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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

#171

Post by jacquesm »

Ccecil wrote: post #169
jacquesm wrote: post #132

Earlier quoted context omitted.

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)

Oh that could have been quite messy if you had done that unattended.

I've gone through a couple of thousand kg of filament in the last year and I've had some 'interesting' failures.

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

#172

Post by trhway »

kaonwarb wrote: post #142
soursoup wrote: post #138

Earlier quoted context omitted.

Loads of commercial aircraft and jet engine parts are manufactured using additive manufacturing, or ”3D printing”

Yes… but more often something like laser-sintered metal printing, which is not going to melt when hot.

Yep, and it works even in the SpaceX Raptor engine.

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

#173

Post by ajross »

jcranmer wrote: post #144
SoftTalker wrote: post #115

Earlier quoted context omitted.

Figured it was experimental; no A&P who cared about his future would install a 3D printed part on a certified aircraft.

Actually, I think all of the jet engine manufacturers these days are using 3d printers for some of their parts? Although you usually find the press releases talking about this using the term "additive manufacturing" instead. See, e.g., this press release from 2018 about a notable jet engine manufacturer using 3d printing: https://www.geaerospace.com/news/articles/manufacturing/manu... (Although note that these are no…

It's not the "3D printed" aspect of the part that's driving the failure, it's that it's made out of thermoplastic. An injection molded part in this situation[1] would likely have failed in the same way.

[1] It's not clear what the source of the heat was or where this was in the motor enclosure. But yeah, one needs to be careful with structural plastic near running engines!

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

#174

Post by geocrasher »

jacquesm wrote: post #129
geocrasher wrote: post #124

Earlier quoted context omitted.

Yes but are they printed with PLA or PETG, or even ABS? Or are they using material designed exactly for their use case, and tested thoroughly before being certified for flight? Or do they get their parts from some vendor at a swap meet who spends most of his time fiddling with his Ender 3?

Neither of those is suitable for this application. Ultem or PEEK. Anything else would be a very bad idea, and even for those two you would want to do a lot of testing.

That was my point. They used the wrong filament. And there isn't really a right one for the cowl of a single engine aircraft

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

#175

Post by nerdponx »

cortesoft wrote: post #87
Treegarden wrote: post #64

Earlier quoted context omitted.

I think by vibe coding he means taking these things at face value instead of rigorously looking if they are up to the standard. When coding you would rigorously look if the code is good / produces any bugs. With vibe coding, you give a prompt and just accept the output, which might be full of errors and blow up (or melt). The analogy is that, yes you can print airplane parts, but they were sloppy and just accepted th…

This is more like adding a third party dependency to your project without vetting it.

The original vibe coding.

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

#176

Post by potato3732842 »

averynicepen wrote: post #105
elicash wrote: post #57

Earlier quoted context omitted.

In what way is this like vibe-coding -- or do you just mean both are bad? According to the report: > The aircraft owner who installed the modified fuel system stated that the 3D-printed induction elbow was purchased in the USA at an airshow, and he understood from the vendor that it was printed from CF-ABS (carbon fibre – acrylonitrile butadiene styrene) filament material, with a glass transition temperature3 of 105°…

3D printing is to mechanical engineering what vibe coding is to computer science. With the rise of accessible 3D printers that can print engineering materials, there are a lot of people who try to create functional parts without any engineering background. Loading conditions, material properties, failure modes, and fatigue cycling are all important but invisible engineering steps that must be taken for a part to func…

You don't need to be able to mathematically jerk the equation off to understand why increasing material at the perimeter adds more strength than the center (within reason and in typical cases) or why you probably shouldn't use something that melts around 200deg in an engine bay.

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

#177

Post by senectus1 »

hatsunearu wrote: post #18

Is this a Part 103 Ultralight? Also it's insane that they used a bolted joint with plastics on a critical place, the plastic will creep under the clamp load and will lose clamp force.

I'm astounded that anyone would sell, buy, or mount this to an engine or in an engine bay.

This is Darwin award nomination stuff for everyone involved.

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

#178

Post by lazide »

jacquesm wrote: post #160
lazide wrote: post #146

Earlier quoted context omitted.

And when someone makes a new affordable tool that opens up making new types of things…. What happens?

Stuff gets made. Just imagine, chainsaws, lathes, welders and now 3D printers. What will they come up with next to give these irresponsible dilettantes a way to create their own objects... what we need here is some proper gatekeeping. Maybe a certificate or two, and some very expensive software that proves that you're a company that is serious. And while we're at it we should forbid home brew software too.

Sounds like you’re the one who isn’t getting the point.

Personally, I think 3D printed drop in auto sears are pretty awesome.

But it changes the game, and the laws don’t know what to do on that front.

I also bet I own more chainsaws than you do.

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

#179

Post by tomhow »

phoronixrly wrote: post #107
Centigonal wrote: post #102

It's important to note the plane is a Cozy Mk IV, which is an experimental light aircraft that is built at home out of foam and fiberglass by following instructions you get online. The design is very good, and hundreds have been flown over the last ~35 years, but Cozy pilots are the aviation equivalent of people who run Arch Linux as their daily driver; many of them are tweaking their aircraft with some frequency. Th…

[flagged]

Please don't post shallow dismissals on HN. We're aiming for a higher standard of discussion here. https://news.ycombinator.com/newsguidelines.html

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

#180

Post by 2muchcoffeeman »

Aurornis wrote: post #147
jcranmer wrote: post #144

Earlier quoted context omitted.

Actually, I think all of the jet engine manufacturers these days are using 3d printers for some of their parts? Although you usually find the press releases talking about this using the term "additive manufacturing" instead. See, e.g., this press release from 2018 about a notable jet engine manufacturer using 3d printing: https://www.geaerospace.com/news/articles/manufacturing/manu... (Although note that these are no…

Manufacturers who use 3D printing use specialized 3D printers, not the same thing that hobbyists use. They also handle all of the testing of parts to ensure they meet the design spec and they have the equipment to validate each printed part to ensure it doesn't have any major defects.

You can see the layer lines in the part. WTF? I don’t build aircraft parts. But I sure as hell wont use thermoplastics in this situation. I don’t even 3D print parts for mildly hot environments where failure is just annoyance.

Whoever built this should be charged.

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