[JoeF]

Stringed Trusses or String Truss

SparOptionStringTruss001.png (37.19 KiB) Viewed 845 times

This will be explored using one-meter segments of hard spar. More than three strings will be used. There will be some diagonal strings. Both cantilever and Kp-Qp rigging will be explored.

Similarly bow-string trusses will be explored using one-meter beam segments.

Also, string trusses having the hard one-meter segments in a mostly straight lay will be explored for tiny-packed HGs.
Note: There is an aim to avoid segment overlap, avoid couplers, avoid splices; the hard tubing segments will just sit in small-ridged cups; cups will be bonded to the rib/bulkhead. The rib/bulkhead helps to form the airfoil LE.

StringTrussRib001.jpg (60.92 KiB) Viewed 845 times

[JoeF]

Matthew starts his thesis with the following clipped remark that sets the scene for the quest of our topic:

Compartment size is often a limiting factor when transporting objects into
space leading to multivariable design limits striving for both minimum volume and
minimum weight systems and structures. As such, components of systems are often
folded or packaged so their stowed volume is significantly reduced.

His thesis: DESIGN, CHARACTERIZATION, CONTROL,
AND OPTIMIZATION OF A ‘SUPER STRING’
DEPLOYABLE TRUSS STRUCTURE

I modify his "Compartment size and weight are two of the limiting factors when sending
structures into space." to "Compartment size and weight are two of the limiting factors when sending
HG structures into public city buses".

[JoeF]

Role of string: aesthetics and technology of tension structures
https://www.e-periodica.ch/cntmng?pid=b ... 98:79::857
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"Suspen beam" might best fit some of my recent notes toward a One-Meter Packed Hang Glider.

StringTrussSuspenBeamAirfoilBulkheadsHoldSegmentedBeam.jpg (53.76 KiB) Viewed 834 times

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Add sail and desired line rigging.

StringTrussSuspenBeamAirfoilBulkheadsHoldSegmentedBeamAddAftRibs.jpg (21.73 KiB) Viewed 834 times

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Structural behaviour and design criteria of under-deck cable-stayed bridges and combined cable-stayed bridges. Part 1: Single-span bridges

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https://cdnsciencepub.com/doi/abs/10.11 ... lCode=cjce

Key words: under-deck cable-staying, combined cable-staying, cable-stayed bridges, extradosed prestressing, intradosed prestressing, prestressing.

[JoeF]

BirthMultiDeckByWenhamInAerialLocomotion.jpg (50.08 KiB) Viewed 786 times

Wenham had a planned hang glider:

MaybeSomeoneWillAdvanceThePlannedWenham

WenhamPlannedUnderDeckCableStayed.jpg (50.95 KiB) Viewed 789 times

and maybe get it packed for city-bus pilot carrying.
Main spar "a" goes into compression under flight loading.
Consider segmenting "a" at one-meter lengths and stabilizing the position of "a" segments to move toward a one-meter packing of the HG.
https://en.wikipedia.org/wiki/Francis_Herbert_Wenham

Wenham had many offers for hang gliding ...

WenhamOFFERS.jpg (104.6 KiB) Viewed 788 times

https://www.ctie.monash.edu.au/hargrave/wenham.html
Someone's interpretation with choice of the paddles in front; I am not sure that is the intended orientation as the drawings in Fig. 5 and Fig. 6 seems to me that the paddles are aft of pilot's feet (what do you think???) : For sure: Wenham wrote about the bowsprit, thus that would be forward.

Aerial Locomotion

WenhamPORTABILITY.jpg (15.64 KiB) Viewed 785 times

Wenham was describing a powered device with the propellers or paddles, but his describing had starting flight with running.

[JoeF]

Fertile to this topic are some posts in the topic that specializes on HG spars. See: https://ushawks.org/forum/viewtopic.php ... 48&#p32582 where a complex spar from EnergyKiteSystems is rehearsed toward a qualification for the One-Meter Pack HG Club.

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There is a challenge concerning the EnergyKiteSystems complex spar recently rehearsed in the HG Spars topic. The challenge relates to the final connection of two subassemblies on the final step of forming the complex spar at flight site. AT that final step things are tight.

Some options being explored:
One possible solution is to dismount from lower edge of wingtip bulkhead the pos-g lines; perhaps slide them off the bulkhead; such would slacken the pos-g line set; that slack would permit the final connecting of the pos-g line set to the end of the compression-element. Then with firm force, lift the pos-g lines into position on the lower edge of the rib bulkhead.

Have the neg-g webbing be in two parts through an square ring; the two parts allow loosening the neg-g webbing and tightening the same. Loosen the neg-g webbing, have a slidable interior sleeve in the wingtip compression segment to allow moving the wingtip compression segment to full slack position to allow mounting the complex spar's lower pos-g lineset to join the wingtip compression element. Then do the joining. Then set the neg-g webbing to flight tautness. Then with strong push: push the other end of the wingtip compression segment into alignment with the second-from-wingtip compression segment's end; when aligned, slide the interior sleeve to its inboard interior stop; then set a small stop pin through a hole to keep the interior sleeve from moving toward the wingtip. Things should be so designed that it would take a good force to push the end of the compression segment into alignment with its neighboring compression segment. The needed force would be a telling check that things are prestressed as wanted. If this solution to the challenge is chosen, then specially, then one wingtip compression segment would not have an interior perma stop, as a reliance of a pin stop applied from the outside into a hole would do the stopping of the movement of the interior sleeve.

Maybe have the pos-g line set integrated with the neg-g webbing. At top center of the neg-g webbing have the ring-adjusting tautness or slackness . With the webbing be slidable around the wingtip end of the wingtip compression segment; have a nice smooth fitting to cap the wingtip compression segment end; a smooth yoke on the outside of the wingtip wand, perhaps. Mount the neg-g-pos-g webbing-line into the tip yokes; then tighten the neg-g webbing at the ring at the upper center; once tightened, tighten an anchoring-positions bolt-washer at the yoke to give distinction between the neg-g length and the pos-g lower length. At neg-g, the neg-g webbing length should not change in length except for a slight stretching as the neg-g forces push the complex spar downwards a bit. This option would have compression segments sleeved as prescribed. This option would not have the neg-g webbing wrapped to anchor as prescribed, because the neg-g webbing would be integrated with the pos-g line set (or webbing, as chosen. See hereon a graphic toward this option:

EKSneggposgWebbingOptionAdjustableTautness.jpg (40.94 KiB) Viewed 781 times

[JoeF]

OneMeterForeRibBulkheadMockupRough001.jpg (86.28 KiB) Viewed 752 times

Shown rib/bulkhead measures in length: one meter.

Rough mockup of 1/2 in thick paper-covered foam board.

Final of such a part for a complex spar could be made in many ways. I will explore several ways. Aim will be low mass, low tote volume, and service to obtain a successful complex spar for a One-Meter Packed Hang Glider in hopes of becoming a member of that OMPHGC. As yet that club has no members.

There will be significant compressing between the rigid compression elements and the pos-g lines that will press on the rib/bulkhead in a region below where the rigid compression spanwise elements will seat. The region involved could be reinforced as needed while then more lightening could occur in other regions of the rib/bulkhead.

Two battens will insert into the rear vertical face of the rib/bulkhead. The battens will be at most one-meter in length.

[JoeF]

Above bulkhead will be put to sleep while a different option is developed. I was not happy with the tote bulk of the bulkheads. Instead there is development interest in a rib/bulkhead that focuses more on the complex spar's minimal needs followed by use of longer-two-part rib/battens and a LE tube or rod affair.

NextComplexSparOptionNov4of2022.jpg (57.53 KiB) Viewed 748 times

This part may tote stacked while the open spaces in the stack could receive other parts of the HG. Or the shown part could be spread about in a packing otherwizs, perhaps acting as part of pack walls.

The four spikes on the shown part will receive parts as follows: The two spikes on the left, say, will receive either the curved rod or curved tube forming a LE airfoil shape. The, right say, two projections will receive aft battens that meet at the TE of the wing.

The attached drawing shows a side view of the shown main black part; the black part is not very wide; thus the side view is represented as a simple line; that is, hidden changes are suppressed in the side view.

The final wing will probably have some false ribs, that is, having just a curved rod to shape the LE. Such fallse ribs will be rooted specially: into the neg-g webbing of the complex spar and into the complex-spar's pos-g lines/webbing.

The featured black part will have one at the keel station of the span. Then for tapering, two copies of each unique tapered part will provide one part for left wing and one part for right wing. Taper rate will depend on span station and decision of linear taper rate, circular taper rate, or elliptical taper rate; mapping such will depend on span and choice of number of stations receiving the part. False curve formers will be placed between the stations that have the hard rib/bulkhead parts that make up the complex spar.

The shown part shows tiny black nubs in the black rib/bulkhead at the bottom; those nubs are integrated in the main part to form a receptive and guiding home for the pos-g lines/webbing. We do not want the red pos-g lines to move from their stations beneath the black part's three integrated legs; those legs will be in firm compression to form the complex spar. We do not want the red long pos-g lines/webbing to move to other parts of the base of the black part, as those are weaker parts.

Wanted is a tapered set of the black parts; that is, the vertical length of the shown three legs are wanted to be most at center of wing and least at the rib/bulkheads near the wingtip. Thus, the resulting complex spar would have a resulting dihedral, but the top of the complex spar would be straight, perhaps some sweep (both will be explored in two different HGs).

NextComplexSparOptionNov4of2022Tapering.jpg (66.33 KiB) Viewed 748 times

[JoeF]

Further notes on following will show in some later post. Thanks.

OptionalComplexSparNeedsNotesNov5of2022.jpg (29.39 KiB) Viewed 741 times

This bulkhead is shorter than an earlier bulkhead for a complex spar.
The black curved item would be a full-span Mylar sheet or CFRP veneer or the like.
The large red is the bulkhead with an orange region of integrated or applied strut.
to receive the compression that will occur when the complex spar is loaded; the spanwise round cross-section compression members will be pressing down on the orange strut part of the bulkhead. The density of such bulkheads may be 10 or so per span, depending of the behavior of the airfoil-forming LE wrap.
The green line has buttons at each end; the green line will play in holding the airfoil shell section in place; there will be no need for hook-and-loop because of the buttoned line deal.
The pos-g lines/webbing will rest and stay in a short valley in the bottom edge of the bulkhead.
The neg-g webbing on top of the spanwise compression member tubes will be hook-and-looped sparsely to the top of the compression member spanwise tubes..
The keel bulkhead will be the tallest; the bulkhead most near wingtip will be the shortest vertically. There will be taper from keel to wingtip in the thickness of the airfoil and tallness of the bulkheads/airfoil formers.
The sail is not indicated in the drawing.
The aft battens for DS are not indicated.
There is an intention to coil the LE shell material for tote. The region inside and outside the coil may be used in pack for storing other parts of the One Meter Packed Hang Glider.

[JoeF]

[JoeF]

Today the new count of 8 billion live persons on Earth
may look forward to the possibility of riding city and rural buses
with a HG that is packed in about 1ftx1ftx1m pack.

1mx1ftx1ftHGpack.jpg (15.84 KiB) Viewed 702 times