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Apr 13, 2019, 01:24 PM
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Im also working with a 3D printer for a few parts, I built a SPA3D with a few pieces printed. Holding up well so far, all ABS except the exhaust deflector.
Now experimenting with cutting flutes like lecrote has, due to lack of 2mm availability and pvc.
Tools Ive made are, twin carpet hook blade knife, printed cutter for slitting coro into a skin,
U shaped blade attached to a soldering gun.

Eventually going to build a spad Lanier Stinger 120 ish aircaft and a diamond dust spad.
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Apr 15, 2019, 01:26 PM
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Quote:
Originally Posted by PaulB
This was my take on 3D printed/ Corro hybrids:-

https://www.rcgroups.com/forums/show...7&postcount=46


This is where I am now.......



Paul
No spar ?
Apr 17, 2019, 03:30 AM
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PaulB's Avatar
Nope, stressed skin, like a foam wing where the foam is just there to keep the skins apart. that should be what the ribs do and all loads should be carried by the curved Corroplast surfaces, so much for theory...... Will it be strong enough?????

No idea.

(Very much) Work in progress.

Plan B.

If the wing does fold and is not strong enough (which I did think about) it would not be too much of a big deal to design and print the ribs with holes to take spars(s).

Paul
Latest blog entry: Just To Say Hello.......
Apr 17, 2019, 11:01 AM
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Extreme Sports's Avatar
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Paul, do yourself a favour and build in a spar from the start. Unless your rib spacing is less than about 50mm, the wing skins between the ribs will not be held apart and the wing will buckle.

The good news is the required spar is very simple, since all it needs to do is hold the skins apart (given you are running the flutes spanwise, so they provide the real strength). If you have 6mm depron or similar, just cut several rectangles the same depth as the ribs and length equal to the spacing between the ribs. Glue them to both skins between the ribs (polyurethane glue works well for this) and you will have a plenty strong wing at almost no extra weight or effort. If you don't have scrap Depron laying around, just slice some foam from your latest appliance purchase - can be thicker than 6mm. Or use balsa. Worst case you can use correx, but make sure the flutes run vertically to counteract the compression loads.

My other suggestion is to space the ribs no more than 100mm - 150mm apart, else the wing profile won't be maintained between the ribs.


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