Building from scratch for my senior project

[h_kay19]

Hi everyone,

Up until now, I've been building model rockets on my own just for fun, and have been really enjoying it. I've always wanted to build a scratch model, but honestly have no one to really show me the processes and techniques in doing so. I kind of have an idea of how to go about it, but that's just from reading off the forum for so long! Now as a student, I have to come up with my senior project, where the goal is to "learn a new skill or hobby" and present it to my school. That said, my idea is to design, build, and launch a rocket from scratch. Initially, I had hoped to come up with a creative design other than just a basic 3FNC rocket, but that might be difficult for my first scratch build.

Because of where I live, rocketry is not a huge hobby, and finding someone to guide me in doing this is pretty much impossible so I wanted to start this thread to ask for any tips, tricks, techniques, warnings, etc. Where do I start? Is openrocket worth looking into? Should I attempt something more unorthodox? What's the best site to buy parts? I'm just asking for any general advice you guys might have for me. And lastly, what's the first scratch build you guys have done? I'm always open to inspiration. Thanks!

 

[neil_w]

That sounds like a great project. Here are a few random thoughts, in no particular order.

1) What have you built so far? This will give us a general idea of your current skill level. Some pictures would be great as well, just because... well, we love pictures.

2) Yes, OpenRocket is definitely worth it, both in general and as part of "learning a new skill". Start with one of the packaged installers here, and post to the Electronics and Software forum with any questions.

3) As for how complex a design to try... well, that depends. No obvious answer there. Personally I find 3FNCs to be boring, but it could be appropriate for your project depending on where you want to focus your effort. Do you want to focus on the simulation/modeling? The actual flying, maybe with an altimeter? Painting/decorating the rocket? Or maybe that actual build itself (my favorite part).

4) My first scratch build: https://www.rocketryforum.com/threads/diamond-cutter-build-thread.129671/

Here's what I think would be a reasonable approach. First install OpenRocket, and learn the basics of how to use it. That's a good little sub-project on its own, and something you could probably talk and/or write about as part of your final presentation. Once you get the hang of it (it's not hard), start creating your design. You can start simple, and focus on getting all the different elements entered correctly, and then if desired make it more complex and/or interesting. Post your design to this forum for review, and we can ensure that you don't miss anything. Then build. Then fly. Through all parts of the process we are here to answer questions as needed.

There are plenty of model rocketeers in California, although I can imagine that much of the state is under a burn ban right now, so there might not be much flying going on, but you never know. Have you looked to see if there are any clubs nearby? Attending a club launch is a great way to learn and meet folks who can offer advice. And it's fun.

No matter how you choose to proceed, good luck with your project!

 

[lakeroadster]

Hi everyone,

Up until now, I've been building model rockets on my own just for fun, and have been really enjoying it. I've always wanted to build a scratch model, but honestly have no one to really show me the processes and techniques in doing so. I kind of have an idea of how to go about it, but that's just from reading off the forum for so long! Now as a student, I have to come up with my senior project, where the goal is to "learn a new skill or hobby" and present it to my school. That said, my idea is to design, build, and launch a rocket from scratch. Initially, I had hoped to come up with a creative design other than just a basic 3FNC rocket, but that might be difficult for my first scratch build.

Because of where I live, rocketry is not a huge hobby, and finding someone to guide me in doing this is pretty much impossible so I wanted to start this thread to ask for any tips, tricks, techniques, warnings, etc. Where do I start? Is openrocket worth looking into? Should I attempt something more unorthodox? What's the best site to buy parts? I'm just asking for any general advice you guys might have for me. And lastly, what's the first scratch build you guys have done? I'm always open to inspiration. Thanks!

We're here to help.

In response to your questions:

1.0 "Where do I start?" Use your imagination. What's your preference? Sci-Fi, Space-X, NASA?

2.0 "Is openrocket worth looking into?" Open rocket is definitely worth your time.

3.0 "Should I attempt something more unorthodox?" Yes Answer 1.0, then design the rocket that trips your trigger. But try to keep the design relatively simple. Not necessarily a 3FNC design, but then again, not a F-35A either.

4.0 "And lastly, what's the first scratch build you guys have done?" X-Wing Alpha

If I were in your shoes.....

I'd design a scratch build rocket that requires nose weight. Then launch that rocket 3 times, video tape the launches, and thus validate that the design is valid.

Then launch that same rocket, video tape the launch, without the nose weight. The erratic flight will show the need to design the rocket such that the center of gravity needs to be ahead of the center of pressure. This launch would need to be done safely, with the personnel at a safe distance from the launch pad.

Kick the tires... and light the fires.

Side note: We built rockets in Freshman shop class. Our shop class teacher, Mr. Fisher, and I shared the love of rocketry. When I was a Senior Mr. Fisher allowed me to build a rocket from a bunch of left over parts from his class, and launch the rocket when the Freshman launched theirs. The only difference between my rocket, and the rockets the Freshman built, were instead of balsa wood fins, mine had card board fins and a D12-5 motor, instead of the C6-5 motor. The Freshman class all launched their rockets, which all performed predictably, all were stable and true. My rocket was the last to launch. It exhibited fin flutter. Meaning that it accelerated.. the fins would flutter (vibrate) which slowed the rocket... once slowed it again accelerated until the flutter slowed it down. You could hear the flutter. It did this like 3 times, then the ejection charged popped, the chute deployed and the rocket floated down, to the cheering crowd of Freshmen. Pretty cool.

 

[Sandy H.]

I see that your username says 'high school rocketeer' below it, so I answered my first question on my own. It is cool your high school has a 'senior project' - mine didn't. I didn't have to do a 'senior project' until I completed my engineering degree in college, so be happy that you have the opportunity to gain and share knowledge with others and probably a good education compared to some others!

Doing a scratch build is no more difficult than building a kit if you're doing a 3FNC and have an extremely basic knowledge of rocketry. But, doing complex scratch builds can be hard and rewarding.

In my opinion, before even starting with Openrocket or RockSIM, download the TIR-30 document by Barrowman and read it. Then do nothing for a day. Then read it again. Then do nothing for a day, maybe highlight a few points that stick out in your mind. Then read it again and start making hand sketches, do some math and do some experiments. If you spend 2-3 weeks, just with this document, I think you will have a good grasp of the fundamentals and can then take advantage of that knowledge to not just rely on simulations and understand the shortcomings of trusting a simulation with blind-faith. I'm not saying Barrowman's equations are a perfect solution, but they are a good starting point and have been refined over the past 50+ years and are part of the simulation software you're likely to use in some form.

Next, I would say to figure out what question you want to answer. It could be 'what is the optimal 3FNC to fly an egg to the highest altitude with a D engine', 'which nosecone is optimal for sub-mach performance', 'how does fin shape affect stability' (or a million other questions, pick your own that interests you)!

Once you know the question you want to answer, devise a plan to test different scenarios, do more math/sims, test, rinse, repeat.

Based on your question, I assume you are likely an engineer or scientist at heart and I hope you enjoy those fields. Struggle to learn more every chance you get.

Best of luck! Post back often.

Sandy.

 

[OverTheTop]

Welcome to the forum. It is great that you get to do a decent project for your senior year.

There is some good advice above so I won't repeat any of that.

What sort of motor are you looking at flying it on? Any thoughts on that yet? It might help guide us here with some options. Are you going LPR, MPR, or HPR?

Open Rocket, or some other simulator is a great tool for designing and making something that should be capable of flying. You can get creative with fin design if you want and OR should be able to give a good indication if it will fly. Pigasus is a good example of this:
https://www.apogeerockets.com/Rocket_Kits/Skill_Level_3_Kits/Pigasus
I would suggest you keep your materials simple. Cardboard airframes and plywood fins are easy to work with and can make rockets capable well into the HPR realm. They are generally not too expensive and any dust from the materials is not very dangerous from a health perspective.

I would also perhaps suggest a rocket using through-the-wall fins to provide them extra strength easily. It is a good technique to know.

If you want your rocket to have a better chance of surviving landing you can keep the back end of the fins more forward than the aft end of the airframe. I have an inclination in that direction. YMMV.

As usual with rocketry, it is your rocket, your flight, so you get to choose what you want to learn from each build, what creative elements you want and how you want it to progress. There will be lots of good suggestions. The choices are all yours to make .

 

[Jeff Lassahn]

Where do you start?
Learn some basics about how to check a design for stability, then go build something and see what happens.

Is OpenRocket worth looking into?
Yes, definitely. It's really useful for checking whether your design is stable, estimating how high it will go, choosing the right engines... and I find I like using it to visualize design ideas. There's also Apogee Components' RockSim which has a few more features but costs money.

Should you attempt something unorthodox?
Yes, eventually. But be don't try to do something too far out of your comfort zone for your first build. Make your first design about the same level of complexity as the kits you've successfully built

What's the best site to buy parts?
If you're doing low power stuff (up to about D engines) two essential resources for buying parts are https://www.balsamachining.com/ and https://www.erockets.biz/ Also https://www.apogeerockets.com/ has some good stuff for sale and also their newsletters and videos have some good info.
If you want to scratch build some rockets but you don't have a particular design in mind, you might consider buying something like the Estes Designers Special so you have a big pile of random parts to experiment with.

What was my first scratch build?
A basic 3FNC design


My second scratch build was
https://www.rocketryforum.com/threads/build-thread-zeerust-alpha.160571/
What was my first scratch build?

 

[teepot]

If your not to far from Las Vegas we are having a 3 day regional launch the third weekend of October, Friday to Sunday. We are Tripoli Las Vegas. Check out our web site. If you come out let me know and I'll tell you how to find me. At current count I have 163 scratch builds. My piece of advice is about parachutes. Think about your landing field and how fast you want it to land. Grass you can come down a little faster. Hard ground a little slower. There a few online calculators that can help you in that regard.

 

[h_kay19]

That sounds like a great project. Here are a few random thoughts, in no particular order.

1) What have you built so far? This will give us a general idea of your current skill level. Some pictures would be great as well, just because... well, we love pictures.

2) Yes, OpenRocket is definitely worth it, both in general and as part of "learning a new skill". Start with one of the packaged installers here, and post to the Electronics and Software forum with any questions.

3) As for how complex a design to try... well, that depends. No obvious answer there. Personally I find 3FNCs to be boring, but it could be appropriate for your project depending on where you want to focus your effort. Do you want to focus on the simulation/modeling? The actual flying, maybe with an altimeter? Painting/decorating the rocket? Or maybe that actual build itself (my favorite part).

4) My first scratch build: https://www.rocketryforum.com/threads/diamond-cutter-build-thread.129671/

Here's what I think would be a reasonable approach. First install OpenRocket, and learn the basics of how to use it. That's a good little sub-project on its own, and something you could probably talk and/or write about as part of your final presentation. Once you get the hang of it (it's not hard), start creating your design. You can start simple, and focus on getting all the different elements entered correctly, and then if desired make it more complex and/or interesting. Post your design to this forum for review, and we can ensure that you don't miss anything. Then build. Then fly. Through all parts of the process we are here to answer questions as needed.

There are plenty of model rocketeers in California, although I can imagine that much of the state is under a burn ban right now, so there might not be much flying going on, but you never know. Have you looked to see if there are any clubs nearby? Attending a club launch is a great way to learn and meet folks who can offer advice. And it's fun.

No matter how you choose to proceed, good luck with your project!

Thanks for all the replies! Currently, I'm paying for all the rockets and supplies myself, so I've worked with more standard 3fnc low power rockets, including the alpha, alpha III, wizard, and the red flare. (All off Estes). My main focus would probably be simulating my build using math (like predicting how high it'll fly, the speed at a given time), and the actual building of the rocket itself. I still have several months before needing to start my senior project, and just need to provide my school with my project proposal, although I think I should start looking into OpenRocket and seeing how it works. I think for my first scratch build I'll stick to a 3fnc for now unless I have time leftover and I can still come up with something a bit more creative.

As for local clubs, I know there's one that meets on Saturdays, but as far as I know, they've been cancelling launch days for a while because of Covid. I've been planning to go out there once they meet again, just to watch.

 

[h_kay19]

I see that your username says 'high school rocketeer' below it, so I answered my first question on my own. It is cool your high school has a 'senior project' - mine didn't. I didn't have to do a 'senior project' until I completed my engineering degree in college, so be happy that you have the opportunity to gain and share knowledge with others and probably a good education compared to some others!

Doing a scratch build is no more difficult than building a kit if you're doing a 3FNC and have an extremely basic knowledge of rocketry. But, doing complex scratch builds can be hard and rewarding.

In my opinion, before even starting with Openrocket or RockSIM, download the TIR-30 document by Barrowman and read it. Then do nothing for a day. Then read it again. Then do nothing for a day, maybe highlight a few points that stick out in your mind. Then read it again and start making hand sketches, do some math and do some experiments. If you spend 2-3 weeks, just with this document, I think you will have a good grasp of the fundamentals and can then take advantage of that knowledge to not just rely on simulations and understand the shortcomings of trusting a simulation with blind-faith. I'm not saying Barrowman's equations are a perfect solution, but they are a good starting point and have been refined over the past 50+ years and are part of the simulation software you're likely to use in some form.

Next, I would say to figure out what question you want to answer. It could be 'what is the optimal 3FNC to fly an egg to the highest altitude with a D engine', 'which nosecone is optimal for sub-mach performance', 'how does fin shape affect stability' (or a million other questions, pick your own that interests you)!

Once you know the question you want to answer, devise a plan to test different scenarios, do more math/sims, test, rinse, repeat.

Based on your question, I assume you are likely an engineer or scientist at heart and I hope you enjoy those fields. Struggle to learn more every chance you get.

Best of luck! Post back often.

Sandy.

I didn't even consider finding a question to answer when building my rocket, but I think I should come up with something and test it. I'm definitely a more math-and-engineering forward person and I think this would make my project a bit more along the lines of a science class-- which is a good thing. I've read the Barrowman equations before, but I'll definitely download the TIR-30 document and read through that until I fully get it. I love math and rockets, but I feel like there's a lot more I need to know and understand, so that document is exactly what I needed. Thanks!

 

[h_kay19]

Welcome to the forum. It is great that you get to do a decent project for your senior year.

There is some good advice above so I won't repeat any of that.

What sort of motor are you looking at flying it on? Any thoughts on that yet? It might help guide us here with some options. Are you going LPR, MPR, or HPR?

Open Rocket, or some other simulator is a great tool for designing and making something that should be capable of flying. You can get creative with fin design if you want and OR should be able to give a good indication if it will fly. Pigasus is a good example of this:
https://www.apogeerockets.com/Rocket_Kits/Skill_Level_3_Kits/Pigasus
I would suggest you keep your materials simple. Cardboard airframes and plywood fins are easy to work with and can make rockets capable well into the HPR realm. They are generally not too expensive and any dust from the materials is not very dangerous from a health perspective.

I would also perhaps suggest a rocket using through-the-wall fins to provide them extra strength easily. It is a good technique to know.

If you want your rocket to have a better chance of surviving landing you can keep the back end of the fins more forward than the aft end of the airframe. I have an inclination in that direction. YMMV.

As usual with rocketry, it is your rocket, your flight, so you get to choose what you want to learn from each build, what creative elements you want and how you want it to progress. There will be lots of good suggestions. The choices are all yours to make .

Getting access to some MPR and all HPR engines and such is harder in California because of safety laws and such, so I'm thinking probably LPR?

 

[h_kay19]

If your not to far from Las Vegas we are having a 3 day regional launch the third weekend of October, Friday to Sunday. We are Tripoli Las Vegas. Check out our web site. If you come out let me know and I'll tell you how to find me. At current count I have 163 scratch builds. My piece of advice is about parachutes. Think about your landing field and how fast you want it to land. Grass you can come down a little faster. Hard ground a little slower. There a few online calculators that can help you in that regard.

That sounds really great! Unfortunately, I live many hours away and I don't think I'd be able to make it out there. That's a ton of scratch builds, I'm going to assume youre an expert on this. I'll keep in mind about the parachute. At first I was going to say "why wouldn't I want a slower landing?" and then quickly remembered the wind... Thanks!

 

[jqavins]

As for local clubs, I know there's one that meets on Saturdays, but as far as I know, they've been cancelling launch days for a while because of Covid. I've been planning to go out there once they meet again, just to watch.

Make that "watch and introduce myself." Talk to those folks. Just beware of one thing: the moment you ask for advice, and quite possibly sooner, you'll get more advice than you bargained for. Ask five questions and you'll get seven answers.

Enough people have said "yes" to the OpenRocket (OR) question that I guess you don't need me to do so as well. RockSim (RS), as Jeff Lassahn mentioned, has some additional features and costs money, $123.60. Is it worth it? That depends on how much the additional features mean to you (duh.) The biggest things that RS supports and OR doesn't are, if I remember right, ring tails, tube fins, and "pods", which are not what they sound like; pods allow for positioning many objects like things on the ends of fins (where the name comes from, I guess), fins that are not perpendicular to the body tube, side-by-side tubes, and lots more.

Also, if you want to use some of that stuff, there's a 30 day trial period with RS, so if you can get your design done inside 30 days then you don't have to pay.

OR was less mature some years ago, and RS cost $100 at the time, so I bought it. I'm glad I have it, but I probably wouldn't spend the money on it today. On the other hand, if I had a really big budget I probably would.

As for whether to do a simple 3FNC of something more complicated, that depends mainly on what you would like to build, obviously, but also on recognizing that some things which make for a more complicated look really are not more complicated to build. Adding an expanded payload section to the front of a rocket, for example, only means adding a transition piece from the body tube to the larger payload tube (an off the shelf part), a length of the larger diameter tube (another off the shelf part) and a payload tube size nose cone (and you need a nose cone anyway). Just enough added complexity to add some visual interest and to learn a little more about construction, but really adding virtually no greater difficulty. And there are other ways to do much the same thing, i.e. adding visual interest and skill-building a little at a time for little added difficulty.

For design ideas, look at catalogs from kit manufacturers. It's "impolite" to copy a design directly, but you certainly can get lots of ideas. "I like that. Oh, and that fin shape is cool. What if I..."

My first scratch build? A 3FNC I threw together from spare parts when I needed something to put a home made LP motor in. (The motor was a complete failure, but I still have the rocket.) The second was one with an elliptical cross section enclosing a two motor cluster using 3D printed and laser cut parts, and the third was a 4FNC which was interesting because I scrounged all the parts and materials from office supplies. The fourth is in the planning stage.

 

[prfesser]

One suggestion: look at the web pages of those who sell commercial kits. Estes of course, but check out others as well. You may be struck by a wonderful idea as you peruse different designs.

Best -- Terry

 

[teepot]

That sounds really great! Unfortunately, I live many hours away and I don't think I'd be able to make it out there. That's a ton of scratch builds, I'm going to assume youre an expert on this. I'll keep in mind about the parachute. At first I was going to say "why wouldn't I want a slower landing?" and then quickly remembered the wind... Thanks!

I'm far from an expert. I am constantly learning new things. From where I am now I look at my early rockets and ask my self why did you do that. As with most things practice helps you to get better.

 

[neil_w]

I'm far from an expert. I am constantly learning new things. From where I am now I look at my early rockets and ask my self why did you do that. As with most things practice helps you to get better.

Which brings up an important point. Between now and the end of the school year there is way more than enough time to scratchbuild several rockets, so you needn't worry about getting it perfect on the first try. The learning process of building, say, three rockets, and making each one better than the one before it, could be part of the project.

 

[jqavins]

I'm far from an expert.

An expert is someone who learns more and more about less and less until s/he knows absolutely everything about absolutely nothing.

(My father told me that one when introducing me to a true expert on vacuum systems.)

 

[mjennings]

As long as your design stays fairly straightforward you could work the barrowman stability equations by hand and compare to OR / RS output. Also if we n doubt due to fire conditions the same math covers water/air rockets as well as a backup plan.
http://mae-nas.eng.usu.edu/MAE_5900_Web/5900/USLI_2010/Flight_Mechanics/Barrowman.html