[QUOTE=claudio;64012]For the spreaders I used 3 layers of 160g/m² and obtained a plate of 1.2m . Too flexible for the purpose !.
I’m preparing a sandwich composed of carbon 160g/m² and plywood 1mm. If still too flexible, I will add another carbon layer./QUOTE]
Claudio, to increase the strength of the spreaders without adding additional layers of carbon (weight) you could consider making systematical foil shape spreaders cores using balsa & then the curved carbon layer will give the spreader extra strength, much more than a flat profile.
Two layers of 160 gsm carbon on short length of a foil shaped spreader I thought would be more than strong enough, don’t you think ?
Cheers Alan
P.S Added pics of TD Model moulded foil shaped spreaders (pair weigh 3 gms untrimmed) with 1.5 mm thick at max chord.
Hi Alan,
I agree with the type you refer to.
The point is that my spreader are “V” formed .
I will think about a solution with the method you suggested, thank you .
Ciao
ClaudioD
My goodness!! If 1.2m isn’t up to the job, who on earth knows what will be?!!
Sorry, couldn’t resist - assume you meant 1.2mm…
Not sure I’m fully understanding your U bolt - to my mind they’re a bolt that’s ‘U’ shaped. Looking at your picture I’m a little confused (not that it takes very much!)
Ah I forgot that ! …ok then how about having V tang on the mast at spreader position & using 3 mm O.D carbon tube to slip over the tang (easy, cheap & quick option for prototyping)
Yes Row is mm ! and you are right is not an ‘U’ but a pseudo ‘Eye’ bolt
typical 'U’bolt : http://www.westmarine.com/buy/popular/u-bolt-s-sailboat-hardware
Mine is a piece of threaded brass rod soldered to a brass tube and then perforated. The length is compatible with the mast support position.
Cheers
ClaudioD
Very kind Anders, thank you.
At model scale of course will be not the same but I found that they also use the short guide tube to fix it to the mast probably with rivets.
Next spreader will be profiled as suggested by Alan construction method. (under construction)
Cheers
ClaudioD
About Spreaders results :
Balsa / carbon not good too fragile !!
Foam / carbon not good and probably useless for my purpose.
Continuing with plywood / glass.
I like the way you’ve used (or appear to have used) battery terminals for the vang end fittings. Where you’ve got LH & RH threads going into the centre adjuster tube is there a reasonable degree of friction so that as the vang is adjusted it stays put? If not, a little PTFE tape wrapped around the threads may do the trick. Just out of interest, is the vang ‘basic’ components based on a brass rigging screw?
Moving back a bit, how’s the experimenting going with the spreader materials? Is the ply core providing a stiffer/stronger structure?
Hi Row,
the Wang main piece is just a turnbuckle with soldered washer to allow better grip. I trust more as pulling device more then pushing , nevertheless I would like to use it as in the drawings. Is still possible to buy a larger turnbuckle.
As you can see my idea is always to use what ever is available around, I do not like to buy already made parts. May be for a definitive design but not for a prototype.
Are not battery terminals but simply squeezed brass tube.
It may useful, as you says, to use some tape to avoid turning.
All metals are brass to permit soldering when needed.
The ply spreaders are just resting to see if they get sturdy. but I’m not so sure. Ready the carbon laminated plate with 1mm plywood in case off.
Tomorrow I will presents the overall results about.
Cheers
ClaudioD
With the boom vang, we have a saying in the UK (probably elsewhere also) : ‘Necessity is the mother of invention…’ - never a truer word spoken!!
One element of your vang design intrigues me though and I’ve noticed it on various build log threads and that is the gooseneck articulation. Obviously it’s patently obvious how it can swing from left to right as the main sheet is adjusted, but how will it move in the vertical plane? Do you just rely on the flexibility of the brass connector?
Here the results for the spreaders !
Interesting to observe that the Balsa/Carbon sandwich is actually the sturdiest, but not good enough for use, another glass or carbon layers will be better.
The second is the Plywood 1.5mm with glass. Here also a couples of 85g glass layers will be good.
The 1.5ply/carbon sandwich is the third but it may be sturdier in a couples of days.
Actually 2 layers 160g carbon is the weakest !
Today was times to re-check again the various weights to control if the construction is in line with the provisions .
The total measured values is 3993g !
Missing parts :
the sails estimated to 55g
the paint for 20g
the bondings for 20g
Total expected final weight 4088g against the 4129g as from design.
Hopefully I will try keep that weight.
ClaudioD
Some progress work with the Hull dedicated to the bonding of various supports.
In future I should develop a better monolithic system ! actually is like a ‘light bricolage’
ClaudioD
Hi Sylvain,
Is Titanium dioxide : see http://en.wikipedia.org/wiki/Titanium_dioxide
Used to thicken the resin. The bonds are very strong.
Titanium dioxide (TiO2) is used also as pigment in gel coats.
Cheers
ClaudioD
