How easy is it to make the tallest amateur rocket?

[rockets]

Well, I have had this question for a couple of weeks, How easy is it to make the tallest amateur rocket?
Could it be done by a design of the Mean Machine, or Tall Boy rocket?
Could you do a 4 inch diameter, 46+ foot tall rocket, powered by a 54 or 75mm motor?
If so, that would be something interesting I'd try in the future.
And yes, I know I'd have to to run many simulations, build scale models for test flights and fly many HPR motors before going for something like this.
AND NOTE: I'm not saying I'd doing this. This is only a question I've had on my mind for weeks, and figured I'd ask you guys on what you think.
Thanks,

 

[timbucktoo]

Download RASAERO


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[dhbarr]

I'd guess that making an incredibly gradual cone would be the way to go here. It would be an extremely labor intensive project, for sure.

 

[qquake2k]

4" x 46ft? I would imagine you'd have to use fiberglass or carbon fiber, and keeping the couplers rigid would be an issue. But it would be cool, if it could be done.

 

[dhbarr]

4" x 46ft? I would imagine you'd have to use fiberglass or carbon fiber, and keeping the couplers rigid would be an issue. But it would be cool, if it could be done.

You could turn a bunch of ~4ft barely conical hardwood mandrels. Use biaxial tubing + heatshrink for the layup. No couplers, just overlap the sections some inches.

Balsa discs in each overlap section, extruded CF rod up the middle. I'll let someone else pay for the launch rig

 

[rstaff3]

Check out 'Stumpy" in this newsletter...https://www.nerocketry.org/newsletters/2003/Oct2003.pdf

 

[kramer714]

I did a 54mmminimum diameter that was 230" long. Flew great, hardest thing was to get the chute out. Was straight for 40 inches and then tapered from 2inch to 1 inch over 190 inches.

 

[RocketFeller]

I saw a rocket fly that was built out of a sailboard mast. It was around20' tall, I believe, and flew/ recovered without an issue.


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[djs]

Two things here

In the LPR/MPR world, you're referring to a "super-roc" which is basically long and skinny. Mean machine type design. However when you talk about length, you will run eventually into structural issues with the cardboard- basically these rockets can sometimes fold or bend like a banana on the way up.

But what I really think you're asking is "I just want to make a really tall rocket- what can I do if price is no object". In this case you can scale up fiberglass to pretty good lengths, but weight will be a killer.

Type the words "mega Darkstar" into google images and you'll see what can be done"

Also for an engineering challenge, check out the build thread on here for the guy that's doing the 3/4 scale Mercury Redstone. That is an impressive build.

 

[rockets]

Check out 'Stumpy" in this newsletter...https://www.nerocketry.org/newsletters/2003/Oct2003.pdf

Well, shoot, I guess I'll have to make it taller.. LOL. :grin:
In fact, that rocket was launched around when I was born..

Thanks,

 

[stealth6]

Forget a MeanMachine upscale......

How about a 45 foot tall "Estes Dude"?
I'd pay double to witness that launch!

s6

 

[stealth6]

And in answer to your actual question, "How easy....?" -

Check out the bottom right picture on page 3 of that THOR newsletter. Notice how it talks about "some" of the team, and that being six or seven people (a few of whom are very skilled & experienced rocket folk)? The hint you should take from this is that the answer is probably "not all that easy in fact".

Still, I say go for it. Easy? probably not. Do-able? absolutely. Worth trying? yep.

Remember to post stories, pics, videos, etc.

s6

 

[fyrwrxz]

Forget a MeanMachine upscale......

How about a 45 foot tall "Estes Dude"?
I'd pay double to witness that launch!

s6

Pressurized with Helium-all you'd have to do to launch it is cut the tie-down string! Recovery might be problematical, but hey-it's really tall!! No motors=really cheap to fly but a real bear to get to the field...or at least the pad. Hmm-using a modified hybrid tank and fill stem and a baro triggered recovery system of det cord....

 

[OverTheTop]

Big project. Tall and skinny should be easier, but some would consider it cheating to go just by length :wink:

I was on the 1:1 V2 project a couple of years back. Two years to build, team of about 20-30 all up I think. Fantastic project. 2.5 years start to end.

Article and video here: https://makezine.com/2015/03/29/amateur-world-record-rocket-launch-success/

Spectator inspection event
View attachment 328788

Me, laying down on the job


Construction was an aluminium frame with Styrofoam covering, held together with a vinyl wrap.

You need some capable people on the team, and a project manager that can wrangle them and keep the whole thing moving.

 

[Bat-mite]

Never been inside one of my rockets before.... :grin:

 

[DavidMcCann]

Build the rockets that make you happy. That's important.

But, why all the circus stunt stuff? Make something, learn and enjoy it. I don't know why everyone wants to build the fastest green rocket that flew on a Tuesday in march...

 

[fyrfytr310]

Build the rockets that make you happy. That's important.

But, why all the circus stunt stuff? Make something, learn and enjoy it. I don't know why everyone wants to build the fastest green rocket that flew on a Tuesday in march...

Cause July is too hot.


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[H_Rocket]

Build the rockets that make you happy. That's important.

But, why all the circus stunt stuff? Make something, learn and enjoy it. I don't know why everyone wants to build the fastest green rocket that flew on a Tuesday in march...

And off the left hand C-2 pad while launched by a dwarf in a clown suit riding a genetically engineered seven foot tall lavender armadillo.


But seriously, as you get that long and skinny, the challenge you will face more than anything will be the stiffness required as the L/D ratio increases. A common problem in super-rocs is they fold up in flight.

 

[fyrwrxz]

And off the left hand C-2 pad while launched by a dwarf in a clown suit riding a genetically engineered seven foot tall lavender armadillo.


But seriously, as you get that long and skinny, the challenge you will face more than anything will be the stiffness required as the L/D ratio increases. A common problem in super-rocs is they fold up in flight.

Hmmm... the only challenge I see is the lavender part-everything else is doable. I need to work on that Tuesday thing, too. Only chance I'll ever have at a record. I already have a V-max and two rattle cans of green....

 

[Bat-mite]

Things one could do as opposed to dreaming about breaking rocketry records:

1. Make some friends, go to the movies.
2. Play a sport.
3. Get a girlfriend, go on dates.
4. Study hard, get an engineering degree, go work for NASA and build real rockets.
   
   Or, here's a good one:
   
   
5. Build rockets within your skill set, go to club launches, have fun, grow in knowledge as you grow in years.

 

[boatgeek]

Like many other people have said, your worry is folding the rocket in half aka column buckling. A couple of people have given examples of rocket sizes that have worked. Here's the math you need to figure out roughly what diameter rocket you need to keep from buckling:

L = rocket length
D = body diameter at midlength
W = weight
T = Maximum thrust, which is also the load at which the rocket buckles
~ = varies by (eg W ~ L * D means that if you double the length of the rocket, while holding diameter constant, you'll double the weight. If you double both length and diameter, weight goes up by a factor of 4)

W ~ L * D
T ~ W
T ~ D^4 / L^2

These equations only work for similar materials, since they depend on elastic stiffness. You can't scale carbon fiber to cardboard and vice versa. They also ignore wall thickness, but I doubt that would be a huge factor unless you change it a lot from one prototype to another.

 

[stealth6]

Like many other people .....snip...... from one prototype to another.

boatgeek,
A funny happenstance - I'm viewing the forum at the moment on my "not at home computer" (ok, I'll admit it, I'm checking in while at work), which means that ads show up. It just so happens that the advertisement photo that pops up inserted into your post looks like this:

How's that for "column buckling"?

s6

 

[boatgeek]

boatgeek,
A funny happenstance - I'm viewing the forum at the moment on my "not at home computer" (ok, I'll admit it, I'm checking in while at work), which means that ads show up. It just so happens that the advertisement photo that pops up inserted into your post looks like this:
View attachment 328817
How's that for "column buckling"?

s6

Obviously, someone forgot the epoxy when they laid up those tubes!

 

[Red Phenix]

The short answer?

Progressively harder with each passing year. People keep pushing the boundaries. They make bigger and bigger rockets - year in, year out.

Good luck.

P.s. I did like the get degree and join NASA comment. Although with so many private companies spinning up, why aspire to limiting yourself to one employer?

 

[Bat-mite]

The short answer?

Progressively harder with each passing year. People keep pushing the boundaries. They make bigger and bigger rockets - year in, year out.

Good luck.

P.s. I did like the get degree and join NASA comment. Although with so many private companies spinning up, why aspire to limiting yourself to one employer?

True! I'm showing my age.