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By TjW
#378901
You could always build a Whitney Porta-wing.
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By Fred Wilson
#378905
The entire range of FexAmerica Hang Gliders in current production are all Short Pack.
http://www.fexamerica.com/

All European manufacturers produce short pack gliders.

Search for Short Pack here on the .org and you will see 100 + previous posts on this topic.
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By Cool Breeze
#378916
Why not telescoping leading edge and keel? Seems like you don't need the same diameter leading edge towards the tips.
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By TjW
#378922
joefaust wrote:That ever remains an option, especially with mods for reflex or "high-hat for pitch control." What are other options?
=========================================================

Another returning theme: solutions involving positive inflation of frame members. Specialized encased air beams?

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

Offered toward the essence of this topic is the following page for potential careful study and meditation:
"Sunday, June 8, 2008
Weekend Wings #20: Inflatable Aircraft"
http://bayourenaissanceman.blogspot.com ... craft.html

I spent most of the summer of 1976 working on an inflatable hang glider for Jim Bede.
This was not the helium-filled wing. I saw pictures of it then, and there are pictures on the internet now, but I never saw that in person.
The wing I worked with was a low-pressure energy structure, in the sense that you could maintain the structure as long as you had battery for the fan to pressurize it. It was a very low pressure system, so leaks were not really an issue. Think of a bounce house in the form of a Marske plank wing as a hang glider, and you wouldn't be far off.
It used a rudder with lines to the swing seat to turn, something like a Quicksilver.

It was easy to set up in the hangar -- unroll it, attach the control bar and power up the fan.
In the field, on a training hill, with wind and rocks, it wasn't so simple. When partially inflated, it would try to beat itself to death on the rocks.

It weighed in at about 75 pounds, and would fit in the trunk of a passenger car, though it was probably a little bulkier than a paraglider because the cloth was a lot stiffer.

Unfortunately, there was a sink rate -- don't remember exact values, it was fairly high but in the realm of values I'd actually experienced in other hang gliders -- at which the fan couldn't maintain the differential pressure to keep the wings stiff. I imagined sinking, the structure getting floppy, increasing the sink rate, which would increase the floppiness... so I only ever flew it on a small hill.

But it was an interesting experience, overall.

My takeaway from that is that if the pressure is high enough that atmospheric pressure is a negligible variable, then sealing and leaks are a critical problem. If the pressure is low enough that leaks are not really a problem, then rapid descents become a problem.
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By raquo
#378927
Hey, thanks for bringing up my favourite HG design topic!

Hang gliders can certainly be made packable to 5 ft even with current technology. Two easy steps:

1) Take any *fex glider (packs to 6 ft), or a bowsprit glider like Bautek Astir (packs to 9 ft)
2) Divide the tubes into more pieces so that the longest one is 5 ft. Use exactly the same joints as in the original design, just more of them because there are more pieces now. They're very lightweight, it's not a real problem.

The real technological limitation is devising an easy and quick way to set up and breakdown from such a short length. The most intriguing approaches I've seen so far: Longbow, Delka, Brett's tensioned-spar designs, Sock hang glider (search this forum).

The company "Prospective Concepts" in Switzerland probably knows more than anyone else about inflatable wing structures. They've built quite a few prototypes with this idea including a Pneumagic hang glider: http://www.prospective-concepts.ch/html ... magic.html They are now focused on some sort of wing-shaped blimp project, so don't expect them to release the inflatable hang glider.

Inflatable designs look theoretically possible, but must be extremely hard to design and manufacture. With no established manufacturers exploring that option, I don't see a lone genius tackling that problem in the nearby future (prove me wrong, guys! Please!).

Rigid wings on the other hand should be much easier to design and to make portable – 90% of what you need to do is to design a strong enough modular spar. I'm not sure whether carbon D-tubes are amenable to this approach, but something like the aluminum framed spar of the Sock glider can be cut up pretty easily I think. There's a pic here: http://www.hanggliding.org/viewtopic.php?t=32471
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By Flyingseb
#378932
I'm surprised that nobody mentioned the Woopy Fly. It has been designed by the same guy who designed the Delka, with a clear target at security.
See the skier's bag? That's his Woopy!

[youtube]http://www.youtube.com/watch?v=_auMLt0RZwg[/youtube]
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By TjW
#378946
joefaust wrote:TjW,
Thanks for any and all your recall on your experiences in the Bede realm!

Fabric, pressure-keeping valves, over-pressure valves, pumps, porosities, ...worth continued explorations.
=================================================
Just to reiterate: that wasn't the wing I worked on. I saw pictures of it on the Newton airport runway, but I never saw that one myself.

It would have been either horrendously expensive to fly, or extremely slow to deflate, I think. How much helium to inflate? How long to compress it all back into a cylinder?

Still, I have to admit it solves the problem of collapsing paragliders pretty neatly.
One of my first thoughts on seeing paragliders collapsing lo those many years ago was a spar made of a Kevlar sock with a urethane liner. The idea was to keep it fairly small volume, so that it could be inflated to fairly high pressure with a CO2 cartridge. It would run tip to tip, so that while you might lose ram air pressurization and the normal airfoil shape, it would be less likely to wind up as a wad of fabric after encountering turbulence.
By old newbie
#378960
TjW wrote:
joefaust wrote:TjW,
Thanks for any and all your recall on your experiences in the Bede realm!

Fabric, pressure-keeping valves, over-pressure valves, pumps, porosities, ...worth continued explorations.
=================================================
Just to reiterate: that wasn't the wing I worked on. I saw pictures of it on the Newton airport runway, but I never saw that one myself.

It would have been either horrendously expensive to fly, or extremely slow to deflate, I think. How much helium to inflate? How long to compress it all back into a cylinder?

Still, I have to admit it solves the problem of collapsing paragliders pretty neatly.
One of my first thoughts on seeing paragliders collapsing lo those many years ago was a spar made of a Kevlar sock with a urethane liner. The idea was to keep it fairly small volume, so that it could be inflated to fairly high pressure with a CO2 cartridge. It would run tip to tip, so that while you might lose ram air pressurization and the normal airfoil shape, it would be less likely to wind up as a wad of fabric after encountering turbulence.

Except the collapse is a good thing. I don't want a rigid wing on string 20' above my head
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By TjW
#378967
old newbie wrote:
TjW wrote:
joefaust wrote:TjW,
Thanks for any and all your recall on your experiences in the Bede realm!

Fabric, pressure-keeping valves, over-pressure valves, pumps, porosities, ...worth continued explorations.
=================================================
Just to reiterate: that wasn't the wing I worked on. I saw pictures of it on the Newton airport runway, but I never saw that one myself.

It would have been either horrendously expensive to fly, or extremely slow to deflate, I think. How much helium to inflate? How long to compress it all back into a cylinder?

Still, I have to admit it solves the problem of collapsing paragliders pretty neatly.
One of my first thoughts on seeing paragliders collapsing lo those many years ago was a spar made of a Kevlar sock with a urethane liner. The idea was to keep it fairly small volume, so that it could be inflated to fairly high pressure with a CO2 cartridge. It would run tip to tip, so that while you might lose ram air pressurization and the normal airfoil shape, it would be less likely to wind up as a wad of fabric after encountering turbulence.

Except the collapse is a good thing. I don't want a rigid wing on string 20' above my head
But it wouldn't be rigid. It would be a limp fabric wing that just happened to be sort of spring-loaded to extend to most of its span so that it can reinflate easily without tying itself in a knot.

It's not really worth arguing about, though.
Hang glider pilots mostly wouldn't be interested in anything that looks like a paraglider.
Paraglider pilots aren't interested in the idea because they seem to think it's safe enough already. "Active piloting" got quoted to me a lot.

I have to admit, this is the first time I've heard anyone maintain that a collapse is a good thing.
By old newbie
#378969
TjW wrote:
old newbie wrote:
TjW wrote: Just to reiterate: that wasn't the wing I worked on. I saw pictures of it on the Newton airport runway, but I never saw that one myself.

It would have been either horrendously expensive to fly, or extremely slow to deflate, I think. How much helium to inflate? How long to compress it all back into a cylinder?

Still, I have to admit it solves the problem of collapsing paragliders pretty neatly.
One of my first thoughts on seeing paragliders collapsing lo those many years ago was a spar made of a Kevlar sock with a urethane liner. The idea was to keep it fairly small volume, so that it could be inflated to fairly high pressure with a CO2 cartridge. It would run tip to tip, so that while you might lose ram air pressurization and the normal airfoil shape, it would be less likely to wind up as a wad of fabric after encountering turbulence.

Except the collapse is a good thing. I don't want a rigid wing on string 20' above my head
But it wouldn't be rigid. It would be a limp fabric wing that just happened to be sort of spring-loaded to extend to most of its span so that it can reinflate easily without tying itself in a knot.

It's not really worth arguing about, though.
Hang glider pilots mostly wouldn't be interested in anything that looks like a paraglider.
Paraglider pilots aren't interested in the idea because they seem to think it's safe enough already. "Active piloting" got quoted to me a lot.

I have to admit, this is the first time I've heard anyone maintain that a collapse is a good thing.
you have to think of the collapse as a fail safe for pitch control. Wing gets too far out in front of you it would continue to dive and you would get wrapped around the glider or land on top of it. We actually don't think they are safe enough and they have been evolving rapidly. Collapse resistance and how they behave when they collapse is a balancing act.
By old newbie
#378971
If your hang strap was 20 feet long you would tumble fairly regularly
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By raquo
#379058
Convenient sail connectors are key to making a truly portable glider I think (well, a non-inflatable one, anyway).

Joe, could you please elaborate a bit on "Rim cord in groove"? Not sure what it is.

I think one of the possible ways to connect two pieces of sail together is for them to connect at something rigid, for example a batten. Imagine a common HG sail with a batten pocket. Now, cut the batten pocket perpendicular to its length every... say... 20 centimeters. Don't touch the main sail. Now, cut the main sail right next to where the batten pocket attaches to it. First 20 cm cut on the left of it, next 20 cm cut on the right of it, then left again, then right again, and so on. In the end you'll end up with your sail cut in two pieces, with each piece having approx. 5 batten pockets each covering 20 cm of the batten, but in combination covering all of it. Now if you insert the batten in these pockets it will be attached to both pieces of sail, and they will follow its profile. if you remove the batten you can roll up and store the pieces of sail separately. Of course you would need to sew a new sail on this idea, not cut up an existing one – I figure a bunch of sail reinforcement would be required.

Damn, that's a lot of words, sorry. Here's a picture I drew, I hope this clears things up (see end of post).

So if you cut up your sail like this, you can have a few very manageable sections of sail that you can easily install on the wing one after another. Now you don't need to think of an elegant way to put a sail onto the glider frame, or to make the frame easily collapsible inside the sail.

Or you can use this technique to split the sail in two, right in the middle. An alternative way to achieve that would be to use something like corset ties – I think some rigid wings use something like this. Again, the holes could be positioned so that the rope goes around a batten on each side of the sail, to keep the wing profile.

Man, I wish zippers were reliable enough to use as sail connectors. I think some models are more than strong enough, it just seems like a not very reliable solution. Maybe with a backup rope and some innovative terminals (edges) that prevent accidental unzipping they could be reasonably reliable.
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By TjW
#379070
If you'd like a simpler way to describe it, just say "like a piano hinge with a removable pin."
By CLOUDSCULPTOR
#379138
Is 5 foot the clincher for you , or something else ?
All the aeros kingposted models go to 6 foot.
i used to regulary fy and antonov c 14 and then a stalker 12 at wallaby . building it up from short pack from air freight with no tools. Needed 60 mins.
I was told they designed then all short packed to allow storage in aptments and reteives by train or bus when few people had cars.
I loved it. Cheaper to repair tubes too.
For quite a while it was the only way they were sold .
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By raquo
#379154
Well one of the implicit constraints we're assuming here is to not need 30-60 minutes time to set up / break down the glider. That's just too much hassle.
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By skyelevator
#379398
Very good to see this come up now and then to let the few manufactures out there know that there IS a market and some of us would pay double (yes) for a truly hikeable hanglider. FEX just doesn't quite do it and although fine I am sure paying new costs for a late eighties design is kinda hard to swallow. But ya, they will build you one. Material science is advancing leaps and bounds with things like carbon nano tubes a reality right now, albeit in the lab. Keep seeing paraglider pilots boarding trams and such overseas or even at places in the states like Crystal Mountain. My hat is off though to the operators of the Wallowa Lake Tramway in NE Oregon, someday....
By old newbie
#379578
I have a 5 lb paraglider and harness, real small bag. If you really thing they plummet from the sky add a 5 lb reserve. I think your goal is a bit too lofty, just lighter simpler hangs would be great, no need to go down to 5'
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By RobertKesselring
#379675
I think it would be a mistake to try to design something that would replace our current hang glider designs with short pack versions of the same things. The reason for this is as follows...

1. Our current wings are highly engineered
2. Adding additional, desirable, design attributes to a highly engineered piece of equipment will require sacrifices in other attributes of the design. In other words, any design which adds short-pack-ability will sacrifice something else (set-up time, safety, handling, performance, cost, etc...)

By focusing only on short-packing options, and what other attributes we sacrifice for short-pack-ability, we might miss desirable attributes that some short pack designs might offer that current designs simply don't offer at all.

For example, an inflatable hang glider might not be desirable if it sacrifices too much in the way of performance, handling, and durability. However, if you make it so that it can be inflated within a couple seconds, by pulling a cord, while in free-fall, you've made a whole new hang-glider-like product which might attract some people away from wing-suite flying or skydiving. They don't care if it only glides 7:1. and handles like a truck. It does what wing suites do by opening in free fall but also offers land-ability without a parachute. It does what parachutes do, by providing for safe landing, but it actually flies and glides instead of just being a steerable air-brake.

This is just one example of functionality which may be added when implementing a fundamentally different design, and not really one I'm particularly trying to push. I'm just saying, lets look at any NEW functionality that new designs can add instead of simply trying to preserve the TRADITIONAL functionality with new designs (which I believe can only be done by substantially increasing cost).
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By raquo
#379682
Well for me portability is certainly new functionality in itself. Namely, it lets me to:

* store my hang glider in my apartment and live where I want, not in a house in the suburbs
* store it in a hotel room and thus take family vacations that are not exclusively about flying HG
* take my HG on a gondola that is too small for full-sized gliders
* travel by plane or train with my HG and then use a rental car without a dedicated HG rack to transport my glider
* get rides from people without HG racks

Let's spare the discussion on whether or not these are useful features. They are useful to me and many others.
Adding additional, desirable, design attributes to a highly engineered piece of equipment will require sacrifices in other attributes of the design. In other words, any design which adds short-pack-ability will sacrifice something else (set-up time, safety, handling, performance, cost, etc...)
This is only true if you add portability as a bolt-on to an existing design. If you come up with a completely new design it could be superior to existing ones in more than one way. For example, a portable non-cantilever rigid wing could be lighter and slower than current rigid wings, both of which could be seen as advantages.
By focusing only on short-packing options, and what other attributes we sacrifice for short-pack-ability, we might miss desirable attributes that some short pack designs might offer that current designs simply don't offer at all.
True, but we're talking about portability because we already feel the need for it. That's our goal in this thread. We could sure talk about other stuff too, but focus is good if you want to solve a specific problem.
By Fletcher
#379698
Anyone checked out

Extendclimb telescoping ladders
The pro series are constructed with aircraft grade aluminum

Unroll the sail, pull a string to telescope frame, pre-flight, hook in, fly
Telescoping rigid wing in the trunk of your car?
:drool: