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1/24 Scratchbuilt Westland Whirlwind Mk.1.


GunnarO

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Wow, what a response ! Thanks  :)

 

@ Cap'n Wannabe: I'm using PLA for now. It's easy to work with, no warping and very little shrinkage. I do have a roll of colorFabb NGEN on order, it's supposed to have very similar printing properties to PLA and stronger than ABS. Looks like an "ideal" material, but not sure I need the strength though.

 

So, how did the print turn out? Well, this test was not so successful.

 

IMG_2265.jpg

 

Some small pieces came loose and the thin walls did not work out well in this orientation. Comparing surface finish with the previous print, it's no doubt that vertical prints is better. 

 

IMG_2270.jpg

 

Back to the drawing board...  :hmmm:

 

Cheers

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Gunnar, I would print fuselage parts perpendicular, as the layers are less visible and easier to sand. I recently tried to print the two halves of a fuselage section as one piece, with a small 0,5 mm wide groove between, where the halves could later be cut/saw apart. The part was printed as a hollow object with a wall-thickness of 1,2 mm to keep good stability.

 

iqFPQfu.jpg

 

Cheers

Alex

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Gunnar, I would print fuselage parts perpendicular, as the layers are less visible and easier to sand. I recently tried to print the two halves of a fuselage section as one piece, with a small 0,5 mm wide groove between, where the halves could later be cut/saw apart. The part was printed as a hollow object with a wall-thickness of 1,2 mm to keep good stability.

 

Cheers

Alex

 

 

You're absolutely right, I just had to try the other way. I guess it's the thin walls that make it difficult to print it properly. I'll try one more print with reduced speed to see how it works out before I make it a little thicker.

 

Cheers

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Part orientation is a bit of a black art, and sometimes the obvious way isn't the best. Popping things on a complete mess of angles, ie nothing aligned with the bed, actually gives a better overall finish and strength. No simple rules really, it depends on the part shapes, the material and build parameters. But try a few odd angles. You might be pleasantly surprised!

Edited by wunwinglow
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  • 2 weeks later...

So... I'm back.

 

After several tests and failures, I've come up with something that seems to works quite well. And it was right in front of me the whole time.

 

I'm using SolidWorks for my 3D models, and it's got some nice tools for checking the models. (I'd just forgotten it...) 3D printers don't like too much overhang on the models, that's usually when they start making spaghetti. So, by utilizing the right tools, I can check what angles are best suited for printing the parts. As wunwinglow said, odd angles tend to work best. I used a draft check to find the best angles that gives the least overhang in the geometry to set the base plate. I try not to make any angle larger than 45 degrees, less than that seems to work fine.

 

swdraft.jpg

 

This worked out nicely, the parts are just a little too long/tall to print without support. I have to add a support for the next, and hopefully final print of the fuselage sides.

 

IMG_2283.jpg

 

IMG_2284.jpg

 

IMG_2287.jpg

 

Cheers

Edited by GunnarO
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Looks like you're getting somewhere! Good job! 

 

How long did the printing of this take?

 

Thanks!

 

I stopped it before it was complete due to flexing of the nose/tail (mostly tail), but I think it was around 11-12 hours for 80-85% of the print. I didn't take any pictures of the printer display and it was to early for me to remember accurately. It was a detail print with 0,1 mm layer thickness, so quite slow. 

 

I'll put on a coat of spray filler to these parts this evening to see if that's enough for a good surface finish while the next print is running.

 

I guess this process is more time consuming than building one from scratch with polystyrene sheets, but at least I can make another one much faster. (not saying I'm going to make more than one Whirlwind in 1/24 scale... although a prototype is tempting...)

 

Cheers

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I have the prototype HK Models Lancaster (Ok, it's a Manchester now) at home which is also 3D-printed. The wall thickness is about two mm and the whole structure is very sturdy. Must have cost an arm and a leg to produce.

Cheers

Cees

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Great project, Gunnar! As I am using an SLA printer, I cannot help you with part orientation; SLA printed parts always have to be placed with a cerain angle to the printing base, parts positioned flat or perpendicularly to the base don't print properly. 

 

Still, I would strongly suggest you increase the wall thickness for these large parts to avoid flexing and deformation. 0,8mm is extremely thin - I always try to have a thickness of around 1,5 - 2,5mm where material thickness can't be seen. Cockpit walls and wing trailing edges shoud be thinner, of course.

 

Can't wait to see more progress. Seems I should start looking for a PLA printer for large parts...

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Great project, Gunnar! As I am using an SLA printer, I cannot help you with part orientation; SLA printed parts always have to be placed with a cerain angle to the printing base, parts positioned flat or perpendicularly to the base don't print properly. 

 

Still, I would strongly suggest you increase the wall thickness for these large parts to avoid flexing and deformation. 0,8mm is extremely thin - I always try to have a thickness of around 1,5 - 2,5mm where material thickness can't be seen. Cockpit walls and wing trailing edges shoud be thinner, of course.

 

Can't wait to see more progress. Seems I should start looking for a PLA printer for large parts...

 

Thanks!

 

I kind of knew about part orientation, but had forgotten it all. I used to have a form1 SLA printer, but found it too messy and didn't use it that much. The resin got old and didn't work so well. It was messy and time consuming to clean the parts and needed sun or UV light to be properly cured. That said, it created parts with great detail. In the end, I sold it. I found the FFF printers to be more suitable for me, easier to print parts and more economical to buy filament instead of resin. I've printed a lot more with my Prusa i3 in the last 6 months than I ever did in 4 years with the Form1. I've seen the Form2 printers are much easier to work with though, that's the drawback of buying the first model of a new technology, it gets quite fast outdated. On the price point, I could buy 4-5 FFF printers for the price of 1 SLA printer and 9 (6,75kg) rolls of filament for a cassette with 1 liter of resin. It is important to think about what you want to use the printer for. For large scale models or rc models, I think the FFF printer is a better choice. For small scale and intricate detailed parts, the SLA printer is probably better, but you can buy a lot of models from online printing services for the price of owning one. What many people don't think of, is the time it takes to make the 3D models to be printed and the extent of CAD knowledge to possess to make them. You have no use of a 3D printer if you can't make the parts you want to print.

 

Anyway, I've already started to increase the wall thickness. They got too flexible for printing correctly. I'll try to keep the 0,8 mm for the cockpit walls. At the moment I'm not planning on opening any panels or hatches, so increasing wall thickness shouldn't pose any problem. I'll probably get some details made by Shapeways, like a brass undercarriage and some flaps detail. They need to be stronger to carry some weight. Litho plates and tin pewter foil are on their way. Riveting- and other tools are ordered, there's a lot gone missing in 20 odd years... Feels good to be back at the workbench :piliot:

 

Cheers

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Great project and I love the technology behind creating you own parts. I't got me thinking about that 1/32 scale RA-5C Vigilante I want.

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