERENT danger that can be associated with our hobby. We can do all we can to minimize the issues. As we should still things can fail, can happen and we should also be aware of those issues.

Everything we do in life carries these concerns. working a job, driving somewhere, cooking food, anything.

But as ive heard on one of the rocketry show commercials

If rocketry scares you... you may want to get train set.

 

[icyclops]

I've seen a plastic model rocket coming in ballistic go right through the roof of an aluminum trailer. Instead of focusing on how dangerous one ballistic rocket is vs another, the focus should be on ensuring that our rockets don't come in ballistic in the first place.

Very true....my point is show me where a metal tipped nose cone is really needed for HP...again I say jokingly no doubt...are you afraid it;s going to melt as it is moving so fast...Plenty of folks launch HP successfully without using metal tipped nose cones....and yes, as I said before....just pray you have no recovery problems as you can tell the lawyers why you needed to tip the nose cone with metal when they pull it out of a structure or a car....hopefully no people around.

And if a plastic or fiber does make a ballistic rentry at least you can say you used some common sense and followed the safety code to the best of your ability. In my opinion, that is not the case when you build the cone with metal. HP safety code says what I inserted above...copied it from their website. You can interpret it as you like but seems very reckless to me....

But what do I know.

 

[Conway Stevens]

Very true....my point is show me where a metal tipped nose cone is really needed for HP...again I say jokingly no doubt...are you afraid it;s going to melt as it is moving so fast...Plenty of folks launch HP successfully without using metal tipped nose cones....and yes, as I said before....just pray you have no recovery problems as you can tell the lawyers why you needed to tip the nose cone with metal when they pull it out of a structure or a car....hopefully no people around.

And if a plastic or fiber does make a ballistic rentry at least you can say you used some common sense and followed the safety code to the best of your ability. In my opinion, that is not the case when you build the cone with metal. HP safety code says what I inserted above...copied it from their website. You can interpret it as you like but seems very reckless to me....

But what do I know.

Here are several reasons for it.

one reason is that It is difficult to almost impossible on filament wound composite nose cones to fully wind the fiber glass, or carbon fiber to a tip of the correct shape or to get it to even wind correctly on the mandrel. So to create a durable easily formed tip that will mount on a shoulered ledge and fasten to the cured nose, that will last and not break the first time the tip touches the ground. Its also similar in strength to filament wound products of fiberglass and carbon fiber. composite tips tends to be slightly cheaper, but the tip can be a bit more brittle and break easily so therefore aluminum is used.

It also acts as a nose weight helping stability in most cases moving the center of gravity forward.

It can be on super sonic flights an ablative tip that will keep shape while forces against the rocket can and gave been witnessed on some composite and plastics to melt or errode from heat if friction

aluminum tips also allow you to put an eye bolt at the very top of the nosecone. This provides you with additional space for parachutes and shock cords as you can use it for head end dual deployment or for added space for rockets flying extra long motors that need added space for parachutes and shock cord with other material you couldnt do that as others are more prone to break. This could cause loss of main deployment.

These are just a few reasons you can accept that there are reasons for it or not.. its as you pointed out your opinion. The rules of NAR high power and TRA both allow it. If they didnt you'd see a rule against it specifically. Each rocket has its need. I have one that uses metal fins and tip. It will push limits that fin flutter, or heat could create an issue while under extreme boost on its way to 40k ft. The nose cone metal tip is for attachment of the tracking system bay.


There are reasons and its not against the high power code. Your interpretation and opinion is where you are seeing it from.

 

[David Schwantz]

All aluminum, several flights on her now.

 

[Sluggo]

What is that thing David.??

 

[David Schwantz]

That is the flying "Grain Bin"
16" DIA 52" tall and flies on a J800T
Chute cannon out the side

 

[mtnmanak]

That is the flying "Grain Bin"
16" DIA 52" tall and flies on a J800T
Chute cannon out the side

That thing is awesome! I think we have answered the metal nosetip questions, so let's derail the thread. Do you have any video of that "Grain Bin" flying?

 

[David Schwantz]

There is. It is posted on this thread, but I cannot figure out how to allow access. I can view it, but no one else can. If anyone knows what to do, let me know.

How to figure base drag

Is there a formula for base drag on a rocket? Building a fin less rocket, and need to determine if I will have enough drag.

www.rocketryforum.com

 

[mtnmanak]

There is. It is posted on this thread, but I cannot figure out how to allow access. I can view it, but no one else can. If anyone knows what to do, let me know.

How to figure base drag

Is there a formula for base drag on a rocket? Building a fin less rocket, and need to determine if I will have enough drag.

www.rocketryforum.com

David, that thing is totally cool! Love it!

I ran into the same restrictions on the google drive. If you know the person who owns the google drive, you need to ask them to open up the file to public permissions. If I can grab the file, would be happy to upload to YouTube for you. The world needs to see that thing fly!

 

[David Schwantz]

Thanks mt.

 

[icyclops]

Hahahaha. What next...a metal outhouse.

 

[Sluggo]

I'll tell ya what that thing is..... That thing is a show stopper.!! If it had ice cream inside I'll retrieve it. Ha.!!

 

[OverTheTop]

What about making a resin tip? Or some other material? Wood?

 

[David Schwantz]

Hahahaha. What next...a metal outhouse.

I could do that

 

[mtnmanak]

I could do that

Here are a few design ideas:

 

[tsmith1315]

What about making a resin tip? Or some other material? Wood?

In the following scenario, there would be no difference between wood, resin, or metal tips:

Is a 5lb rocket falling from 5000' with a metal tip more or less dangerous than a 5lb rocket falling from 5000' with a smooshy foam nerf tip?

 

[watheyak]

tell the lawyers why you needed to tip

They won't care. The lawyers, and everybody else but you evidently, are sensible enough to know the nosecone tip plays zero part in the scenario you presented.

I also find it really, really weird that you're being such a safety honk aboit materials, yet in another thread, you're relentlessly arguing on the merits of mercury switches for deployment. Further showcasing a poor understanding of physics, safety and common sense.