[HN Gopher] MIT largest open-source car design dataset, incl aer...
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       MIT largest open-source car design dataset, incl aerodynamics, to
       speed design
        
       Author : toss1
       Score  : 127 points
       Date   : 2024-12-06 18:07 UTC (1 days ago)
        
 (HTM) web link (news.mit.edu)
 (TXT) w3m dump (news.mit.edu)
        
       | WhatsName wrote:
       | I recently wanted to design a flying wing/rc plane. Is there any
       | FOSS to get reasonable results for aerodynamics?
        
         | jpb0104 wrote:
         | This guy seems to have a good handle on diy aero. Both air and
         | water.
         | 
         | https://youtube.com/@rctestflight
        
         | nickmcc wrote:
         | Check out: https://ecalc.ch/wingdesigner.htm
        
         | BoostandEthanol wrote:
         | OpenFOAM I think is the go to for open source CFD, although
         | I've never tried it myself. There's also XFOIL which, since
         | you're talking about a flying wing, might be enough for your
         | use case.
         | 
         | Even for a finicky flying wing, I think if you keep an eye on
         | the way the pitching moment shifts with pitch, I don't see why
         | picking an airfoil shape for the frame and hand calcs couldn't
         | get you to a design that flies reasonably.
        
         | Stevvo wrote:
         | The usual way is to use a wing with known aerodynamics. Choose
         | one on airfoiltools.com
        
         | SonicScrub wrote:
         | Using a computational fluids model like OpenFOAM is overkill
         | for reasonable estimates of aerodynamic performance and
         | stability, provided you stick to normal-ish designs. The term
         | you want to Google is "vortex lattice" and/or "potential flow"
         | solvers, of which there are many open source softwares
         | available specifically geared towards typical aircraft
         | configurations, with simple, easy to use interfaces.
         | 
         | Some good ones to look at to get started with nice guis
         | 
         | - VSP Aero
         | 
         | - XFOIL (for 2D airfoil analysis only, also generates inputs
         | for 3D VLM solvers)
         | 
         | - AVL
         | 
         | And some others if you want perhaps a little higher fidelity,
         | and don't mind text/code interfaces:
         | 
         | -FreeWake
         | 
         | - Datcom (not technically a potential flow models, but a
         | database)
         | 
         | To get the most value out of these softwares, you will need
         | some background in aeronautics. You need to have an
         | understanding of what a potential flow models can and cannot
         | accurately model. It also helps to have knowledge about what
         | forms aircraft stability/control and performance data is
         | typically communicated in, as these softwares will use that
         | terminology.
        
           | kingkongjaffa wrote:
           | I used xfoil in my aerodynamics masters degree, it absolutely
           | good enough for hobby applications
        
             | SonicScrub wrote:
             | The 2D model alone maybe be sufficient for OPs needs, but
             | I'd advocate for going at least a little further with some
             | form of 3D model. The wing tip effects are significant
             | enough to warrant some form of "next step" after the
             | initial 2D analysis. Although simple algebraic
             | relationships are likely good enough to satisfy this end.
             | 
             | However, the 3D tools above give you a little bit more,
             | that I feel warrant their consideration by the op. These
             | models can yield performance of wing-tail-body
             | configurations that include wake effects. They also can
             | give stability analysis in both longitudinal/lateral axes.
             | The stability effects being especially important if OP
             | wants to design a flying-wing, which are a tad more
             | challenging to get right than just slapping a "good-enough"
             | sized tail on a classic config plane.
        
         | addaon wrote:
         | For this type of problem, unless you are trying to set range or
         | climb rate records, understanding lift and moment (and control
         | derivatives) is more important than accurately modeling drag.
         | Panel methods shine at this, and are both easier to use and
         | much much faster than CFD -- enough that wrapping them in
         | optimizers is trivial. I personally prefer AVL, but there are
         | other open source alternatives as well.
        
       | ericjmorey wrote:
       | Datafiles available at:
       | https://dataverse.harvard.edu/dataverse/DrivAerNet
       | 
       | Issue tracking at: https://github.com/Mohamedelrefaie/DrivAerNet
        
       | Y_Y wrote:
       | Did they verb speed? Verbing bads otherwise readable prose.
        
         | liamdgray wrote:
         | Yes. They had verbed it by the 12th century, according to:
         | https://www.merriam-webster.com/dictionary/speed#word-histor...
        
           | Y_Y wrote:
           | Only in the archaic sense 3a, "to prosper in an undertaking",
           | which is surely not what's meant in the TFA.
        
             | liamdgray wrote:
             | Have you known anyone who received a ticket (citation) for
             | "speeding" while driving?
        
         | anon291 wrote:
         | I sped read the title so didn't notice
        
         | mmooss wrote:
         | While I don't always love 'denominalization' (if I that's the
         | right word), the verb 'speed' is a common one, e.g., 'speed
         | up'.
         | 
         | Every word we use was created at some point, often in the same
         | way. There is nothing magical about the people and the words
         | they created in 1824 that makes them better than us and words
         | we create in 2024, except perhaps that the 1824 words we still
         | use have stood the test of time.
         | 
         | Also, as far as I can tell, the verb form is as old as the noun
         | form.
        
           | senkora wrote:
           | (CW: pedantry)
           | 
           | Well actually, "speed up" is a phrasal verb that is
           | semantically distinct from "speed".
           | 
           | https://en.m.wikipedia.org/wiki/English_phrasal_verbs
           | 
           | But that all's irrelevant because this article uses verb
           | definition 5 from Wiktionary for "speed":
           | 
           | > (transitive) To increase the rate at which something
           | occurs.
           | 
           | https://en.m.wikipedia.org/wiki/English_phrasal_verbs
        
             | wrycoder wrote:
             | "He was speeding." Love English!
        
         | navane wrote:
         | I read moby dick for the first time last summer. That guy verbs
         | nouns, adjects verbs and nouns adjects like he's building
         | language from first principles. It takes a bit getting used to,
         | but eventually it both speeds up and broadens language. Why use
         | different roots for each category? And with each root connoting
         | slightly different, why not use that and pick the exact root
         | that means best?
        
       | morphle wrote:
       | Its a few hundred gigabyte. You can only login with an
       | institutional account. My research institute is very small, can I
       | borrow someone's login credentials? (email in profile).
        
         | hackernewds wrote:
         | It is not meant for non credentialed individuals?
        
           | gus_massa wrote:
           | From the repo
           | 
           | > _Please note the (CC BY-NC 4.0) license terms, as outlined
           | in the License section._
           | 
           | In spite of the title and the article says "open souce" many
           | times, it's free as in "source abailable".
        
       | MichaelTheGeek wrote:
       | Very nice.
        
       | tomjen3 wrote:
       | O great. More cars that look identical.
        
         | dietr1ch wrote:
         | Isn't this more efficient? Cheaper parts, everyone benefits
         | from improvements to it.
         | 
         | I wouldn't mind if there were only a handful of designs around
         | with some tweaks depending on performance/comfort. Also,
         | nowadays many different models share parts, like lights or
         | rearview mirrors, showing there's a need for efficiency and
         | scale bigger than the made-up need for fashionable cars.
        
           | grecy wrote:
           | I've always been shocked there are not way more common parts
           | between vehicles and brands.
           | 
           | Alternators, starters, ac compressors and so much more could
           | just be small, medium, large, extra large.
           | 
           | The price would drop dramatically.
        
             | psychlops wrote:
             | > The price would drop dramatically.
             | 
             | Aaaaand, that's why they aren't modular. Take a look at
             | something with obvious common parts like a side mirror.
             | They are all intentionally designed adding special shapes
             | to make them as unique as possible to the car. Never a
             | simple square or rectangle.
        
           | cwayon wrote:
           | Good design is emotional. It adds spark to most of our
           | everyday sightseeing, inspires and is too often overlooked-
           | at least in recent times. Regarding the recent trends among
           | car design... We are in a dark age.
           | 
           | I agree that many parts can be interchangeable but modularity
           | can be done in a way that doesn't result in every car looking
           | like the blobs we see about today. I wouldn't mind if there
           | were only a handful of designs around with slight variations
           | in trim and specs -so long as I like those designs of course!
           | I know that is subjective so lets keep things interesting and
           | focus on making things that get the job done but also in
           | varying styles. Both can be achieved.
           | 
           | The need for fashion is made up, yes- but so is everything
           | else. There's a balance between overly individualistic cars
           | and the most cost efficient, reliable and uninspiring 4 door.
           | Lately we have been leaning too far into the latter.
        
           | spookie wrote:
           | No one wants that. Neither consumer nor business.
           | 
           | Think about every GPU having 8GB VRAM. Nobody wants that.
        
         | ForHackernews wrote:
         | Aerodynamics is aerodynamics, but we should embrace wild paint
         | jobs.
        
       | RobotToaster wrote:
       | > Creative Commons Attribution-NonCommercial
       | 
       | Non-commercial licenses are not open source.
        
         | csours wrote:
         | I wonder if you might say something more substantial? This
         | seems like a low effort nitpick as written.
        
           | spookie wrote:
           | Fails at criteria 6.
        
       | bmitc wrote:
       | For what use is this?
        
       | aquafox wrote:
       | Somewhat related: Can someone tell me why all those new electric
       | cars are so poorly designed in terms of size and weight? Most of
       | them weight over 2t and have a large frontal area (VW ID.4 is the
       | prime example). I just want an economical family vehicle
       | (lightweight, hatchback design) and there aren't that many
       | options. Isn't that something loads of people want or am I the
       | exotic one?
        
         | bagels wrote:
         | People are not buying as many compact cars.
         | 
         | Electric cars need large, massive batteries to have a useful
         | range.
         | 
         | It's as simple as those two things.
        
         | wyager wrote:
         | > I just want an economical family vehicle
         | 
         | Then buy an ICE vehicle. It's a more mature, cost-effective,
         | and power/energy-dense technology
        
           | aquafox wrote:
           | But the efficiency factor of an EV is 60% as opposed to 20%
           | for an ICE, which means you can get a similar range with much
           | lower energy density.
        
             | sedatk wrote:
             | ...at the expense of door handles and good looking tires.
        
         | carabiner wrote:
         | Now you're seeing why electric aircraft are struggling.
        
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       (page generated 2024-12-07 23:00 UTC)