I like the first version of the 'clamping pyramid' best. What would be the point of a larger pyramid. The larger the legs of the angle the more susceptible it will be to bending when the spar case pulls. An angle with shorter legs will be more weight efficient. I would swap the flat keders for round ropes. Only the front edge of the keder contributes to holding the edge of the spar case in place. A rope has the additional benefit of flexibility.
Without bolts, the angle of the second version will certainly come off as the bladder is pressurized. Yes, the bladder will press up. But without bolts, there is nothing that holds the angle down...
Kai, thanks for teaming on the challenges. Sorting options! When the rubber hits the road, eyes will open to resultants and probably tweaks and lessons. Last night my subconscious erupted on a possible advance over the most recent posted option of marrying the CE to the spar case. I describe this morning's option below:
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Legs will be shorter than drawn. Channel: 6061-T6 Keders bonded to spar case; if the one face is insufficient, then the spar case may wrap around the end of the keder strap and be bonded also to the other broad flat face of the keder. Leave the case unbonded at one end of the keder, so hinging of the case may occur during pack; the keder strap will be wrappable during pack.
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=========================== A second run of CE, if wanted Note: Keders would not be needed, but tolerate the injury of holes in the spar case, as the screws would need passage through the case to the wood plug. Note: the plug need not be wood. If the plug is not wood, but say aluminum bar, then such mass would add compression resistance. Spar case motion longitudinally is resisted by screws and friction with the plug and channel.
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================================ Notes: = Reaching out for heat-treatment quote regarding 6061-0 to 606-T6. = I am not yet finding channel at wanted dimensions in the temper T6 for 6061. 48 in lenght, 1.25 in base, 0.5 in legs, thickness: 0.125 or 0.13 in and also 0.063 in = Ordered MicroJig Complete for table-saw safety while making wood plugs for CE-spar-case assembly. Tool will be part of other kite-making projects. = Notion: spreading thin plate to cover cavity if legs of channel spread too much to affect bladder behavior at the points .....
Where along the span of Wing5-M1 will compression elements do the most good? How much of that good is needed and where? The rigging of the splinted air beam spar makes a difference on such questions. How likely is buckling of the air beam and where is that likelihood?
One approach to finding answers (besides analytic high-powered programs which are not being used by me; others are welcome to use those tools) to the need questions is to make up the wing without any compression-resisting elements. Then load test the wing physically in full-life form; photograph the buckling; add compression-resisting segments to the spar case to resist what is seen on camera. Test again with some added splint. Then watch again for buckling; add CE sized segments as needed to stop the buckling; taper mass of the compression-resisting elements as needed.
What are some ways to add segments during such experimentation? Have ready various sizes and weights of compression-resisting elements. Have sewn to the spar case loop full span; and have hook ribbon on the various trial segments of compression-resisting element. Say, work with 36-in and 48-inch lengths. Whip hook ribbon to the trial elements. Slap-press the trial elements to the loop line where buckling occurs. If the hook leaps off the loop, then string tie the element to the spar case sending a stitch line through and under the loop ribbon and back up over the element; tie a knot; such keeps the element hugging the hook to the loop ribbon where separation occurred signaling buckling tendency. The result of such process will probably show a tapering of compression-resisting material; and in some sections of the span, it probably will occur that no compression-resistance material will be needed. Note: Run helical tension straps from the two ends of the experimental trial compression-resistance segments. Note: Deflation of the bladder will be needed to sew through for adding trial segments unless some strings are placed permanently along the loop ribbon for ready use when needed; do not tie the strings until separation of hook from loop occurs; the separation will be a ready indicator of sections needing compression-resisting element. Before beefing up a segment, tie strings at the center of the separation points.
Observing the buckling will tend to move the compression-element applique line from the 2 o'clock towards noon or towards 3 o'clock. A CELD single line is sought; an optimal position would care well for lift and drag buckling forces.
The described process will materially calculate minimum needs for compression-resistance. Then adding mass at need sections will beef up safety factor. Time for higher flights? The trial compression element segments may be with bamboo, wood, aluminum tubing, aluminum angle, aluminum channel, aluminum bar, fiber glass, carbon fiber, thin-wall steel broom sticks, or other materials. I do not want to embed more compression-element mass than is needed for safe flight for soft-S flights in mild conditions at Dockweiler. Upwards and onwards after that first level of flight becomes satisfactory.
That is, I am shying away from just installing full span a homogeneous compression assembly, as that will over-serve and bring weight that will not be necessary. The carryback grade for Wing5 iterations is important; part of carryback satisfaction involves weight. Starting with more than needed would hide the minimum needed.
So, soon: I will install a loop ribbon firmly to the spar case film along the 2'oclock line where 9 o'clock is the LE of the spar's cross section circle. In the install I will place a line segments every 4 inches that grab the spar case and the ribbon; the strings won't be used until a separation of a trial compression element is observed. The first next step would then be to tie down the trial compression element at the center of the separation; then test again. Use lighter segments first; then heavier as needed. Gradually install elements until buckling and separation of the hook-and-loop do not occur. Temporary string whipping of hook ribbon to test CE segments could save on hook-ribbon expense; as adhesive wears, consider double-sided tape to run many experiments.
Spar case with run of loop ribbon at 2 o'clock line. The tie strings might be used to snug trial hook-ribboned compression-element segments to the loop ribbon.
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--------------------------- Misc. Wing5 project notes: = More hook-and-loop is on its way for HG use. = A quality hot knife for synthetic fabrics and webbing cutting is on its way.
LA Best Metals gave a quote for 5 pieces of 6061-T6 channel. They found a cooperating supplier. Quote was satisfactory; but I told them that the matter is a no-go for now. I did my thinking on the side to reach my no-go decision: Here are the rough unedited side notes:
5 pcs for full spar compression. The coupling might be of bar. Buckling will occur at the joins, if not beefed up equivalently. The 4 ft will go over the rig points, at least. That is two. Maybe two for the keel: overlap and join with bolts for the keel for 8 ft less 6 inches for the join. Invert one so the legs stick out different directions. That leaves one unused piece of channel.
Am I fooling myself?
Compression member trials. Where will buckling occur?
The channel also closes the spar case. Allows bladder and spar case to be handled and be separate parts. The channel should be strong enough to hold the pull of the inflated spar case. And stop any buckling of the air beam spar.
What do I risk in the $212? I need to bus to get the parts; no problem. Or friend-lift with car.
The coupler outboard concerns me:
Weight of the 5 pieces? 2.5 x .125 x240= 75 in3 Density: 2.7 g/cm3 1230 cm3. 3320 g 7.5 pounds. With couples and wood and screws, this will go up to 10 pounds. Sail, ribs, keel, X, lines, loop, spar case, bladder Whew! getting toward????? Carbon fiber for less weight.
Optimizing CE needs by experiment. The channels seem oversolve to me. I want to explore the first air beam with hook and loop with materials on hand like thin steel tubes, wood, trash aluminum.
I've wanted "openable spar case" leading to closing such with a combined duty of compression element attachment. But the interest in experiments as described in prior post may lead to different solutions on closing the spar case: sewing, tying hemmed rods, zipper, etc. while using the compression-element finding as described in prior post. I do not want to have any more compression-resistant mass than needed for small safety margin; oversolving may bring more mass than needed or wanted.
============================= One spar-closing tactic option is the use of castellated hem edges where a pack-time-coilable rod goes full span-length in the castellated hems of two joining edges of the spar case; the rod takes the hoop tension of the inflated spar case. The rod plays also as a small airbeam buckling resisting member. Roughing the surface of the rod could "marry" the rod to the spar case longitudinally for low slippage during flight loading. Think of piano hinge and long hinge pin. But the "pin" or rod will be removable because of the hem size. Bladder poke out might be mitigated by an interior flap of stiff plastic film. A con on this is some distortion of the spar case.... some pucker from one castle to the opposite next castle. Another con is the threading the rod through the series of opposite-facing castles.
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Close cousin to the castellated hem is a two-rod method with simple hems. Each spar-case edge has a hem with a coilable rod in it. Then hand tie strings to firmly bring the rods to a kissing adjacency; the strings would hold the hoop tension of the inflated spar case. The rods would be separated from the spar case for packing; rods would be coilable or segmented and packed straight; overlap in hem would be need if segmentation is used; coils can be hazardous during packed tote. Holes in the edge filled with quick double hooks may be an option for the marriage of the rods. Again, the two rods would give some anti-buckling service. A plus here: no castles. Another plus: quick insertion of rods, especially if full-span rods (coiled pack). Con: Do the hooking or tying.
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The install of a zipper is an option. Con: install and potential of zipper malfunction needing zipper replacement cycle.
Alternative: give up trying to have openable spar; just close the spar by sewing or bonding or welding or fusing or double-skin overlapping with use of adhesives, etc. Con: cannot have easy access to the interior of the long spar case for works and bladder care. Just have wing-tip ends openable, maybe using short 24-in or so zippers. Adventures ahead!
The two rods can become active keder in keder-rail segments or be tied together, say every 5 inches with strong ties using, say a shoelace knot or the like: firm and releasable. Note: If the rod insert is to be segmented, then coupling would be needed, say four couplers to form the coupling of five segments. The rods need not be the compression element of the splinted air-beam spar, but could be, if tension straps become involved that grab two different stations along the rods or the like. Or compression elements may be developed as needed for integration with the spar case; such is the aim in early iterations of Wing5, that is, to explore adding compression elements for resisting air-beam buckling as discovered by flight loading explorations.
This tactic invites a loop spar case or "hem-by-default" where a tubular material is let be flat on the ground; two hems form; insert the coilable rods or forms into the hems; bring the two rods or the like next to each other; tie them together to resist spar opening at inflation. Spar case wing tips are closed to a flat line; that line sees four layers that may be perma-sewn to resist inflation. The case need not be air tight, as the bladder does the job of keeping the pressurized air.
Note: there is opportunity to slip into the double wall some shelling flats where useful; or pack one's lunch into the huge pocket. The flats might be carbon-fiber veneer. There is also the opportunity to easily change out the rods or tape segmented stiffeners at strategic places on the rods. Tie the two rods together before inflation and before attaching the mainsail to the spar case.
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If not the full double-wall, then form hems at the two edges of the spar-case:
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William A. Allen (a top early HG photographer) captured the two struts on both sides of master modeler Mark Smith's full-sized hang glider: =======================================
Wing5-M1, not yet built, notes, including about call from Jim Haddox, the BladderMan. Jim is scratching a quote for two bladders for me. I had contacted him in 2012 on some energy kite matters. I sent him specs for the bladders; easy does it; if I do not get his-made bladders by Sept. 21, 2021, then I will substitute less-satisfactory bladders. Jim's will be lower in mass than my unsatisfactory substitutes; no problem; glad to have Jim as part of the project. My tooling and materials are not yet competitive with outsourcing the bladders. Four pages of notes from last two hours:
Some parts did not appear in my summary on those two pages imaged above, notes of the last two hours: rib struts note that ribs and keel will each be of two parts Means of adjusting tension on rigging lines Legend: RR :: Rigging Ring; HH : High Hat ; RRL :left RR, RRR: right RR, drawing probably has such reverse sided. TW : tumble wing{s} Bladder might stay in spar case, if I can keep sand out of the spar case for packing-tote. Hang loop was mentioned, but not shown in sketch. ========================= Crew was not mentioned, but crew is essential for safety and experiments ... tie strings sketch of "lines" does not show full count of lines Will need a CE segment on top center of inflated spar to suffer faced loads and prevent excessive deformation/buckling of the inflated spar.
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Wing5-M1 progress notes: Paid Jim for two custom bladders from Florida. Each will have three dump valves and one inflate valve. He thought three dump valves was oversolve, but I kept them in the specification; at pack I do not want extra volume. Hoop circumference of bladder: 48" and lay-flat: 24". Spar case will lay-flat at 23" or less with hoop circumference of 46" or less; the bladder will remain larger than the spar case. Bladder will not stretch, but only its wall will be compressed during inflation.
The investment above had me rethink my former decision of keeping a long openable spar case. The Dockweiler sand, the roughness to the quality thin-walled bladder, the chance of have some "blow-out" along a longitudinal openable arrangement, the time to assemble and disassemble an openable spar case... are items that have hit me. It now looks like the spar case will be perma-closed; leave the bladder inside; the spar-bladder will be immediately ready for inflation upon simple unpacking. When bladder needs repair or the spar case needs repair or work, then an end of the spar case will be openable by de-bolting which will let one take the bladder out; then the spar case could be inverted or not for work.
Now, focus can be on special opportunities upon the decision to keep the spar case closed and the bladder perma-encased. Pucker pockets, added pockets, pucker ridges ... are items that could be explored for the spar case. With adhesives, hand sewing, welding (depending on case material), taping... hook-n-loop (HnL) ribbon parts may be mounted originally or after sealing away the bladder inside. Less time assembling and packing == more time for flying.
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Arrangements on the exterior of the spar case will serve sail rooting, rib-strut rooting, rigging-ring (RR) connecting, and compression-element mounting.
With the decision, other options may be explored.
Last edited by JoeF on Sun Sep 05, 2021 4:46 pm, edited 1 time in total.
Wing5-M1 will not be complete until certain tests have been accomplished. So, an all-up HG flight date with a completed HG Wing5-M1 will not be as first noted. Rather tests of certain kinds will be on subassemblies at Dockweiler on Sept 21, 2021, weather permitting.
TEST OBJECTIVES FOR SEPT. 21: HH subassembly: With four sandbags buried: KP and four out lines to the sand. Mount two counter-rotating tumble wings on side lines; one wing on left, one wing on right. The windward lines mimic the keel; the Earth will be the keel and the Earth will be the trailing edge. Observations of the HH TWs will be made. Feeling experience will be had. Touching the lines during wind operation will instruct. Each wing will stay in position on its axle line by use of a line stop, a loose bead bearing, and then a bearing installing in the wing itself. The loose bead will allow easy rotation of the TW. Observe constancy of motion; observe by touch the tension on the wing holding line, observe by touch and pull the tension on the line that goes windward (keel mimic). =====================
Bus pack will be practiced. I will take city buses and do the hike. Real bladdered spar case and real unfinished sail will be wrapped around some stick-like parts and taken on the bus. Two or three or four wheels will be at the ready for hiking the pack. There will be in the pack enough items to mimic the full-completed HG without it actually being completed. The pump will be in the tote; hose and nozzles. Tapes. RR, CE segments variety, rib-mimics variety, keel mimic two parts, line sets, lines for experiments, cell phone, helmet, goggles, clothing, food, water, sunscreen,
Play sailing the tip-ribbed sail separate from all other parts: The mainsail without mid-sail rib pockets, but just with sail-tip hems, but with hook ribbon applied to sail LE, will be with crew help play sailed manually. At some moment, it is hoped that two pilots at once will play-sail hang glide for a couple of feet. The 6.5'' x 20' sail with tip ribs in the hems of tip edges of the sail will be two-hand held by each of the two pilots. Each pilot will keep angle of attack of his or her tip rib to effect the playing and mini jump glides.
The spar separate from all other parts will be used in various experiments. Packing and unpacking the spar. Inflating the spar's bladder; opening and closing the dump valves. Using the pump, nozzles, and hose to pump up the spar. Try various pressures in the experiments. Two-pilot holding the spar in the wind at various inflate pressures; watch buckling. Run into the wind broadside at various inflated pressures. Toss the 20 ft inflated spar. Roll the spar. At say 70% inflation, fold the spar in half and tie the two tips together to form a 10-ft sofa; rest in the hold of the folded semi-inflated spar. Rotate the spar broadside into the wind and get a Magnus-effect tossed unmanned glider flight; observed the dynamics of the gliding spar at various pressures. Applique some CEs to the surface of the spar for more toss and run and glide experiments; observe changes in the dynamics of the reinforced heavier inflated spar: two-pilot run, free-toss rotational unmanned glider. Etc.
Marry the sail to the inflated spar; have the tip ribs in sail and tied to the spar tip. Then experiment with the arrangement (no keel, no KP, no TCF (triangle control frame). Stay-line kite the arrangement. Sand-bag a bridle set for the TE of the sail. Rig two-line bridle to stay and kite the spar. Anchor the TE lines, anchor the two-to-one Y LE bridle, have two pilots man tip yaw-assist line. Kite the spar-with-sail in such stayed/guyed format. Hopefully there will be wind enough to kite the arrangement. no mid-ribs, no rib struts, observe spar buckling. Add CE segments first near where the Y front bridle operates. Check bladder pressures. Kite with the CEs added. Make notes. Feel it all.
Go fly the Condor 225.
Pack up wings. Pack up the IncompleteMimicWing5-M1 parts into tote configuration. Be thankful for crew and day of experiments.
With lessons continuing in following weeks and months and years, advance the 5-ft-or-less-packed-HG Movement until a firm new sector of the sport of hang gliding blossoms. At some tipping point: extant manufacturers or new entrepreneurs of kite wings, kitesurfing wings inflatables, hang gliders, are predicted to come into the new hang gliding sectors strongly and firmly. The new sector will be characterized by not having to use cars or trucks, but using easy city-buses to transport to hiking spots a hang glider. The packs will be non-offensive to the public, will be easily placed in car back seats (hitch-hike?), will hike easily, will provide an inflated camping-sleeping tent and sofa, will provide a water rafter, will provide a water-sailing craft. And in maturity, a system of during-flight spar inflation constant-pressure keeping for changes of altitude, changes in air temperature, and changes in flight requirements. At first: Dockweiler-only wings; but then wings that will be fit for flying thermals. I am sensing 4-ft packs and even 3-ft packs. Others may see 2-ft packs.
So, Wing5-M1 will have to wait to be flown at a date maybe in October or so. Full gliding pitch stability must be accomplished before serious glides are made. Some 150-lb of sand in bag collection as pilot will be tossed for test glide hanging from wing in October, hopefully. Safe-Splat (best: no splat) will be reviewed for possible inclusion in flight testing.
========================== M-1 spar can mimic the following, but be longer, not 6 ft but 10 ft long:
============================ The two coming bladders may be used to make two spars, each 20-ft. length. That teases several things: Put two inflated spars side-by-side, perhaps hoop-tied at about 6 ft intervals: provide sleep sofa for three crew. ___o ___o ____o zzzzzzzzzzzzzzzzzzzzzzzzz Or think towards using the two bladders in Wing5 iterations that use left and right spars: each spar from 12-ft long to 20-ft long. That would give options of HG span of 24-ft span up to 40-ft span. A long bladder of 20.7 ft long could supply inner bladdering for shorter spar cases, like 12-ft, 14-ft, etc. up to 20-ft span. ==================================== Thanks, Kai. Sure way not to fly: don't "Go!" Or positively said: "Go! .... gives a possibility of flight or crash." Support tease:
Home
for teaming on the challenges. Sorting options! When the rubber hits the road, eyes will open to resultants and probably tweaks and lessons. 
rib struts
The investment above had me rethink my former decision of keeping a long openable spar case. The Dockweiler sand, the roughness to the quality thin-walled bladder, the chance of have some "blow-out" along a longitudinal openable arrangement, the time to assemble and disassemble an openable spar case... are items that have hit me. It now looks like the spar case will be perma-closed; leave the bladder inside; the spar-bladder will be immediately ready for inflation upon simple unpacking. When bladder needs repair or the spar case needs repair or work, then an end of the spar case will be openable by de-bolting which will let one take the bladder out; then the spar case could be inverted or not for work. 
