3D Printed RS750

The Forum for RacingSparrow radio controlled yachts. Focussing on build your own scratch building, free plans for download and a comprehensive builders guide book.

Best wishes and happy sailing, Bryn Heveldt.
bobgrabcad
Joined: 11 Jul 2017, 16:15

11 Jul 2017, 18:24 #1

Hi all,

I have used an experimental large-format 3D printer [that I have had designed and built for my company] to print two trial hulls for my RS750 project. I am using Onshape as my CAD package for the design. I created planes corresponding to the bulkheads and then traced the profiles using splines in the program. I lofted the sections to create the hull geometry, and then shelled it to 4mm wall diameter as below. So far I have the keel bulb and the strut and sheath modelled. Now is the weird bit where I am actually modelling the bulkheads (only as many and insofar as I require either stiffness or mounting points for servos etc.) I'm keen to get cracking on this bit - i.e. designing the internal layout, but I am stuck without servo diagrams - which I don't have because the TX/RX kitset from Futaba specced in the RS book that I bought has been discontinued.

Could anyone tell me what a decent - better than bargain basement - setup would look like? I'd prefer to not overspec the thing, but I don't just want the cheapest and nastiest option. The crucial bit that would help me is to have two things included in the info:

- The names of ALL the components - TX / RX / controller / servo (so I can buy it all and get a working yacht out the back).

- It would be a bonus if there are diagrams that go with these so I can crack on with the design.

As you can imagine - 3D printing is so fast that my bottleneck is design, not manufacturing (although painting and finishing will also be quite time consuming).

If anyone can get me both bits of info as above, I'll print you a custom hull of your own design for free (excl. shipping - especially to down under etc...!) - up to 1.5 metres in length.

Image

Here's some shots of the hulls (one I printed with 0.75mm step height and the other in 0.5mm steps). The better quality is - counter-intuitively - to be found in the hull with the larger step height because I had a few issues with thermal build-up in the finer layer one - what we call operating outside the Goldilocks Zone in 3DP...

Image

Here's a quick test-print that I did on my small Mendel 3D printer of Bulkhead F - just to see if my hull profile looked about right.

Image

I will probably adjust the design of the hull to include the keel box. It's great using the big printer, because it only takes around 2 hours to print a hull - and of course I don't have to use my small printers to make the hull in sections and then join them. I printed the hulls shown above in PLA-g (polylactic acid matrix with graphene and a few other additives. Density around 1.15). It was printed stern down - with bow pointed up at the sky.

Oh, last bit of info - I'm going to print the keel bulb former on a small printer in PLA. I was thinking about doing a single pour mould of P.O.P. (i.e. single use!) by printing the bulb former with the sprue in place, and then putting the thing upside down in a barbeque to melt out the PLA prior to the lead pour. Good idea? Bad idea?

Thanks for any help in advance!

Bob
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racingSparrow
Site Admin
Joined: 06 Sep 2012, 03:27

13 Jul 2017, 20:32 #2

great looking models! next level.
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racingSparrow
Site Admin
Joined: 06 Sep 2012, 03:27

13 Jul 2017, 20:47 #3

check out this thread about cheap electronics:

receiver-and-controller-t186.html
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