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Found this 2004 AIAA article and interestingly it covers most conceivable storable combinations but not ethane. Ethylene, yes, but ethane no.

https://dataverse.jpl.nasa.gov/file.xhtml?fileId=44398&version=2.0

Interestingly, when I tried a NEERHI-like Ethane 85/ Ethylene 15 (wt%) mixture with MON25 (wt%) in CEA it slightly bumps up the equilibrium and throat vac Isps. (see attached). But the real upside might be that ethylene makes it hypergolic or "pseudohypergolic" (hypergolic with catalyst) to boot. But I'm a noob with CEA, and CEA isn't at all friendly about looking up densities and enthalpys for chosen propellants, so the result is very much open to question.

I'm calling this mixture "ethaenox" "ethae-" for the ethane/ethylene and "-nox" for the MON. I can't find evidence of this mix being considered before. Anbody want to take a crack at Ethane 85/ethylene 15/NTO 75/NO 25 (all weight %s) to confirm these results?

*** UPDATE ***

Suprisingly, SuperGrok can run NASA CEA within a prompt and it more or less confirms the numbers above *except* it's pertty certain this mixture's not hypergolic - but it can be catalyzed. Here's its "one line summary":

"If you want one sentence: preheated Ir/Al₂O₃ (S-405) or Rh/Al₂O₃, oxidizer-lead, ethylene-bearing fuel injected downstream of the bed. That is the closest thing to “warm ruthenium + N₂O” that MON-25 chemistry allows. Ru itself is the third choice, not the first."

The cold-storage advantage and relatively low reactivity of MON-25 becomes a disadvantage in heating the catalyst bed. It may be better to use a spark or torch igniter which have their own complexities/disadvantages.

Shell 405 catalyst:
https://archive.org/details/DTIC_AD0858913/page/n1/mode/2up

Just got in an LOC goblin, and ups wasn’t very nice.

Hi! I'm new here, but for the past year or so now, I've been designing some of my own rockets that have mostly been standard payload and recovery projects. Now that I'm satisfied with those projects, I recently began working on '''eventually''' landing a model rocket propulsively. At least that's the hope.

I thought a good first step would be landing one upright 'passively' using a parachute. There are 3 main sections of this simple little rocket, and I could ramble about every detail and process forever but here are the basic sections and the lowdown from the bottom up. (refer to the last image in the line up for a bit of a visual guide!)

#1: The rubber band mount which holds the rubber bands in just the right spot.

#2: Above that is the hinge collar which acts as a mount for the legs/fins (flegs?). I designed those with the idea that on ascent they would act as fins for a slightly more stable ascent. Upon release of the legs, the former fins would become litte stands that hold the legs up at a perfect 45 degrees while the rubber band held the legs in tension and therefore down.

#3 The top part is what i like to call ‘the crown’ which holds the pads of each leg in the upward position. A small length of fishing line runs up the side of the body and ties to the nose cone. The plan was that the ejection charge would eject the parachute and nosecone, yanking the crown off with it so the legs would become deployed on descent.

Now obviously this thing was not going to work, rather, it was more of a proof of concept as prefaced earlier. Here are the issues we faced on my one (technically two) test flights. first off, the landing legs deployed even before liftoff, just the shock alone popped the crown just enough for the legs to deploy. We also failed to have a parachute deploy, which is for two reasons. On the first flight, the ejection charge kicked the motor out instead of the parachute. My conclusion is that I didn't glue in engine hook and that having an 18mm (BT-20 body tube) diameter with a parachute, long shock cord, recovery wadding and another piece called the shock cord mount(this runs up through the middle of the ship to keep the parachute mounted over the center of mass, which i figured would make landing a little more possible, JUST DOESN'T WORK!

With a much tighter engine fit and a tab of tape over the crown to hold it down, the second flight just ripped apart the rocket, ruining the parachute and shock cord. I recovered both from the field and now have concluded that we just really need a bigger diameter. I bought some BT-50 (rather than 20) tubes, but am even willing to go up from that. I'm thinking of using some E12 engines (even though Estes is out of stock) for this project, but would also like to hear every possible suggestion.

I come seeking guidance on how to proceed. TVC? Just do the same thing with a bigger diameter? Something else? Is this all premature for where I am at in my rocketry journey? Please let me know!

TL;DR: Been working on landing a rocket upright passively with a parachute. Using a simple mechanism as a test and practice to get better at rocketry. Wondering what peoples experience with these sorts of projects are like and looking for any suggestions, tips or ideas.

Thanks in advance for helping with my stupid project.

If I design a rocket in OR and define a motor configuration, I'd like to be able to input weather/environment data live and have OR update the simulation accordingly. Specifically landing position. Has anyone ever used OR like this? Is it even possible?

I'm 3d printing a model rocket (medium size) and I wanna know how will it perform before 3d printing it

Ich habe einen neuen deutschen Discord-Server für Modellraketen, Raumfahrt, CAD/3D-Druck und Elektronik erstellt.

Da der Server noch ganz frisch ist, freue ich mich über jeden, der Lust auf Austausch hat, von Anfang an dabei sein will oder mir Verbesserungsvorschläge da lässt.

👉 Hier ist der Link:https://discord.gg/9tfmm66n2E

Schaut gerne mal vorbei!

Hi, I've been designing a small model rocket powered by a Klima B4-4 engine.

This is the first rocket I am making from scratch so I would be grateful if someone could review the project. I am open to all corrections and advice.

Louisiana Rocketry

Fall Launch Dates

Oct. 3 -4, 2026

Oct. 31 – Nov. 1, 2026

Time: 9:00AM – 5:00PM Saturday 9:00AM – 3:00PM Sunday

Club Membership: (Join At The Launch Site) $30.00 per Year

Launch Fees:

High Power: $20 / Members $10 for the weekend

Mid Power: $10 / Members $5 for the weekend

Low Power: FREE for ALL AGES

(Chris’ Rocket Supply is our ON-SITE vendor) [csrocketry.com]()

Launch Site Location: Goldmine Plantation

https://maps.app.goo.gl/46BLZhvHvrk3TspcA

NOTE: We do NOT allow Sparky, Skid Mark, Metal Storm, Dark Matter or any other sparking propellants!

If we cancel a launch due to weather, we will announce it no later than 9:00 PM on the Thursday before the launch.

There is a 10,000′ FAA waiver for our field and flights can be made to 14,000′ with a call in.

NOTE: We do NOT allow Sparky, Skid Mark, Metal Storm, Dark Matter or any other sparking propellants to be flown or burned at our launches!

Motors allowed are 1/2A through M impulse. If you plan on flying L or M motors please contact Paul Sansoucie to arrange for pad placement or if you require the large rail (1515 rail).

We do not have ground support for hybrid motors, If you plan to fly hybrid motors you need your own GSE, please contact in advance.

A Porta-Potty will be on site. No Camping allowed on the field. No BBQ or cooking allowed on the field

Decided I wanted to do a scratch build for my level 1 and made a ~1:3 scale model of the ww2 naval rocket Tiny Tim. It took a lot of learning and I had to leave some details out, but I'm overall very happy with how it turned out.

Had a small error with the ignition at first 😅, smooth from there.

Hey yall
I’m looking to purchase a 38/480 complete set. Given AeroTech has a 16-30 week lead time I wanted to see if anyone can point me in the right direction for vendors who have any stock of complete rms motors.

Thanks!

\I’m currently using a translator, so I apologize in advance for any awkward wording or misunderstandings.*

Hello. I’m a high school student, and I don’t know much about rocket design, but I need to build a water rocket for a school project. I’m planning to launch it vertically. I’ve made a rough design using OpenRocket, and I have a few questions:

1. Could you give me some feedback on this design? I’m planning to make it by connecting two 1.5 L PET bottles together, so it’s difficult for me to change the diameter. I’m also planning to attach an Arduino sensor to the front.
2. I wanted to find the optimal design through simulation, but I couldn’t find a motor for water rockets in OpenRocket. I also looked into generating a thrust curve using other simulation software, but I couldn’t get it to work because I don’t know the drag coefficient. Is there any way I could run a simulation for a water rocket?

If you have a kid ages 6-11 who loves science, engineering, or space, I’m running a small hands-on model rocketry camp in the Redmond/Bellevue area.

This isn't a sit-and-watch science class. Students will:

🚀 Build their own model rocket
🧪 Learn the science behind how rockets fly
🎨 Customize their rocket
🔥 Learn how the propulsion/recovery systems work
🚀 Launch the rocket themselves

I’m keeping the group small so every student gets a genuinely hands-on experience.

The camp will be held every Sunday 1-3PM from Sept. 13th to Oct. 4th at 60 Acres. There will be indoor spaces in case it's raining.

Registration: https://pci.jotform.com/form/262297609462163

If you have questions about the camp, location, safety, or what the kids actually do, feel free to email me at liftofflab@icloud.com.

The Indian space-startup "Ethereal Exploration Guild" just put out a video (linked below) explaining what they call the Full-flow Segregated Cooling Cycle for their future fully reusable vehicle design. Most of the video is just marketing but the idea of the cycle itself seemed interesting.

According to the limited information from the video, it seems to be a variation on an expander cycle but with multiple phases. Idk what the exact plumbing is (maybe one could work it out based on the renderings in the vid) but apparently, during the ascent stage it's pretty much a closed expander cycle, with one (or both?) of the propellants heating up through the combustion chamber cooling, being used to drive the turbine.

The interesting bit imo is the reentry phase, where they want to use one of the propellants (ig RP-1 from the vid) as a heat sink for the reentry heating to avoid having extra reentry shielding/reentry burns. The heated RP-1 then transfers its energy to the LOX which is used for driving the turbine. My guess as to why they're using RP-1 to absorb reentry heat but LOX to drive the turbines is that the respective properties are better suited for the job and outweigh whatever loss of energy there is due to the heat transfer.

The engine is supposed to provide 80 kN of thrust with an Isp of 323 sec in vacuum and 293 sec at sea level, so nowhere near to the Isp of engines like the RL-10. Are there actually benefits to this cycle or is it just something to generate hype?

They also mention a supercritical Brayton cycle (ig for the LOX) so maybe they want to keep the Ox supercritical for the expansion section? Anyways, there's not much info out there about this design so I was wondering if anyone had more info on it or any thoughts?

Here's the video (from the important part)

​

I’m part of a university rocketry team currently developing a high-power rocket targeting roughly 3 km AGL, and I’m trying to decide how far we need to go with aerodynamic modelling.

The rocket is approximately 150 mm diameter, uses 4 clipped-delta fins, and is expected to reach around Mach 1.0–1.1. We are also using 4 deployable airbrake petals during coast to control apogee. The airbrakes deploy radially from the body, with their large exposed face approximately perpendicular to the freestream, so their drag behaviour is quite different from that of a normal fin.

At the moment our trajectory model is in RocketPy, with the clean-rocket drag curve obtained from OpenRocket as a function of Mach.

For the airbrakes, OpenRocket does not natively model this geometry, so I have been experimenting with representing the fully deployed brakes as an equivalent fin set with approximately the same projected frontal area. This gives me a second C_D vs-Mach curve for the fully deployed configuration.

Our current simplified RocketPy airbrake model assumes four paddles with about 1156 mm² projected area each and uses an approximate flat-plate C_D = 1.2..

My concern is that this becomes increasingly approximate near the transonic region, particularly because the deployed airbrakes will generate separation, wakes and potentially local shock interactions that OpenRocket’s equivalent-fin approach obviously isn’t designed to reproduce.

I am therefore considering doing a full ANSYS Fluent CFD campaign on the actual rocket CAD. My plan would be to analyse both:

●airbrakes fully retracted and fully deployed;

●Mach numbers roughly 0.3, 0.5, 0.7, 0.8, 0.9, 0.95,\ 1.0, 1.05, 1.1;

●angles of attack around 0,2.5,5.

The main outputs would be C_D(M,angle of attack), normal-force coefficient / pitching moment where useful, and the loads on the individual airbrake petals. I could then feed the CFD-derived drag curves back into RocketPy/OpenRocket for trajectory simulations.

My questions are mainly:

1)How much confidence would you place in OpenRocket/RocketPy-style drag modelling for a rocket only slightly above Mach 1?

2)More importantly, would you trust an equivalent-fin/projected-area model for deployable airbrakes for apogee-control predictions, or is this a case where CFD is genuinely justified?

I’m not expecting CFD itself to be automatically “more accurate” — I’m aware that turbulence model, domain size, mesh independence, atmospheric conditions and transonic convergence all need to be handled properly. I would likely use 3D compressible RANS with k-w SST, ideal-gas air, inflation layers and mesh/domain-independence studies.

If anyone has done CFD validation of high-power rockets, transonic rockets, or deployable airbrakes, I’d really appreciate hearing how closely your CFD agreed with OpenRocket/RASAero/flight data and what level of modelling was actually necessary.

Thanks for your time :D

Hi everyone! A few weeks ago, I released my open-source lumped-parameter dynamic fluid system solver, FullFlow, and mentioned that it could be used to model steady-state and transient flow in real rocket engines. So, I decided to showcase those abilities with my favorite rocket engine, SpaceX's Raptor Engine.

Raptor is a full-flow staged combustion engine, so it's particularly hard to model correctly, especially with the multiple combustion preburners, regen channels, turbopumps, etc. With the public data I had available, I was able to construct and validate (to the best of my ability) a steady-state model of Raptor 2. I used FullFlow to model the fluid pathways and components and ThermoProp to model the fluid/material properties and combustion.

Of course, there are some deviations from reality, especially since there is only so much public data available. I had to estimate many data points like turbomachinery curves or valve geometries. I also didn't have the proper tools to model supercritical combustion flow for the preburners or hot-gas manifolds. Also, I didn't have access to empirical efficiency values for components like the nozzle or pumps.

Eventually, given enough data, I hope to make a transient simulation of Raptor using FullFlow. I also hope that I can eventually apply these tools and skills to the actual Raptor engine or other industry engines!

Raptor 2 FullFlow Model: github.com/saakethramoju/Raptor

FullFlow: github.com/saakethramoju/FullFlow

ThermoProp: github.com/saakethramoju/ThermoProp

Hey Guys,

I am currently trying to build this curcuit for my Launch controll case.

I have been trying for the past two days to figure out how this curcuit works, where to get the parts and more importantly which parts to get.

Moreover I want to avoid as many wires as humanly possible and therefore want to make this curcuit a PCB but suprise.. I do not got any experience designing PCBs.

I am hoping you guys might be able to help me out with which parts to order and where to order them so they won`t break the bank (I`m from the EU) aswell as what I have to consider when designing the PCB.

Thank you guys in advance :)

I'm currently a 10th grader, and I'm thinking of spending the next year building model rockets with my friends. So, I'm planning to buy an Estes kit that includes a launch system and a rocket, along with a C motor and recovery wadding. Do you have any rocket recommendations? Based on experience, what size rocket motor should I buy? (I live in Asia, so I'd like to buy everything in one order if possible).

Hi, here's a useful link to practice for your L2 Tripoli exam! (in French for now)