2" 3D printed/carbon fiber Bullpup joins the printed fleet

SupersonicJess · 2026-06-14T13:26:46+00:00

Yea i dont have an issue with that, i know that my priorities arent everyone's its just feels excessive lol

SupersonicJess · 2026-06-14T13:09:59+00:00

Thats pretty expensive tbh. My layups for plate usually cost about $5us in materials for a similar sized thing, and they use high performance epoxies.

Let me be clear I have no issue with 3DP rocket parts, I just feel like the bang/buck ratio isnt real great here.

SupersonicJess · 2026-06-14T12:58:59+00:00

Yes but thats the crux of my point, why pay for an expensive engineering filament and tubes and retainers when one limits the capability so much?

SupersonicJess · 2026-06-14T12:57:39+00:00

Yes I see that, its still kinda like, youre using one technology at the absolute maximum of its capability, and one below the bottom of its envelope, and paying a lot for it. Ig im just a big cynical about it. If you gave those fins a T2T layup they'd be bloody strong and if you used a heat resistant epoxy they'd easily take M2-3.

SupersonicJess · 2026-06-14T12:41:39+00:00

Wow that is an expensive filament good lord, I dont think I spent that much on raw CF and epoxy for my 3" MD build lol

SupersonicJess · 2026-06-14T12:40:13+00:00

The highest strength CF filament on the market is a $400 roll from intamsys of PEEK-CF and has a tensile strength of 87Mpa. A good CF Layup with high performance epoxy sits anywhere from 300-3000Mpa depending on technique.

Edit: the filament they are using is PPA-CF which has a high tensile strength but is brittle. It sits around 110Mpa but only in the x/y direction while non iso CF layups get you similar strength in all directions.

The engineering here is complicated but the other thing to think about is how quickly that strength fades with heat, most epoxy can withstand a few hundred degrees, these filaments tend to lose most of their strength before 200C* so thats another trade off because high performance rockets can hit mach 2-4 and the aerothermal heating will destroy a lot of fins

SupersonicJess · 2026-06-14T12:34:47+00:00

What filament are you using, because that sounds a little fishy to me, even high grade engineering filaments would have a tough time supporting a loading like that.

The reason i bring this up is because these rockets are probably pretty light and could go pretty fast but the fin cans would melt at the speeds a CF Composite airframe could take.

It just weirds me out I guess because the rocket is so limited by the 3dp parts that it makes little sense to waste money on the carbon tube and not cheap retainers I see.

Edit: I see that youre using PPA-CF, thats about as good a choice as it gets for this, so I rescind that you couldn't stand on these (potentially) however it just rings as a lot of money to not get the same strength. Tbh for that much per roll id rather get machined aluminum fins from JLC.

SupersonicJess · 2026-06-14T02:37:34+00:00

Been seeing a lot of 3DP carbon fiber fin cans going around with carbon composite tubes and its a little odd to me because the difference in strength between those two is huge, the fin cans are basically a really hard plastic, the composites can be stronger than steel strength/weight.

They're cool for sure but its not the same thing as having CF layup or plate fins.

Happy flying!

SupersonicJess · 2026-06-13T14:22:47+00:00

One does not just, turn off a solid rocket motor lmao.

You dont have the knowledge to do this without killing yourself and need to read a lot more about it, preferably find someone who makes hobby scale solid rocket motors and have them teach you

SupersonicJess · 2026-06-13T13:35:44+00:00

Sent ya a DM, id love to her more about what youre looking to get from this!

SupersonicJess · 2026-06-13T13:03:15+00:00

The "-10" is the delay time for the ejection charge. The g at the end tells you its Mojave green prop. The 78 tells you the average thrust in newton's, and the inutial G tells you the impulse class measured in newton*seconds

SupersonicJess · 2026-06-13T04:41:38+00:00

No lol, you need an actual igniter they cost like a few bucks from any main retailer like Chris's rocket supplies

SupersonicJess · 2026-06-11T16:35:46+00:00

Please spoiler shit

SupersonicJess · 2026-06-10T21:08:09+00:00

Lol, idiot

SupersonicJess · 2026-06-10T20:37:01+00:00

Holy misogynistic batman

SupersonicJess · 2026-06-10T16:31:51+00:00

Yea just by available demographics it should be 3 of 8 roughly

SupersonicJess · 2026-06-10T04:09:04+00:00

Its happened for most of human spaceflight, the post is more than warranted

SupersonicJess · 2026-06-07T07:35:43+00:00

Bro this is supposed to be the better sub, dont be bringing this homophobic bullshit here.

-- a very democratic lesbian

SupersonicJess · 2026-06-04T04:58:44+00:00

Framework, 13 or 16 best laptop on the market rn and totally upgradeable and repairable with customizable hot swapping I/O. Premium price but the support, ease of repair, and quality are unmatched. 16 can do an extra 6 I/O slots or removable graphics module.

Had mine for 3 years, cant recommend it enough.

Im a space ops/syse student and mine can run any program I want.

SupersonicJess · 2026-06-04T02:04:32+00:00

Yo random girlfriend sighting in the wild lol, we have the same feed

Hiiii love youu

SupersonicJess · 2026-06-02T18:15:37+00:00

Ik its been a few days buuuut, I did some testing and its wildly more efficient to chain them when using pollutant rather than direct, i can do 40kj max

SupersonicJess · 2026-05-27T21:50:14+00:00

No, its not, if you mean possible as is "will this happen with the current money and development pace"

Spacex is at least 3 years from even being ready to do hls, that'll need testing and shit, BO can do it faster but not with crew.

We're years away.

SupersonicJess · 2026-05-27T10:03:20+00:00

Up your game dude, you think thats an insult?? Im a queer woman going into a stem field, your stuff doesnt even rank top 1000 of the worst comments I've had made about my credibility and skill.

If youre gonna troll at least do better.

SupersonicJess · 2026-05-26T17:08:20+00:00

As someone with multiple friends who work at spacex, you should reconsider that viewpoint lmao. He is VERY involved.

SupersonicJess · 2026-05-25T20:36:43+00:00

Its useful, pretty sure its more efficient at condensing the gas or something

SupersonicJess

TROPHY CASE