eznfrank
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| posted on 4/5/10 at 11:32 AM |
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Triangulation on cycle wing carriers?
I need to fix my cycle wing carriers (cos I buggered them up) and I wondered if a tiny triangulation in the corners would help with the strength?
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Wumps
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| posted on 4/5/10 at 11:56 AM |
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It appears that many designs incorporate this so I would say yes.
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MikeRJ
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| posted on 4/5/10 at 11:58 AM |
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It could help, but you need to make sure you don't just introduce another stress raiser by doing this, or it will simply move the point of
failure.
A smooth curve rather than a straight line will help to spread the stress out over a wider area (just like Locost bottom wishbone plates)
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flak monkey
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| posted on 4/5/10 at 12:04 PM |
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You need to constrain the wing in all 3 dimensions to stop it bouncing around.
This isn't particularly difficult and usually just involves adding a 3rd stay like this
 
Front sus
The top 2 were the originals which both broke (both sides as well) in under 100miles.
The one at the foreground of the pic was added and they are now pretty much solid and have been ok for the last 6000miles.
You may also notice I added in small 'triangulations' where the flat bar meets the main stay which stopped them breaking off short term
before fitting the 3rd stay.
Sera
http://www.motosera.com
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BenB
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| posted on 4/5/10 at 12:06 PM |
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I'd also suggest curved angulation, good idea. Would look lighter too!
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andylancaster3000
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| posted on 4/5/10 at 12:21 PM |
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I witter on about this all the time but if you can move away from using flat strip and use just tube you'll end up with a far stiffer, lighter,
less fatigue prone structure. We had a play with some small diameter tube and a tube bender and came up with these:
Dead stiff, absolutely no fluttering and you can still get the arch nice and close to the wheel. No sign of failure yet (ignoring the damage when
some tin-top reversed into me at snett last year  )
Just my two pennies... 
[Edited on 4/5/10 by andylancaster3000]
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daviep
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| posted on 4/5/10 at 01:10 PM |
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I also did mine in round tube, but used a much smaller size, 10mm hydraulic tubing to be exact. 1000miles and no breakage but they do flutter a
bit.
Regards
Davie
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