Mile high rocket on $1000 budget w/ 1lb payload help.

[HHaase]

Welcome to the forum! I'll just watch from the sidelines to keep from overwhelming you with info. I did want to say this looks like a really fun project for the kids and I look forward to seeing how it progresses.

-Hans

 

[boatgeek]

Does the Hypertek motor come with an ejection charge? If not, you'll need to do electronic deployment no matter what. That will require a fair bit of testing, so your local adults helping you should plan for that. An Eggtimer quark (or Missileworks RRC2+) are also very simple to use and will handle dual deploy setups. That might be more straightforward than the Quantum.

You will be helped immeasurably if you can find a local mentor from a NAR or TRA club.

 

[David Schwantz]

If you need to land with in a certain radius, do not use a drogue chute, use streamer instead. Will still slow rocket down but with much less drift. Deploy main with a Quark or JLCR.

 

[mandbn]

Another question is should the rocket have any vents in it or anything to prevent it from deploying early due to the pressure change?

 

[heada]

Indeed, yes! You need to vent both areas for main and drogue as well as have sensing holes/vents in your av-bay. These can be fairly small (2 or 3, each 1/8") for the main/drogue but the av-bay needs larger, normally 3 1/4" or so.

 

[Nytrunner]

Another question is should the rocket have any vents in it or anything to prevent it from deploying early due to the pressure change?

Very good question!
Learning exercise for you: What's the pressure difference between ground level where you're launching and 1 mile above that?
Grd level pressure will be the pressure of your unvented bay, and the difference between that and the altitude pressure will create a small force that wants to separate your sections. Multiply the pressure difference by the cross sectional area of your airframe tube, and you know the separation force

From flight experience, you probably are fine without venting the bay on such a low flight, but it never hurts to drill a small hole in the side.
Tip: You want to make sure your sections fit together just right, but not too tight/loose. If you pick up your rocket from the top section, the bottom shouldn't slide off, but if you start to shake it gently, it should start to slide. If the bottom slides right off, you're too loose. If you have to pull each section apart with force, it could be too tight

 

[mikec]

Does the Hypertek motor come with an ejection charge?

No hybrid ever includes an ejection charge, which makes using a hybrid in this context even more perplexing.

Presumably this is SystemsGo https://www.systemsgo.org/ -- I've never gotten how this program is supposed to work; it comes up from time to time on TRF.

 

[heada]

No hybrid ever includes an ejection charge, which makes using a hybrid in this context even more perplexing.

Presumably this is SystemsGo https://www.systemsgo.org/ -- I've never gotten how this program is supposed to work; it comes up from time to time on TRF.

If it is based on SystemsGo, that was started in 1996, before the BATFE battle which removed APCP from the explosives list. Hybrid motors were unregulated at that time and so were easier to do for something like a school. Now that APCP is unregulated, they could update their program to allow APCP motors and the design possibilities would open up significantly. Motor selection choices alone would go from less than a dozen to hundreds.

Edit: mandbn - you may want to talk to your teacher/advisor/program director and ask if the program can be updated to allow APCP motors. There are no additional requirements for APCP motors in that performance class versus hybrid motors of the same class. It would create many, many more options for the students and significantly simplify the ground support equipment needed to launch the rockets.

 

[Sluggo]

Yeah, we pretty much are taught a bunch of basic physics concepts and told to apply them to our rockets. In the first semester, we built 3 very small model rockets that we had to design ourselves but this is our first large one and they aren't giving us many hints.

Maybe your first large one is just a bit too large. Learn to fly an E motor before you learn to fly an L . hint.

 

[Sluggo]

In my rocket science class at school, we are building a rocket that is supposed to be able to fly a mile high carrying a 1 pound payload, which doesn't include the weight of the altimeter. Also, it should land within a recovery radius of 2500 ft with the wind settings I added to my open rocket file which I will upload. We have a $1000 budget and this is what I have so far, but I am struggling. I mostly need help lowering the recovery radius and squeezing out some more height because I haven't even added the weight of the charges to the design yet. I don't have many engine options but they are all in the file, and they are different prices. Our budget can't do the L engines or the J300 series ones. I need help please.

I find it hilarious that you're building a rocket to go a mile high with a one pound payload and your concerned that the weight doesn't include the Altimeter. That my friend is a red flag.

 

[Cnorm]

Ignore Sluggo. He has an opinion and a keyboard but no relevant solutions.

Did you watch the Apogee video about dual deployment linked in the post above? It's got great information in it.

Thrustcurve.org is another good resource. You can input the diameter and weight of your rocket and it will give you a table of hybrid motors with their altitudes, speeds, and other good info. It's simplified, but a bit more efficient than Open rocket to quickly get you in the ballpark with weight and diameter.

 

[Sluggo]

Ignore Sluggo. He has an opinion and a keyboard but no relevant solutions.

Did you watch the Apogee video about dual deployment linked in the post above? It's got great information in it.

Thrustcurve.org is another good resource. You can input the diameter and weight of your rocket and it will give you a table of hybrid motors with their altitudes, speeds, and other good info. It's simplified, but a bit more efficient than Open rocket to quickly get you in the ballpark with weight and diameter.

Sounds to me that YOU should be the one ignoring Sluggo. Read what I posted. If that doesn't make sense to you, you MIGHT be being irresponsible.
To the OP..... You will get a lot of good info here. Just take your time and be sure you understand what is being said. A very small percentage of rocketeers have reached a mile high. World wide. I'm not saying you can't. I'm simply saying keep things in perspective. You can learn a lot by flying mid power rockets before you take high power rocketry to the max. I hope you achieve your goals in due time.
Also, notice on the forum here, there is a subforum called High Power Rocketry. You should get a thread going there. Those people are the ones who can give you the best advice. Above all, make it fun. Safety first.

 

[mikec]

Don't blame the student for seeking help, blame the organization that thinks throwing kids into the deep end like this with no adequate mentorship is a good educational strategy.

Maybe this is a worthwhile thing, but it sure doesn't seem like it to me. Does anybody have any experience with SystemsGo? (assuming that's who we're talking about.)

 

[Sluggo]

Don't blame the student for seeking help, blame the organization that thinks throwing kids into the deep end like this with no adequate mentorship is a good educational strategy.

Maybe this is a worthwhile thing, but it sure doesn't seem like it to me. Does anybody have any experience with SystemsGo? (assuming that's who we're talking about.)

Spot on Mike. You have the proper perspective. Thanks for this post.^^^^^^^^^^^^^

 

[Buckeye]

Don't blame the student for seeking help, blame the organization that thinks throwing kids into the deep end like this with no adequate mentorship is a good educational strategy.

Agree. Also blame the school admin/teacher for throwing a bunch of minors into a complicated and potentially-dangerous project with no mentors. Outsourcing the payload to the 5th graders???? I can take a guess as to what kind of school this is...

 

[dr wogz]

hey, they gotta start somewhere.. Why not with a bit of ambition & learn how to deal with a potentially burst bubble..

And, there are two things here: doing the paperwork / leg work to even see if it feasible / possible. And 2; actually doing it.

They are coming here asking the questions they feel are right, and are looking for some guidance. We have the experience.. Lets share it instead of ragging on them..

and.. a 1 lb payload without the altimeter is like saying the F-150 can carry 3/4 of a ton, and that doesn't include the engine, or driver, or spare tire.. The altimeter is part of the airframe, like the motor case, the glue the...

 

[JoePfeiffer]

You'll be fine at these speeds as long as you use the high power grade cardboard (not the Estes thin wall stuff). If you were getting up near Mach 1.5-2, I'd worry more. If you have the budget, use a slightly better grade of epoxy than the 5-minute stuff from Home Depot or the hobby store.

Carpenter's glue (like Titbond II or III) is just as strong as epoxy for wood/cardboard applications.

 

[JoePfeiffer]

All this said, find a local club that does high power rocketry and get a mentor. They'll walk you through all these things.

This is the most important and best advice that has appeared in this thread.

 

[TimothyG]

This is the most important and best advice that has appeared in this thread.

This is the largest high-power group on the internet that i know of. If they can't find assistance and mentorship here why would they then try at a smaller local group? The comments about mentorship on this website are astoundingly repetitive, and could be argued as an impedance to the youth that frequent this sight. Either offer assistance/guidance or don't.

 

[boatgeek]

This is the largest high-power group on the internet that i know of. If they can't find assistance and mentorship here why would they then try at a smaller local group? The comments about mentorship on this website are astoundingly repetitive, and could be argued as an impedance to the youth that frequent this sight. Either offer assistance/guidance or don't.

They've gotten a fair amount of design advice here, I think most of it good. However, there's a lot of advice that is hard to do over the Internet and easier to do in person. Things like building ejection charges, checking coupler fit, ejection charge testing, etc. Those kinds of things are invaluable to a first-timer. It's also often helpful to have one person who says "there are many ways to do this and here's my choice" rather than 10 people saying the same thing and arguing with each other.

 

[neil_w]

It's also often helpful to have one person who says "there are many ways to do this and here's my choice" rather than 10 people saying the same thing and arguing with each other.

Bingo.

If a 1-to-1 mentor is not available, certainly the collective advice from this forum is great too. Just takes more effort to filter.

 

[Johnly]

Let me step into this conversation with a perspective of someone who has been part of the NASA Student Launch Program staff for a dozen years. Without question this type of program will be a learning experience well beyond you can achieve in a standard class room and well worth your time and effort. It has been proven time and time again, an engaged rocketry mentor will enhance your success rate and help your steer clear of pitfalls that could delay your progress.
To that end, let's start with your geographic location, the timeline to launch, and a budget breakdown for your program. With this information I will see if I can identify a skilled HPR flier in your area to assist you. The next step would be to determine your launch infrastructure needs and work on a basic airframe design that matches your payload, budget, and program timeline.

 

[PayLoad]

May I also suggest not re-inventing the wheel. There are already kits available that can achieve this, designs that will do as you wish.

 

[mandbn]

Would it be a reasonable idea to 3d print our fins?

 

[mandbn]

Also what about 3d printing the nosecone?

 

[PayLoad]

Would it be a reasonable idea to 3d print our fins?

Also what about 3d printing the nosecone?

NO - not at all - these are common off the shelf items. Do not re-invent the wheel.

 

[mandbn]

Does anyone know what kind of shock cord materials and lengths would be ideal for this rocket design that is 3300 grams roughly and a total of 60 inches including nosecone? Here is the file:

 

[doug_kosty]

I would strongly suggest that you not ask for assistance in a stream of consciousness fashion as you appear to be doing right now. Stop, collect your thoughts and compose a clear list of areas where you need help. Based on the questions you are posting, you really need someone to take a couple of hours and chat with your group about the project. Perhaps a Zoom session with an experienced HPR flyer would be good. I can help, and there are others with loads of experience that would be happy to carve out some time for a one on one session.

 

[Johnly]

Would it be a reasonable idea to 3d print our fins?

It would not. It adds too many structural variables to the fins that could be avoided just by using aircraft plywood or fiberglass.

3D printing the nosecone might be an option if it was a benefit to your overall design, otherwise would be effort without impact.

 

[Bruce]

Jolly logic chute release would be a bad idea given your budget as it would eat up a chunk of it. I was a big fan of jolly logic products but for the price given a student group, I'd recommend against it. A line cutter is simple to make for a dollar or so in the material if you have access to a lathe. Also a great introductory project for learning how to work with a lathe. I'd go eggtimer quark redundant pair with apogee charges and line-cutters. You can get very lightweight with this setup and it's well within the limits of the electronics without taking a bite out of your budget. If you have a problem with getting/making a line cutter pm me and I may be able to help. I make them for a few cents and treat them as single-use or disposable depending on the application.

I'd be interested in making a line cutter on a lathe. Might you be able to give us an outline or a few sketches of how it's done?