[quote=revintage][quote]a=34 BT=FT*.9 for each wire, H=838mm, Tornado[/quote]
At last I found some info about Nacra bridles, they use the same angle as Tornado. Calculated 5.0 and 5.8(not NA) and they both are 34 degrees.
My previous figures for Nacra 5.5 where way off. With Frankencat bridle height of should be min. 85cm, not 107cm.
If you go down to 46cm, load is 2.9 which means the rear going will have to take 1.1 of the forestay tension.
If you go down to 33cm, load is 3.9 which means the rear going will have to take 2.1 of the forestay tension.
A static tension of 100kg would be no problem.
Still wonder how many times higher the dynamic load upwind will be? :-x
If we tie the rear going wire(5mm Dux) to the center of the rear beam we will get severe deflection with a dynamic load of maybe 4-500kg.
If we instead split the wire in two, to another bridle behind the striker rod, with each end tied to the inside beam ends(tube walls 5mm at the ends), things look a little better. It should be made of a single loop turning back at the rear end of the turnbuckle.
The striker rod is made up of M16 threaded stainless rod, with a 20x2mm alu tube covering it. It is used to prebend the main beam with a 40x3mm stainless striker band. As the rear wires only will go through an eye at the bottom no for/aft forces will be present.
Cleaned up the GC32 to show my idea. You will have to imagine the forestay bridle and bowsprit is lifted 34cm. The rear bridle tension is a guesstimate.
Using the same 5mm Hampidjan Dynice Dux as in the forestay, makes this a light construction, although the rope is $7.50/m in Sweden.
[img]http://racerdirekt.com/pelican.png[/img]<!-- editby --><em>Edited by revintage on Jun 12, 2018 - 06:12 AM.</em><!-- end editby --> [/quote]
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