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Post by jake on Apr 21, 2008 22:35:49 GMT 10
hey guys!
thinking of building a wing like gerards or zipper's (slope tour wing) and just wondering how the joiner tubes should be put in? i was thinking cutting plugs of foam out, insert spar and glue the plug together and back in the plane. or drilling (sounds crooked just thinking about it!)
also was thinking split the battery pack between the wing halves with connector between them.
any ideas would be great!
ta,
jake
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Post by callun on Apr 21, 2008 23:32:50 GMT 10
Lots of people seem to use a router bit on a dremel or similar with good results, or so they say.
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Post by windsock on Apr 24, 2008 16:19:12 GMT 10
After doing my splitter, I would suggest that you need perfectly aligned joiner tubes. Mine have a small amount of movement, I need to but a strip of tape along the top and bottom to make it firmer. So a tight fit is the best.
I don't know how drilling epp will go, my gut feeling is not well. The idea of splitting the battery is a good idea. What type of plane are you going to use?
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Post by jake on Apr 24, 2008 17:15:22 GMT 10
i was thinking of using a scorpion from off the edge or a jazz from canterbury sailplanes. i'm just kinda mulling it around in my head at the moment.
i think the way i see it i should line the joiner up on top of the wing and cut a hole block out ala ballast tube, glue the foam round the joiner and the back in the wing. not sure about routing slots out as theres nothing really over the top of it.
but i've just realised thats how some spars are installed! hmm...
my how the projects list grows!
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Post by skyboyken on Apr 25, 2008 20:43:48 GMT 10
FWIW, however you do your joiner tubes, they are only glued to the foam next to them.
If you do a good glue joint then the failure mode will be the foam tearing away from itself, leaving the glue joint intact. This is exactly the failure mode I and others have had when the fuselage and the wing separate on a Reaper, by way of example.
Given all that, I would think a dremelled slot with as large a diameter joiner outer as possible, PU'ed in place would seem to me to be as strong a system as you'll get. I say this because of the unique ability of PU to expand and actually penetrate the foam to some degree.
The other thing is the length of the joiners. Simply put, the longer the better. The loads on the joiners decrease rapidly with distance from centreline, so spreading loads out this way works well. If you use carbon joiners the weight really isn't a worry. In fact it's a benefit because you can replace them with steel when you want ballast.
Finally, you probably just need to accept that you'll never have as much lightness, stiffness and strength as a 1 piece wing. 'You pays your money and you takes your choices'!
Whatever you decide to build, go great!
Ken.
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