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Mar 16, 2018, 07:41 PM
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I'm designing a printable electric glider. - Melusine twin boom


2320 mm wingspan. About 1450 g empty weight when printed in PLA. The prototype needs 200g of lead in the nose cone. I should have used 12x11 mm carbon tubes for the tail booms instead of 12x10 mm. That would probably prevent adding nose weight.

I designed a landing gear for it too and nose pieces to add FPV camera servo gimbals. The landing gear looks much better in real life than the CAD makes it look.

The parts were all printed on a Sunhokey Prusa i3 and a Wanhao Duplicator i3. The tallest part is 183 mm and they all fit on a 200x200 bed.

I tested printable folding props today. Very smooth. I made three different blade sizes.

I will probably sell the STL files on cults3D once I'm done testing it. I haven't flown it yet.

My Cults3D profile: https://cults3d.com/en/users/tahustvedt/creations

My free stuff is also on Thingiverse: https://www.thingiverse.com/tahustvedt/about
Last edited by Lynxman; May 05, 2018 at 10:25 AM.
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Mar 17, 2018, 03:32 PM
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Looks good. Iīm curious to see how did you managed the interior of the wing and fuselage.

Fred
Mar 17, 2018, 04:26 PM
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The fuselage is heavy duty, with 0,8 mm thick walls, to survive belly landings. The wings are single extrusion, 0,4 thick skin, with single extrusion ovals inside and a solid layer every 300 layers. It's a bit heavy but I wanted it to be durable too. I'm considering if I should add chordwise holes to the internal ovals too, but am not sure it will actually reduce the weight.

The best material to print it from is probably PP. It's about 10-15% lighter than PLA. I tried some sections in wood filled PP and it was significantly lighter.
Last edited by Lynxman; Mar 17, 2018 at 04:38 PM.
Mar 17, 2018, 04:45 PM
FDF - Front Door Flyer
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If youīre at 1450g print weight for a 2.3 meter wing its not that bad, On bigger planes I had thought about making double walls everywhere but the inner wall would be holed like perforated metal sheet, with holes 10-30mm or so.

What cad are you using?
Mar 17, 2018, 06:22 PM
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I use 3D Studio Max 2018. I would like to switch to something cheaper, like Fusion 360, but it takes forever to relearn a new software.

The weight of 1450 g includes the 12x10x770 carbon tubes for the tail booms, and the 10x8 and 8x6 mm wing joiner tubes. It's ok, but it's probably 400-500 g heavier than a wood and film plane.
Mar 19, 2018, 05:43 PM
Registered User
Quote:
Originally Posted by Lynxman
The fuselage is heavy duty, with 0,8 mm thick walls, to survive belly landings. The wings are single extrusion, 0,4 thick skin, with single extrusion ovals inside and a solid layer every 300 layers. It's a bit heavy but I wanted it to be durable too. I'm considering if I should add chordwise holes to the internal ovals too, but am not sure it will actually reduce the weight.

The best material to print it from is probably PP. It's about 10-15% lighter than PLA. I tried some sections in wood filled PP and it was significantly lighter.
Those internal ovals will be adding a huge amount of weight. If you add some angular ribs with oval holes cut in them you'll have a very similar robustness with a lot less weight.
Mar 19, 2018, 07:49 PM
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Quote:
Originally Posted by Lynxman
I use 3D Studio Max 2018. I would like to switch to something cheaper, like Fusion 360, but it takes forever to relearn a new software.

The weight of 1450 g includes the 12x10x770 carbon tubes for the tail booms, and the 10x8 and 8x6 mm wing joiner tubes. It's ok, but it's probably 400-500 g heavier than a wood and film plane.
Fusion itīs easy to learn but youīre better with 3ds max, much more powerful for this kind of modelling, I wish had it.

Have a look at my klingberg wing stl files, thatīs what you need to make your wing lighter, you can always add one carbon tube spar because your wings airfoil is thin but no more than that. IMO
Mar 20, 2018, 08:44 AM
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The oval crossection is very strong. I worry about durability when belly landing with the long wingspan catching the ground. I want to try a lighter structure after I have flown this. The criss cross pattern will be explored. Can probably save 300 g or so.
Last edited by Lynxman; Mar 20, 2018 at 08:50 AM.
Mar 24, 2018, 10:27 AM
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I went out to try the glider today on a frozen river but ran into problems. The PLA shrunk in the cold and warped the elevator. I'll have to relieve the tension before I try again.
Last edited by Lynxman; Mar 24, 2018 at 10:41 AM.
Mar 24, 2018, 11:52 AM
FDF - Front Door Flyer
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Why not printing it in PET?
Mar 24, 2018, 12:22 PM
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PETG is much heavier.
Mar 24, 2018, 12:30 PM
FDF - Front Door Flyer
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5% or so. But depends on the brand. You can just make some elements in pet, donīt need to make the whole plane.
Mar 24, 2018, 12:35 PM
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You're right, only a little heavier. The problem is probably that I glued carbon rod as the elevator hinge pin. It might be a good idea to use the same material as the surfaces as the hinge, or not glue the hinge pin except at one end.

I'd like to print in PP. It's 25% lighter than PLA.
Mar 28, 2018, 08:36 AM
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I finally got to fly it. It was very gusty so it's not a good test of the handling, really, but it's extremely efficient, and has an incredible glide ratio. I haven't flown gliders in many year though. I will add crow for the next flight so that I can get it down more easilly.

The 3D printed folding prop works like a charm too. It roars quite a bit, but that's because of the proximity to the wing trailing edge. Only 15 mm distance between the prop and wing. Power was really good even with just 550 W or something like that. The maiden energy consumption was 1,44 Wh per minute of shenanigans, but I clearly didn't have to use the motor anywhere near as much as I did.

I'm rendering the video now and will upload soon.
Last edited by Lynxman; Mar 28, 2018 at 08:47 AM.
Mar 28, 2018, 09:05 AM
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Here it is. I'm calling it "Melusine".

Melusine - A 3D printable electric glider and FPV platform. (7 min 9 sec)


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