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Old Nov 08, 2012, 09:11 PM
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United States, MN, Brainerd
Joined Oct 2004
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Looking at available space (servos are actually closer than the first drawing), and considering the arc of the swing arm being inefficient and requiring a lot of "swing-space", I think a linear pull system will be better.
This goes back to one of Jerry's original design proposals with a simple spring.
Because Syren has eight separate braces (P&S x Main&Fore x Course&Top), a compact "trapped" system seemed a better option than free lines or swinging arms.
The posted design is simply 8 short pieces of rectangular brass tubes. Four are soldered together for each side (P&S) with a bracket to attach to the center servo (being slightly higher, its mounting screw heads are at about the right height for the brackets).
Dims and alignments have to be checked - drawing is still very rough.
This design uses the total L between servos for travel of the brace adjusting block, with the bungees (or springs) having a lot of room for their travel.
I prefer bungee to springs - easily adjustable L, small dismeter, tension range adjust by adding strands, bungee has higher stretch ratio.
The block bodies will be made from delrin stock for easy slide within the tubes. The tubes and blocks are rectangular to prevent twist and resultant tangling.
Small screw stops can be added to the ends of the tubes to prevent block escape.
More thought necessary, but given that this fits the existing setup with only the addition of the tubesets to the center servo and solves the problem of block travel space tradeoff with bungee/spring space, it's likely to be the way I'll start testing.
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