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Ultra-Portable Hang Glider (UPHG)
Design Movement ===============================================================
Stay-Line Anchoring Using Joe Loops In previous discussions, a
single Joe Loop was considered as an option for anchoring both the
flying and
landing crossline stays at a given spar-strut junction. However, this approach presented some challenges, including
slipperiness and
snubbing considerations. Additionally, an important factor was not previously addressed: the inability to tailor
differential strengths for handling distinct flight and landing loads.
This technical note explores an alternative approach—using
two Joe Loops at a single spar-strut join—to independently secure the
flying stay and the
landing stay, offering improved load distribution and control.
Diagonal plane-framing lines at the same join are not discussed here, as they can be addressed separately.
Two Joe Loops at the Join Instead of a single loop, two independent
Joe Loops are employed, each cinching around the spar and passing through itself for a secure hold. This method allows for:
- Independent cinching, ensuring each loop maintains proper tension without interference.
- Better load management, with loops sized and rated according to the expected forces from flight and landing.
- Color coding or labeling for quick identification and correct joint matching.
- Differentiated loop strengths, where inboard loops (handling greater loads) are made heavier than outboard join loops.
- Length optimization, with forward stay loops long enough to pass through camber-adjusting components, while aft loops remain shorter as they do not require additional routing.
- Dyneema construction, ensuring high strength and low weight.
To mitigate slippage and enhance stability, a
small rubber snubbing ring can be placed over each loop, positioned
outboard of the Joe Cup flange, to neatly secure the cinch.
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by Semper Fidelis » Tue Mar 25, 2025 2:12 pm 
