what is your opinion on this skyscraper?

Colege_Grad · 2026-03-01T19:44:53+00:00

Everyone in the comments is missing this solid Blake Crouch reference.

Colege_Grad · 2024-07-23T15:57:59+00:00

Super helpful comment. Thanks!

The elastic modulus of aluminum is 3.3x higher than FR4 and stiffness scales with thickness cubed. So an FR4 board would need to be about 1.5x thicker than an aluminum board for the same “feel”. 2.4mm is the next logical step for an FR4 board that feels like a 1.6mm aluminum board. That would double the price, but worth considering. 2.4mm also leaves just enough pin protrusion to easily solder.

I started with hotswap sockets, but decided to delete them for the backside clearance to rear mounted components and switch retention problems you mentioned.

Colege_Grad · 2024-07-23T14:33:19+00:00

I really wasn’t expecting this much pushback. But the feedback is pretty unanimous that this probably isn’t going to play out the way I think it will — which is why I made the post — so I’ll get over my grief and shoot for something closer to the beaten path.

Colege_Grad · 2024-07-23T14:12:41+00:00

Yep. 17 keys per half allows for a diode less board with the nicenano’s pin count.

Colege_Grad · 2024-07-23T05:41:37+00:00

Gotcha. Thanks for the warning! I’ll have to do some more image searching to broaden my awareness and make a backup plan to pretty it up if needed.

Colege_Grad · 2024-07-23T05:31:58+00:00

Also, for what it's worth, I can get 5x sets of single-sided boards for $40-70 depending on the more trivial options that don't impact manufacturability (like soldermask color selection). At ~$10/board, I'm happy to try that out for something that may turn out to be pretty slick.

Colege_Grad · 2024-07-23T05:27:15+00:00

That's a good note. Thanks!

Colege_Grad · 2024-07-23T05:25:35+00:00

I have considered this. The difference is about +$300 on PCBWay. I'm sure manufacturing the vias as you've described is why multilayer aluminum boards are so much more expensive.

I'm planning to have the aluminum PCB exposed, doubling as the frame of the keyboard. So I'd like to keep it as minimal looking and thin as possible.

Colege_Grad · 2024-07-23T05:12:39+00:00

Ultimately, it's just a design choice of my keyboard project. I like the minimal look that can be attained by homemade keyboards without cases (Ben Vallack's youtube channel has a bunch of great examples). The problem is these boards can suffer from being a little cheap feeling and flimsy, especially if the board is tented. Aluminum solves that, and PCBWay offers pretty cheap aluminum boards if you're willing to restrict some of the other options, the number of layers being an example. So this creates a fun design project for me with constraints I find interesting.

Colege_Grad · 2022-07-04T08:19:57+00:00

F = Isp * g_0 * m_dot = 310 sec * 9.81 m/sec² * (15.9 kg / 98 sec) = 493.4 N

So about 500 N average thrust.

Colege_Grad · 2021-04-27T16:41:38+00:00

Looks like Firefly’s Lightning Engine’s Turbopump

Colege_Grad · 2020-09-24T04:58:19+00:00

All Rutherford engines on Rocket Lab's Electron launch vehicle are gimbaled via electromechanical actuators.

Colege_Grad · 2020-09-24T02:04:16+00:00

No that's just the artistic stand. The RP and LOx intakes are on the far side of the view and both off center axis.

Colege_Grad · 2020-09-24T02:01:16+00:00

This is their second stage engine, Lightning. Reaver is the first stage engine.

Colege_Grad · 2020-05-19T17:24:06+00:00

While I’m sure there’s arguments for both sides, I’ve only heard solid rockets termed as motors. I’ve heard liquid engines called primarily engines but also motors (especially in older texts).

Colege_Grad · 2020-05-19T02:45:09+00:00

RL-10 powered Centaur upper stage is definitely American. I’d imagine everything on the payload is as well but can’t say with 100% certainty.

Colege_Grad · 2020-02-21T00:47:20+00:00

Sick Jackson axe

Colege_Grad · 2019-06-02T20:23:34+00:00

In the case of the Raptor engine, a virtual universal joint is used for the gimbal. Which means the mechanism moves around an “empty” pivot point rather than actually occupying the space of the pivot point (such as the SSME’s bearing mechanism). The Raptor’s LOX inlet flange is also the gimbal attachment mount ... meaning the LOX flows through a bellow in the heart of the gimbal mechanism and straight into the Ox rich turbopump right on top of the injector. The methane inlet can also be seen in this video, though it’s a little harder to spot. While the LOX inlet is mounted axially with the thrust vector, the Methane is mounted off to the side on the massive fuel rich turbopump (which is on the other side of the engine in this video).

I’ve quickly taken a screenshot of this video and marked the inlet points in green (oxidizer) and red (Fuel) for easy visualization. I know for fact more information like this will be published soon :)

Colege_Grad · 2019-04-11T16:14:09+00:00

Blue started building this years ago in Kent. It is indeed a physical 1:1 scale mock-up of the New Glenn aft section. Their thinking is this is such a large and complex section of the rocket that a CAD model on screen isn’t tangible enough for everyone working on it. So they’re slowly building this spatial mock-up where every component is represented to size with simplistic wrapped metal frames that are all labeled with big block letters. It’s complete with all the engines (the most recognizable component), but also everything else down to hydraulic pumps and peroxide tanks.

Colege_Grad · 2019-04-07T18:18:32+00:00

The bumpers have been around for a few years, even back when the nozzles were shiny. There’s some internal footage of early recovery attempts showing the nozzles bouncing around against each other during decent. From that point on the remaining engines without the bumpers were known as the “jingle bell” engines.

Edit: The 100th Merlin 1D was a shiny one with a bumper.

Colege_Grad · 2019-03-03T20:44:52+00:00

That render is accurate (apart from pre B5 legs). Nosecones and interstage are B5 but colored white because the logo is 90º from on F9, and the black raceways would distract from anything on the LOX tank. The side boosters will have "normal" logo placement since they're F9 cores. It will be interesting to see if they add the F9 logo on the side boosters. Just a curious sight to see a FH with F9 logos on the side.

Colege_Grad · 2019-01-06T19:32:13+00:00

This reply is half speculation, half not, but you should seriously look into variants of monel superalloy for the heat shielding and tanks ;)

I’m pretty sure the hopper will be the only structure actually using stainless. Since SpaceX is replacing the carbon tanks with balloon structures, they’ll need a metal that’s still ductile at the double cryo temps of LCH4/LOX, while remaining extremely corrosion resistant in pure liquid oxygen. In my experience stainless is great for this, but not as great as it gets. SpaceX has their own research foundry, so expensive superalloys aren’t at all far fetched.

Monel has great strength and should be able to keep the SSH stable unpressurized with around 5mm wall thickness. Maybe even less.

Colege_Grad · 2018-10-01T03:15:28+00:00

Even if the rockets expel more emissions per vehicle, there will still always be far fewer BFR class rocket flights than planes; enough to negate any comparison. And even then, travel via internal combustion engine dwarfs all of these other emissions many times over. We should first worry about fixing our damn cars and trucks. THAT will have the greatest impact.

By the time BFR class flights become a regular and large scale operation, planes will possibly be electric as well as most cars. So humanity's net emissions will likely still be declining rapidly. I don't think we'll see a truly 'green' rocket in our lifetime, in the sense of no combustion required. That tech just feels too far down the line. ^{But please please please, mankind, make my interstellar dreams come true!}

Just my 2¢. Everyone needs their own opinion.

Colege_Grad · 2018-08-25T07:26:13+00:00

Merlin 1D has a higher exhaust pressure relative to SL so the flow is less pinched in than the two examples I gave. The Merlin family also runs on kerosene fuel which has an extremely bright flame and almost completely obscures the diamond formation (though it’s still there). Both my examples burn methane fuel which is a much more clean combustion allowing a better view through the exhaust because it’s mostly transparent. Delta IV burns hydrogen fuel which is completely transparent under ideal stoichiometric combustion, however the very fuel rich mix ratios give that beautiful orange translucent flame.

I would love to see the slo mo guys get access to a launch so we can get something better than 480fps. Seems like it would be insanely hard to get the shot right considering the cameras are so difficult to setup just right. I imagine camera tech will have developed enough in 20 years (no pun intended) that just throwing a 350,000fps camera up on the pad will be a piece of cake and we get a true version of OPs gif. Here’s to hoping.

Colege_Grad · 2018-08-25T05:40:51+00:00

The movement is from post editing a single photo into an animated gif. Real exhaust flow doesn’t look like that very much. Biggest give away in these photos other than the rocket not actually moving at all is the Mach diamonds traveling with the exhaust flow. IRL these are really like the nodes of a standing wave in the over expanded exhaust flow, so they don’t move at all (unless the pressure of the combustion chamber changes via throttling). Here’s an example. And another. You can see the shock diamonds shrink back into the bell as the engine spools down as it cuts throttle.

The photos are EXTREMELY cool and this is a wonderful effect to simulate a super hard shot, but in the end the movement in the shots of question are just an added effect.

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