While I'm working on designing a wing to fit my moses fuselage, which is somewhat driving the design, I am starting to think about just making a fuselage and bonding the wings to the fuselage and attach it to a standard aluminium strut.
What do you think of the idea of using standard carbon tubes? I can get a 20mmx18mm tube, and glue a 18x16 mum inside, then a 16x14 to give 20 OD x 14 ID, 3mm walls. Then I could fill center to allow screwing to the Alu strut. the ends I would fill and shape, bonding the wings to the fuselage. The wings I would design with " seats" for the cylindrical fuselage.
The tubes are not super cheap, about 60 euros together for 1m lengths.
The advantage is i get accurate cylinder to create seat for wings and control AoA setting while bonding.
I can also get a 12mm solid CF UniD rod, and glue 14 and 16mm tubes over it.
3mm walls might be ok tho, but man, why would you pay 60E for that? I've paid 10$ for the above tube, so it's ok as one off.
A wood piece slightly tapered from 28mm to 20 is way way more stronger than carbon tube when wrapped with carbon with same walls. And it floats. Plus, you not buying 1m carbon tube and using 70cm...I can stand on that (60kg) with only one UNI layer around the wood (length wise), and will slap one more 45/45 biax to accommodate for torsion.
Cost? Cheap as chips. Duno, 20$? That's coz wood is expensive here, like, just that wood piece was 15$, plus carbon...
That's 60E for 3 tubes. If I go to 2 tubes I get down to about 40E.
My plan was to 3d print a spacer between the cylinder fuse and the aluminum mast. Both surfaces are accurate so easy to do.
And I could just embed some stainless inserts into the filked carbon tube and screw the wings to it.
Get your point about making my own.
If its easy and you want to try it then give it a go. I've changed my mind on my suggestion, 20x1mm tube would be better. Then perhaps consider 18x1 insert from fron wind to just past the mast. The rear stab doesnt need the same strength/stiffness as the mast to front wing connection.
At the risk of telling you how to suck eggs, Mount the front wing on the bottom of the fuse and the rear wing on the top. This means the water will be pushing the wings into the fuse and not trying to tear the wings off the fuse... Its much lower force on the bolts if you do it this way!!!..... It might be obvious, however some major brands miss this design feature. I was looking at one (Ketos i think). The rear wing was bolted on the bottom with 2 x 5 or 6mm bolts. On the foil i was looking at the bolts had come loose. Stupid design!
If you slide and glue smaller diameter tubes inside each others, then you don't need them 1 m long. And 50 cm ones are much much less expensive. For 70 cm long fuse even 40 cm tubes would be OK. Then, I would sculpt the wings fuse connection areas with some additional layers of carbon, wrap it into couple of carbon sleeves and call it a day. (Easier said that done, of course, my fuse project took forever to complete).
I could do this: Take a 680mm long 20mmx18mm tube and insert a 300mm 18x16mm tube into it as re-inforcement for the front wing and strut connection.
This is the tube i would buy- its my normal supplier- but i might be able to find another source-
woven-finish-carbon-fibre-tube-20mm-17mm.jpg (14.1 KiB) Viewed 1434 times
I would fill the fuselage where wings and strut would be attached. And i could easily put M6x15mm 318 SS inserts into the fuselage for the wings. Then i would design a " spacer" for the fuse on top of front wing and bottom of rear wing and 3D print it. The spacers would form the ends of the fuselage too.
It does not sound that difficult. Advantage is i can get a Slingshot alu strut pretty good price, and i can easily try out this entire set up on a spare board. Screwing the wings on lets me modify the wings and change the AoA.
An easy option is to forget the tube, go the dowel. Sink your nuts into the dowel then rather than try and vac bag carbon, use carbon sleeve, http://www.playwithcarbon.com/products/ ... leeve.html,
It expands when pushed together, slide over the dowel, apply the resin, then pull the ends tight. Add a few layers and when dry apply a filler coat, gives a nice professional finish.