The future of hang glider development
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- čas přidán 22. 08. 2024
- To get to a really new design of hang glider needs needs new methods and new tools. Please support me in developing these through my new Patreon page here:
/ hgdev
The repository of the design and analysis tools so far is here:
gitlab.com/HG-dev
Hang glider design has come on massively over the years, however the last major advance was now over a quarter of a century ago with the first topless gliders in the late 1990s. Since then although there's been clear improvements in hang glider design, these are incremental and now in a zero sum, trading off performance against handling.
To get to a really new design needs new methods and new tools, I'm aiming to use these to develop a truly new 7th generation glider.
This is the first of what will be a series of more technical videos describing the design process.
Thank you for additional video footage to (in order of appearance), Joyce and Tony Swait, Pete Attley and BBC Look North. Thank you for technical work (so far!) to Jonathan Howes, Julian Todd, Richard Hunt, Jeremy Soper and Sean CT.
![Flying 100 miles by hang-glider over the tallest mountains of California [Narrated]](/img/n.gif)
I started flying in 1978. I trained on a Seagull Seahawk. The first glider I owned was a UP condor. I got to fly the Comet in 1981 and it blew me away. It is amazing how much progress in design there has been since I became a pilot in the aerodynamics, frame structure, and materials. I really don't know if there will be a "7th generation" hang glider design, but I hope there is. If you look at the history of sailplane design over the years, the biggest gains have been made by using composite material, and increasing the aspect ratio. Hang gliders have taken a similar path. The ETA is said to be the highest performing sailplane in the world. It has a wingspan of 101 ft 5 in, a wing area of 200 sq feet, and an aspect ratio of 51.3! It boast a L/D of 70:1, with a minimum sink of around 80 ft/min. I just threw that in because it is truly amazing.
I think the biggest obstacle to greatly improving hang glider performance is also what also makes our sport so special, that being able to foot launch and land. The physical constraints of our own bodies are at the heart of the problem. We can only lift so much weight and still have the ability to reach launching airspeeds. and then there's a similar constraint when we land. Rigid wing gliders like the ATOS may be about the best we can get performance wise, and still be able to foot launch and land.
One lesson we may be able to learn from nature is found in the albatross. This bird has the highest soaring performance in nature with a L/D of around 22:1. Nature has had millions of years to perfect this soaring bird, and the ATOS closely matches its performance. If you've ever seen videos of albatrosses launching or landing in light wind conditions, they have great difficulty pulling it off, and sometimes whack just like us. As a side note I found out recently, the albatross uses the dynamic soaring technique to remain airborne over the open ocean for days and sometimes weeks without ever landing. There are some great videos of them using this technique here on CZcams if you have never seen it.
So I guess my point is that if an order of magnitude in soaring performance is what you're looking for, it may be that the only way to have it is to fly sailplanes. They don't suffer the constraints imposed by our physical abilities, but you'll be losing what I think makes our sport special, that is the ability to run down a slope and get airborne under our own steam and then soar like an eagle.
Thanks for this. Albatrosses are particularly impressive given that they are still (compared to a hang glider) relatively small. The lower Reynolds number means that getting 22:1 L/D is even more impressive. If you scaled one up to hang glider wingspan it would be considerably higher, scale it up to sailplane size (and ballast to get the speed) and it would be getting close to those sailplane numbers you quoted. We do think there's gains to be got though. Flexwings have a pretty poor spanwise load distribution, fixing that adds a fair bit. Combined with a modest increase in span and the ideas we have to keep the handling good at the increased span and we'll have something very good indeed.
I just had an evening boating around in a low-hours Will Wing Sport 2. The glider was just flawless. Every turn, dive, stall, mush, spiral, climb out, thermal, launch, landing, all done easily and predictably with confidence. I guess what I’m saying is that, to me, that level of refinement in handling, stability and (relative) performance is just extraordinary. Maybe the materials used could be improved but honestly, in terms of transportation, cost and setup time, it’s just hard to beat for what it is! That’s why I’m truly interested to see what you have up your sleeve Tim. Best of luck.
I was heavily involved in Hang Gliding for decades. Design basically stalled late 90s early 2000s. At that time, we were working to solve the 2 major problems to move to the next level. 1) The pilot is now the biggest percentage of the drag in the lift/drag hang glider equation. 2) As a "twisted wing" all chord lines are at a different angle of attack. The entire wing is never producing lift while still producing drag.
Solution one. Find a way to not only streamline the pilot/harness, but also find a way to make the pilot centerline be at "0" angle of attack (match the current glide slope) when gliding to greatly reduce drag, and even shape the harness to be a "lifting body" on a glide.
Solution 2, removing a lot of (all) wing twist while maintaining handling, stability, and avoiding harsh stall/spin characteristics. Also reduce overall weight and complexity.
Those are problems, but it seems like they're not being addressed by designers. Things have basically stalled for decades.
Good luck. Hopefully you are the "Guy" that promotes the sport to the next level.
issue1: To reduce drag, why don't we incorporate the driver into the wings and let autopilot do the rest?
It's supposed to be a "Hang" glider, remember?
@@pubu2010 I'm not referring to the sport itself but rather to the engineering aspects of an issue and a solutions. Just as sports like polo; football; cycling and sailing... have embraced technology to enhance competitiveness, "hang" gliding will similarly benefit from technological advancements while preserving its core essence and it"s name
Its not comfortable to fly with your feet above your head. The fix is to design a harness and control frame that's designed for supine style and use it with a comp PG style harness.
OK. Harness design. First resolve the issue of functionality both prone and upright. The pilot should rotate around the "hip" area instead of any attachment on the "back" when coming upright for landing. It should also happen with very little effort. The pilot should also not settle down into the leg loops appreciably either. Harness that allow the pilot to descend or drop lower when going upright, and even worse, attach only to the back and take any effort to stay truly upright are terrible for landing. They make everything harder and almost every harness ever made has this problem. There is a simple solution.
Next, when prone, a simple foot-actuated system can set the angle of the pilot. Lots of harnesses do this. Some way to know when the glide slope is matched is the necessity for greatly reduced drag. Also, everything should be included into the harness. Radio, glider bag, oxygen, smoke bombs, etc etc. Another note: the curve of the small of the back is a great location for the parachute. Not the chest and certainly not either side of the pilot.
Second, the pilots centerline needs to match the glide-slope (head low) only when gliding between thermals. It's not so important when climbing.
You deserverve the recognition of all the hang gliding community, for being a piece of resistance and still looking for big developments. Thank you. I believe in you and hope to own such a wing in the future. I'll do my best to support.
There are almost a score of hang glider manufacturers around the world.
Here in the United States, everyone flies 4 brands - Wills Wing, North Wing, Icaro2000 and Moyes.
The biggest reason we don't fly other gliders is because other brands are so hard to acquire.
I'd love to see an Avian, Finsterwalder or LaMouette, but in terms of distribution, those brands just never seem to make it here. I think "the future of hang gliding development" really needs all manufactures around the world to improve their marketing/distribution and make it easier to purchase their products.
Manufacturers are *the most important facet* of our sport. Without you good folks *making* the aircraft, pilots have nothing to fly. So, I hope all manufacturers can improve their marketing and distribution. After all, you can design the greatest hang glider ever made, but without great marketing and distribution, you won't sell any.
Tim, I love your ambition and effort on this. I think it's really cool. And I love the history aspect of this video. You taught me a few things I never knew.
A bunch of people here in the US fly one of the gliders from ATOS
You could just order from Finsterwalder directly, their gliders are easy to ship to your door, being packable to 2m.
Unfortunately, as far as I know, their sailmaker has retired last year, and they don't make hang gliders anymore. (EDIT: apologies, it looks like I was wrong, and they're still making gliders - see response below)
I disagree that manufacturers are the most important at this point. It is the *instructors* and their ability to *bring new people into the sport* that will drive production. Real hang gliding enthusiasts should be looking to teach! I'm doing just that. We will always have wings to fly, dacron ones last so long that I already own enough wings to fly until I die. But I want more friends flying by my side, and next generation wings too. We need more people, more numbers, more sales.
@@nikita.gazarov I emailed Finsterwalder and received a reply from Sandra Göhl and Martin Fischer who both assured me, Finsterwalder is still building hang gliders. They informed me the employee who retired worked in the office and was not a sailmaker.
@@HangGlidingFlightSchool Oh, really, that's great! Sorry for bad info :( My information was from Mike Golder, by email on 2023-02-27: "it does not look like we shall have a follow up to our old sail maker. She is presently making up half a dozen or so sails for us, but after these have been sold we shall only be providing the hardware (components), for our gliders."
I guess it's another point to your argument that hang glider manufacturers need better marketing. Their FB page is all PG, helmets, and carabiners, the last time they posted one of their hang gliders was in 2022. Same for their youtube channel.
The future of hanggliding is a finsterwalder like frame and portability and the performance and attention to details from Icaro2000 sails. Put them together with ever lighter materials and you have the Hangglider of the future that we all want. Despite old, I would never change my super practical and portable Finsterwalder Airfex to any hangglider on this planet that doesn't pack without tools down to 1.8m. The Finsterwalders are a marvel of German engineering, it only needs a sail update.
I've been working on the fundamental concepts for a seventh generation wing within Tim's group.
Many people have stated that slightly less performance plus nice handling and lower weight with nice details is the way ahead. It really isn't. Here is why:
These discussions usually come from a perspective of attempting to give paraglider-like convenience with hg-like stability and control in turbulence. The market for this is tiny as it's barely different from what is available right now, and is not sifficiently attractive to offer most pilots an appreciable gain, in any respect, over a typical B category paraglider.
What should the objective be? Occasionally an aircraft appears that is so good that it renders everything else second rate. To do this it needs handling and performance with maximum livability. The jump that we are working towards has the potential to give performance exceeding that of current competition wings, with (ultimately) lower weight than most current Class 1 (flexwings), much simpler and less demanding landing characteristics, higher agility and lower control forces along with better built-in turn coordination.
It isn't simple as it's a strongly coupled aerodynamic/structural optimisation (I've been developing computer design codes for this).
It does not have to be built only for top performance. A perfectly reasonable variant woukd have more wing area, a very low landing soeed and still have similar, or better glide performance than current topless wings, although at lower speeds.
This is a new family of wings, not simply a tweak on the status quo.
so not true LaurenMartins! I don't know which modern gliders you have flown, but the Finsterwalder is years beyond when it comes to handling compared to modern intermediates like Wills Wing, Aeros, Bautek,... To me it seems you just got used to this old glider and do not have much comparison.
Anyway, what most Pilots want is light gliders with good handling and performance. Almost nobody talks about short-pack-gliders, as it either adds extra time to set up or handling/performance suffers.
I have not flown the Airfex, but the LIghtfex is terrible in my opionion.
@@HowesAeroyour nonsensical self serving performance at all costs ideas has been killing hanggliding for the last 30 years and you still want to continue down this path and expect different results. We are begging for lighter more portable Hanggliders.
@LaurenMartins You clearly did not fully read my comment. "Performance at all costs" is the exact opposite of what we are working on.
As for simply copying Finsterwalder but with better detail engineering, that is for Finsterwalder to do if they see a market. Simply copying their work would be disreputable behaviour.
@@HowesAero when you have a finsterwalder you will see how perfect it is. There is no other way.
Great to know that there are still good keeps of the flame. In my 52 years of hang gliding (mostly in New England) and still at it, I feel so privileged to be apart of these communities of flyers through the early decades. I think there’s one area of the flex wing design and refinement that’s been overlooked some and that of wing tip the vortex drag flow reduction. Think raptor wing tip vortex feathers as they create multiple smaller vortexes creating lesser overall drag then one big air swirl. I’ve toyed with the thought of adding three off set shallow flow fences to the upper tip panels to reduce drag at higher speeds. We know some heavy high speed trike wings utilize small tabs to help with boundary control.
As a fellow aerospace engineer I suggest the following:
- woopy-fly-style design for a well defined, super light weight aero shape
- seated flying position allowing the use of cheap and light weight PG harnesses + makes landing easier
- better means of control than just weight shifting (e.g. flaps, spoilers, wingtwist...)
- since this then is a novel vehicle: try to argue the regulator out of the stupid negativ g requirements.
Not only does hang glider design need a kick in the pants. But also its promotion among family units and groups that simply want to float a couple feet off the ground, on flat ground, or gentle bunny hill after receiving a great presentation on its history, aerodynamics, techniques and instruction. There are four threshold skills in hang gliding to get into the sport, and the first one can be done almost anywhere providing a source for other schools that can escalate into the other phases.
can you elaborate what those 4 threshold skills are and how can people taste flight just about anywhere? The easiest way I know for people to get their feet off the ground is a shallow dune, and not everywhere has them, or even a grass slope with a suitable landing in front of it.
@@ericoschmitt The last three do not apply. They do need either special natural resources or technology. The first threshold skill is following a line on the ground, with tight hang strap, keeping wings level in some wind. But, if one increases the wind even more, with a big enough glider, it will pick up the student and they'll get a thrill. If led to that point, after a good entertaining ground school, some analog and electronic simulators, these participants usually walk away happy with what they have experienced, and relieved that even their toddler children were involved. This is basically a part-time fun job program for gig workers, or even just people with weekends free.
@@user-xe4fm1sr7r that promotion idea is really nice, I actually did it with todlers who were spending the afternoon at the club with their teachers. I run the glider over grass with a bunch of 6 y.o :D
I still don't understand exactly what you are talking about regarding 'other 3 threshold skills' though....
The second threshold skill is flying straight and level in various wind conditions. This means there must be means of gaining elevation (tow, propulsion or a hill) that allows the student to attempt to fly straight and level and land either in run out landings or a full flare.
The third threshold skill is be able to turn left and right or vice versa to land on a designated landing line. There is some decision making involved because the landing line is changed slightly in repetitions.
The fourth threshold is the ability to decide whether to launch off a mountain, or get towed, or propelled to an altitude where when attempts to soar. But recognizes that attempt ia failing and still lands in the landing zone using all the approach set-up techniques to avoid hard perimeters, livestock, fences, powerlines, buildings, and water. They use the appropriate landing technique - either run-outs or flares or combination.
Great stuff Tim.
Looking forward to these.
I have always found flying wing fundamental's intimidatingly involved.
The brute force of a tail seems much more forgiving for some of us less skilled dreamer/designers.
Keep them coming, would love to see you break into new territory!
You are right about the fact that trying to control the twist at the outboard of the wing, and providing the necessary rigidity at this far outboard area, is a design non sens compared to putting a tail on an extended keel or accepting a mast and lufflines. But the appeal of a pure flying wing is magical, and it is where design meets art, in the sens that i understand the pursuit of such a pure form factor. Also, since twist is needed for stall prevention at low speeds, it is understandable that a twist based pitch stability method is tempting to chose.
I think the next gen hangglider will branch into various concepts and ideas, very hybrid in nature. I am still working of a few concepts and at one point i will be searching for avenues to implement my designs ideas.
@@dempart5558
"Implementing design ideas"
Implementing: That's the point where 99% of us dreamers get stuck... Either chasing diminishing returns in optimization or failing to accept uncomfortable compromises.
I managed to settle on a design (Powered three axis sub70kg) and actually started building that, more a science experiment to see if it could be done... On paper I can make the weight limitation but there is always a gap between calculation and reality so that remains to be seen.
Its performance will be no better than an average flex wing except in its control authority.
In the interim, I have built a Sub70 trike to get me back into the air... High speed taxiing and one crow hop in that so far.
I'll get back to the three axis once the trike is earning its keep :)
Great stuff Tim!. I remember when I flew a little in the late '70s, there were some of those designs you shown in the video. I remember the Fledgling with , I think they called them drag-aerlerons and a glider called Antares with no cross-tube, but a bowspirit extension of the keel and wires to hold the leading edges forward. I guess all these things are worth a try. I'm looking forward to more of these videos.
Bautek offered the Astir until recently and people praise the handling. The extra cables also create extra drag and kill the glide at anything above trim speed though.
I'm not familiar with the Astir. I'll check it out. Thanks!
Congrats for your work. A topless glider with bearings at the wing tips and some sort of FLAPS would be THE dream machine
Yet another aero guy here... I bought a WillsWing Raven 209 from Torrey Pines back in 82ish. Moved to Ohio got married and it all went by the wayside. I loved that glider, Urusla. When she was strapped onto my 200sx for transport it was quite the sight.
I am retired now and working on FreeCad in my spare time. While my dance card is full, I am sure I can get the right people if you have questions. I know one guy who just did his Master's aero/mech work solely in FreeCad for a wind turbine. (wind turbine sounds sexier than wind turbine). My work on FreeCad is in the CAM area. I have a 3 axis CNC in the basement that can easily do A6061-T6
Thank you, yes I'm using FreeCAD extensively, we plan to turn the sail making scripts into a full workbench, we'll get in touch if we get stuck. I've been using the Cfd-OF workbench to run OpenFOAM for verification, but we're using OpenVSP and VSPAERO as design tools.
Hg needs to compete with PG. Lighter, easier to carry...that would be the next generation...imo
Great work Tim and Avian! Hope you get loots of support for this project! 👏👏👏
as a long term HG pilot and now 15 yrs sailplane driver, there are some interesting areas of potential cross-pollenation to consider. Without going into detail I will simply list them here:
1 winglets
2 zig-zag spoiler strips
3 trailing edge aeriation to keep flow attached
4 water ballast
5 fencing. Windflow lines on your computer model did not indicate progressive spanwise flow.
6 variable anhedral
7 flaps
8 harness development, e.g. aerodynamic shape, ruddering, helmet fairing (moto gp)
9 ways of improving high speed polar
10 other ways fo controlling draggy washout (integrate with VG?)
Hope some of this triggers some ideas.
ATB B
@@beebee766 thanks, some of those are features of the design we're working on ;-) When you say 'zig zag spoiler strips' are you taking about turbulators? As in a small ridge to create a small turbulent boundary layer to resist large scale separation (these are often zig zag but don't have to be)? We already have those features on uprights and base bars and the stitching lines on the wing can act as such.
@@avianhanggliders1985 yes turbulator strips. zigzag to keep separation localised.
Also on winglets and top of fuselage.
I believe HG development may well point in the direction of improving the higher speed polars, ballasting, VG adjusting other things as well, more ways of keeping the flow attached.
With regards to induced drag, we had an acronym: TINFOS - There Is No substitute For Span. In an Open Class glider this was the case (my Nimbus has 26m span! 60:1 @ 57 knts, but poor handling) now the optimum is around 21m with a vast improvement in the high speed polar.
These new ships now have a heavier wing loading EMPTY of water ballast than I do FULL!
Still some big changes going on.....
BB
Good spirts! Maybe you could open a chapter in your project for packability to polite busability at low mass with moderate performance. We have given strong reference to your works in US Hawks forum in the topic: "The 5 ft-packed-HG Movement
Postby JoeF » Wed Jun 10, 2015 9:24 am" The pack aim is the treasured parameter, not super flight performance. It is anticipated the separation from dependence on cars, vans, trucks while allowing easy hiking and common use of city buses may bring on a new game for hang gliding. For some of us a "next-gen HG" will be one easily and politely carriable in the interior of a common city bus by the pilot.
I've been working on concept development with Tim. A really small pack wing has been discussed as the primary concept under consideration might facilitate it. First, we need to prove it out however.
As a windsurfer I would suggest you to look into construction of windsurfing sails. The mast is bent there, and it creates camber and quite rigid foil section. It does not need secondary beams. Film materials used for sails are smooth and light.
To make progress in any area of R&D I think it is virtually essential to draw as much wisdom and info as possible from parallel developments and existing technologies. It's often the only way to keep smaller projects cost-effective - or even viable!
Windsurfing and kitesurfing are hugely popular sports so are able to successfully bring new developments to fruition. They bear several similarities and practical considerations to hang gliding: They too need to be affordable, reliable, efficient, simple, light, etc. And yet be manageable for a wide range of operator skill levels. They operate at similar reynolds, need a good L/D but also needs to be able to be manoeuvrable and even perform tight turns.
Both windsurfing and kite surfing have taken big leaps forward in recent years. Some of this seems to have happened by developing new materials, but much seems to have come from thinking outside the box and getting a better understanding about (and accurate prediction of) the deformation of such materials under load.
Thank you pursuing innovation. Variable sail area would be great. More area for thermally and slow flight and “retract” extra sail into a high wing loading wind for great glides and performance. Move the pilot into the wing to further reduce drag. Just brainstorming. Keep up good work.
The bigest problem with hang gliding will always be Accessibility.
Thats why paragliding is booming.
I applaud your effort and hope you succeed. I'm not an engineer, but have lots of flying time in lots of different aircraft. Everything I've ever flown has been a product of compromise. Hang gliders are no exception (as many commentators have already said in one way or another). If you look at sailplane progress it has been mainly due to increased aspect ratios, refined airfoils and composite construction. Hang gliders have naturally limiting wing span dimensions for reasons of weight and transportation. In order to accommodate launch and landing on legs means slow speeds and therefore very light wing loading. This combination means low aspect ratios, so I don't see how its possible to get a significant increase in performance given these parameters. Unfortunately, if you want to carry a wing on top of your car and launch it by running down a hill, we will be stuck with L/D performance around the current numbers. I hope I'm wrong!
I really liked the person who commented on the virtues of the Sport 2. A simple, reliable, affordable and fun to fly glider (BTW, the three is even better!). The quest for more performance will most certainly entail a compromise in the simplicity and cost categories.
BUT.... I will quote an old proverb my boss used to have on hanging on his office wall. "Man who says it cannot be done should not stand in the way of the man doing it."
Best of luck!
Thank you! Although HG will never reach aspect ratio, in practice the current limiting factor is directional (roll and yaw) handling and control. We could build HG with more span that packed to the same length as current without significantly sacrificing rigging time or effort, you just wouldn't be able to steer the thing! So improving handling opens the door to more span. Atoses do this through using aerodynamic controls, but we have a different approach.
@@avianhanggliders1985
Your approach definitely seems on target, especially if you figure out how to get increased span length with portability.
I owned a T2C for a while and loved the flat glide and better speed range, but too often felt like a passenger and not the pilot. The glider was stiff and in strong conditions could be difficult to turn. For this reason, I was always cautious getting close to the ridge for fear of not being able to turn away. To my fault, I was on the light side of the wing loading which definitely impacts the controllability, so if I had gotten the smaller 136 I might still be flying it today. Wills seems to have made progress with bearing tips, but some sort of aerodynamic control would seem a better solution. Here again, complication, weight, and cost seem to be the conspirators fighting your success.
I hope you win!
Tim Swait appears to be at the forefront of flexwing design in the UK and Europe.
The quality of construction of his wings for sub-70 trikes is a cut above the rest
Good content, Sir. I wish there was a channel with much the same insight and detail, for paragliding! I can ‘watch-on’ and enjoy your work nevertheless 😃
I wait with baited breath for more vids.
Please keep working!
Another idea to reduce risks of life testing - use FPV drones technologies. You will need to build a 80-kg dummy with actuators imitating what a pilot is doing with hands and body, moving CoG back and forth, sides, and probably turns.
Seems the easiest path is to finally upgrade the airfoils used. The current crop have a very significant nose down pitching moment and hence require a lot of washout and that kills performance. Lots of better airfoils to choose from.
yeah, man. hang gliders ARE amazing!
The development of hang gliding, especially the single surface and intermediate hang gliders has stalled over the last decade or so. Advancing the sport with lighter equipment may appeal to more people as well as reducing drag and/or improving flight characteristics is the area that can possibly be improved on. Lighter equipment and handling characteristics might help us get a lot more people interested in this amazing sport especially for new novice and intermediate pilots. That is what we need to focus on to get people people's attention and then our HG numbers will increase. I really appreciate & admire what all hang gliding companies do, but I do hope we can evolve further and better.
I hope my comment here can help generate useful discussion, as a sample of one type of mentality and set of selective impressions that need to be solved/accommodated for such that hang gliding can be revitalized or even competitive with paragliding, as far as attracting new pilots. As follows:
For many years, I have wanted to select and train in either paragliding or hang gliding, as a cheap way of getting to personally fly and enjoy the sky with like-minded individuals. Every time I run the calculus for deciding whether to pick up hang gliding or paragliding (or both), it has always resulted in my deciding to wait and watch and to continue to admire. Both arts (paragliding and hang gliding) are frustrating to my aviator instincts and sensibilities, as I have been a private pilot (powered fixed-wing) since I was a teenager, and that as I design and fly unmanned systems for work/research, I see issues in both arts that dissuade me from investing effort in either.
I tend toward wanting to learn hang gliding over paragliding for the following reasons:
1. A (relatively) rigid wing that holds its shape, and it bends the air, not the other way around.
2. Negative G-loading capability (to a degree), as opposed to gift wrapping.
3. Higher wind penetration, better cross-country potential, better performance.
However, standing on its own, but also when comparing to paragliding, I have a few concerns about hang gliding that I wish to be resolved:
1. The weight-shift control method seems crude, even primitive. Shifting the static margin to produce pitching moments feels gross, and while weight left-or-right indeed produces rolling moments, does this not also produce adverse yaw? Why is shifting weight necessary? Why don't all hang gliders have elevons?
2. What is the actual control bandwidth? For a full deflection of weight left/right and fore/aft, what are the roll and pitch rates when stabilized in equilibrium? How does this compare to a typical paraglider? I want something that is highly controllable with high control bandwidth. I.e. what does a control full-deflection step response look like? What is the time constant?
3. How deep can I modulate the drag on the aircraft? What is the L/D between the clean cruise condition and the most draggy configuration? If this is too shallow, I feel this makes landing consistently more difficult and sensitive to dynamic conditions.
4. Paraglider portability is severely attractive; just the notion of being able to pack a complete flying machine into a bag and go hiking with it is very appealing. Setting up a hang glider seems to be well toward the other end of the logistical spectrum, very near that of sailplanes, with trailers and cars and gliderports and such. I might as well just work on saving toward owning a sailplane if hang gliding requires almost as much effort to set up for each flight? What is the cutting edge in hang glider design that can approach the paraglider-side of the logistical spectrum?
5. Adapting a hang glider for powered flight is almost neolithic, compared to the paramotor world. Are there any projects that mount a drive system to the hang glider itself rather than as a pod attached to the harness?
I really want to like hang gliding, but the practical side of me selects for paragliding. Deferring the decision to commit to either, I have in the meantime acquired a sailplane rating as an add-on to my private pilot rating. It is more expensive and difficult, but should I just stick to sailplanes? I want to find a cheap way to soar; is there a hang glider solution that would be appealing to me?
A lot of points there, but quick answers to them:
1. Actually, weight shift control is one of the real appeals from hang gliding. Moving your body to control the wing feels natural. Flying a hang glider is like riding a bike or a motorcycle compared to 3 axis aircraft which are more like driving a car
2. Control responsiveness is very good on the low performance wings, not so good on high performance ones. This is at the heart of why we are doing this project, to change that.
3. Not enough. You have VG, which does degrade the glide for landing, but if our developments work as well as we hope then we'll need an additional flap/airbrake/spoiler
4. PG are always going to win on convenience. A PG is better than an HG when it's on the ground, but an HG is better than a PG when it's in the air! That said the logistics for HG are much better than sailplane. No trailer needed, you can carry it around, foot launch it, you don't need an airfield, tug or winch. Rigging and derigging is pretty quick if you focus on it, generally I spend more time chatting that actually rigging though!
5. Actually HG is definitely better than PG when it comes to power. You can fly in a wider range of conditions and still go forwards and you need a car to transport a paramotor as with a powered HG or nanotrike. In the early days they did put the power units on the glider this is very dangerous, there were a number of accidents before it was found that attaching them to the pilot (or trike) was much better.
"I might as well just work on saving toward owning a sailplane if hang gliding requires almost as much effort to set up for each flight?"
For most of us, the main purpose of hang gliding is to have fun, not to have convenience.
You
You answered your question. get a sailplane. Most sailplane pilots are aging out of the sport. so there is a lot low end used planes out there. You can buy a used 25/1 L/D glider for $5000 dollars keep it tied down ready to go.
Adding to Tim's points:
1.Pitch control is even *too effective* in high aspect ratio wings to the point the Aeros Combat and the Air ATOS have added horizontal stabilizers. Roll control is quite light in intermediate gliders, and reasonable in high performance wings. With the VG loose they are quite decent IMO. Weight shift means directly feeling the air in your hands and body, that's a big appeal for me, not a disadvantage.
Further more, considering your interest in sailplanes, you will probably love what rigid wings have to offer (Air Atos). I've flown them and they are amazing, and have 'power steering' in the roll axis. Their glide ratio nowadays is reaching 21:1+ with optimized pod harness and position. They are ridiculously good.
3. Atos have flaps and even air brakes if you want. Flex wings can be landed using drogue chutes too, which will make the approach steeper.
4. You can't make them more portable than a Finsterwalder Funfex, but if you are into spending on a sailplane you could instead just teach someone how to rig your hang glider and pay him/her to do it for you while you drink coconut water at the launch, and then you also get a dedicated rescue driver. I've already met two guys who actually pay a monthly salary just to have another guy available whenever they want to fly! Plus quite a few others with varied kinds of arrangements in order to get a helper/rescue driver. You can always find a nice guy who drives uber who will happily take a 'day off' in the mountains if you cover his day wage and call the day before.
5. Pod engines are in fact the best solution, and quite safe. Some people have them with electric motors and enought batteries just to get enough height to then soar.
lighter sail material, non removable battens, telescopic folding under 2m, less than 15kg
The weight shift control system is what "makes" a hang glider.
That technology has gone as far as it can go; your proofs are the gliders of Felix Ruehle.
High performance designs are an engineering deadend and have contributed to the demise of the sport.
Hang gliding needs to focus on CREATING AND NURTURING NEW PILOTS with an emphasis on beginning and intermediate level designs.
The US hang gliding association has also worked very hard to kill the sport over the last 20 years.
Felix Rühles Atos does not use weight shift control...
@@jakobb598 um, sorry son, but it looks like you need a richer understanding of how pitch is controlled on all of Mr. Rühles gliders as it is done by weight shift.
Additionally the roll inputs on the ATOS require very similar control inputs to those that a hang glider pilot uses.
In fact the MAIN reason that he designed his spoileron actuation system to function the way that it does was so that hang glider pilots would have an easy transition to his rigid wing designs.
Right dad, pitch is still controlled by weight-shifting -> which is the best thing about HG if you ask me.
High aspect ratio rigid wings will, however, always struggle due to roll-damping. Flexwings can overcome this to a degree at the cost of suboptimal AoA at the tips.
What is needed to get both - good maneuverability + high AR - are more powerful steering means. Spoilers are good, wingtwist would work as well...
It's amazing that you're doing all this work with open source tools, and making your own stuff open source too! We need more of that in the world, I think. I would love to contribute at some point, as a programmer and an aviation enthusiast (although more of the sailplane kind) it is right up my street.
I've often imagined a hang glider where the pilot doesn't hang at all, but flies with the harness flush with the wing, either immediately below it, placed between the wings, or immediately above, in imitation of avian anatomy. The pilot would rotate around an axle from vertical launch position to horizontal flight position. Enabling roll and pitch control in such a configuration, I'm sure the engineers could work out.
That makes for a really interesting study. The surprising result is that separating the pilot from the wing prevents a "dip" in the spanwise loading where a fuselage/pod interacts directly with the wing. That dip in span loading carries a high cost in lift induced drag. Sailplane design minimises this with extremely careful shaping of the wing/fuselage junction and keeping the fuselage as slim as possible by comparison with the span. A pilot well below the wing avoids all that entirely and actually has a drag benefit because of this. Obviously that benefit is easily thrown away by having a poor design of pilot enclosure and some HG harnesses are terrible in that respect.
nice one Tim!
Love it!
Has anyone ever tried having a tail wing, which you can perhaps control with your feet? Watching seagulls fly you can see they twist their tail feathers sometimes.
Some very early designs had tail surface controls, I think they were either controlled by the hands or by the action of weight shifting though. I don't know any examples of using foot controls. Quite hard to make that work.
Would a CofG instrumentation might be useful to tell you how much off the CofG you are (on a 2d plane) ? Eg a circle with your CofG as a dot relative to the centre. I don’t know much about this sport but am interested.
The future is to get weight and bulk right down. blow-up frames would appear to be the only way though i imagine that you would need to find fabric weaves that have different tension and compression in one direction than others. Strain guages on the tubes can uncover that as well as simulation. In the field of vody armour they are experimenting with similar techniques
Inflatable frames can blow when you climb higher, that has been tried. Weight could still be greatly reduced with carbon in the way bicycle frames evolved: monocoque airfoil shaped tubes. We are still using round tubes for everything, except the Aeros Combat C using elliptical for the leading edge.
Inflatable is fine, you just need to chose the correct part. The wing spars are not suitable imo, since carbon is simply much much much stronger (telescoping tubes) -> one needs to utilize every material to its fullest to make it light. The rest of the wing where loads are spread out over the entire surface is better. High pressure inflatables are quiet heavy though (air tight rip-stop surface material with internal cells to make it safe etc.). - I did a calculation for a completely inflatable wing once using drop-stitch-fabric and couldnt get the weight below 34kg. For this reason I would use a low pressure inflatable structure (like PGs) that provides the aero. shape with one or two internal carbon telescoping wingspars.
@@jakobb598 For ram-air, then the lower surface could be inflatable, skipping the lower straight battens. Not that much saving though, and a bit more drag from at least one hole per side. Well, WW did try that with the RamAir, not great, but might be worth another try.
Wow, didnt know about the RamAir from WW, thanks for bringing it up!! I think the concept - while cool - didnt go far enough. Sail tension (upper) needs to come down dramatically as well to reduce loads on the structure. This can, however, hardly be achieved with current designs especially if you rely on VG to make you glider somewhat aerodynamic. I wouldnt be suprised if the final solution looks like a straight PG with a carbon wingspar and a few battens. Will see...
@@jakobb598 I think ram air could be useful for the under surface on intermediate performance gliders, so you get slightly lighter sail and no under surface battens. The thing is the internal fabric ribs as in a paraglider would get in the way of the crossbar when packing the glider. One way to overcome that is to use this idea on a single surface design that inflates a kammtail under surface ending just in front of the cross bar. If you look up single surface paragliders, their leading edge under surface ends abruptly, but the air flow stays laminar past that. Moreover, this could be made in a way to partially deflate in a higher angle of attack or slower speeds, keeping the gentle characteristics of the original single surface when landing. Ok, I went too far I guess.
looks great! i have some ideas for a next gen hangglider, but they're pretty revolutionary ;) any way i can contribute ?
Very interesting opener. I'm looking at getting into trike flying, so watch a lot of flexwing microlighting videos. I wonder what changes have been made to create the '9' wing. Are you able to access that data. I worked as a Weights Engineer on many new aircraft. I did notice tge new designs for components were few and far between and improvements were miniscule.
Thank you. If you're thinking of going sub-70 then please do check out our RioT. I can't really comment on other manufacturer's wing developments and no I don't have any data about the Nine.
Instead of trying to invent a 7th generation design , why not keep your current puma high preformance wing and experiment with adding spoilers its been done before on flexwings
(the sensor) with great success.
Remember, we're trying to improve both handling and performance. Spoilerons would certainly help handling (at the cost of weight, complexity and disqualification from Class 1 comps), but they do nothing for performance, in fact they reduce it rather. Of course you can get the performance back by increasing the span and using a lot of carbon to enforce the wing shape (as you no longer need it to flex for handling), but then you have an Atos. What we're looking at is a true flexwing but with a combination of features to make it both handle and perform better.
i cant watch this, it makes me want to hang glide again, TOO badly! Must....wait...til kids...grow up....their mom...is.....nuts....
Add not nosing over in turbulent air threatening (or executing) a tumble. There's really nothing like bouncing off your bottom surface fighting for control. And a market? Today a shadow of the enthusiasm from when I left in ~'97, the sport's decline already well evident to me. Hey, but good luck in your endeavor!
Maybe an H2 bladder inside the double surface area of the glider could decrease weight/increase performance? 🤔
What system do you use to collect your flight data?
may I join research & improvements?
I'm using Gitlab issues as a sort of forum, so write an introduction to yourself on this issue:
gitlab.com/HG-dev/aerodynamic-modelling/-/issues/2
I think the future of hanggliding is vertical take off and landing.
What is the round machine at 11:36?
Oh, that's just a Stargate I've been working on 😜
Actually it's a carbon braider. That isn't the Avian factory, the University of Sheffield Advanced Manufacturing Research Centre were doing the laser scanning for us, that's their factory. More about it here: czcams.com/video/jewVcNBaAFo/video.htmlsi=cwHQJP49Iv5ysXav
That is really neat!
Are you using a Prandtl span loaded wing?
By Prandtl, you mean the load distribution that gives minimu induced drag for a given bending structure mass as being plugged by Albion Bowers, also called "BSLD". Prandtl would not appreciate this mis-use of his work and the same Prandtl paper also presented the elliptical loading as the most efficient for a given span.
Minimum structural mass is not the same as minimum bending material mass as, particularly for a low wing loading aircraft, skin mass is a very significant portion of the overall structural mass. Using a BSLS would require more span for the same load and flight speed to achieve the same glide ratio as an elliptical loading. As adding span beyond a reasonable limit is highly undesirable for practical reasons, and elliptical distribution wins hands down for a practical aircraft. Adding winglets modifies the optimum and non-planar wing design is a subject all on its own (but is a lot of fun to develop).
@@HowesAero I am aware that Prandtl developed both span distributions based on two different design constraints, (1 fixed span or 2 wing root bending moment). As far as I am aware, the 2 concepts were developed & published some years apart, even if the elliptical solution was referenced in the 2nd paper. However, I have not seen an English language translation of the paper. So I don't know if that is the case or not. I have seen a German language copy of the paper which includes diagrams that indicate what is going on, though not being able to read the text, I don't have a detailed technical understanding of the maths. I can see that it gives a spanwise lift distribution similar to the bell shaped distribution employed by the Hortons in their flying wing designs to solve the adverse yaw reaction problem to aileron control. Of note, this allows a longer span to be carried for the same root bending moment also a reducing induced drag which the Horton designs are well known for.
Tiplets work by exploiting the tip vortex to rotate the reaction vector forward, the reaction vector can be viewed as a large inboard vector 90 deg to the free stream & a smaller forward vector that cancels some of the aircraft's total drag, making the design a little more efficient.
The Prandtl wing is in effect doing a similar thing, only the reaction vectors are now lift & thrust, rather than inboard & thrust. Both solutions improve total L/D performance. I have not seen any comments regarding tiplets & adverse yaw though, so I don't know if that is similar for both designs.
However it is this adverse yaw effect that I thought might offer a control & handling solution for longer span hang glider designs. If the lighter loaded tip increased camber slightly, this would be the same as down aileron, increasing lift & thrust on the up-going tip while doing the opposite on the loaded down tip, yawing the glider in the banked direction.
This is similar to how flexible sailing skiff rigs work, to depower and reduce induced drag in response to gusts. The 18 ft skiff class is well known for this technology, much of which was developed by Frank Bethwaite & his son Julian in modern decades.
FLAPS! OK, just give me FLAPS. Stopped flying top less because they are needed there and drogue is a bad option. Sticking with my sport 2's for now which are fine without this. Still would be nice though.
Whenever a video avoids supplying actual performance figures, it annoys me.
Also, when terms like batten are used - WTF is that. How about a diagram or two? Maybe there is some rocket scientist guy just about to get involved in high tech hang gliders, but is put off by all your jargon!
Now, for example, I would like to know what the glide slope angle is for a 1960 hang glider versus a 1970 one and so on. Also, what is your aim? Another video says that the Concordia 28meter wing glider has a glide slope of 75:1 and that a "hang glider" (the year was not mentioned) was only 16:1 or thereabouts. If you can only get to say 18:1 with computer simulations and carbon fibre, isn't that a waste of time?
Also, if you don't have ANY spare time, how does getting given money by others, going to help that?
Crazy idea :
Would it be feasible to assist take-off , towed by a large quadcopter?
After ascent, the drone could be cut free and return 'home'.
I figure..Probably not worth the cost and increased failure points 🤷🏻
It certainly could, but large drones cost money. On the other hand some guys in the UK have been working on a self-launching whinch controlled wirelessly by the pilot. You still need a big field or stretch of road for the line though. I think one (or some?) of them is from the Green Dragons flight school. Just search for self launch hang glider/paraglider whinch and you can find it.
don't think design has ever been the problem, plenty of impossible pipe dreams out there never built. The problem has been materials and fabrication of something that works and doesn't flip over and kill the pilot. At current, IMHO, inflatable structures are most interesting. I built 250# psi 1000denier ballistic nylon fabric bladders at Vertigo. I could tolerate lower performance, Comet like performance today, from an inflatable glider packable in a sedan trunk. An inflatable structure enables design considerations like negative load where the outer wing deforms out of the way and recovers to positive flight without failing.
There's certainly lots of wild pipe dreams, but I'd say that's not the same thing as designs. If they tumble and kill the pilot then that's generally not a problem with materials or fabrication, that's because it wasn't designed properly. So the point of this project isn't just to come up with crazy ideas for the sake of it, it's to do the hard work of really designing it, using simulation as part of the design process so that when we build it (and we already have the materials and manufacturing pretty well sorted), it'll not only performance well, but it also won't flip over and kill the pilot! (since the pilot will be me, I have a particular interest in that!) That's the whole point of what we're trying to do. On the specific point of inflatable structures, I did look at that and read some papers on it. In my view the negatives outweigh the positives. There's a big potential safety issue. Also there's the issue of changing air pressure with altitude changing the stiffness of your structure and so all your handling qualities. Also carbon fibre gives an helluva lot of bang for your buck in terms of stiffness and low weight and the price of carbon is way less that it was, in some circumstances it can be more economical than some of the aluminium tubes we currently use for hang gliders.
Low pressure inflatables for the airfoil/wing shape + carbon for the load bearing structure makes best use of each atom.
I think paradigm shift needs to happen. Existing hanggliders are excellent mature designs. Some thoughts: Be wary of inflatable wing spars, unless topped up with air on decent, their over-pressure is lost.
Has anyone considered forward sweep, like birds, bats and pterosaurs. Denny Reid in New Zealand did work on this, and presents what could be a solution for simplicity. portability and exceptional performance.
@@clivehooper4511 Mark West has a low sweep, forward swept proto flying.
High performance thin film Solar power with some small drone engines and props could be a revolution...
AI-enhanced gliders that automatically adjust to air currents for improved safety and range could be good
how would it adjust? why would anyone want to take the skill out of the sport?
somethings wrong with your youtube - it's erasing comments, and you have no working place I can find to discuss anything or join. you're missing STL files, your .dat files are some weird non-standard format and putting them into CFD shows them significantly wrong (very early separation) - might be "ok" if you're planning to let the wing move into the right shape, but the .dat file should start with the right shape in the first place in that case... Check your listings' admin panel - you probably need to un-delete more than just my last comment!
On the off-chance it doesn't also delete this comment (update - it did - this is a repost)... your AF.dat at ~ Re1M (1.5m chord @ 10m/s) https foils dot pro /hg-dev/yours.png and what I'd suggest instead: https foils dot pro /hg-dev/mine.png
Chris, I don't delete any comments (unless obviously written by bots), I certainly haven't deleted any by you. CZcams does have built in content moderation, if that's deleted your comments then that's not me, I have it set to 'Basic' which lets most things through. For technical discussion it's better to raise it as an Issue on Gitlab (click New Issue here: gitlab.com/HG-dev/aerodynamic-modelling/-/issues) than to try to do it through comments on a CZcams video! Dat aerofoil files aren't standardised, there's many ways of defining them. The one I used was the one used by OpenVSP as that's what I"m using to run the analysis. They might load with other other software or they might need converting. The VSP files are effectively the masters. I'm not sure which files you're specifically referring to, but it's probably the ones extracted from the laser scan data. In which case these are the actual sections of the current, as manufactured wing. No they're not ideal, but they're also not at all untypical of hang glider wings in general. That's why we're doing all this, as I said in the video there's a lot of room for improvement!! Bear in mind also that the Git repo is a work in progress, it's nothing like a release, it's being constantly updated while we're working on it.
@@avianhanggliders1985 Cool! Through trial-and-error, I see youtube secretly erases every comment (other than yours, the channel owner) with a URL in it (and, by "secretly" I mean the we - the people posting the comment, can see it just fine, but nobody else does, then a few hours later it's gone for us too). I wasn't sure if "Raising an issue" would seem too rude (ruder than I probably already sound anyhow!). Airfoil .dat files are a defacto industry standard - I wrote the "Airfoil Tools" fusion 360 addin, which included finding every possible airfoil (.dat and .csv) file I could get from everywhere on the internet, and ensuring that my import code understands ALL of them (*huge job*, considering tabs/spaces/commas/line-ends/scientific notations/infinite different headers and footers, normalization, 3d, etc etc) - the only actual "standard" part they all had in common was "Coordinate Points: The subsequent lines contain the x and y coordinates of the airfoil's surface, typically starting from the trailing edge, around the leading edge, and back to the trailing edge."... but if you data comes from a scanner and not an airfoil project, then that makes sense.
p.s. I replied to my own commend 5 more times earlier - and I now notice it erased all 5 of those as well... I'll re-post after this comment.
I quite often have comments deleted automatically. No bad language or animosity. I cannot see any pattern to it. Some stay up OK, others disappear.
I think the future of hang gliding is called Atos
Atoses are great, we are also a dealer for AIR. However they also have downsides. Being so heavy that they need two bags to carry them and cost being the main ones.
besides the weight (40+ kg) it is quite painful to see them land, when it is difficult and the glider finally stalls putting that immense weight (+harness) on your knees, ankles and backbone...
Also the design of the Flex wing is so genius and simple. Much cheaper too and less prone to transport damage. I love my Flexi ;)