I was checking out something unrelated and stumbled across this video. It’s a discussion of a homebuilt aircraft crash that luckily wasn’t fatal but easily could have been.
Somebody was going to fly-ins and selling a 3D-printed air intake piece for certain aircraft engines claiming strength, light weight, and temperature resistance. They claimed it was carbon fiber-filled ABS.
It turns out it wasn’t ABS at all. It was PLA and during a flight the engine compartment got warm enough that the PLA softened and collapsed from the pressure differential across it. With no air the engine quit and the pilot was only able to glide to the airport but crashed into runway approach lighting.
I doubt the person selling the parts is here, but for (name your diety’s) sake, you don’t 3D print important aircraft parts - especially engine parts - out of the wrong plastic and even then, make sure plastic is even appropriate. Go substituting 3D prints for critical parts and you can endanger your own life or others.
The swapping of PLA for ABS should have been obvious to anyone skilled with ABS and PLA so I can only assume the swapping was intentional and the person selling the parts thought it could make printing easier and “mo money, mo money, mo money”. It’s for an induction part so not really hot right? They failed on about every aspect of making something safe for sale and nearly killed someone.
There’s likely a number of aircraft out there with this same time bomb ticking away. The person who decided PLA = ABS could still kill people with this. It wasn’t even a good print. There’s support defects big time visible in the photo. Likely just some inexperienced clown with a 3D printer that thought he could pay for his trips to fly-ins. Bad print out of the wrong material sold for aircraft use. What could go wrong?
Here’s the after crash photo of the collapsed intake part and a link to a video about the crash. Video is from last December. That flattened area is supposed to be a tube.
This is not the topic I expected based on the title. Additive manufacturing is used all the time in the aerospace industry. I was hoping to read something awe inspiring.
3d printing and aviation is still great. I made a IFR gauge mounting set for by buddy’s Cessna 132 last year. But messing with engine components (especially on a single engine aircraft) is dangerous and idiotic.
On one hand: wow, what ignorance, malice, and greed; and he will get away with it too.
One the other hand: who the ■■■■ buys untested safety critical parts from the back of a van, suckers truly are born every minute. I guess these rich kids with planes have never had the life experience of the “stereo van” in the back of the parking lot.
I don’t know about the UK, but in the US FAR 21.303(b)(2) allows non-certified parts to go on certain aircraft, provided the owner meaningfully participates in the fabrication of the parts - meaning they can’t just buy the parts and slap them on. A similar rule might have prevented this in the UK.
That said, if the aircraft was registered as experimental, pretty much anything goes.
While I agree whoever fabricated the part should face consequences, in private aviation it’s always on the owner/operator to work with certified A&P mechanics and those mechanics would never risk their license putting parts of unknown provenance on an aircraft.
So the owner was either going the experimental aircraft route and failed to do their due diligence, or there’s a much bigger problem.
Oh, I actually heard about that story, and it can really be summed up in a nutshell: Parts that keep you alive? Don’t 3D print or buy 3D-printed parts.
I don’t buy my car brakes on AliExpress or print out my own brake pads, either.
On the other hand… there were also companies that got into the U-boat business with a cheap gaming controller… we all know how that ended.
Strictly speaking, this doesn’t even have anything to do with 3D printing - it’s just people shooting at their own lives as well as those of others. In the past, this was called a crime; today, it’s often referred to as “temporary prototyping”.
They were basically at the depth of the Titanic when the sub imploded.
The Titanic is at about 12,500 feet/3800 meters at a pressure of around 380 to 400 atmospheres - about 6000 psi.
So the air and people in that sub went from 1 atmosphere (or a few depending on if pressurized) to around 400 atmospheres as the water collapsed and breached the hull.
A 25:1 diesel engine compression ratio is considered high with 23:1 more common. That 25:1 would be like a hull collapse at a much shallower depth and result in pressure heating to around 900F. The occupants in that sub were subjected to pressure around 16 times as high as what you get in an exotic diesel engine at top dead center.
Temperature in that sub would have skyrocketed in that instant and some part of them likely combusted. If you compress air at 25C and 1 atmosphere to 400 atmospheres, it heats to around 2500F - about 1/4 the temperature of the surface of the sun.
But it was all over so fast they wouldn’t have seen or felt anything. As far as they knew, one moment they were there and then time stopped.
It’s not at all. The fuel injectors in modern jet engines are 3D printed now to get the precise channels and fuel distributions for most efficient burning, more power, better fuel economy, etc. They also couldn’t be manufactured conventionally either because of the internal channels and such.
On the other hand, they were tested out the wazzoo to make sure they were fit for purpose.
That intake elbow was obviously not fit for purpose at least because it was made with the wrong plastic, obviously untested, and it looks like there may not have been much consideration to layer orientation and strength. In one direction it could be quite strong while not so strong the other with an air filter hanging off of it. But maybe layer direction was considered?
At any rate, the printed intake elbow was obviously not tested or it would have been obvious it would get floppy at elevated but normal engine compartment temperatures.
I don’t think anyone was saying 3D printing isn’t appropriate for aircraft parts but they do need to have every consideration that other parts get. They should be tested properly and made sure they are fit for purpose. Things like clips or tablet holders or other non-mission critical parts aren’t as important but as was pointed out above, even the simple things can snowball.
I think what happened is somebody might have thought it was a way to pay for air show / fly-in trips. Telling people it was printed with a different plastic indicates deception and the realization he was selling defective parts. It could just have been wholesale rip people off and who cares about consequences or they might have thought it wasn’t a significant difference. Either way, the people buying the parts failed by not making sure the parts were fit for use before risking their lives, and the guy who printed and sold them hopefully has lawsuits incoming and even jail time.
But nothing wrong with 3D printed parts as long as they are fit for service. And a lot of things hobbyist pilots might print might not be especially in high load and high heat applications.
Responsibly means exhaustive testing, which is beyond most small companies let alone some backyard maker. I have been in aerospace for decades and familiar with those certification requirements.
Read up on the current auto industry. They’re making plastic parts and engines are completely shot after a few thousand miles. Not to mention they’ve jacked the prices on new cars unbelievably.
Plastic oil pans? Yeah, that’s not an accident waiting to happen! Don’t get me started on the paneling and body. Have you watched the videos where the people use one finger and press these plastic pieces inwards?!?! $80,000+ cars that do this.
I have no qualms about using the right plastic for “certain” parts, so as long as heat and/or durability tolerances has been factored in the designs. But some things are just at the best (and safest) with metals.
No. But you obviously dont understand what goes into designing a car. I only worked in automanfactuing for 6 months, but even with that time, I got an understanding of what actually goes into a car.
Ask yourself what the benefit of a plastic oil pan is?
Why was that decision made?
Planned Obsolescence is BS most of the time and definitely not in the auto industry.
Look up “Design Lifetime”
You can design something to last 500 years. You can design something to last 20. Which one is going to be more expensive? It is all about finding a balance.
That statement is truly laughable!!! Wow. Coming from someone in the industry, too???
It most definitely IS a thing and car manufacturers most certainly have this concept in mind! If the engineering was so outstanding, as you seem to lean towards, then explain the current condition of new cars that mechanics cannot work on because of the plastic parts being total garbage, having seal issues right off the lots and that the consumer is paying almost double the price for a vehicle with CHEAPER (in cost and durability) parts.
As for a plastic oil pan, for an example, yeah…the reports of the plastic cracking or that you have to replace the entire oil pan for $$$$ when it does are increasing daily. Compared to the metal ones where all you had to do was replace a gasket…after 200,000 miles!
Your argument that plastic parts will last 500 years, well, yes. But those parts will be sitting in a landfill for 499 years and 6 months out of the 500. Doesn’t track with my feeble mind and inexperience.
Your entire point is laughable. You show so little understanding on how these systems work. Plastic is not a bad thing, in many ways it is better than metal. Why do you think almost every super car / hyper car is made out of carbon fiber (plastic).
Ever heard of the CAFE standards? (in my opinion some of the dumbest regulations ever made). The industry is chasing fuel economy, or the manufacture will get fined by the government. Even a few pounds off translates to better fuel economy and lower carbon emissions.
Is plastic that bad? or do you have you been trained to have a negative connotation by looking at it as disposable?
Think about it. Intake manifolds, fuel tanks, valve covers, radiators (half), coolant expansion tanks, engine covers, thermostat housings, core supports, headlights, bumpers. All plastic.
BTW, my friend has a 2018 Mustang GT with a plastic oil pan. The thing has 230K on it and has not had to be replaced or had any leaks. Seems like it works.
Something that might be interesting…
TL;DR - Advanced polymers are amazing, there is nothing wrong with using plastic where applicable, people have a negative connotation of plastic because they look at it as disposable.
