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A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

bbc.com

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Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

#161

Post by jacobgkau »

cloudfudge wrote: post #152
Ntrails wrote: post #99

Earlier quoted context omitted.

I think the idea was that 3D printing made doing a thing accessible, previously required solid fundamental knowledge (and very expensive kit). Now you can just take some specs off the internet and press go. The comparison does not seem as absurd to me as it does to you. vOv

The lesson here is that one should never attempt analogies on HN, because people can't just relax and try to see the point of the analogy. They are compelled to fixate on the fact that an analogy is different from the thing it is being compared to. I see multiple examples of it in this thread.

I feel like Hacker News commenters love to make analogies more than average people in your average space, though. You can't come across a biology/health topic on here without someone chiming in with "it's like if X was code and it had this bug" or "it's like this body part is the Y of the computer."

Analogies can be useful sometimes, but people also shouldn't feel like they need to see everything through the lens of their primary domain, because it usually results in losing nuances.

Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

#162

Post by jacquesm »

ComputerGuru wrote: post #149
jacquesm wrote: post #120

Earlier quoted context omitted.

But not that much better compared the better filaments out there. Fair chance it was printed out of PLA, ABS or PETG, by the shade of the part it looks like it was CF loaded filament. A better choice would have been PEEK. But even then, I would have done a lot of on-the-ground testing before trusting my life to a part from the printer.

There’s a massive difference between the thermal properties of the materials you listed.

Yes, that's why I listed them. And even then: none of those first three are (safely) usable for this application. PEEK or ULTEM or something better than that.

Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

#164

Post by shmeeed »

ToucanLoucan wrote: post #85
lemonwaterlime wrote: post #40

Taken at face value, this is engineering negligence. I've done industrial design with plastics and 3D printed parts. Regardless of the forming techniques, with plastics you still need to consider properties like minimum melting temperatures, tensile stress, and so forth. Then you must test that rigorously. This is all standard procedure. That information is in the data sheet for the material. I did a quick search and…

Also, strictly as a combo 3D-printing and engine enthusiast: Never with a GUN to my head would I install 3D printed parts in a CAR engine, let alone in an aircraft engine. This is spectacularly poor judgement on the part of the owner.

FWIW, I wouldn't hesitate to install a 3D printed air-filter housing in my car, if I had printed it myself out of e.g. PAHT or sourced it from a trusty vendor. It's not rocket science, just engineering.

Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

#165

Post by pfdietz »

I just watched a fun video of a guy bringing a 1978 Datsun 280Z up to date. He kept the existing engine but upgraded it with modern electronic ignition and computer control. As part of all that, he fabricated various parts in plastic by 3D printing, but then had the final versions made elsewhere in metal -- some by a CNC shop you send CAD files to, and one by a manual machinist in Switzerland with his own Youtube channel. The latter has to be case hardened, which the machinist did.

The 3D printed plastic parts were very useful to prove out the parts' shapes.

https://www.youtube.com/watch?v=jZ38C-M3tyk -- engine upgrade

https://www.youtube.com/watch?v=D2bxsEyYdo0 -- My Mechanics making the part

Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

#166

Post by jacobgkau »

defrost wrote: post #128
phoronixrly wrote: post #111

Earlier quoted context omitted.

I call bullshit. 3d-printing is just a manufacturing method. Basic woodworking is much cheaper and more accessible than 3d-printing, do you call it vibe-coding?

If you carve a wooden part with "the right shape" for an engineering application that the part lacks the physical properties that allow it to perform under load stress ... then yes, that's vibe carving. Looks good - falls apart in practice, and a junior can't tell the difference as they "look the same" to the inexperienced eye. From practical experience, you cannot just replace a tyre on a car with any old bit of woo…

What you're describing is more like someone who doesn't know computer science principles hacking on code, manually. Part of the definition of "vibe coding" is that AI agents (of questionable quality) did the actual work.

Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

#167

Post by [deleted] »

cloudfudge wrote: post #158
bsder wrote: post #148

Earlier quoted context omitted.

> Never with a GUN to my head would I install 3D printed parts in a CAR engine, let alone in an aircraft engine. The fabrication technology doesn't matter. The qualification process, on the other hand ... This is the primary reason why I never got a pilot's license. I suspect I would spend far too much time making sure the maintenance was up to standard and far too little actually enjoying flying.

> The fabrication technology doesn't matter. The qualification process, on the other hand ... Well, yes, but... In this case the fabrication technology and the lack of qualification process likely go hand in hand. They wouldn't have a qualification process unless they were manufacturing enough of these that plastic 3d printing wouldn't be cost effective. The shortcut is the point.

[deleted]

Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

#168

Post by cloudfudge »

jacobgkau wrote: post #161
cloudfudge wrote: post #152

Earlier quoted context omitted.

The lesson here is that one should never attempt analogies on HN, because people can't just relax and try to see the point of the analogy. They are compelled to fixate on the fact that an analogy is different from the thing it is being compared to. I see multiple examples of it in this thread.

I feel like Hacker News commenters love to make analogies more than average people in your average space, though. You can't come across a biology/health topic on here without someone chiming in with "it's like if X was code and it had this bug" or "it's like this body part is the Y of the computer." Analogies can be useful sometimes, but people also shouldn't feel like they need to see everything through the lens of…

On the other hand, if you are communicating with a bunch of people who share that primary domain, it can be a useful way of making a point.

(unless that primary domain tends to attract a lot of people who tend to the hyper-literal /s)

Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

#169

Post by Ccecil »

jacquesm wrote: post #132
Ccecil wrote: post #100

Not to be a 3d print snob but.... Aside from the failure it looks like it wasn't the best print to start with. Lots of rashing from support and curling at the edges. You can see on the flats where the support was and the outer curve of the elbow looks like it likely wasn't airtight. Appears to me to be printed with the inlet facing upwards. Better support planning, settings and possibly orientation may have helped. O…

I've almost made that exact same mistake (but not on a critical part). I had a bunch of identical rolls with CF loaded filament of different base materials and just looking at the filament you really couldn't tell.

Right...I have loaded the wrong material before.

It didn't take long before I noticed. PLA is super liquid at ABS temps :)

(Not to mention that in my case ABS bed temps would melt the bottom of the PLA)

Re: A Cozy Mk IV light aircraft crashed after 3D-printed part was weakened by heat

#170

Post by lutusp »

They included everything but the 3D printed material. If it was PLA, no surprise (and no excuse). Even ABS might not stand up to the temperatures at that location. I hate it when a news report tells you everything except details that might make a difference going forward.
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