[Semper Fidelis]

Erika Klein opined this week: "a quick shortpack hang glider is the number one thing our sport needs."

I DO AGREE !!

A little bit late on the TPHG 5.7, sorry. I'll let you know because this movement IS important for the future of HG
https://ushawks.org/forum/viewtopic.php?f=2&t=4354

Anticipating to see you all at Dockweiler

Semper Fidelis

[JoeF]

Dynamic Cross Link

[JoeF]

Tim Swait of Avian is speaking in the video
Dynamic Cross Link
DXL

---

I make note: Be ready to notice in some historical constructions the equivalent dynamics in a nose There have been hundreds of noses in HG make flow over a century. The fine tuning of the DXL on a high performance hang glider may well see some assets from Avian's explorations. Spar twist impacts on washout angles are to be watched carefully.

---

[JoeF]

Tube coupling thoroughly explored may bless design reaching for low mass and low pack volume.
[Forum Draft for USHawks.org]

TITLE: Tube Coupling Ways and Means for Ultra-Compact Hang Glider Spars (TPHG Concept)

Author: Joe Faust (discussion with AI assistant)

---

## ORIGINAL QUESTION

Tube coupling ways and means? There must be hundreds of ways to couple two tubes! Some way may better bless the design of hang glider with low pack volume and low mass. Explore scores of ways by list.

---

## EXPLORATION OF TUBE COUPLING METHODS

Designing joints for tubular structures (like spars in a compact hang glider) is a classic mechanical problem. There truly are dozens of viable coupling strategies, each trading off mass, stiffness, assembly speed, and pack volume.

Below is a structured exploration of many approaches used in aerospace, tents, bicycles, masts, medical tubing, and deployable structures.

They are grouped by mechanical principle.

---

1. Slip-Fit Couplers (Sleeve Methods)

---

1. External sleeve coupler
2. Internal sleeve coupler
3. Half-length internal plug
4. Stepped internal plug
5. Bonded permanent sleeve
6. Removable sleeve
7. Tapered sleeve
8. Split sleeve with clamp
9. Sleeve with adhesive bonding
10. Sleeve with friction tape build-up

---

2. Telescopic Nesting Couplers

---

11. Plain telescoping tube
12. Telescoping with stop shoulder
13. Telescoping with internal plug
14. Telescoping with strap stop
15. Telescoping with detent
16. Telescoping with ball lock
17. Telescoping with spring button
18. Telescoping with friction collet
19. Telescoping with compression ring
20. Nested tubes with tension cord

---

3. Pin-Based Couplers

---

21. Cross pin
22. Quick-release detent pin
23. Bolt and nut through both tubes
24. Clevis pin
25. Double shear pin
26. Spring button pin
27. Bayonet pin
28. Hairpin cotter
29. Magnetic pin retention
30. Sliding pin latch

---

4. Threaded Couplers

---

31. Male/female threaded tube
32. Threaded sleeve
33. Union coupling
34. Buttress thread coupling
35. ACME thread coupling
36. Left/right turnbuckle coupling
37. Threaded plug
38. Threaded collar
39. Threaded insert bonded in tube
40. Multi-start thread for fast engagement

---

5. Clamp Couplers

---

41. Split clamp collar
42. Hose clamp coupling
43. Toggle clamp
44. Cam lever clamp
45. Collet clamp
46. Compression nut ferrule
47. Bicycle seatpost clamp
48. Band clamp
49. Over-center lever clamp
50. Radial wedge clamp

---

6. Bayonet / Twist-Lock Couplers

---

51. Bayonet lug twist lock
52. Quarter-turn stud
53. Helical cam lock
54. Twist collet
55. Twist wedge lock
56. Helical slot locking pin
57. Rotary latch
58. Spring bayonet
59. Ball-groove twist lock
60. Double lug bayonet

---

7. Expanding Plug Systems

---

61. Cone expanding plug
62. Split wedge plug
63. Rubber compression plug
64. Expanding collet plug
65. Inflatable bladder plug
66. Threaded expansion anchor
67. Cam expansion plug
68. Dual cone expander
69. Radial wedge expander
70. Expandable foam plug

---

8. Strap / Tension Couplers

---

71. External tension strap
72. Internal Dyneema loop
73. Sock coupling
74. Tape wrap coupling
75. Fiber braid sleeve
76. Cord lash joint
77. Chinese finger trap braid
78. Kevlar tension sleeve
79. Lashing with cleat
80. Webbing buckle strap

---

9. Magnetic Couplers

---

81. Magnetic face coupling
82. Magnet + pin hybrid
83. Magnetic collet
84. Magnetically indexed sleeve
85. Electromagnetic latch

---

10. Geometry-Based Couplers

---

86. Square tube slip joint
87. Hexagonal tube join
88. Triangular tube nesting
89. Keyed spline joint
90. D-shaped tube
91. Fluted tube engagement
92. Star-shaped plug
93. Rib-and-groove tube
94. Polygon plug
95. Spline shaft coupling

---

11. Hybrid Couplers

---

96. Sleeve + pin
97. Sleeve + strap
98. Plug + strap
99. Plug + magnet alignment
100. Sleeve + bayonet
101. Plug + collet
102. Telescoping + cam lock
103. Tension strap + expanding plug
104. Sleeve + adhesive + pin
105. Fiber braid + compression collar

---

## LIGHTWEIGHT COUPLERS COMMON IN AEROSPACE

Some designs repeatedly appear in ultralight structures:

• Long internal plug
• Bonded internal plug
• External sleeve
• Tapered plug
• Carbon fiber wrap joint
• Dyneema braid sleeve
• Shock cord alignment
• Strap-limited telescopic joint
• Thin split collet
• Cone expander plug
• Ball detent plug
• Leaf spring button
• Bayonet twist lock
• Kevlar lashing joint
• Fabric sock coupler

---

## UNUSUAL COUPLERS FROM DEPLOYABLE STRUCTURES

These ideas come from deployable antennas, satellite booms, and experimental lightweight structures.

1. Joe-Cup Coupler

Protective cup plug at tube ends.

Functions:

• protects carbon tube edge
• provides axial load seat
• allows controlled insertion depth
• enables deep nesting

2. Joe-Strap Coupler

Dyneema or Kevlar strap looped around internal plug.

Functions:

• limits insertion
• carries tension loads
• avoids pins or bolts
• allows full nesting

3. Fiber Finger-Trap Coupler

Braided sleeve that tightens under load.

• extremely light
• self-tightening
• no rigid parts

4. Tape Spiral Joint

Composite tape wrapped during assembly.

• very strong
• almost zero hardware

5. Elastomer Compression Joint

Rubber sleeve compressed axially.

• protects tube ends
• damps vibration

6. Inflatable Plug

Small bladder expands inside tube.

• perfect centering
• no metal hardware

7. Magnetic Alignment Plug

Magnets guide tube alignment during assembly.

8. Slotted Flexure Plug

Plug with longitudinal slots acting like a spring collet.

9. Wedge-Lock Ring

Split ring wedges into groove under compression.

10. Fabric Sock Coupler

Sail sleeve itself stabilizes joint.

11. Cable-Tension System

Internal cable keeps all segments aligned.

12. Polygon Tube Joint

Hex or fluted tubes resist rotation without extra parts.

---

## COUPLERS PARTICULARLY INTERESTING FOR TPHG

Considering goals of:

• tiny packed volume
• telescopic nesting
• compression spars

these are especially promising:

• strap-limited telescopic joint
• long internal carbon plug
• Dyneema braid sleeve
• cone expanding plug
• fabric sock coupler

---

## FIVE COUPLER IDEAS TAILORED TO TPHG

1. Compression-Dome Joe-Cup Joint

Joe-Cup cap with domed elastomer pad.

Benefits:

• spreads compression load
• protects tube ends
• slight compliance reduces stress peaks

2. Dyneema Spine Joint

Continuous Dyneema cord running through all spar segments.

Benefits:

• keeps segments aligned
• prevents loss during assembly
• extremely light

3. Sail-Sock Stabilized Joint

The wing sock provides lateral stabilization.

Load sharing:

compression → tube faces
lateral stiffness → sail fabric

4. Flexure-Plug Joint

Slotted carbon plug acting as a spring collet.

Benefits:

• perfect centering
• very light
• no extra hardware

5. Strap-Preloaded Joint

Joe-Strap slightly tensioned during assembly.

Results:

• immediate joint tightness
• vibration reduction
• self-tightening under load

---

## PROMISING HYBRID SYSTEM

Possible architecture for a Tiny Packed Hang Glider spar:

1. Joe-Cup cap protecting tube ends
2. domed compression pad
3. long internal alignment plug
4. Dyneema Joe-Strap insertion limiter
5. sail sock providing lateral stabilization

Load paths:

compression → tube faces / plug
tension → strap
lateral stiffness → sail sock

---

## FINAL OBSERVATION

Many successful ultralight structures follow these principles:

• avoid drilling holes in composite tubes
• distribute loads gradually
• use tension fibers rather than metal fasteners
• protect tube ends from crushing

The Joe-Cup and Joe-Strap concepts align closely with these principles and may prove well suited to the Tiny Packed Hang Glider concept.

End of draft.

[dhmartens]

The good news is the 5 foot telescopic glider is no longer a threat to the military drone movement as they have a $400 solution drone so we can be declassified and proceed.
Our weight shift drone is currently at the $2,000 pricepoint.

[Bob Kuczewski]

1. External sleeve coupler
2. Internal sleeve coupler
3. Half-length internal plug
4. Stepped internal plug
5. Bonded permanent sleeve
6. Removable sleeve
7. Tapered sleeve
8. Split sleeve with clamp
9. Sleeve with adhesive bonding
10. Sleeve with friction tape build-up

---

2. Telescopic Nesting Couplers

---

11. Plain telescoping tube
12. Telescoping with stop shoulder
13. Telescoping with internal plug
14. Telescoping with strap stop
15. Telescoping with detent
16. Telescoping with ball lock
17. Telescoping with spring button
18. Telescoping with friction collet
19. Telescoping with compression ring
20. Nested tubes with tension cord

---

3. Pin-Based Couplers

---

21. Cross pin
22. Quick-release detent pin
23. Bolt and nut through both tubes
24. Clevis pin
25. Double shear pin
26. Spring button pin
27. Bayonet pin
28. Hairpin cotter
29. Magnetic pin retention
30. Sliding pin latch

---

4. Threaded Couplers

---

31. Male/female threaded tube
32. Threaded sleeve
33. Union coupling
34. Buttress thread coupling
35. ACME thread coupling
36. Left/right turnbuckle coupling
37. Threaded plug
38. Threaded collar
39. Threaded insert bonded in tube
40. Multi-start thread for fast engagement

---

5. Clamp Couplers

---

41. Split clamp collar
42. Hose clamp coupling
43. Toggle clamp
44. Cam lever clamp
45. Collet clamp
46. Compression nut ferrule
47. Bicycle seatpost clamp
48. Band clamp
49. Over-center lever clamp
50. Radial wedge clamp

---

6. Bayonet / Twist-Lock Couplers

---

51. Bayonet lug twist lock
52. Quarter-turn stud
53. Helical cam lock
54. Twist collet
55. Twist wedge lock
56. Helical slot locking pin
57. Rotary latch
58. Spring bayonet
59. Ball-groove twist lock
60. Double lug bayonet

---

7. Expanding Plug Systems

---

61. Cone expanding plug
62. Split wedge plug
63. Rubber compression plug
64. Expanding collet plug
65. Inflatable bladder plug
66. Threaded expansion anchor
67. Cam expansion plug
68. Dual cone expander
69. Radial wedge expander
70. Expandable foam plug

---

8. Strap / Tension Couplers

---

71. External tension strap
72. Internal Dyneema loop
73. Sock coupling
74. Tape wrap coupling
75. Fiber braid sleeve
76. Cord lash joint
77. Chinese finger trap braid
78. Kevlar tension sleeve
79. Lashing with cleat
80. Webbing buckle strap

---

9. Magnetic Couplers

---

81. Magnetic face coupling
82. Magnet + pin hybrid
83. Magnetic collet
84. Magnetically indexed sleeve
85. Electromagnetic latch

---

10. Geometry-Based Couplers

---

86. Square tube slip joint
87. Hexagonal tube join
88. Triangular tube nesting
89. Keyed spline joint
90. D-shaped tube
91. Fluted tube engagement
92. Star-shaped plug
93. Rib-and-groove tube
94. Polygon plug
95. Spline shaft coupling

---

11. Hybrid Couplers

---

96. Sleeve + pin
97. Sleeve + strap
98. Plug + strap
99. Plug + magnet alignment
100. Sleeve + bayonet
101. Plug + collet
102. Telescoping + cam lock
103. Tension strap + expanding plug
104. Sleeve + adhesive + pin
105. Fiber braid + compression collar

Joe,

Your list of options is mind-knumbing. It reminds me of this quote by "Bubba" from Forrest Gump:

"Shrimp is the fruit of the sea. You can barbecue it, boil it, broil it, bake it, sauté it. There's, um, shrimp kabobs, shrimp creole, ... (next scene) ... shrimp gumbo, pan fried, deep fried, stir fried. There's pineapple shrimp and lemon shrimp, coconut shrimp, pepper shrimp, ... (next scene) ... shrimp soup, shrimp stew, shrimp salad, shrimp in potatoes, shrimp burger, shrimp sandwich. That's, that's about it."

I think the person building that model may not have put enough thought into it. The model seems to do a lot of "cross controlling (pilot rotating rather than translating). The problem may be based on the fact that the hands are free to slide along the control bar and don't actually grip it. But it's a good effort, and the problems can be overcome. Thanks for posting it.

[dhmartens]

There is a slight chance I can demo and short pack the prototype at the SHGA birthday celebration 3/15/2026 however, I will appear highly depleted in battling her tripple positive breast cancer after 6 years as all my funds have been diverted to usda organic food for 6 years. Hungary Joe can corraberate. The prototype costs $2.50 so elimiating 150,000 russians in Ukrains costs less that half the cost of a single Tomahawk.

We have other worries this AI too

[Chris McKeon]

So I can see how when John Heiney is here working on My Predator. I will be asking Him questions as to the possibility of being able to Short Pack My Predator in spite of Those Le. Gths of Carbon Fiber Tubing. Short-Packing I got zone just love the concept

[dhmartens]

Here it is! Video of breaking down the:

Telescopic portable hang glider Prototype #5foothangglidermovement

[JoeF]

Nice offer, Doug!
=============================================================

---

Dictated note via voice=to-text from cell phone into an email draft on St. Patrick's Day from one J. Patrick M.F.

For the beak have the two lines go from left to nose to right without break. Those two lines will support the airbeam that will also go from left to right without nose break. This should save several connections and give a smoother nose. Less parts. Still packable. One air valve.

---