[JoeF]

Continuing
the
Ultra-Portable Hang Glider (UPHG)
Design Movement (UPHG-dm)

In the original discussion thread, the title aimed to capture a vision but didn’t fully encapsulate the key priorities: 5-ft-or-less in length, low mass, polite portability, and ultra-portability. Over the years, refining the title to better reflect these goals has been an ongoing challenge. While "low pack volume" was a central theme, it wasn’t quite conveyed in the original phrasing.

Through community growth and discussion, we now introduce a new, more fitting title that embraces both our original intent and the ongoing evolution of this movement: UP for Ultra-Portable, leading to UPHG for the Ultra-Portable Hang Glider Design Movement (UPHGdm). The “UP” element is especially fitting—it embodies both portability and flight, while also signaling the continuance of our pursuit.

This discussion is not just a reset but a natural continuation of the design movement. The two discussion threads remain fertile ground for refining and advancing ideas. While some pilots may prefer a pack length slightly beyond 5 feet, others may target 5 feet, 4 feet, or even as compact as 3 feet or 1 meter. Portability is about more than just length—it may involve modular sub-packs, multiple packs, or specialized pack shapes rather than a one-size-fits-all approach.

The decision to establish this new thread was ultimately solidified by Florian’s final urging, tipping the scales in favor of a space that better reflects our evolving goals.

This is a continuation, not a conclusion. Titles may be a balancing act, but this one aims to honor both the origins and the ongoing journey of UPHG-dm. Let’s keep pushing the boundaries of ultra-portable hang glider design!



Titles may involve a balancing act.


Steady loving care will bring the effective feathers ...

FeatherPorting.JPG (31.47 KiB) Viewed 147 times

[JoeF]

Exploratory Study: Dyneema Cordage

This note is intended for exploratory purposes, with no specific recommendations. We are investigating various aspects of Dyneema cordage for potential applications. Please refer to the following resource for more information:

AmSteel-Blue Dyneema Spools

Key areas for further investigation:

Cutting: Best tools and practices for cutting the Dyneema cordage.

Cleaning: Best practices for maintaining Dyneema cordage.

Protecting: Methods to protect the cordage from wear and environmental damage.

Stowing: Approaches for compact and safe storage of Dyneema lines.

Shrink-wrap Sheathing: The use of shrink-wrap for additional protection or durability.

Testing: Suggested testing methods for strength, durability, and reliability.

Terminating: Techniques for properly terminating Dyneema cordage to prevent failure.

Looping: Effective ways to create loops and eyelets.

Knotting: Exploring appropriate knots for Dyneema, including their strength and reliability.

With detail prompting ChatGPT chimed in:

Aspects of Cordage Inclusion in Hang Glider Making You Might Be Forgetting

When considering cordage in hang glider design, you’ve covered many of the primary factors, but here are a few additional aspects you might want to explore or expand on:

1. Stretch and Elasticity
- Stretch Characteristics: Dyneema is known for its low stretch, but understanding its behavior under load and over time (e.g., creep) is important, especially in areas that must maintain a consistent tension.
- Elasticity under Different Conditions: How cordage responds to varying temperatures, humidity, and UV exposure could affect performance.

2. UV Resistance
- Long-term Durability: Dyneema, while strong, can degrade when exposed to UV rays over time. Consider whether a UV-resistant coating or sheathing is required for areas frequently exposed to sunlight.

3. Load Distribution
- Tension Load Analysis: Evaluating how cordage distributes load across the structure—whether it serves as a primary load-bearing component or as a stabilizing support.
- Abrasion Resistance: In areas where the cordage might rub against metal or other rough surfaces, ensuring the material has sufficient abrasion resistance to prevent premature wear.

4. Weight Considerations
- Weight-to-Strength Ratio: While Dyneema is lightweight, consider how much weight it adds to the glider compared to other materials, especially in larger lengths.
- Impact on Overall Balance: How cordage in various parts of the glider impacts the overall weight distribution and balance during flight.

5. Flexibility and Knot Performance
- Flexibility in Dynamic Loads: How well does the cordage perform in dynamic load conditions, such as during turbulence or when adjusting control surfaces?
- Knot Security: While Dyneema holds knots well, testing the security of knots under stress, as well as the long-term integrity of knots in varying weather conditions, is crucial.

6. Sailing and Tuning
- Control Line Tuning: How adjustable lines (e.g., for the control bar or other rigging) using Dyneema perform in terms of fine-tuning the glider's handling and response.
- Slack Management: Ensuring there is no slack in the lines during flight, especially in situations where precise line tension is critical.

7. Attachment Points & Terminals
- End Terminals: Investigate what types of end-terminals (e.g., ferrules, crimps, or knots) are best suited for attaching Dyneema cordage to other components, ensuring a secure connection without compromising strength.
- Integration with Other Materials: How Dyneema cordage interacts with other materials in the hang glider’s construction (e.g., carbon fiber or aluminum spars) when used in combination, particularly regarding abrasion or friction.

8. Environmental Impact and Sustainability
- Material Sourcing: Consideration of the environmental impact of Dyneema production and its long-term disposal (e.g., biodegradability or recycling).
- Sustainability: Alternatives or complementary materials to Dyneema that might offer similar performance but with a more sustainable lifecycle.

9. Maintenance and Inspection
- Routine Checks: Developing a system for regular inspection of cordage, particularly where it interfaces with the frame or other moving parts, to ensure that wear is noticed early before it affects performance.
- Re-tensioning: Understanding the need for re-tensioning lines after certain periods, especially after exposure to significant stress or environmental factors.

These considerations could help ensure a more comprehensive approach when using cordage in the hang glider's design, enhancing safety, durability, and performance.

[JoeF]

Core Ten
"Core Ten" in this developmental note refers to an experimental core structure consisting of 10 tubes: 3 on left and 3 on right of a keel; that is 7. Now for the three more: 1 kingpost and two queenposts. Presto: 10. Keep the 3 on the left in a plane; keep the 3 on the right with a plane. Have the keel share in both of those planes. 3+1+3+1+2=10. So much for the deep math.!
Otto Lilienthal and brother Gustave had a very early strap-on wing of about 50 square feet; they did some wing running with the wing. The Core Ten in a 50 sq. ft wing could be had using tubes that are 5 ft in length. Such use in a Core 10 without sweep could see a left-wing of 25 sq. ft and a right wing of 25 sq. ft for the total of 50 sq. ft. For each of the side squares have two diagonal stay lines. Stay the spatial position of the two side wings with stay lines to the kingpost and two queenposts. Further have a stay line from the nose to kingpost to tail. And two stay lines from nose to tail involving the two queenposts. Cover the two squares and have some experience doing wing running with 50 sq. ft of wing cover.

Core10frame001.jpg (6.41 KiB) Viewed 69 times

Core10frame003.jpg (15.8 KiB) Viewed 69 times

Play with Core Ten for tiny packing on way to UPHG exploration.

[JoeF]

With two more tubes one gets almost the same area for an exploratory frame as obtained for Core Ten.
Above post was about "Core Ten". This note is about a cousin, Core 12.

Core 12 is a higher aspect ratio wing than Core Ten

Core12almost50sqft.jpg (28.57 KiB) Viewed 50 times

Both Core Ten and Core 12 are only meant for exploration of tiny-packing influences,
stay-line anchoring, camber-forming, etc.
  These platforms are for wing running --at most--, not flight.  
Consider wheels or skids if one wing runs.
Stumbling or drastic nose-down still could be dangerous, even fatal.
Helmet, knee pads, gloves?????? Consider reflex or High Hat!
Maybe have a nose skid?
.

Both Core Ten and Core 12 may be built using many kinds of choices for various reasons.
These matters could be part of the path to some ultra-portable hang glider UPHG.


Note: To have one tube less in a pack, the triangle control frame's "basebar" is not a bar or tube,
but tensed line using cross line stay side lines.
===================================================================================

[Bob Kuczewski]

Hi Joe,

I always find your 3-D ideas interesting, but sometimes difficult to understand. A while back I coded up a 3D viewer for expressing hang glider framing. It's available here:

     https://ushawks.org/designer/frame_designer.htm

The format for each line is just two points followed by a line thickness and a color:    [x1,y1,z1,  x2,y2,z2,   thickness,   color].

This file, for example, shows a cube at the origin with line lengths of 10 (+/- 5), a line thickness of 3, and in green:

[
 [-5, 0, 0,   0,-5, 0,  3,  "00ff00"],
 [-5, 0, 0,   0, 5, 0,  3,  "00ff00"],
 [-5, 0, 0,   0, 0,-5,  3,  "00ff00"],
 [-5, 0, 0,   0, 0, 5,  3,  "00ff00"],
 [ 5, 0, 0,   0,-5, 0,  3,  "00ff00"],
 [ 5, 0, 0,   0, 5, 0,  3,  "00ff00"],
 [ 5, 0, 0,   0, 0,-5,  3,  "00ff00"],
 [ 5, 0, 0,   0, 0, 5,  3,  "00ff00"],
 [ 0,-5, 0,   0, 0,-5,  3,  "00ff00"],
 [ 0,-5, 0,   0, 0, 5,  3,  "00ff00"],
 [ 0, 5, 0,   0, 0,-5,  3,  "00ff00"],
 [ 0, 5, 0,   0, 0, 5,  3,  "00ff00"],
]

There are more examples here: https://ushawks.org/forum/viewtopic.php ... 549#p32621

Don't worry about being exact, or about the colors or format. If you can just give some approximate points for each line, I'll be happy to put them in the proper format. The program also produces what's called "Wavefront .obj" format which can be imported into almost any real 3D rendering program (including Blender and many others). So you can build 3D models from a pure mathematical description.

Since you've only got about a dozen or so lines, it might not be too hard to just make estimates to get started.

I've also written and posted a somewhat easier graphical version here:

     https://ushawks.org/designer/object_builder.htm

That version lets you place points graphically in each of the three orthogonal views (along x, along y, or along z). But points placed in either of those three views are placed on the plane of the view (third coordinate is 0). So you have to use the other views to drag along the third axis. It's a little cumbersome, but not too difficult once you get used to it. It can also generate the file format above or the Wavefront .obj format.

Finally, if you don't mind keeping track of the indexes, the Wavefront .obj format isn't too hard to use by itself. The Wikipedia link above is a good starting point.

[JoeF]

Thanks, Bob. I explored and posted earlier using your program.Thanks again.
Below is a use of the program along with after-use tweaks in Paint.

Core12.jpg (38.13 KiB) Viewed 47 times

[Bob Kuczewski]

Aha!!

Now I see it much better.

Can you post the model file?

[Bob Kuczewski]

Actually, I think I just built a version myself:

Copy_of_Joes.png (29.94 KiB) Viewed 43 times

Did I miss any wires?

Here's the model with mirroring enabled:

[
 [  0.00,  2.62,  0.00,   15.49, -4.85,  0.00,   0.4, "5555ff" ],
 [  0.00, -3.32,  0.00,   15.49, -4.85,  0.00,   0.4, "5555ff" ],
 [  8.71, -1.58,  0.00,   15.49, -4.85,  0.00,   0.5, "ff0000" ],
 [  8.10, -4.12,  0.00,   15.49, -4.85,  0.00,   0.5, "ff0000" ],
 [  0.00,  0.04,  0.06,    1.48,  1.39, -3.59,   0.5, "ff0000" ],
 [  0.00,  2.62,  0.00,    0.00, -3.32,  0.00,   0.5, "ff0000" ],
 [  0.00,  0.82,  0.00,    0.00,  0.77,  4.26,   0.5, "ff0000" ],
 [  0.00,  2.62,  0.00,    0.00,  0.77,  4.26,   0.1, "aaaaaa" ],
 [  8.10, -4.12,  0.00,    0.00,  0.77,  4.26,   0.1, "aaaaaa" ],
 [  0.00, -3.32,  0.00,    0.00,  0.77,  4.26,   0.1, "aaaaaa" ],
 [  1.48,  1.39, -3.59,    0.00,  1.48, -3.61,   0.4, "aaaaaa" ],
 [  0.00,  2.62,  0.00,    1.48,  1.39, -3.59,   0.1, "aaaaaa" ],
 [  0.00,  0.77,  4.26,    8.71, -1.58,  0.00,   0.1, "aaaaaa" ],
 [  1.48,  1.39, -3.59,    0.00, -3.32,  0.00,   0.1, "aaaaaa" ],
 [  1.48,  1.39, -3.59,    8.71, -1.58,  0.00,   0.1, "aaaaaa" ],
 [  1.48,  1.39, -3.59,    8.10, -4.12,  0.00,   0.1, "aaaaaa" ],
]

[JoeF]

Still rusty on the program; posting requested file is yet beyond me; I took copy of image and then played with the item in Paint.
Below is directly from your most recent file, but rotated to show a wire that was hidden in what you posted. So, it does seem you captured all the wires (stay lines). Thanks.

Core12yesallwiresSecond.JPG (26.18 KiB) Viewed 31 times

Core 12


Note: In my shop I am having "crossline" be a continuous line from left anchor to right anchor but through a post (king or queen),
or in the case of keel-based: from nose to tail through a queenpost. And I am exploring that a loop be the first part of a line anchoring; then from a left loop to a right loop goes a crossline; or in case of fore and aft: from loop at nose through post to loop at tail. Thus, in Core 12 we see on top of the wing 3 crosslines, and on bottom we see 4 flying crosslines. The images being shared do not detail the anchoring loops used by the crosslines. The "control bar" of the triangle control frame is not a "bar" or "tube" but a sheathed section of running lateral two crosslines in tension.

The Core 12 using 12 tubes of 5 ft length (or other lengths, if one chooses) gives a potential experimental platform in the process of developing some UPHG (ultra portable hang glider. Joe Cups are anticipated for four joins of the spars. The spar segments could be sized so that in tote there is a good level of nesting of tubes.

Upon the Core 12 platform one may explore sail coverings, cambering options, line tensioning schemes, Joe-Cup modifications, crossline lengths, centerings, failure modes, balances, pitch controls, reflexing, ribbings, ergonomics, hang points, assembly logistics, disassembly logistics, packings, tote modes, pitch stabilities, wearings, options, High Hats, wheels, skis, creeps, ...
=====================================I let ChatGPT have a go upon being fed the above prose: ===================================

Here's a polished version of your text with refined grammar, structure, and readability. I've also included side notes on spelling and terminology that might interest the hang gliding community.

ChatGPT said:
Here is your response formatted in phpBB coding for easy posting on USHawks.org:

Core 12


Still getting up to speed with the program—posting the requested file is beyond me for now. I copied the image and modified it in Paint.

The version below is directly from your most recent file but rotated to reveal a previously hidden wire. It does seem that you captured all the wires (stay lines). Thanks!

Crossline Terminology and Concept
In my shop, I define a crossline as a continuous line extending from a left anchor to a right anchor while passing through a post (kingpost or queenpost). For keel-based configurations, the crossline extends from the nose to the tail through a queenpost.

I’m also exploring an anchoring method where a loop serves as the starting point. A crossline then spans between a left loop and a right loop—or, in the case of a fore-and-aft arrangement, from a nose loop through a post to a tail loop.

In Core 12, we observe:

• Three crosslines on top of the wing. [two lateral, one fore-aft]
• Four flying crosslines underneath. [two lateral, two fore-aft]

The images shared do not yet detail the anchoring loops for the crosslines.

Notably, the "control bar" of the triangle control frame is not a conventional bar or tube but rather a sheathed section of two running lateral crosslines in tension.

Core 12 as an Experimental Platform
The Core 12 framework consists of 12 tubes, each 5 feet in length (or alternative lengths, depending on preference). This structure serves as a potential experimental platform for developing an UPHG (Ultra Portable Hang Glider).

Key elements of Core 12:

• Joe Cups are anticipated at four spar joints.
• Spar segments can be sized to allow efficient nesting of tubes for compact packing.
• The framework enables exploration of:
  
  • Sail coverings
  • Cambering options
  • Line tensioning schemes
  • Joe Cup modifications
  • Crossline lengths and centering
  • Failure modes and load balances
  • Pitch control and reflexing
  • Ribbing and ergonomic considerations
  • Hang point placement
  • Assembly and disassembly logistics
  • Packing and transport modes
  • Stability testing (pitch and structural wear)
  • Additional accessories: High Hats, wheels, skis, creepers, etc.

===================================================

Side Notes on Spelling & Terminology for the Hang Glider Community:

• Crossline vs. Cross Line:
  
  
  
  • "Crossline" (one word) makes sense in your context, as it refers to a specific structural element.
  • "Cross line" (two words) could imply a broader meaning or a general crossing of lines.
  
  
• UPHG (Ultra Portable Hang Glider):
  
  
  
  • This acronym is a solid descriptor! It clearly communicates the goal of achieving extreme portability.
  
  
• Control Bar (vs. "Running Lateral Crosslines in Tension")
  
  
  
  • Your phrasing describes the function well, but "control bar" is still widely recognized. Perhaps "tensioned crossline control system" could bridge the concept with existing terminology?
  
  
• Creeps?
  
  
  
  • You mention "creeps" alongside wheels and skis—are you referring to ground skids or low-friction elements? Might be worth clarifying.

Your terminology innovations make sense within the TPHG [sic, or UPHG] context, and defining these terms helps align understanding within the community. Let me know if you'd like further refinements!

Note: Because my prompt was unclear about "creeps" then ChatGPT introduced a possible valuable term "creepers". Lines upon tensioned use will creep to elongations; perhaps devices for retensioning to specs might be called "creepers."

[Bob Kuczewski]

Still rusty on the program; posting requested file is yet beyond me; I took copy of image and then played with the item in Paint.
Below is directly from your most recent file, but rotated to show a wire that was hidden in what you posted. So, it does seem you captured all the wires (stay lines). Thanks.

Great job on rotating to see all lines!!   

It was bugging me (slightly) that I had chosen a view that obscured one of the lines. It's great that you could load the model and rotate it for better visibility.  

You mentioned that posting the requested file is beyond you. It's actually much easier than you might expect. Here's the control section of the current program:

Object_Designer_Controls.png (136.09 KiB) Viewed 21 times

There are two buttons titled "Make Segment File ▼" and "Load Segment File ▲". These transfer the data between the internal model (drawn on the screen above the buttons) and the text model (shown below those buttons). So to make a text version of your model, just click the "Make Segment File ▼" button, and whatever you've drawn will be shown in the text box. Try it out. Make three points and connect them with three lines. Then click the "Make Segment File ▼" button, and you'll see the text representation of your model in the text box. You can just select, copy, and paste that text into a post or a text file to save it. Then to load it, you just copy it back into that box and press the "Load Segment File ▲" button and you can continue editing graphically. Using the text model could also let you build different parts of a model separately and then combine the parts by editing and combining the separate lines of text into one model file.

The latest version of the program also contains a numeric field to the right of the "Make Segment File ▼" button. That field controls the precision of the points when copied to the text model. That number is defaulted to -1 which implies full precision. Here's the text model of a tetrahedron at full precision:

[
[4.65,4.527779134114583,0,-0.016666666666666666,0.8611124674479167,6.305555216471354, 1, "ff0000"],
[-0.016666666666666666,0.8611124674479167,6.305555216471354,-0.08333333333333333,-4.472220865885417,0, 1, "ff0000"],
[-0.08333333333333333,-4.472220865885417,0,4.65,4.527779134114583,0, 1, "ff0000"],
[4.65,4.527779134114583,0,-4.683333333333334,4.461112467447917,0, 1, "ff0000"],
[-4.683333333333334,4.461112467447917,0,-0.08333333333333333,-4.472220865885417,0, 1, "ff0000"],
[-0.016666666666666666,0.8611124674479167,6.305555216471354,-4.683333333333334,4.461112467447917,0, 1, "ff0000"],
]

As you can see, there is way more precision in that model than is justified by me just clicking a few points on the screen. It's also very ugly and difficult to read. I can clean it up by changing the precision from -1 to 2. That will give me two digits to the right of the decimal point. Here's the result when I set the precision to 2 and again click the "Make Segment File ▼" button:

[
[4.65,4.53,0.00,-0.02,0.86,6.31, 1, "ff0000"],
[-0.02,0.86,6.31,-0.08,-4.47,0.00, 1, "ff0000"],
[-0.08,-4.47,0.00,4.65,4.53,0.00, 1, "ff0000"],
[4.65,4.53,0.00,-4.68,4.46,0.00, 1, "ff0000"],
[-4.68,4.46,0.00,-0.08,-4.47,0.00, 1, "ff0000"],
[-0.02,0.86,6.31,-4.68,4.46,0.00, 1, "ff0000"],
]

As you can see, all the numbers show only two places to the right of the decimal point. I can make it even neater by also clicking the "Align" button to get:

[
 [  4.65,  4.53, 0.00,   -0.02,  0.86, 6.31,   1, "ff0000" ],
 [ -0.02,  0.86, 6.31,   -0.08, -4.47, 0.00,   1, "ff0000" ],
 [ -0.08, -4.47, 0.00,    4.65,  4.53, 0.00,   1, "ff0000" ],
 [  4.65,  4.53, 0.00,   -4.68,  4.46, 0.00,   1, "ff0000" ],
 [ -4.68,  4.46, 0.00,   -0.08, -4.47, 0.00,   1, "ff0000" ],
 [ -0.02,  0.86, 6.31,   -4.68,  4.46, 0.00,   1, "ff0000" ],
]

The last version is much neater and easier to read. Note that at this point, the internal model would still be at full precision. If I want to effectively "round" the internal precision, I could click the "Load Segment File ▲" button, and those values in the text model will be transferred to the internal model. The rounding feature is handy, but be careful. If, for example, you had two intentionally separate points in the model that were only 0.003 units apart, then rounding to 2 places might make them coincident. Remember that the model retains full precision until you over-write it with the "Load Segment File ▲" button. So if you made the text model with 1 decimal place and didn't think it was accurate enough, you could change the precision setting and make the text model again at higher precision. But whatever you load back into the internal model will overwrite the previous version, and that previous version will be lost.

You can experiment with precision very easily. Just make a triangle with three points and three lines. Then save it with some precision, say 2. Then load it back and watch to see if the loaded version changes at all. I've found that with a precision of 2, any rounding of the points is pretty much unnoticeable. With a precision of 1, there are noticeable movements of the points, but the shape still looks very close. Rounding to a precision of 0 can move points quite a bit. But sometimes that's what you want to have integer valued points which essentially puts them on a grid. So the precision value can be used to make the text look neater and it can also be used to adjust the actual model. The choice of usage is up to you.

Finally, I should add that this is still a very primitive tool. It's major bug is that it just draws the lines without consideration of depth. So some lines that would normally be behind other lines may be drawn in front of them. This can make it confusing to look at. The confusion can be reduced by rotating while viewing. Our human visual system is pretty good at using motion to help define the structure of an object. If you need a nicely rendered version, you might have to do some graphics editing of the resulting image to put the lines in the proper 3D stacking order. Note that this is primarily a problem when using wide lines of differing colors. With thin lines, the overlap is difficult to see, and with a monochrome model, it doesn't matter which line is on top since it's all the same color. Finally, while the rendering might be inaccurate, the 3Dmodel will still be correct. So you can always export it to ".obj" format with the "lines.obj" button (copy and paste from the pop up window) and import it into another 3D rendering program. This program is only intended to help us easily share 3D concepts and not as a full 3D rendering package.