A 1/48 scale model of the SpaceX Falcon Heavy rocket | Hacker News Reader

A 1/48 scale model of the SpaceX Falcon Heavy rocket

bps.space

820 pointspmorici94 comments

This is all the more impressive when you realise all the design, build, programming, filming, editing and even the music is done by one guy. I highly recommend subscribing to his YouTube channel to keep up with his current project: https://youtu.be/eh8ic1-5wFo

I also suggest you watch his live streams where he works on the electronics/avionics. It really helped me get back into electronics (albeit in a domain other than space). Very interesting, inspiring and he makes it seem so easy.

Aside: for some reason, the guy reminds of Kevin Macalister from Home Alone, when he's putting together his plans to catch the burglars!

Truly amazing.

> Also, do I even have to say it? Of course those boosters are gonna land! The propulsive landing test program is isolated from the Falcon Heavy program right now, but the two will merge as the success rate for both programs increases.

It seems like it would be really hard to land the boosters with no throttle.

There's been a few clues that we won't forever be without throttle. IIRC it looked like he was tinkering with a hybrid propellant system. Could also create a flame diverter if he's stuck with solid propellant.

I just watched a couple of his videos, and it sounds like he got pretty close to landing with solid propellant ('echo'), but ultimately decided that it was too finicky and ended that project to move onto a liquid biprop rocket.

Are liquid engines still in the realm of hobbyists? The estes engines he's using are pretty widely used and understood to be fairly safe, is there something equivalent for liquid rockets?

One of spaceX’s founding engineers was building liquid fueled hobby rocket engines in his friend’s garage before joining spacex

https://en.m.wikipedia.org/wiki/Tom_Mueller

>> understood to be fairly safe, is there something equivalent for liquid rockets?

No. Lighter fluid can be a reasonable fuel, but the oxidizer is the issue. Either you use liquid oxygen (very cold, explosive, generally dangerous) or something nasty like nitric acid or MMH that will eat your flesh for lunch.

Given the altitudes involved, I would suggest that small jet/turbine engines meant for model aircraft would be more useful. They wouldn't need oxidizer.

LOX isn't explosive. And LN2 is quite popular/widely used, and of arguably little danger.

What I'm not sure about is whether it's safe to get (small amounts of) LOX spilled on your hand (LN2 is safe, my hands still work and the teacher didn't complain in like 2012 (between 2008 and 2015, but I can't guarantee anything tighter)).

Yes, LOX is cold. So what? Just look at, say, [0] for information on what materials you can use for the LOX parts. Just use a simple pressurized tank configuration. Small amounts (sub-kg) of LOX only really restrict you from certain surfaces, such as asphalt, due to the risk of LOX spilling into the ground and turning it explosive.

Otherwise it's arguably safer than everything except maybe 30% peroxide/aluminium in a hybrid rocket.

[0]: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/197600...

Nitrous oxide is a viable and easily handled oxidizer for hobby engines.

The common steel canisters seem to weight 30g, full (including carton packaging), with 8g payload.

The vacuum ISP of a N2O monopropellant is given on Wikipedia as up to 180s, but the cartridge weight drops that to 48s. One could be chilled with dry ice to a vapor pressure of 2bar, but it's still far from easy to handle when weight is a substantial issue and you want to dynamically control flow, I'd figure.

yeah Nitrous Oxide is the oxidizer of choice for hobbyists. It gets used in hybrid rockets and there is/was a couple companies making hybrid rockets available for sale.

Making a tank that's light enough to fly but does not turn into a pipe bomb is _one_ of the hard parts. Also, ignition is and fueling is difficult. iirc Tripoli requires remote fill on hybrid rockets and since a lot of these experimental engines are flown in the desert at FAR (https://friendsofamateurrocketry.org/) temp. becomes an issue.

people are doing it though, i mean it's really impressive to see how far amateurs can push things. We may see the first individual reach the Karman Line this September at BALLS if Covid19 doesn't get in the way. A couple of college teams have done it but not just a random guy. Granted, the guy I'm betting on is very well known in the hobby and not "random" at all.

>> LOX isn't explosive.

Ya, well see what happens when you load it into a model rocket beside some kerosene. Then attach some electronics. Whether oxygen can technically burn or not is moot. There will be fire.

Except that a hybrid rocket engine burning something like e.g. PMMA is also easy to throttle, and doesn't blow up like a mixed mist cloud of keosene/LOX.

Also, fire != explosion. The former is only hot, the latter has a tendency to throw shrapnel.

About 10-15 years back a friend and his other high powered model rocketry buddies were flying rockets that used nitrous oxide as an oxidiser (and using polypropylene or cardboard as the fuel!)

They were just squirting compressed liquefied N2O in to their motors, but were talking about the possibility of throttling by adding a controllable valve.

super late to the thread but i hope you read this. I'm in the high power rocketry scene and liquid engines are out there in the amateur world but uncommon.

You don't see many flights though but there's plenty of test footage. I think one main reason for lack of flights is that Tripoli and NAR ( the two main self-governing bodies for high power rocketry ) currently do not insure bi-propellant rockets at their events. Another reason, is configuring the engine for flight is complicated because of the tanks and pressurization required. It seems like most amateurs run out of effort or money once they have a working injector, combustion chamber, and nozzle. The last mile ( tanks and pressurization ) seem to be out of reach mostly.

btw, if anyone has an engine they want to fly I will happily build you an airframe! :)

There's another guy who's been blowing up the /r/electronics subreddit for making his own pick'n'place machine.

It makes me wonder if their endgame is productizing their projects, or trying to "make it" as YouTubers, or they are just having fun and documenting the process of their fun-having.

He's already productized it, mainly the flight computer: https://bps.space/shop

It's not a bad a early career move, especially if you're still in college--much better than a paper resume.

Peter Stripol is my favorite of these types of channels. Guy built (and flew!) an airplane out of styrofoam.

Do you have a link for that pickandplace machine?

Not offhand, but if you search for reddit user /r/sphawes or YouTube page "Stephen the Robot", you should be able to find it.

https://www.youtube.com/watch?v=GtZcnIEi710

From his about page: "I studied music production in college, and after seeing the ambition of SpaceX, and the excitement in the new space industry, I was hooked. I wanted to work in aerospace... "

At first, I wondered what SpaceX role would suit him best and why SpaceX hadn't hired him. Then it occurred to me that humanity might be better off with passionate polymaths such as him working outside as opposed to inside the establishment. After all, Elon Musk started his aerospace career outside the establishment. And SpaceX is now establishment?

Polymaths have been quite productive in crypto and other low-startup-cost environments. But, apparently, not so much in autonomous vehicles, etc. This could be a function of the learnings required for physical world projects, to wit: quaternions, telematics, aerodynamics, etc.

So, would we/he be better off inside or outside the Borg? Thoughts?

What he's done is super impressive and cool, but has he acquired the necessary base knowledge to work on an avionics, propulsion, etc team at SpaceX?

I'm not in any of those fields, but I'd have to imagine there's a large amount of background knowledge that someone with an aero or mechanical engineering degree has, that he hasn't picked up with model rockets.

Majority of engineers with a degree are useless right after graduation. Its a ton of random math that (most) of which you don't use again since you use modeling software.

Source: Did Aero

Someone doing this as a Amateur can damn well pick up whatever they need to.

> Its a ton of random math that (most) of which you don't use again since you use modeling software.

You absolutely need that math because you need to know when the modeling software is giving the wrong answer. You’re supposed to do quick and dirty calc by hand (ok fine I use mathematica) in a simplified system, then you refine with numerical software and compare the two. It’s shockingly easy to get the wrong answer with numerical CAD.

Not a mech eng but I've taken several eng classes and do a lot of DIY stuff. I've been designing a swing set/exercise rig for myself in Inventor and using FEA to sanity check my beam sizes for the given loads, just cause why not. Since I already had it parameterized, I wanted to see what load it would take with legs made out of 1.25x5.5 boards, just cause. The sim showed it would take several hundred pounds with almost no lateral deflection. Hmmm.

Anyone who's worked with decking boards knows they are pretty wobbly by themselves. I'm staring at the results, intuitively knowing they're dead wrong. So I model a plain column of one of these boards 16' long and 2000lbs, straight down. Zero side deflection.

Ah, I realized, it doesn't model buckling.

Map != territory.

It's always important to have multiple perspective of inference on a problem.

I agree that a fresh-grad engineer will need some hand-holding in order to get them up to speed, but I disagree they are equivalent to an amateur in the similar field. The mathematical/engineering education obtained through their degree teaches them the thinking and underlying scientific principles that justifies concepts/design, which is knowledge often lacked in amateur community.

Using a modeling software still requires validation from an engineer and the "random math" is useful for that. Often times we have to do redundant calculations to confirm that the computer solution is logical. Beyond that, the "random math" is often key to the development of an innovative method that is superior to existing solutions.

In general, amateur's goal is to make something work. Engineer's goal is to make something work, prove it works, and show why the solution was chosen.

Might be true, but SpaceX is only hiring mechanical/aerospace engineering degree holders for the relevant positions: https://boards.greenhouse.io/spacex/jobs/4740817002?gh_jid=4...

> BASIC QUALIFICATIONS:

> Bachelor’s degree in mechanical or aerospace engineering

> 1+ years of experience designing and analyzing mechanical systems via professional work experience, project/research-based student experience, or a combination of both

which OP doesn't have. They're not just hiring randos who can do math, they're looking for people with specific backgrounds in this domain.

There are of course other jobs, like PR, graphic designers, accounting, HR, benefits, facilities, that require zero engineering background, that all big companies must have to just keep the lights on.

Dam I was 20ish and doing now what I did back then I might well stay in mech eng.

I did the specialised mech eng A1 BTEC in the UK that had been set up to service speclised industries - all but of my class worked in bleeding edge RnD.

I did identify in one class that a lump of wreckage was an A4 fuel pump (that is the Agerat 4 aka the V2)

Even at space X level of innovation ?

I was under that impression that maths could still be useful when working at the very bleeding edge of an engineering field.

Bear in mind that companies at the scale of Space X doing safety critical work tend to parcel up tasks fairly minutely. Everything is compartmentalised, tested separately and there are whole teams devoted to the large scale architecture and integration. There's a joke that back in the space race days, an engineer might be responsible for a single screw on the Saturn V (and you'd be damn sure if the thing blew up, it wasn't your screw that did it). Same thing happens with ESA and NASA contractors.

There are lots of engineers who are basically building things to a spec and aren't what you might call innovating.

I think someone who builds rockets to this level would be absolutely fine in an entry position. They just might need to get some of the theory first. Saying that, he clearly understands mechanical design and control theory.

Didn't one of the chief engineers at SpaceX start out with model rockets?

This doesn’t seem to be SpaceX philosophy. See from about 3:25 where Elon discusses the problems caused by departmental structure, not questioning constraints, and ‘optimising something that shouldn’t exist’.

https://www.youtube.com/watch?v=ZDUOaqyup5s

I'd hire this guy in an instant over a rando with a degree and no experience. Engineering degrees are by themselves not very useful, but they are an indicator that you can learn and to an extent teach yourself you need to know to solve problems. This guy has demonstrated that he would probably be extremely successful in most any engineering role I can imagine having a need for, with the possible exception of needing consultation on some really bleeding edge theoretical stuff that would normally be best served by a PhD.

He buys the rocket motors. From his FAQ:

> Do you make your own motors?

> Nope, I use commercially available propellants. Usually black powder motors from Estes or APCP motors from Aerotech. For custom or more complicated builds, BPS.space outsources propellant work to other manufacturers, who can often achieve higher precision and predictability than any consumer setup. I learn best by experimentation, which works very well for software and electronics, less so for explosives and propellants.

> I also got a C+ in chemistry during high school - designing and making rocket propellant is not a good idea for me :)

It sounds like he makes the rocket housings then tweaks some parameters to make them fly.

As someone with experience on the model rocket side, the electronics part of the project is highly impressive, especially using thrust vectoring to get most of the way to landing.

Still, there's a huge gap, IMO, between that and building SpaceX level avionics

Watch one of his videos explaining how his flight computers work. If you still think he's just "making rocket housings" afterwards, thats fine. But watch a video first: https://www.youtube.com/channel/UCILl8ozWuxnFYXIe2svjHhg

In some vid he says he had the chance to go to spacex, but than wanted to continue what he's doing.

Autonomous vehicles is maybe not the best example, with geohot, of all people, founding a self-driving car startup.

That's exactly the content I'm on HN for

Yes, this is cool to see.

But at the same time it shows that rocket tech is not as difficult as people make it out to be. (Rockets were difficult when we didn't have computers.) Also, some universities have student teams which regularly launch similar rockets.

I'm personally hoping for someone to build an IC fab or even a wafer stepper in their garage.

> But at the same time it shows that rocket tech is not as difficult as people make it out to be.

It really doesn't. The scale model probably weighs a few pounds where as the real Falcon Heavy weighs 3 million pounds [1]. Think about what a different scale that is!

Also note that the scale model's (really cool) test flight failed -- with the real Falcon Heavy that lesson would cost something like $150M.

I think this is kind of similar to: it's really easy to query/serve a SQL database even if it's a few tens of terabytes in size. But make it a few tens of exabytes, and things are dramatically more difficult due to the scale. The architecture that works at the terabyte size (single machine) falls over completely.

[1] https://en.wikipedia.org/wiki/Falcon_Heavy

This thing doesn’t fly as high as a bottle rocket. What makes building rockets hard not the avionics but economics and the good old rocket equation. A cool model is really solving a very different but still fun problem.

Rare gem - the bulk is made of open source stuff no one asked for, rants against employers, and weird calls to revolution. Worth staying for the rare ones tho.

Those open source tools are sometimes how I stay employed. Wouldn't want to be without HN.

True - but I am referring to useless open source posts. Forgot to add those claiming OOP, code documentation, and so on, are useless. Waste of time and are a distraction from what you mentioned.

The whole time I was reading this article, I was hoping I would eventually see a "buy now" button at the end. Alas...

He has a shop here - https://bps.space/shop

I remember my first play around with the small rocket kits. 1 small motor and you press “Fire” annnnd it’s gone. You can’t see it anymore and it’s lost lol.

That just means you put too big a motor in it! Each motor letter designation is double the total impulse of the previous one - it's a log scale. If you stick a C motor into a small, well-built, lightweight rocket, it's going to go over a thousand feet. Unless you painted it a very bright color, you're probably going to struggle... so stick to the A motors for your maiden flight!

(Also: launch from the upwind edge of the field!)

Gimballed thrust puts this squarely into all the cool hobbies involve ITAR territory.

The tube launched rocket looked decidedly weapon-like too.

Cool tech though. Hope he doesn't get into trouble

He’s been pretty careful to not do anything illegal (he’s talked about this in a few live-streams), for example not open-sourcing any of his control software and using just local IMU data for in-flight control.

Is this a typically US thing or does this kind of thing risk getting you into trouble elsewhere too? I mean the first thing you'd want to try once you have a "platform" is things like GPS guidance, adding wings & making cruising rockets, trying terrain guidance etc. Isn't the cat out of the bag with this kind of tech already, much like strong crypto was once a non-exportaple technology in the US, but now it isn't? What exactly is the tech that is off limits (I don't mean tech that will get someone to come to your house and ask questions, but tech that is actually 100 % certainly illegal?)

Didn't work out great for this guy from New Zealand: http://www.aardvark.co.nz/pjet/cruise.shtml

(Not "go to jail" bad, but "The New Zealand government has moved aggressively to shut down this project -- and by using quite unscrupulous methods which appear to be in breach of the law." type of bad...)

Accessible to nation state actors, and order-able off Alibaba, are 2 different levels of "available.

You would be surprised, that most acts of aggression do not have months of planning and 1M+ engineering budgets. Remember the most "special" tooling the 9/11 terrorists had was some cash plus basic flight training.

The guy even looks a bit like Elon. 1/48 scale net worth too?

They don't call him budget Elon for no reason.

If he is not running his own orbital rocket company in 10 years I will be amazed.

Shouldn't it be 1 / 110,592 scale net worth though? Saying 1/48th model is a bit misleading as it's 1/48th in 3 dimensions, whereas worth is one dimensional.

Not really, since we're really talking about the size of swimming pool you need to hold the coins you dive into.

A net worth of 1/48th of Musk’s would be enough to buy eight Falcon 9 launches.

If it's possible to fit that electronic hardware on something the size of a credit card how does it compare to what is used for that purpose in a real orbital rocket other than redundacy features?

It's basically the same technology. They're pretty common in airplanes nowadays. Here is an example of a portable unit intended for use as a backup:

https://www.aircraftspruce.com/catalog/avpages/iLevilSport.p...

And another one designed to be panel-mounted:

https://www.dynonavionics.com/pocket-panel.php

If you want to get more details, the search terms you want are EFIS (electronic flight instrument system) and AHRS (attitude and heading reference system, pronounced "ay-harz").

Longtime supporter of Joe and his incredible model flights. Also worth looking up his Sprite development!

Been watching Joe for a long time. The dude deserves more support

How high does this thing go? I read the article but as far as I can tell, it was never mentioned.

Based on the videos, maybe 100-300ft?

That's really cool!

I wonder what the bottom-line price tag on something like that would be.

Qu8k (https://ddeville.com/derek/Qu8k.html) is some impressive amateur rocketry from 2011.

Well, not exactly. First stage has 27 Merlin 1D engines.

Depends which Falcon. Falcone 9 has 10 Merlin engines, while Heavy has 28.

https://www.spacex.com/media/falcon_users_guide_042020.pdf

Wow, he is even is trying to design landable boosters like in the real thing! WTF!

If SpaceX doesn't hire him, then Space Force surely has an opening!

Did it blow up during an engine test?

SpaceX has a huge potential opportunity for raising funding / earning profits via toy licensing and sales: https://www.barrons.com/articles/spacex-overwhelmed-by-deman...

Wouldn't it be interesting if Elon could achieve his Mars objectives faster not by selling LEO satellite services or space launch capacity but by selling and/or licensing toys (and sparking dreams) here on Earth?

Despite the current pandemic, this is a great time to be a young person. Dreams and human potential seem infinite.

Edit: Who would own the IP, NASA or SpaceX or both?

Absolutely. I would buy the heck out of a 4000-piece Falcon Heavy LEGO set, and I suspect I’m not alone.

Saturn V scale Falcon 9 fan submission under review.

https://ideas.lego.com/projects/1abc6458-52e8-4e7d-a04c-04ba...

Yep, it can go right next to my 1969 piece Saturn V.

Saturn V scale Falcon 9 fan submission under review.

https://ideas.lego.com/projects/1abc6458-52e8-4e7d-a04c-04ba...

That is genius. They should continue the trend and do a 2020 Falcon (or whatever year they choose).

I went looking for a Falcon toy for my kids a year or two ago and was really surprised to find nothing. They should definitely license toys.

He could sell them in the Tesla showrooms and really drive up traffic, too. Crazy amounts of opportunities here.

I know this is a tactic Elon has definitely used before - i.e. hats and flamethrowers to fund the Boring company.

I can't find the source because Google is a bit biased towards giving me articles about yesterday's launch but I know at a press conference w/ NASA Elon stated the technology they're developing for NASA should not be considered proprietary and that NASA could do what they wanted with it. With that being said, the Falcon 9 designs have to be SpaceX's IP.

I was just watching this channel yesterday after the SpaceX launch. Anyone know what he uses for the actual rocket engine bit? They don’t seem like something that can be throttled.

And yes he definitely looks like Elon!

If nothing has changed from my childhood, probably Estes model rocket engines, that are solid fuel.

A single guy has probably achieved what a whole division of a large corporation or a large govt agency would not be able to achieve in years

I don't think you understand the breadth of rocket science, material science or the convexification of the mathematical model required to do what spacex does. While this is very cool and pretty, it's still an advanced toy.

In a just world, he would have 1/48th of Elon’s fame/fortune too.

Unfortunately, sending 1/48 of an astronaut into orbit is not as valuable.

At around $3k per kilo to orbit, I'd bet he'd be _very_ happy with the $6k or so 1/48th of a ~100kg astronaut+spacesuit would mean per launch!

He ain't getting anywhere near orbit using Estes motors though... Not even 1/48th of the way to orbit I'd guess...

(Hmmm, spaceflight.com's pricing page says they'll send a 3U 5kg cubesat payload to LEO for $295,000... That's I guess pretty close to "1/24th of an astronaut to orbit"? Minus the ~10,000% surcharge for "manrated" though, I'm guessing.)

Sending 1/48th of an astronaut into orbit would be a great achievement actually. The problem is when you said an astronaut into 1/48th of an orbit, which is what this is currently doing :)

1/24th* since it was two astronauts, no?

amazing perseverence, but a bit overproduced :)

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