my school does the NASA SLI program. we've always done our fin cans 3d printed out of ULTEM 9085, but we normally have a company print it as all we have (as of right now) are old lulzbots that don't work very well. and every year the fincan costs anywhere from 700-2000 dollars. let's say we need at least 2 a year and we are spending ridiculous amounts of money on a single component. so we have been looking at getting a better printer to do it ourselves, we (or I) been looking at the creatbot f430. it has up to 420c on nozzle, 140c on bed and 70c heated chamber, and costs anywhere from 3000-5000, depending on when you get it and if it's on sale. however it seems there's some debate on whether it can properly do ultem. some say it's great, some say it can't at all, some say it can but not very well. and same story for PEEK.

so i'm wondering, what other filaments may work for our fincan? i'm thinking maybe polycarbonate? it still has extremely strong specs, not quite as good as ultem but it's still very good. only problem is ridgidity, it's somewhat flexible so i've been looking at carbon fiber polycarb? what about cf nylon? or any other suggestions?

for some reason entacore website is down and i need the control software for entacore aim altimeter in three hpurs. please provide a github link or something

Hi guys, I'm curently building a tvc rocket for a school project. i have a low budget to do it and I was planning to use omega avionics to build it but my school didn't buy the components on time so the teensy 3.5 is no longer available in france. I need a flight computer in emergency to finish, i have only a month to finish it.

I need a tvc flight computer that uses if possible a mpu6050 board and a bmp 388 board because they already oredered it. it should fit in a 74 mm tube (can be smaller)

The LOC-IV is one of the ADVANCED SERIES of kits, which include factory pre-slotted airframe and through-the-wall fin construction, Now including payload section! The LOC IV has been the best selling kit in our history (perhaps all of high power history as well) Recently upgraded to 38mm motor mount and to-the-motor mount construction, this kit is the perfect Level 1 certification rocket kit. You can even park fly it well on F and G motors with the optional MMA-2 motor adapter. As evolution would have it, this 4-inch LOC-IV rocket kit now sports a 23" booster section and 11" payload for optional dual deployment set up.

I am a Cub Scout leader and we are having a rocket launch soon. I wanted to use the data captured from the Jolly Logic to create a line graph that shows max altitude and the slope of descent over time. Nothing fancy. We are using the Jolly Logic altimeter two. Has anyone here done this? Sorry I am rather new at this but I think it would be a fun thing to show the kids!

(Link to my current tableau public dashboard with data)

https://public.tableau.com/views/RocketLaunchDashboard/FlightDasboard?:language=en-US&publish=yes&:sid=&:display_count=n&:origin=viz_share_link

What I kind want it to look like (The Jolly Logic 3 can graph on your phone)
https://www.apogeerockets.com/images/jolly-logic_products/alt-three-two-data-graph.jpg

So I have a AP physics lab where I have to make a rocket out of strictly paper and masking tape, and is also capable of being launched from a 60 psi air rocket launcher. So the goal of this lab is to get the greatest amount of hang time without the use of any TYPE of parachute, so far with this rocket design in the picture I am able to get 6-7 seconds of hang time on the way up and down. Is there anyway to slow down the descent without using a parachute? Or any other better ideas to meet this criteria?

Title^. The shipping costs for some of these motors are more than the motors themselves so I really don't want to buy them online. I'd rather drive but I don't know of any vendors.

The Michigan Aeronautical Science Association (MASA) will be hotfiring our 2800lbf regeneratively cooled kerolox engine, ME-5, today at the Reaction Research Society Mojave Test Area!

We are the student-led liquid rocketry team at the University of Michigan with the aim of developing the most powerful student built bipropellant liquid rockets.

Tune into our hotfire livestream to see ME-5 in action. Hotfire is currently scheduled to happen in a few hours (around 1:30pm PST): Youtube Stream

This seems like an awesome project to do but I have no idea how hard or dangerous it would be to try it. It seems like it wouldn't be hard to do, I would just attach a thin copper wire connected to a spool to the rocket and then shoot it off in a thunderstorm. But this is obviously a pretty dangerous idea and I don't know how I would perform it safely.

https://preview.redd.it/q264aisxf50d1.png?width=1365&format=png&auto=webp&s=ee6b8c59ad33fb2a884504a38837bec670912be2

https://preview.redd.it/f28xagb3g50d1.png?width=1363&format=png&auto=webp&s=5a2d6596c5a94c9ee32859aebf86df5fd4e54862

I'm researching motor selection right now and I'm confused on what the difference between these 3 types of motors are. Furthermore, which of these 3 systems should I invest in? I'm wanting to use my LOC IV kit for both my L1 and L2 certification. And if it's useful information at all, I also want to incorporate electronics after getting the L1 certification. I can see myself doing at least half a dozen launches with this kit.

Hello, I'm an undergraduate student in mechanical engineering, and I'm having some difficulty with the structural analysis of a rocket nozzle that I'm designing for a project. I want to analyze the stresses within the nozzle generated by the static pressure of the fluid passing through it during propulsion. I know I need to first conduct a heat transfer analysis to find the yield stress at a given temperature, and I'm using convection in this case, but I'm not entirely sure if that's the only type I should consider. Another concern is about my stress analysis; I want to use thick-walled pressure vessel theory and then apply the von Mises failure criterion, but I'm not sure if this model is appropriate since the cross-sectional area changes along the length of the nozzle. I'm open to any suggestions or proposals to improve my analysis.

As the title suggests, is it a bad idea for a motor retaining ring to be 3d-printed out of ABS? I'm not sure what sort of forces/heat the motor retaining ring would be exposed to which is why I'm asking. Thanks in advance!

I'm DIY-ing a launch rail but I want to make sure I'm buying the right sized rail. I found this 1010 8-foot rail from Grainger and I just want to double check this is the right one before I purchase it.

Picture of item listing

I'm new to rocketry, and I'm the process of developing an altimeter. Trying to create flight data with a vacuum is unreliable and I wonder if someone could share a raw details from a flight with temperature, pressure and accelerometer readings. The idea is to have another micro feed the data from a flight to the altimeter to give repeatable results.

Thanks in advance.

Hey, I accidentally ordered potassium chloride instead of potassium nitrate. How can i make Rocket propellent with KCl?

As suggested by many on this sub, I am beginning my journey in liquids with a very small engine. Probably something small enough to be called a spark igniter. To increase the safety of this project even more, I was wondering if compressed air (containing ~20% oxygen, of course) could be used in place of pure GOX. Or, in other words, would using compressed air in place of GOX reduce the risk of spontaneous combustion that exists in GOX systems? If so, this also means that I would be able to use regular (not oxygen safe) valves, regulators, seals, and grease, right?

I'm planning to purchase a Loc-IV kit and I'm going to be swapping out some of the parts. I'm also going to have to purchase some extra supplies like epoxy and rail buttons. I just wanted to know if there was anything I was missing, could add, or change out. Thanks in advance!

• Loc-IV Kit - $107.65
  • 15' 3/8'' Nylon Shock Cord with Sewn loops (non-elastic)
  • 36'' Ripstop Nylon Parachute
  • Z-clip motor retainer
  • Launch Lug

My Concerns with the above kit parts:

1. Is the Shock Cord long enough, and should I swap it out for a Kevlar one?I've read that Kevlar is heat-resistant, so I don't have to worry about it be burned during the ejection of the nose cone. But I'm not sure how much of a problem shock cord being burned through is though. Is it worthwhile for me to swap it out?
2. I don't know much about choosing Parachutes, so is the one that comes with the kit fine?
3. Is it worth my money to buy a Motor retaining ring like this? What are the pros and cons to using a z-clip or retaining ring?
4. The kit uses a Launch lug but I'm thinking about swapping it out for a rail button. Though, I am a little concerned about how I would attach them. Apogee sells this kit that involves securing the rail buttons directly to the cardboard body tube. But I'm concerned this might not be a sturdy connection. Should I instead attach it to a little square wood piece that either sits on the inside of the body tube or attached to the centering rings?
5. For parachute protection, I'm thinking about having both a Nomex chute protector and some dog barf. Is that overkill or will the Nomex chute protector by itself be fine? Either way, I've found this 18" Nomex Chute Protector for $12.97 that I think will do and I'll just stop by my local Home Depot for the Dog Barf. I'm not sure how much Dog Barf I'll need to buy though if I do end up buying it.

Extra Materials:

• Thread Locker (Loctite) - to make sure anything with threads can't come undone during flight

• Super Glue - to make temporary connections to make epoxying the fins and centering rings easier.

• Sand Paper - to roughen surfaces for better epoxy bonding and bevel the fins.

• Epoxy

  • About how much epoxy should I buy and where could I buy it? I found this epoxy on Amazon but it's kind of expensive and I don't know if I'll need all 8 ozs.

• I'll also buy some stuff later on for painting and making it look pretty but I'll worry about that later.

• Elmer's Wood Filler - to seal the fins for some water proofing and filling in gaps to reduce drag on fins

DIY Launch Rail:

After building the rocket, I'm wanting to launch it on some sort of G-class motor just to make sure everything works before I drive out to my local launch site and launch it on a H motor for certification. But since I'm using rail buttons instead of launch lugs, I'll have to DIY a rail. I'm thinking about making the base a "plus sign" out of some PVC pipe and putting the 1010 rail in the middle. Is that a bad idea? If not, where could I buy some cheap 1010 rail and about how much should I need?

I keep seeing videos of people "sealing" their fins. My first question is what is the purpose of sealing the fins? Does it add extra strength? My second question is how do I seal the fins? The videos aren't showing what they're using.

Unrelated, but should I paint each Indvidual component before assembling them together or paint afterwards?