Bob Kuczewski wrote:JoeF wrote:In a telescoping-tube system, give special attention to the largest (outermost) tube in the nest.
:
these bulking features can significantly improve frame integrity, buckling resistance, and joint strength.
The outermost tube also protects the others during transport and storage!!
Yes, indeed, Bob!
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Exploration notes on a new direction of joins without Joe-Cups or Joe Straps, but rather hidden splining and shear pinning along with final anti-wobble little insert and a keeper for that little insert:
Sequence and mechanics1.
Storage - The split-ring anti-wobble inserts are
flexible enough to be stored separately without permanent deformation.
- Being small and flexible, they tolerate transport stress easily.
2.
Child tube preparation - Leave a
thin Teflon or similar flat band on the child tube, positioned to later act as a backing or stop for the insert.
- This band stays on the tube throughout packing and tote — it does not interfere with nesting.
3.
Assembly - Press the split-ring insert into the radial gap between the child and mother tube.
- The band on the child tube acts as a
firming surface, allowing the ring to be scooched over it, seating the insert snugly against the gap.
- This combination
locks the anti-wobble ring in place, ensures radial support, and maintains alignment during spline engagement.
4.
Spline and shear-pin engagement - With the insert held snug by the band, you can slide the child forward until splines engage the mother’s internal spline set.
- Insert the shear pin last to lock axial position.
Advantages of this method- Minimal additional hardware: no clamps or adhesives needed in the field.
- Flexible inserts are
protected in storage but firm once in place.
- Assembly is
repeatable, quick, and low-risk, even in field conditions.
- Ensures
anti-wobble and torque transfer without interfering with shear-pin installation.
This approach gives you a
clean, field-ready telescopic spar joint where all three functions — axial location, torsion transfer, and wobble suppression — are neatly separated and managed.
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These notes above regards a big shift in a packing and spar-segment formation option that does not use Joe Cups or Joe Straps. The shift is to a situation where a set of two or more spar segments nest incompletely while allowing bulking of an end of spar segment and plugging an end of a spar segment. The nest grows in length by a couple inches or as desired for end-spar-segment treatment. There is a "stacking" in the nesting that occurs. This new option can occur when dropping the assumption of "full-length nesting" for packing and tote time. Bulking one end and plugging one end allows a firm shear pinning while protecting the vulnerable CF tube segment ends.
Special spline part bonding to the outside of the child tube and the i side of the mother tube about 1 inch from the end to about 3 inch from the ends allow a spline marriage for handling the spar torque until the spar torque meets its reaction with the keel or like means of reacting to the spar torque.
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Sample new "stack nesting": Root mother tube No. 1 has plug in its keel-end that is say one inch long permanently bonded to the inside of that tube end; that plug prevents a child nested tube from going past that plug. But then the first child nested tube may nest toted with a bulky collar where the bulky collar does not fit inside the mother tube, but stacks by simply resting on the bulked end of the mother tube. Such formations could stop there if the spar is full then, but one might add another child tube with the same system of plug keelwise end and bulk collar wingtip end. Then there would be a three tube nest, but slightly stacked. Tolerate the stacking length for pack or design first mother tube, etc to be slightly shorter to help meet pack length wanted, be it 4 ft or 5 ft or 6 ft. Protecting the vulnerable CF tube ends and handling torque transfer are the causals for this adventure.
E.g., spline parts may start tube-inward away from the shear pinning.
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