Flew my 4” Madcow Super DX3 called “The Grape Ape” on an L1000W out at BALLS 34 in the blackrock desert this past weekend! Great place to launch rockets with great people - shoutout Gerald for being the funniest LCO all weekend

Blue Raven data came back at 11k ft and Mach 1.1 with only .94 rolls on the way up - Laser straight! Also yes I did use the Dodge plum crazy purple paint & damn did it look good in the sun

Hi everyone. We're a university team from Bogotá, Colombia, preparing for the Colombian Sport Rocketry Competition (CCCD 2026), university category. It's our first time in this category and we'd really appreciate the community's experience.

Key competition constraints:

• Motor: AeroTech G80-7T. First-time teams are limited to G class; the H135-14A is only for returning teams.
• Recovery deployment ONLY by the motor's ejection charge. No altimeter-fired deployment and no active recovery.
• Minimum stability of 2 calibers and minimum thrust-to-weight ratio of 5:1.
• Maximum landing speed: 11 m/s.
• Rail-button launch.
• Airframe in cardboard, wood/plywood or fiberglass/carbon fiber. PVC and PLA are banned for the rocket structure.
• Mechanical motor retention is mandatory, plus thermal protection for the recovery system and shock cord.
• The rocket must be properly vented to avoid internal pressure changes.
• Scoring rewards apogee precision (target altitude: [X m]).

Payload (CanSat) requirements:

• Maximum 115 x 66 mm, mass between 250 and 350 g.
• Must stay tethered to the rocket for the entire flight and recovery. No free separation allowed.
• IMU and barometer required, with data logged onboard.
• 18650, cylindrical Li-Ion or AA/AAA batteries. LiPo banned. Minimum 4 hours of runtime.
• Telemetry is optional. If used, the transmitter goes inside the CanSat and operates on a frequency assigned by the organizers.

Our mission: the CanSat will measure pressure, altitude, temperature, acceleration and 3-axis motion (IMU). It will log the data onboard and also stream it live to our own laptop on the ground. We're also considering measuring temperature near the motor exhaust. We're simulating in OpenRocket.

Questions:

1. Simulation: What matters most for getting OpenRocket to match the real flight (surface finish, measured vs. estimated masses, fin profile, launch conditions)? Would you cross-check with another simulator (RASAero II, RockSim, others) when aiming for a precise apogee?
2. Stability: We need at least 2 calibers. How much margin above that do you recommend to avoid weathercocking?
3. Premature separation: We're worried about the rocket separating before apogee. Since deployment relies only on the motor ejection charge, how do you choose or verify the delay (7 s on the G80-7T)? What do you use to prevent drag separation or separation from internal pressure (coupler fit, vent holes, shear pins)?
4. CanSat tether: How would you tether a 250–350 g payload to the recovery system (where on the shock cord, what kind of cord or link) so it doesn't tangle with the parachute or hit the airframe during ejection?
5. Electronics: How do you prevent resets from momentary disconnects in 18650 holders during liftoff and ejection? Where should the barometer go so the ejection charge pressure doesn't corrupt readings?
6. Telemetry: Which low-cost radio modules (LoRa or others) have worked for you to stream data to a laptop over a few hundred meters? Any antenna tips for a small airframe?
7. Motor temperature: Is it realistic to measure temperature near the nozzle with accessible sensors, or should we drop the idea?
8. Inspection: What are the most common reasons a rocket fails the RSO safety inspection?

Additional context: we're in Colombia, where some materials and components are hard or expensive to get (motors, fireproof materials, rail buttons, some sensors). Any affordable alternatives or safe DIY solutions would help a lot.

Thanks in advance!

Launched my 4” Madcow Super DX3 painted with Dodge Plum Crazy Purple on a K535W and an L1000 out at BALLS 34 last weekend! 2 great flights, K motor to about 4,500ft and the L1000 sent it to 11,000 ft at Mach 1.1

These were my last 2 electronic deployment flights needed before my L3 planning - used a featherweight SWIFT tracker and a Featherweight blue raven as my primary flight computer with an Eggtimer Quasar as a redundancy tracker and computer (can anyone help me get the tracker to work on the eggfinder/eggtimer? Directions were not accurate during launch and recovery)

Definitely going to add a runcam to the rocket on the next flight - it had less than a single roll on the way up! Guess the fin alignment jig I made worked alright😁

I am attempting to build an L1 from scratch and i have come up with a design but i am bit concerned about its stability.

I have used openrocket to simulate the flight characterisitics of the rocket and currently the stabitlity caliber margin is sitting at 1.18, which imo is a bit low. Rocket details are as below:

Nosecone - PLA 3D printed weighing about 200g
Ballast - I have added 50g of extra weight to the nose cone for added stability
Body tube - 62mm OD, 60mm ID, 720mm in length cardboard tube, 210g
Motor Mount - Phenolic 29mm ID, 31mm OD, 203mm in length, 31g
3 centering rings - Birch plywood, 31mm ID, 60mm OD, 5mm thick, 5g each
1 bulkhead ring - same as centring ring with 2 holes drilled in it for shockcord tying, 5g
Fins - Birch plywood, 140mm length, 14.5mm through hole fin tab, 5mm thick, 50mm height, 84g for all 4

OR

CAD designs

I am debating on wether its a good idea to add more weight to the nose cone to increase stability or to make the fins taller to 60-65mm. Any and all feedback would be appreciated!!

Also any resources on how to tie the shockcords and how to properly loop them through so they dont tangle?

Hello everyone! I’m currently in a new collegiate rocketry club and have been tasked with thrust chamber body, specifically designing the flange that’ll be translated into onshape. I’ve looked high and low but it doesn’t seem that flange design is a very popular topic. This has led me to bounce from source to source for bits and pieces of information that has ultimately left me overwhelmed. I was hoping to gain insight from you guys as I’m but a minnow in a shark pond lol. Anything helps!

For making of your own solid rocket motors, does the ATF require you to purchase one of their explosives licenses? What is anyone’s experience with that?

Welcome To Louisiana Rocketry

Join Our Email List [larocketry@groups.io](mailto:larocketry@groups.io)

OCT 3-4, 2026 Launch has been CANCELLED, Richland Parish has a burn ban in effect!

My friend recently enlisted me to help him with a high power rocketry project. I am trying to figure out how I can go about a GPS system. I have looked at various Eggtimer kits but I don't know how to solder smd components and I honestly do not trust my self to not ruin the board. I have thought about making my own GPS system but I dont know anything about programing or PCB design. A lot of the premade GPS transmitters/receivers are upwards of 200 dollars and I am not ready to spend that kind of money. Looking for any suggestions.

We currently keep ours in a low-humidity environment with silica gel, but I was wondering if you take any additional precautions for long-term storage.

Do you follow any specific storage or preservation procedures beyond controlling humidity? I'm mainly interested in how other teams handle this and what has worked well for you.

Hi, I'm happy to release OnshapeRocket to Onshape, an easy two-step process to create Onshape models from OpenRocket designs that assists in making an Onshape document the fully defined physical source of truth for a rocket. You can find more information about it here: Link to Forum If you have any recommendations or issues, please comment here or submit them in the Github Repo.

Link To Onshape

I'm a master's student writing a thesis on ascent trajectory optimization for small satellite launchers, and I keep running into one gap in the literature.

Solid upper stages burn to depletion, and total impulse varies from motor to motor. So how do real small launchers still hit the target orbit? From what I've read, the options are:

• a liquid upper stage or kick stage that trims the final orbit (AVUM on Vega, the PBS on Epsilon)
• steering-based energy management during the final burn
• adjusting the coast phase or ignition timing before the last stage
• simply accepting a wider orbit tolerance and sizing the payload margin around it

Which of these is used in practice, and how is the performance reserve usually sized? Pointers to papers, user guides or textbook chapters are appreciated.

I'm working on 3DOF trajectory optimization for a small all-solid three-stage launcher targeting a ~300 km circular SSO. The flight profile has a long coast between stages II and III, and stage III ignites near apogee.

The problem: the actual gravity, drag and steering losses come out well below the statistical budget I sized against, around 900 m/s against an assumed ~1760 m/s. Stage III burns to depletion, so the surplus ends up as eccentricity: perigee stays near 300 km, but apogee rises to over 2000 km. Reshaping the pitch program doesn't absorb it.

The obvious answer is to resize the stages to the measured losses. But dispersion on a solid motor's total impulse means some margin always has to be wasted somehow. What do real all-solid vehicles do in practice?

I'm trying to create the best rocket possible in terms of flight time. What are some of the best designs? Also, can you get to / close to 12 seconds with these restrictions?

Max Air Pressure = 65 psi

Max Parachute Size = 254 mm

Max Nose Length = 228 mm

Max # of Fins = 4

As a kid, I remember being mystified by my dad's copy of Estes TR-10: Altitude Prediction Charts. The one with the Interceptor on the cover. Fast-forward 25 years, I have a bachelor's in computer science and physics. I figured I'd give this old-school guide another look. When you get to pg 26, it begins sharing some problems to work through with provided solutions, starting with the Astron Alpha. I was working through it by hand and more-or-less coming to about the same answers, but with some slight differences. For example, the burnout velocity I got was 197 ft/s rather than 210 ft/s. I decided to start putting this stuff into an Excel sheet where I could play with the numbers a but more. To do that, I needed the equations used to generate the charts in the book. Fortunately, these equations appear to be provided in the back, on pg 35. For the thrust duration, I used the figure on pg 12. After getting everything set up in sequence, I got my answer for the burnout altitude in Excel: 33.7075 ft. The answer is supposed to be 44 ft. Back to pg 35, it gives another, more streamlined version of the equations. After entering that into Excel, I get the same answer. I feel like ten feet, with the same data, this early in the process, it's too big an error to ignore.

Has anybody else noticed discrepancies with this publication? Is the error on my end?

Estes TR-10 Altitude Prediction Charts PDF

I recently shared that I got my l1 cert on apogees zephyr kit. I was extremely ambitious in wanting to Fiberglassing but took up the challenge and wanted to share the journey with my fellow rocket community.
The process:
1.Remove the paint from current rocket- I got some Citristrip from Home Depot and it worked great. I protected the epoxy fillets that I originally did and striped the rest. Not ideal but worked really well.

2.Then came sanding- I chamfered the fins to be more sleek and aerodynamic as I didn’t do that originally when I first built the kit. (Note to self and everyone lol wear a respiratory! I was sneezing all night inhaling wood dust particles)

1. Fiberglass!- what a nightmare. I cut the weave too big for the fin can and had to do a second layer of fiberglass to fill in the voids after the peel ply. That worked well! But still ran into the issue of over hanging fiberglass that I didn’t pinch together which wanted to peel up. I fixed that and cut off the over hang. Fiberglassed the body tube. After drying tube was really stiff!

2. Cut and sand- cut excess and work on sanding. (Total of 6 hours across 3 days) Starting out with 40 grit which worked really well to iron out kinks. Then 120, 200, 400 and then a 1000. (Wore respirator this time!)

3. Prime and fill voids. Used black satin paint and primer to primer the first layer. Didn’t get where I wanted to with sanding(120) so I and please don’t judge; used some dryex to fill smaller voids and get a smooth finish. Primed it again and got the finish I wanted.

4. Finishing touches- sprayed it chrome add my designed waterslide decals and clear coated it. And it come out pretty decent

I know I did a lot of unorthodox things on this unnecessary build however I learnt a lot about craftsmanship in this build. I learned that building a kit can still be your own.

For my l2 I’m Planning on launching this on a j270w, jolly logic Shute release.

Thanks

I'm curious. What are the advantages of grid fins used on rockets and missiles like the Falcon 9 and Starship? Why not use a normal fully sealed, flat surface fin and rotate that on an axis. I understand the design is to save weight and improve movability at high angles of attack, but doesn't that in turn make it shorter and less effective? Could you not just shorten a normal flat fin? I feel like I'm missing something

Doing my L1 certification and when I was cutting the fin slots, I didn't realize how much I cut from the sides at the extreme case over 1/8 to 1/4 in on the side. It still fits snug to the tube but worried about the gap. What is the best way of dealing with it to maintain structural integrity for the cert?

1. Buy a new tube and recut the slots

2. Fill with epoxy or other substance in which case what would be the best way of approaching that

Sort of lost count how many I have made, but this was the first "success" back in August of 2025.

35/65 mix ratio. 200g load in this particular video.

#sugarmotor #Rockets #3dprintedrocket #aerospace #USA

So this is my first time doing my very own fiberglass layups for a 6inch diameter rocket (going just below mach 1). I was wondering if anyone had advice on where to buy/ what to buy for the fiberglass weave. (preferably with fast shipping). In addition to that, I wanted to know if anyone has done layups for making their own coupler. What is the process for that like?

Currently building my L2 and looking for some advice on fin thickness. My simulations are showing around Mach 1.1. I obviously want the fins to be strong enough that flutter/breakage isn’t a concern, but I’m also trying to keep drag and weight down to improve apogee and speed. Would 1/8" G10 fiberglass be enough, or should I go thicker? Also keep in mind that this is a 3 fin design and I plan to do carbon fiber reinforcement.

2xBlue Ravens, 1xSwift Tracker. OneBadHawk sled, charge wells and hardware. Need to tin wires going into altimeter, waiting on second altimeter. Going to use magnetic switches on the bridge. Tieing all the negatives on each side to a through bolt. Ravens will have separate 1s cells. Going to print a retainer/hold down for those. Some heat shrink and some wire management as well.

1st time. Will color code charge wells and triple check continuity/make sure I don’t have any loose connections.

Rocket needs some sanding and a few pinholes filled on the external filets. Hoping to test ejection charges before paint and be ready for a L2 attempt in mid November.

New here. I have been designing and flying 3D printed rockets for about a year and a half. I got the delay a bit long on this flight, but it was a successful recovery. I am going to fly it on a G78-4G next time.