Light sport aircraft 3d printing

[Balazs91]

Hello,
I just started to explore the world of 3D printers and I have a theoretical question for you.
Is it possible with today's technology to print a whole small aircraft fuselage in one piece without the wings? (approximately 2.0m x 2.5m x 7.0m dimensions). Here's an example: http://goo.gl/Q9lhiK
What printing method would you recommend for that?
I'm an aviation enthusiastic and my (near? far?) future goal is to build an ultralight airplane with an empty weight under 120 kg. That's why I thought about 3D printing as a solution to create lightweight and strong fuselage and other components.
Cheers!

[LambdaFF]

7 meters in one go in a desktop printer ? Perhaps, but you'll have to make the machine yourself. It doesn't exist that I know of but someone could use the reprap toolbox to do it.

For many reasons, this is not practical though.

[Balazs91]

7 meters in one go in a desktop printer ? Perhaps, but you'll have to make the machine yourself. It doesn't exist that I know of but someone could use the reprap toolbox to do it.

For many reasons, this is not practical though.

Thanks for your reply!
It's not practical because of money reasons? What would you recommend instead? Assembly from smaller pieces?

[Sebastian Finke]

... my (near? far?) future goal is to build an ultralight airplane with an empty weight under 120 kg...

You'll want composites, like carbon fibre. In terms of density nothing beats that. 3D print an aircraft under 120kg? Never happen...

[LambdaFF]

Thanks for your reply!
It's not practical because of money reasons? What would you recommend instead? Assembly from smaller pieces?

Well, 3D printing in one go would mean supports here and there : lots of waste.

3D printing is not fast compared to other production means, it's just fast for the 1st item as compared to a full industrialisation.

Also, the profile would be weak parallel to the main printing plane : an assembly would be stronger because the components could have mixed directions.

What's important in an aircraft is early failure detection : you can inspect metal assemblies for cracks, you can do tapping composite components for delamination detection. The whole point is : the detection and the failure are HOURS or DAYS apart, leaving you ample margin for safe operations. For a plastic 3D printed part you'd need to prove that the layer delamination can be contained for hours after being detectable. Good luck with that if it's all printed in one go.

If it's printed in one go, you can't just swap a subcomponent for a repair : not practical.

Shall I go on ?

The most practical use of 3D printing in this case would be to use it to manufacture molds for composites. I've seen some machined from LAB : comparatively quite expensive and not much reusable.

[Balazs91]

You'll want composites, like carbon fibre. In terms of density nothing beats that. 3D print an aircraft under 120kg? Never happen...

In America there is an Ultralight airplane category for those single-seater aircraft what weigh less than 254 lbs (115 kg). And believe me, there are already many of them flying. There are some regulations for those type of aircraft, like the maximum 102 km/h speed, stall speed is less than 44 km/h and of course the weight limitation. If you are interested in, you can find many examples here: https://www.eaa.org/en/eaa/aviation-...light-aircraft
http://www.ultralightnews.com/ssulbg.../pictures.html
Yes, some of those look a little bit ugly, but with today's technology it's more than possible to build one what looks and flies amazing.

[Balazs91]

Thank you LambdaFF, it helped me a lot! I'll start to learn more about those composite printers.
My original thought was about a one-piece fuselage can be the strongest and lightest because you don't have to assemble the parts but now I can see the disadvantages, especially to swap a subcomponent. So the smaller is the better.

[Sebastian Finke]

In America there is an Ultralight airplane category for those single-seater aircraft what weigh less than 254 lbs (115 kg). And believe me, there are already many of them flying. There are some regulations for those type of aircraft, like the maximum 102 km/h speed, stall speed is less than 44 km/h and of course the weight limitation. If you are interested in, you can find many examples here: https://www.eaa.org/en/eaa/aviation-...light-aircraft
http://www.ultralightnews.com/ssulbg.../pictures.html
Yes, some of those look a little bit ugly, but with today's technology it's more than possible to build one what looks and flies amazing.

But not 3D printed...

[Balazs91]

But not 3D printed...

Not yet. If it's possible to create a 120kg airplane with conventional technology, it's also possible with 3D print technology. My question was what is the best way to do it?

[LambdaFF]

Thank you LambdaFF, it helped me a lot! I'll start to learn more about those composite printers.

Hey, I think there is a misunderstanding. While there IS a printer doing carbon fibers (think MARK ONE), I was talking about making a mold in plastic then putting a release agent (silicon ? PTFE ?) and putting resin and carbon fiber / glass fiber on it to make the part. The (huge) advantage is that for each ply of fabric you manually put in the mold, you can choose the fiber direction thus fully optimizing strength in the desired directions.
Once the resin is cured the release agent will help you separate the part from the mold.
You can then reuse the mold to make more identical parts.