Solid-fuel boosted long range rc jet.

[cmccully]

I was wondering what I should use to boost my long-range jet project?

 

[iter]

Are you trolling for fun or is some sort of FBI sting?

Ari.

 

[bobkrech]

Why don't you tell us a little bit about your project and yourself.

Bob

 

[cmccully]

I'm Cole McCully I'm 16 and I've been designing a long range jet like this for like 2 yrs now and was just trying to get some intel. basically i want to fly it to about 30,000 ft and then activate the boosters which should hopefully put it well above 50,00 ft! well there you have it! any more questions?

 

[blackbrandt]

Do you have any experience with stuff like this?

 

[cmccully]

Some but not much most of my experience is vicariously through others.

 

[jsargevt]

I was wondering what I should use to boost my long-range jet project?

I think that you can do magical things with diet coke and mentos.

Back to reality- I don't think that you're going to find a lot of help with this as you are a little short on details with your reply. If you are serious about this I think that people on this forum would love to see what you have designed and how you intend to achieve this, admittedly lofty, goal while staying complaint with the regulations of model rocketry and model aeronautics.

At a minimum you're looking at rocket motors which require you to be 18 or have an "of age mentor" who will fly on your behalf. Additionally, just getting a rocket to 30,000 feet and back successfully is much more difficult than you likely imagine. I couldn't fathom getting any kind of an airplane/glider that high successfully.

So please don't be put off by the replies you're getting (including mine) but I admit that I am a little skeptical that you have a design that will work. I would love to have you prove me wrong.

 

[cmccully]

I apologize for being vague. I believe that with a strong enough air frame and by using the right materials that it is possible. I've been researching DIY rocketry and it looks as though the only alternative to "rocket-candy" is to use something along the lines of rubber as a fuel and either Nitrous oxide or pure oxygen as an oxydizer. I will try and upload some drawings within the week. I am currently considering using the Arduino platform for prototyping and then I hope to custom make a pcb that will fill the needs required.

 

[cmccully]

I had no idea that it was that vague sorry guys I kinda pulled a crappy one there. I will try really hard to get those pics up soon. Oh and I was thinking about starting by building a long range jet powered by EDF units. I am going to try and get this above or at 30,000'... maybe. It definetely would be awesome considering the ramifications!

 

[jsargevt]

I apologize for being vague. I believe that with a strong enough air frame and by using the right materials that it is possible. I've been researching DIY rocketry and it looks as though the only alternative to "rocket-candy" is to use something along the lines of rubber as a fuel and either Nitrous oxide or pure oxygen as an oxydizer. I will try and upload some drawings within the week. I am currently considering using the Arduino platform for prototyping and then I hope to custom make a pcb that will fill the needs required.

OK just so you know - you won't get any chemical info on making rocket motors on here until you're certified and are permitted access to the "research" area. You will get help for commercially-available solid and hybrid rocket motors.

I am not sure how you are going to do this in a way that is consistent with the rules but hey if anything it should be interesting to hear what you are thinking.

 

[kjohnson]

Check out stuff like this:
https://flitetest.com/articles/fpv-to-space-and-back
To see what sort of issues just piloting the plane poses.

kj

 

[cmccully]

I understand that I probably am not old enough for some people to even consider giving me explosive formulas for rocket engines. I have already researched all that I need to now about building solid-fueled rocket engines. What I was wondering Is that can you guys give me tips on the design part of it?I was basically wanting info on air-frame design the place I could possibly get good engines and what may work better then the EDF unit for getting it up there. The weather balloon idea is a good one except for the faa weight limit(6lbs!). Do you guys think that if I can get the concept drawings and the air-frame design on here that you guys might be able to help?

 

[CCotner]

I understand that I probably am not old enough for some people to even consider giving me explosive formulas for rocket engines. I have already researched all that I need to now about building solid-fueled rocket engines. What I was wondering Is that can you guys give me tips on the design part of it?I was basically wanting info on air-frame design the place I could possibly get good engines and what may work better then the EDF unit for getting it up there. The weather balloon idea is a good one except for the faa weight limit(6lbs!). Do you guys think that if I can get the concept drawings and the air-frame design on here that you guys might be able to help?

Whether you're out of your league isn't really relevant; we're out of our league. This is a rocketry forum, not an RC aircraft forum; while I've no doubt that some of us have designed aircraft structures before, a jet-turbine powered aircraft with hours of endurance pretty far off-topic on a forum where even rocket-boosted gliders are sidelined.

You're going to want something long-burning with low thrust, or your airframe will need to be too heavy to withstand the forces. Beyond that, all I know is that there's a lot of engineering challenges that I know I didn't have the tools to solve when I was your age. I don't even mean things you can learn in an engineering text; I mean basics of calculus, not to mention physics and upwards.

 

[cmccully]

My plan is to design and build something that nobody would expect me to. I want to start off by designing and building a prototype and then from there use a crowdfunding site such as Kickstarter and so maybe with that I can do what I want to do. I need you guys to understand something else about me, I have been studying aerospace engineering for about 4 yrs. I did a short stint in Civil Air Patrol and learned many things there as well. I understand exactly how just about every part on a plane works. And plus my dad is a very talented mechanic. Mainly what i was looking for on here was more knowledge regarding ignition techniques,CATO prevention,and anything else you guys could come up with. And I understand the physics side of plane building the only thing I'm missing in that area is the basics in rocket propulsion. I want to build something that's not just a RTF plane kit with a rocket engine zip-tied to the back. My idea with this project is to do something no other 16-year-old kid has ever done before.

 

[TheAviator]

The biggest suggestion that I think many of us will make is to start small. Build and fly some model/mid-power rockets. Get familiar with the techniques used for that. Build some small aircraft and get used to flying them. Combine them together in a small R/C rocket glider. A large system will have many things that can go wrong, and getting many of these problems worked out on the small scale will help when you work your way up.

Also understand that everything above a certain altitude (FL180, or 18,000ft MSL, I believe) is controlled airspace and you will have trouble flying that high if you can get permission at all.

Please also understand that we only have your word on whether you indeed have an engineering background. Don't take it personally, but your questions here suggest otherwise. Feel free to prove me wrong.

 

[billspad]

I have already researched all that I need to now about building solid-fueled rocket engines. What I was wondering Is that can you guys give me tips on the design part of it

Mainly what i was looking for on here was more knowledge regarding ignition techniques,CATO prevention,and anything else you guys could come up with. And I understand the physics side of plane building the only thing I'm missing in that area is the basics in rocket propulsion.

So which is it?

 

[shrox]

My plan is to design and build something that nobody would expect me to. I want to start off by designing and building a prototype and then from there use a crowdfunding site such as Kickstarter and so maybe with that I can do what I want to do. I need you guys to understand something else about me, I have been studying aerospace engineering for about 4 yrs. I did a short stint in Civil Air Patrol and learned many things there as well. I understand exactly how just about every part on a plane works. And plus my dad is a very talented mechanic. Mainly what i was looking for on here was more knowledge regarding ignition techniques,CATO prevention,and anything else you guys could come up with. And I understand the physics side of plane building the only thing I'm missing in that area is the basics in rocket propulsion. I want to build something that's not just a RTF plane kit with a rocket engine zip-tied to the back. My idea with this project is to do something no other 16-year-old kid has ever done before.

Kickstarter is for businesses with a prototype. I had a Kickstarter project, and it took a bit of fudging and the cool factor to get model rockets to fit under their guidelines. There are other sites though that are for non-business ideas.

 

[cmccully]

Thanks for the feedback, I am planning this as a buisiness idea I want to eventually commercialize the market of unmanned space cargo carriers. Thanks again.

 

[powderburner]

It sounds to me like you are way beyond "not knowing what you don't know," and not in a good direction.

Have you calculated anything even as simple as rule-of-thumb propellant weight fractions for vehicles with orbital payloads? This alone will give you an appreciation (that is, scare the @#$%$% out of you) for the challenges you face in building anything that will survive this ascent profile. What you are imagining is tough for the professionals (how many Pegasus-class launch vehicles do you know of?) and is going to be pretty much impossible for a 16-yr-old....or even a whole bunch of 26-yr-olds.

And this does not even touch on the reviews, licenses, permits, scheduling, acceptable corridors, etc, for launching prototypes at anywhere near these altitudes. Government paperwork alone will require an army of coordinators. If this type of thing is attempted informally these days by Joe Citizen, he will quickly end up in DHS custody.

You have tremendous ambition. Perhaps you should try smaller steps first?

(From a retired aerospace engineer who has worked on atmospheric acft, launch vehicles, space vehicles, exotic propulsion concepts, exotic light-weight structure development, among other things.)

 

[CarVac]

Thanks for the feedback, I am planning this as a buisiness idea I want to eventually commercialize the market of unmanned space cargo carriers. Thanks again.

What market? You're assuming demand is there.

You should join the mailing list Arocket and see how much of the technical conversations on rocket propulsion and the like you can understand. I can say that I understand basically all of it, and I know perhaps only 5% of what I'd need to accomplish what you are aiming for.

Something like that will at least help you learn the scope of what's feasible for amateurs, and what's best left to the professionals. And, in side discussions, you may also find out what won't even be touched by professionals due to the lack of demand.

Also, if you're hoping to get funding from Kickstarter, you have much to learn about business, young grasshoppah. There are certain things that work with crowdfunding, and this...isn't one of them. And even if it were to be crowdfunding-compatible, it apparently takes a tremendous amount of work to successfully garner a decent amount of support.

 

[cmccully]

This is quite sad... The fact that humankind was launching rockets into space in the sixties with 1/10 perhaps 1/100 of the computing power we have today. And today because people are too comfortable in their own little box they just don't want to dream about the legit possibilities that are out there.A man can jump at 280,000' but nobody can launch a rocket that even gets close?! Come on guys!

 

[jsargevt]

This is quite sad... The fact that humankind was launching rockets into space in the sixties with 1/10 perhaps 1/100 of the computing power we have today. And today because people are too comfortable in their own little box they just don't want to dream about the legit possibilities that are out there.A man can jump at 280,000' but nobody can launch a rocket that even gets close?! Come on guys!

It isn't that we lack the technology or creativity, but for most of us this is a hobby. The amount of capital needed to get to 280,000' is much higher than most sane people want to spend. Add on that you are into amateur rocketry territory you open a whole new can of bureaucracy to ensure safety and such. You don't want some yahoo lighting up a rocket to 200,000 feet without any notification to anybody - that could potentially have worldwide implications in this day and age. The yahoo in question certainly would be held in detention. The rules, right or wrong, exist for a reason.

The only reason "WE" don't do anything has to do with money or politics. Right now there is NO commercial value to going into space, at least no short term value. In your proposal what is the long term goal? How do you expect to turn a profit? If you're not able to show anyone the money you're going to have a hard time getting any. As far as getting help from us? We make toy rockets and launch them for fun.

So unless you're flush with cash to burn why don't you take some time to build some smaller rockets and understand how these work. The physics and math is the same if you launch an A8 to 100 feet as it is sending up a N5800 to 65000 feet. Start small to get the basics with the long term goal in the back of your mind. We can help with that. If you just want to jump into the middle of the ocean and start swimming I'm pretty sure that you're going to be going solo.

Good luck and I hope that you give model rockets a shot while you dream of the stars.

 

[Area66]

This is quite sad... The fact that humankind was launching rockets into space in the sixties with 1/10 perhaps 1/100 of the computing power we have today.

lol, the flight computer of the Saturn V was processing 12k instruction per second , the computer I'm writing from proceed 48 billion instructions per seconds ( 12 cores at 4.00 Ghz) it’s just 4 million more. A simple arduino is more than a thousand times more powerful than a Saturn V computer.

 

[cmccully]

That's why I find it quite sad that a civilian with more computing power than a whole government can't (through the correct channels) launch something into space.

 

[MClark]

Apparently 12k/second and a slide rule is good enough to get a man on the moon.
All the computing power in the world will not lift a payload an inch off the ground.

M

 

[jsargevt]

That's why I find it quite sad that a civilian with more computing power than a whole government can't (through the correct channels) launch something into space.

They CAN. https://www.the-rocketman.com/CSXT/default.asp It is just insanely expensive to do so with little financial incentive when completed.

If you want to see the future, research SpaceX and VirginGalactic (and whomever else is privately doing this kind of commercialization). If you want to do what you're thinking you need to compete with them. I hope you have a healthy bank account.

 

[tsai]

As mentioned above, it's not that we can't do it, it's that we choose to not spend the money to do it.

The N5800 reload is ~$1,200. The hardware to fly the reload in is another $650. Assuming you minimize weight and basically put a nose cone and fins on this, you can get to ~60,000' - no where close to space. Rockets in this range are on the order of 15-18lbs in weight, and the large majority of the weight is fuel.

Back to your original question: Let's take your assumption that you're starting out at 30,000 with the goal of 50,000. Since the air density is much less at 30,000, and you're only looking for ~20,000 of additional altitude, I'm guessing you could probably get away with a smaller long-burn motor. My choice would be the CTI K300, or the Aerotech K250. The CTI motor weighs about 5 lbs, and I'm guessing (back of the napkin) that the total max weight to get from 30,000 to 50,000 with that motor is likely to be in the 8-10 lb range with a reasonably efficient airframe.

Can you design/build your jet to get to 30,000 and weigh less than 5 lbs? If not, what's the weight of your proposed platform, and we can do some math in the other direction to figure out how much motor you'll need.

I'm also completely ignoring the various certifications, waivers, and other paperwork needed to actually attempt this. Let's start with looking at it purely technically.

That's why I find it quite sad that a civilian with more computing power than a whole government can't (through the correct channels) launch something into space.

 

[cmccully]

I think with some ingenuity I can get the airframe and platform down to around 15-20 lbs. And thank-you I really wanted to start this way.(ignoring regs and focusing on the design side of things.

 

[tsai]

I think with some ingenuity I can get the airframe and platform down to around 15-20 lbs. And thank-you I really wanted to start this way.(ignoring regs and focusing on the design side of things.

Would the 15-20 lbs include enough power to lift ~30-35 lbs loaded on the ground? Also, you'll need to withstand forces somewhere around Mach1, so don't forget to account for airframe stress at that speed. For the EDF unit, can it be sealed while under rocket power? If not, it's going to be a significant drag inducer, and it, too, will need to be able to withstand Mach1 airflow through the system.

In general, the basic formula is simple. For X weight, you need Y thrust. At Y thrust, your maximum speed is Z. Can your materials withstand that speed. If not, revisit the design and add strength by using more/different material, which probably increases the weight... Keep looping until it works.

This is one of the reasons why everyone is saying to start small and work up. Get a better handle on how things work at a smaller and less dangerous scale, and as you move up in size, you'll find what and where the failure points are in a gradual fashion, fixing them as you go. If you jump straight into the larger scale, you may have a spectacular fireball of failure from which you may learn nothing about why it failed because there are so many possible answers to why, and not enough pieces to provide proof of any of them.

 

[cmccully]

What exactly is that equation? and if it were possible to make getting to space "cheap" then would anyone be interested?