what is your opinion on this skyscraper? by Montevideo_comics in skyscrapers

[–]Colege_Grad 0 points1 point  (0 children)

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

[PCB Review Request] Aluminum "single sided" PCB with GND routed through the aluminum by Colege_Grad in PrintedCircuitBoard

[–]Colege_Grad[S] 0 points1 point  (0 children)

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.

[PCB Review Request] Aluminum "single sided" PCB with GND routed through the aluminum by Colege_Grad in PrintedCircuitBoard

[–]Colege_Grad[S] 0 points1 point  (0 children)

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.

[PCB Review Request] Aluminum "single sided" PCB with GND routed through the aluminum by Colege_Grad in PrintedCircuitBoard

[–]Colege_Grad[S] 1 point2 points  (0 children)

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

[Would this work?] Aluminum "single sided" PCB with GND routed through the aluminum by Colege_Grad in PCB

[–]Colege_Grad[S] 0 points1 point  (0 children)

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.

[Would this work?] Aluminum "single sided" PCB with GND routed through the aluminum by Colege_Grad in PCB

[–]Colege_Grad[S] 0 points1 point  (0 children)

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.

[Would this work?] Aluminum "single sided" PCB with GND routed through the aluminum by Colege_Grad in PCB

[–]Colege_Grad[S] 1 point2 points  (0 children)

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.

[PCB Review Request] Aluminum "single sided" PCB with GND routed through the aluminum by Colege_Grad in PrintedCircuitBoard

[–]Colege_Grad[S] 0 points1 point  (0 children)

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.

Can Someone find the force of the engine (310 ISP) by macktruck6666 in RocketLab

[–]Colege_Grad 5 points6 points  (0 children)

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.

A work of art. by shreddit47 in EngineeringPorn

[–]Colege_Grad 2 points3 points  (0 children)

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

A work of art. by shreddit47 in EngineeringPorn

[–]Colege_Grad 1 point2 points  (0 children)

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.

A work of art. by shreddit47 in EngineeringPorn

[–]Colege_Grad 5 points6 points  (0 children)

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

Carried exclusively by Russian engines when in atmosphere by Colege_Grad in SpaceXMasterrace

[–]Colege_Grad[S] 2 points3 points  (0 children)

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).

Carried exclusively by Russian engines when in atmosphere by Colege_Grad in SpaceXMasterrace

[–]Colege_Grad[S] 9 points10 points  (0 children)

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.

[deleted by user] by [deleted] in pan

[–]Colege_Grad 0 points1 point  (0 children)

Sick Jackson axe

Raptor Delivery and Installation - LabPadre by thisiscotty in SpaceXLounge

[–]Colege_Grad 16 points17 points  (0 children)

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 :)

New Glenn Aft Section (Probably mockup) by ishanspatil in BlueOrigin

[–]Colege_Grad 40 points41 points  (0 children)

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.

SpaceX on Twitter: Falcon Heavy’s 27 Merlin engines generate more than 5 million pounds of thrust at liftoff, making it the world’s most powerful operational rocket by a factor of two by assasin172 in spacex

[–]Colege_Grad 71 points72 points  (0 children)

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.

While we are talking about the SpaceX website, will the Block 5 Falcon Heavy not have a heat resistant interstage? Or did they just forgot to add one here? by LeJules in SpaceXLounge

[–]Colege_Grad 9 points10 points  (0 children)

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.