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By TjW
#402240
Yep. I'd like to see a modern version of the Fledgling. Still with a kingpost, mostly aluminum, fewer wires.
Cheaper, lighter and slower than an ATOS.
Stick a landing gear setup like the EZ-Flyer on it and it would be a very relaxing way to fly.
Don't need to worry about running fast enough to launch. Don't need to worry about making it turn. Don't need to worry about running fast enough to land. Don't need to worry about composite repairs.
I remember other pilots being concerned about "all those battens to stuff" on the Fledge. There were six per side.
You know what else has six battens per side? Hitler. Oh wait, no. The Falcon.
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By red
#402243
TjW wrote:
Thu Feb 08, 2018 9:59 am
Yep. I'd like to see a modern version of the Fledgling. Still with a kingpost, mostly aluminum, fewer wires. Cheaper, lighter and slower than an ATOS. Stick a landing gear setup like the EZ-Flyer on it and it would be a very relaxing way to fly. Don't need to worry about running fast enough to launch. Don't need to worry about making it turn. Don't need to worry about running fast enough to land. Don't need to worry about composite repairs.
I remember other pilots being concerned about "all those battens to stuff" on the Fledge. There were six per side.
You know what else has six battens per side? Hitler. Oh wait, no. The Falcon.
TjW,

The "original" production Fledgling A was the small version, with two bottom sidewires per side (8 total, top & bottom). The larger Fledgling B version had four there (16 sidewires, top & bottom) which did cost a lot in drag. I think that larger 7075 tubing could make a Fledgling B with just two bottom sidewires per side (8 total), or a topless strutted Fledgling B version might be even better.

No doubt, I'd really like to have a lighter rigid wing than an ATOS, one that I could afford to repair, if needed. Never needed to repair my Fledgling, really, but at least it was a glider that I could repair reliably.

I always laugh when the same pilots (who once derided "all those ribs" in my Fledgling) are now busy stuffing 20+ ribs into a flexwing, without a second thought. :lol:
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By TjW
#402254
The other thing a Fledge replacement could use would be more span. The limitation on span is mostly to be able to turn it via weight shift. Maybe put curved tips on the end of the existing planform instead of the droop tip. That way it could still fold up to a reasonable length.
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By red
#402255
TjW wrote:
Thu Feb 08, 2018 9:12 pm
The other thing a Fledge replacement could use would be more span. The limitation on span is mostly to be able to turn it via weight shift. Maybe put curved tips on the end of the existing planform instead of the droop tip. That way it could still fold up to a reasonable length.
TjW,

With the drooper tips assembled, the Fledgling needed a rudder deployed full-time, to make a turn. Most Fledgling pilots that I flew with just rolled up the drooper tips and safety-pinned them to the sail, or simply cut them off. Then you used a rudder to initiate a turn, but not during a turn.
The Fledgling was a tail-heavy beast on the ground, and more span would make it worse, in that department.

Image
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By TjW
#402257
Yep. That's where the EZ-flyer undercarriage comes in. Also, some of that might be ameliorated by sweeping the rear spar a little less.
By Lazypilot
#402262
Raquo wrote:
" Whoa, that Alien – curved tips in 1980? Looks so much like a Sport2 with a tail!

Looks like curved tips were too stiff and didn't work out well judging by what the delta82 comments say about this glider."

Bob Trampenau, the designer and constructor of the "Seedwings Sensor" series of fine high performance hang gliders in Santa Barbara Ca., had curved tips way before anyone else, in 1976. In that year he was flying hang gliders with cross-bar enclosing double surfaced sails with of course curved tips. Bob says : "I like raked tips".

For many years we've seen the airliners being equipped with Whitcomb Winglets, that are almost vertical in their arrangement. Boeing developed the "blended winglet", they are a beauty to behold, as opposed to the flat plate things crudely bolted to the wingtips of the less expensive brand of jet airliner. The wing just curves from almost level to almost vertical. Pretty, and likely with less drag.

But their latest design, a mostly composite construction "787 Dreamliner", has raked tips, not winglets. It's my understanding that the "upright" winglets would have benefited the airplane more in climb than the raked tips, but the raked tips were better in cruise flight. Their idea is, I think, that the airplane spends gobs more time and distance in cruise mode than climb, so they went with what they felt would provide the most long-term benefit.

Winglets work by harnessing the spiral-shaped airflow at the wingtip of I guess any airplane or glider. The air flows out towards the wingtip on the lower surface of the wing, seeking the path of least resistance, upwards around the wingtip and flows inward towards the root of the wing on the top surface. This airflow is not parallel to the direction of flight, and since the lift force is 90 degrees to the airflow, the winglet's "lift" is angled forward. This is a "thrust" that counters the drag the wingtip vortice (the "horizontal tornado") causes. I like to think of the winglet as being somewhat like the turbo-charger in a car, where the hot exhaust gasses are pressed into service for improved performance, instead of just blowing out the back. Those tip vortices are being used to get back some of what was lost by virtue of an airplane wing being essentially a "pump" of sorts, a very leaky pump. Because the pump leaks, the high-pressure air under the wing tries to escape by sneaking around the tip, that's where the leak is.

So Richard Whitcomb saw that there was airflow in a different direction there, and reasoned that it could be put to work.

Anyone with more than a passing interest in the aeronautical art would enjoy reading of him and his "area rule", that when included in a re-design of a jet fighter plane allowed it to fulfil its promise of going supersonic. It couldn't until the fuselage was re-shaped to eliminate a drag that was not understood until he came along.

The area rule is usually associated with very high speed flight. But about 15 years ago I had a Rc glider named Filip V, and the forward fuselage was shaped in a way that reminded me of the changed shape of I think it was the F-105.

That glider was quieter at high speeds than any Rc glider that I had ever had "buzz" me on launch, and it also had very respectable energy retention, considering it's very low weight. I can't help but think that it was "area ruled" to some extent and that was the reason for it's outstanding performance. But I could be very very wrong, and many of those that know me will tell you it's more likely than not.

I like flights of fancy, I'm a fanciful flyer at heart.
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By Lucky_Chevy
#402263
Whitcomb was a genius and well ahead of his time. He was closely associated with the Coke bottle design of some jets. Reasoned that planes were displacing air, especially at supersonic speeds when the air doesn't have a chance to get out of the way, and the plane should part the air as smoothly as possible; like a diver entering the water. He did some modeling where he sliced an airplane like a sausage and compared the areas of the slices. On a hunch he constructed models that where the difference in areas between slices transitioned smoothly across the airplane and made a breakthrough in aerodynamics.
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By remmoore
#402264
TjW wrote:
Thu Feb 08, 2018 9:59 am
Cheaper, lighter and slower than an ATOS.
Stick a landing gear setup like the EZ-Flyer on it and it would be a very relaxing way to fly.
Don't need to worry about running fast enough to launch. Don't need to worry about making it turn. Don't need to worry about running fast enough to land. Don't need to worry about composite repairs.
As someone who has flown rigids continuously for the past 15 years, I'm not feeling your comments. My ATOS VR launches very easily, lifting off my shoulders quicker than my last flexwing. It definitely lands easier, and has the landing glide angle of a Falcon with flaps on. Super relaxing and easy to fly, with a roll response similar to my last flexwing. Best of all - my rigid is a glide-monster. Maybe that doesn't mean much at some sites, but it allows me to do things I could never do with my flexwing at most of the places I fly. I love it and have no plans to ever go back to hi-perf flexwings.

Composite repairs? Unless you're talking about the leading edge, such repairs are typically easy, cheap, and kinda fun. I've owned four rigids, starting with the Exxtacy, and never needed a LE repair.

I'm sure the Fledge had some good attributes, especially in it's day, but I'll keep my VR, thank you.

RM
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By raquo
#402265
There are also plenty of people who say that the latest T2C flies like a charm, is easy to handle and easy to land, and even some that say it is easier to handle than a Sport 2. This just shows that different people have different ideas and preferences, and that no single design can appeal to everyone.

It's great that an ATOS works for you. As for me, I don't even know what flex wing you're comparing it to, so it doesn't tell me much that you're saying that it lands easier. In my observations topless flexies are not easy to land at all, and those are not something I will ever consider flying.

I only have a couple ATOS-es flying around me, both extremely experienced pilots, and I don't ever see ATOS come in on full flaps dropping like a Falcon. They normally come in pretty similar to high performance flexies. I think our pilots make use of full flaps because it makes the flare window much narrower, or something like that.

Regardless of flying characteristics, ATOS-es are simply out of reach financially for most pilots. My friends are typically buying used gliders in $2K – $4K range, and no one is even considering to buy a used rigid wing because replacing a D spar would cost more than the glider is worth.
User avatar
By red
#402267
raquo wrote:
Fri Feb 09, 2018 5:00 pm
It's great that an ATOS works for you.
Regardless of flying characteristics, ATOS-es are simply out of reach financially for most pilots. My friends are typically buying used gliders in $2K – $4K range, and no one is even considering to buy a used rigid wing because replacing a D spar would cost more than the glider is worth.
Raquo,

That financial aspect is true for me, too. Actually, it's worse than that, to replace a busted spar. You can wait a L-O-N-G time for them to get around to making a new spar for you. Shipping will take forever, and that will cost a fortune, too. Lately, I heard that ATOS has destroyed the molds for some early models, which means that you will NEVER get that spar. If you bust one, just go buy another glider, right? Then you can hope that you can sell your good spar and maybe the sail to other ATOS owners.

I really believe that we can build a tube-and-fabric successor to the Fledgling, with two side wires, or maybe struts. I'm all for power steering, and power brakes. Any patents on that design (if any ever existed) would now be expired, a long time ago. Any expired patent is now Public Domain, and free to all who want to use it.
User avatar
By raquo
#402268
I can't edit my previous post anymore, but I meant to say "our pilots DON'T make use of full flaps because it makes the flare window much narrower".
User avatar
By remmoore
#402269
OK, so I wasn't saying rigids are for everyone. I was simply rebutting the earlier claims.

Regarding your comments:
I'm not claiming your ATOS-buddies are doing it wrong, but my experience with full flaps (or nearly full) has been very positive. It's amazing how steep of a glide angle I can achieve on landing - it's like having a drogue chute, but no chance of oscillation or deflation. Any pilot with decent flair abilities would have no trouble with the ATOS.

In terms of cost - there are good, used ATOS's out there for $2500-$3500. There was recently a good used VR just like mine for $3500. I've never bought a new one, and ATOS's don't have to be a rich man's glider.

Yes, if you absolutely destroy a d-spar (something that's pretty hard to do) the glider is nearly worthless. They can be safely repaired - I know of only a couple of rigid pilots who needed to have that done. I've never come close to needing such a repair.

Don't want a rigid? That's OK - like I said, they're not for everyone. Some folks might want to check their assumptions against reality, however.

RM
By Lazypilot
#402270
Lucky_Chevy wrote:
Fri Feb 09, 2018 3:47 pm
Whitcomb was a genius and well ahead of his time. He was closely associated with the Coke bottle design of some jets. Reasoned that planes were displacing air, especially at supersonic speeds when the air doesn't have a chance to get out of the way, and the plane should part the air as smoothly as possible; like a diver entering the water. He did some modeling where he sliced an airplane like a sausage and compared the areas of the slices. On a hunch he constructed models that where the difference in areas between slices transitioned smoothly across the airplane and made a breakthrough in aerodynamics.
The Rc glider's fuselage was largest in cross-section a little ways in front of the wing leading edge. It tapered back in a way that seemed to me made it so that there was a lot less wetted area where the wing fitted the fuselage. I didn't pay much if any attention to this until I got it built and flew it. One of the first impressions I got was how quickly it accelerated in only a shallow dive, and how well it retained it's energy when pulling G, such as looping. And then I made some high speed passes on the slope. and even when going I'm sure 50 to 60 mph only a few feet from me the thing was silent. Most gliders make sound in that area of flight, but this thing amazed not just me but also other experienced flyers.

Well, like many toy planes she didn't make it to old age. But I kept the pieces of the fiberglass fuselage for a long time, always hoping that one day I could piece it back together enough to make a copy. And dag nab it, it went out of production. Can't win for losing some days.
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By raquo
#402271
I've never seen a used ATOS for sale for less than ~$5K, and even that was thousands of miles away from me. And those would be much older, heavier models.

While carbon D cell repairs are possible, I don't know anyone around here who would be legitimately qualified to perform those. Maybe there's someone who did a minor repair once and it didn't fail. Maybe not.

I can't really argue too much about how steeply an ATOS falls out of the sky on full flaps without personal experience on an ATOS, but I'm pretty sure you can comfortably land a Falcon in a smaller field than you can comfortably land an ATOS in, and you can comfortably land a paraglider in a smaller field than a Falcon. And this ability is probably the #1 reason why most/best XC around here is done by PG pilots. I would appreciate any evidence of ATOS's full-flaps glidepath being comparable to that of a fully pulled in Falcon. That is often mentioned but I have never seen it (although to be fair, not that I looked very hard).

ATOS-es are of course very fine flying machines, but they are optimized for L/D. Many pilots don't want to pay for 15+ L/D with extra weight and cost, or we'd see more ATOS pilots. Much improved controllability alone would be enough of an improvement over flexies, but rigids could get other advantages as well, such as portability. But no one is developing those.
By Lazypilot
#402273
The history of Hg has the rigid wings getting the advantage of glide and aerodynamic controls that reduce pilot fatigue.

But they have never caught on with the general Hg population.

I think that The Next Best Thing will be a hybrid design. It will have "aerodynamic" control, but no hinged surfaces, no actuating wires or pulleys or such. Instead it will be "warpable" by the pilot, and the whole wing will be an aileron, and the tail simply bent to a chosen shape. The whole idea being K.I.S.S...

Taking a lesson from paragliding, only 20 or more years late, this glider will have a performance envelope aimed at being as slow as possible, with excellent control response. These will help the pilot to enjoy his or her flight all the more, and make ultralight soaring available to more people, as the amount of athleticism required for membership in our exclusive club will be reduced. Wheeled launching and landing will improve the safety potential and with the flying machines less intimidating more folks will sign up. Performance? Obviously if you want a high aspect ratio, the main ingredient in the glide angle stew, you can have it. But if the glide of your Sport 2 is satisfying enough for you right now, you can get that easily, and by not being greedy for glide angle you'll be rewarded with a lighter glider that can turn a tighter radius than a paraglider. And have just as easy of a time launching and landing in zero wind as they do. Paragliding has taught us that the secret to making the miles isn't necessarily a flat glide at high speeds, it's the willingness to go for it, a willingness that comes from being comfortable with putting the thing down anywhere with minimal fuss. The ability to effectively work even the smallest and weakest of lift, 'cause sometimes that's all there is at this moment, but it get's better further on...

We here on this site know that the paraglider is not the answer. I personally don't want any of the rigids available. I want folding ribs and a quick set up, I want to be able to make it myself if I can. I wouldn't mind a recover project every season or two if it saves a lot of $, something to do on a cold winter's day. We can use a relatively inexpensive mass produced and readily available material for the covering. Notice I don't say "sail".

Most of you know by now my severe disappointment with Class 1 Hg. I'm sounding the rallying cry for improvement, and I believe we'll get it, in some form. I'm thinking that about 25% of the pilots will see things my way on this eventually.

But folks that have never tasted a really good flying machine will continue to like what's being foisted upon them now. If they only knew that when they hear the words "Hang Glider" they don't have to get a mental picture of a swept-aft flying wing with the pilot hanging from it by long straps. They'll get a choice someday, and the option will be superb quick control response, no more wondering if the damn thing will get turned before something bad happens, no more sore shoulders after only 2 hours of thermalling, and being relaxed on final approach, even into the smallest of LZ's, no more wondering if their "flare timing" is gonna cost them a DT or a broken arm or get a round of applause.

A grass roots effort to take ultralight soaring into a new age is building in folks consciousness. If we can get a co-operative thing going, with individuals contributing their specialty, and no one claiming ownership of any design idea or concept, like at the 1971 Otto Lilienthal Meet, when the "authorities" wanted to know who was in charge and nobody owned up to it. We'll do the same thing with the BNG (Brave New Glider), no one will get sued by anybody because no one will admit to creating anything. It will truly be an Internet Glider, owned by no one and everyone. An Engineer can design a component, wrap it up in brown paper with all the info needed, and abandon it on a street corner, anonymously, and of course the local air junkie parked down the street sees this (How did he know ? heh-heh-heh) and recovers the package, takes it down to Billy Bob's Garage where the BNG prototype is being discreetly assembled. Shhhh! Keep it quiet until vehicle testing is done and flight testing is underway. Be patient, one day soon the plans and materials list will show up on your Desktop or Smartphone. And that guy you met who everyone says is the best handyman in town is looking for a little work, and you're short of time and skills in that area but have a good job with more pay and you're okay, so you hire the guy to get you airworthy once again.

Watched the 75th Birthday celebration of John Lennon again the other night. Good show. They say that he was a dreamer, but he wasn't the only one.

Build it and they will come.
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By raquo
#402274
Lazypilot wrote:
Fri Feb 09, 2018 8:52 pm
I think that The Next Best Thing will be a hybrid design. It will have "aerodynamic" control, but no hinged surfaces, no actuating wires or pulleys or such. Instead it will be "warpable" by the pilot, and the whole wing will be an aileron, and the tail simply bent to a chosen shape.
I understand the hinges part – paragliders' trailing edge warping, and Sensor's flaps don't have hinges. But how could you possibly get rid of wires/pulleys? You mean still by weight shift, but perhaps some different mechanism than what we have now with billow shift?
By Lazypilot
#402278
Picture yourself on a boat on a river, with tangerine trees and marmalade skies....

No, that was the song that jumped my brain when I wrote, oh so innocently, "picture yourself". It should have gone on to say that you're in a glider, not suspended below it. And when you make an effort to turn to the left, the airframe can contort in such a manner that the entire right wing noses up slightly, the left wing noses down a bit, the tail twists in anticipation of a yawing moment being needed. So how does one make an airframe that does this? Inquiring minds want to know!
I don't have a structure designed yet, but I'm making progress. I'm not really qualified to design an aircraft, I have only an airframe and powerplant mechanics certificate. Yes I can change out a part of a Hg but I don't consider myself a mechanic, I did work on planes after getting licensed, but it didn't take long to recognize that I wasn't cut out for it, as a profession anyway. I've been building model planes and gliders all my life, and flew Class 1 Hg's for 40 years, was an instructor/observer in the early '80's.

My glider might have a form of adjustable CofG and billow, but how you define those things will determine if it does.

I think the best thing is to be able to alter camber, thickness, and reflex while flying, and I imagine the CofG will need to be located differently for one configuration over another. The birds alter CofG by sweeping their wings fore'n'aft, perhaps we can vary the planform by a little bit, spread the wings wider and forward while at the same time spreading and cambering the tail.

That out of the way, I will say that the glider I'm trying to create, in model form, has what you would think of as two keels. These longitudinal beams support the pilot between them, and hopefully will provide some protection for the pilot in some low speed accidents, such as getting blown over on launch, blowing a launch (catching a tip on a bush and ground looping, failure to attain/maintain adequate airspeed, bad luck).
By use of effort amplifying levers or other mechanisms, or perhaps just direct action, the beams can be moved into or out of alignment with each other. The right beam is a component of the right side of the glider, the left one is a part of the left side of the glider. The two halves of the glider are connected by a horizontal component at the nose and tail. They are made so that the pilot can "tilt" them, resulting in the beams changing their pitch attitude relative to each other.
The way I'm trying it now has a wing spar, fully cantilever, that is also hinged in three places, the center hinge is also made so that the spar halves can rotate a bit opposite each other, so that each wing can have it's own angle of incidence. This is how I hope to control roll, by twisting the airframe and making each wing change it's incidence.

The other two hinged points of the spar allow the spar to effectively shorten, so when you fold the glider the center hinge and the other two work together and the spars will move inboard as they also sweep aft. This results in the ribs, both the nose ribs and the aft ribs, folding along the sides of the spar. One option I'm considering, if this project gains too much weight, is to make the glider separate into a right and left half for easier loading and carrying around, you'd need two trips to the truck but for most that's not an issue. What might be an issue is bulk, I suspect that if I'm not clever this thing could have some frontal area going down the road on a car, and not as many gliders would fit on the rack. Gotta get creative with the folding stuff.

The tail I'm envisioning is much like the one found on the red tail hawk. It will be able to tilt, or "bank" so that it can provide some yawing moment, and it will also be enlisted to damp and/or assist in control of pitching motions. But just as our present and past flex wings are allowed to yaw away from the direction of flight to some degree, so will my glider, maybe. Ya never know, the darn thing could end up with a big rudder on it. But I think that the system we use today, of having the dihedral or anhedral "just right" so that a skewed slipstream resulting from adverse yaw doesn't create much, if any, rolling moment. But like I said, ya just never know how you're gonna think next month or year or whatever. We learn by making mistakes, that's a reason for flying to be hazardous. It will be awhile yet before I have an Rc model ready to fly, and a lot of how this thing works will be determined by my experiences there. For economic and practical reasons my first models will be small, in the 1 to 3 meter span size. Before a full scale version is built a very large scale model will be used to try to determine if a full scale glider can be flown safely. But ya never know, maybe I'll just whip something up and go to the sand dunes, like it was done going on 50 years ago. A manned version will have to be vehicle tested before flights of any significance are made.

The area between the wings has to be able to flex fairly easily, allowing each wing to set it's AoA by itself, but the use of servo tabs and trim tabs will give the pilot control of that. The wings but only when commanded. Have you ever heard of George Spratt's "Control Wing"? I'm hoping to be able to use some of his ideas, coupled with my own. The airplane he designed wasn't all that efficient, but it was able to be flown by inexperienced pilots as safely as a plane can be flown. His wings could rotate in pitch, separately or collectively. Supposedly this gave a smoother ride in turbulence, with each wing being pitch stable and free to find it's designed AoA. My hope is that my glider will be pretty much pitch neutral without any work being done by the tail, except for compensating the CofG location. Of course it would be cool if I could vary the sweep of the wing slightly, from a little aft sweep to a little forward sweep, with forward sweep it would be like moving the CofG aft, so the tail could be employed to provide lift, essentially decreasing wing loading. We've all watched in wonder as the Hawk, poised motionless in a wind equal to or greater than the bird's minimum flying speed, so he could see movement on the ground. It's fun to watch them do this when the conditions are marginal, and the bird spreads his wings forward and droops his tail, trying with all his might to get the lowest possible flying airspeed. The trick is to design an efficient tail, and it will be a real trip trying to actually fly tail heavy like that. I think that with a glider that's got a lot of overall length, and is damped sufficiently in pitch, a skilled flyer could keep his balance in that mode, after all we're gonna be goin' really slow, and at low speeds things don't happen too awful fast. A highly skilled flyer, with his attention sharply focused could pull it off. He'll just have to be spring-loaded to move the glider back to a stable condition real fast, get rid of that positive incidence in the tail and get the wings back to a position that provides a bit of nose-heavy before she pitches down too much. Or noses up way too sharply when the tail stalled...

It's said that nose-heavy airplanes fly sluggishly.

But tail-heavy airplanes fly once...

And the above brings up another thing. I'm old school analog, and so I think in terms of basic mechanics to solve problems. In this co-op-to-be most of the engineers are likely to be younger folks, they don't usually fly the 2 channel, rudder and elevator Rc gliders like I do, no no no, they've got "multi-copter" drones that are artificially stabilised with computers. They don't actually "fly" the drone, they tell it where to go and it does it autonomously. They can turn on or off some of the automatic functions and fly them a bit.
But what I'm getting at is if a drone can be artificially stabilized, why couldn't the BNG be done similarly? With computerized stability the trim drag could be reduced to zero, and pilots could focus more of their attention on centering lift or deciding the configuration of camber and reflex to get best glide to goal. Imagine entering a thermal and telling your glider to bank left 37 degrees and hold the bank and airspeed steady while you eat your peanut butter sandwich. :surrender:

That wouldn't be my style, but who knows what these whippersnappers might get into in Future Games. Control their gliders by tilting a Smartphone this way and that? If you can imagine it they'll do it someday. Your self-driving car will load up your diver by itself and take it to the hill, where your self-assembling glider will fly away and record the flight so you can stay home and nail down a piece, then you'll plug yourself in to a thingy that will blow wind in your face and feed sensation directly to your nerve endings, even artificial G forces. You'll experience the flight just as you would have if you had been there. Now that's getting a handle on the safety thing! And all on your own schedule...

Ok let's have some simple fun and get imaginative.
Grab a sheet of thin foam, or cardboard or stiff paper. Draw a planform shape on it that is a mixture of bird (Hawk?) Manta Ray (low aspect yeah, but they look cool) and an F-22 Raptor fighter plane and a butterfly. This may take awhile, but it will keep you out of as much trouble as it will get you into later on.

This BNG that I'm thinking of has gobs of area, we want to go slow and while small gliders with hard-working airfoils can slow up decently, they have a more abrupt stall and a longer recovery arc. We want a glider that, if stalled, practically immediately is flying again. And we want to be able to use a relatively thin section with really mellow characteristics. Little or no pitching moment, a modest lift and as low drag as we can get. We want a very modest wingspan, so we can turn in really tight radius turns with a minimal bank angle. We want to sink slowly and circle in small thermals. We want a stall speed as low as it is humanly possible to attain.

Now, gobs of area and a short wingspan add up to a low aspect ratio. To get as much glide as we can from this thing we'll literally have to bend over backwards to reduce parasitic drag wherever it can be found. To keep it light we're tempted to use wire bracing, but I believe that although a fully cantilever construction may exact a weight penalty it may be necessary because of the drag thing. This is one of several reasons why the pilot can't be hanging down below the glider, we've got to get up into the thing and not be exposed to the airflow. Once you get used to it, you'll like it, especially in cold weather. But I'm not saying that you can't have great visibility---I'm trying to make one where my head is very close to the center of the leading edge of the wing when reclined, I'll have the option of going prone at any time should I desire.

So I can look straight out to the side, and by varying my posture a bit I can look either over or under the wing, which may be forward swept a bit. To help with the weight problem I'm experimenting with the "joined wing" configuration, or maybe just some of it. So a form of canard design, mixed in with the previous suggestions, might have some very real advantages. The models are flying well, so we'll see. Just for fun, cut out a delta wing from foamboard, de-papered.

Use a planform reminiscent of the Standard Rogallo/Dickenson design, with the centerline being the same length as the L.E.'s. Add a small vertical fin, I have at least some of the fin on the bottom to use as a handle.

After you find the CofG and the reflex needed to get it to glide, remove the nose weight and reflex, and cut two big holes in the glider, one for each wing. The shape of these holes should somewhat sorta kinda mimic the existing planform. You'll be removing about 1/3rd or so of the area.

Add some decalage, it won't need much, by adding some camber to the aft portion of what is now the foreplane. Before you add too much of that you can add a tad of reflex to the inboard area of the aftplane. Oh yeah you'll need to balance it, but what you're going to find is that: This "joined wing" glider has a much better glide than what you got with the delta glider you made it from. And, it requires considerably less nose weight, so even though you removed a lot of area your wing loading went down from what the delta wing had.

You may want to cut out the holes a bit small to start, and gradually make them bigger and the fore and aft planes smaller as a result. It's a fun hobby, try it. The foam board I like best comes from the Dollar Tree store. While there grab a $1 hot glue gun and a $1 package of hot glue. Don't bother working with foam if you don't have the sharpest of blades.

A few sheets of foam board will keep me happy for days. I go to a park, make gliders of all styles, get 'em trimmed out then give 'em to the kids (and adults!) that take some interest. It's a lot of fun. Now that pot is legal...
By Lazypilot
#402288
A design having two keels, maybe 2 ' apart, and those keels extending forward maybe 8', and a canard wing mounted on the nose. The pilot can control the canard in pitch and roll, so it would be designed so that the pilot steers the canard, and his BNG would follow it.

Roll the canard to the left, it will bank until a link going to the fuselage cancels the roll-inducing elevons on the canard.

When the canard banks to the left, it moves the keels it is attached to, with the left one pointing more downward and the opposite for the right wing. This action causes the wings to get a differential incidence, and the glider rolls left.

When the pilot rolls the canard to the left, and at the same time adds up-elevator, the banked canard's lift vector gets tilted to the left, and the application of up-elevator boosts it's power. The canard pulls the nose around, countering any adverse yawing that may have set up.

Because I want to sit with my head placed at or near the center of the glider, resting on the "nose plate", My weight will be far forward, and to keep balanced I was considering forward swept wings. But I want there to be no sweep in either direction so pitch isn't affected by varying amounts of washout or wash-in.

The canard configuration puts a bit more structure ahead of the pilot, and has the potential to absorb energy in an impact.

I think that a variable CofG can vary the canard's wing loading, so perhaps a pilot can tune his glider by adding or subtracting camber of the canard. There's just so many things to consider when contemplating the flying machine. There will never be any boredom found here, I know that.

Using the canard wing, or a tail surface, as a big "servo tab" to move something, such as a wing, intrigues me.

I wonder if a small canard or/and a tail surface could be attached to the nose or ass of a conventional high performance Hg, not for direct control but to serve as a muscle to twist the wings, and the control comes from that.
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By raquo
#402290
You have to consider that wind gusts will also act on all aerodynamic surfaces and they should not induce movement of those surfaces that will compound the effect of such a gust, otherwise the glider will be quite unstable.

I've heard many times that canards don't mix with thermal soaring – also some kind of stability problems but I don't remember what exactly. Try searching this site, pretty sure it had been discussed.

Aeroelasticity would make forward swept wings unstable, e.g. an upward gust on the right wing will cause it to increase its angle of incidence causing even higher lift on that wing, magnifying the gust's effect.
By thermaleo
#402293
I have long thought - in idle dreams because I am not an engineer - that the best hang glider wing would be one in which after launch the pilot could easily swing his feet forward and comfortably relax in supine position, in a simple faired harness that was mostly inside the wing, with his head approximately level with the trailing edge, so he could easily look over or under in a manner like some of the WW1 biplane fighters. Control would, for most of the flight, be effected by a simple side stick, like the Swift.

The design would allow the wing to be foot launched, using some sort of structural control frame, but then, by some simple and clever leverage, would allow the whole pilot to swing up and into the center section of the wing.

Lest you scoff at the engineering required I can only say that once upon a time I piloted a J bar Mooney for many flights, and was always amazed that this 4 seater 150kt + airplane had landing gear that was raised and lowered by the pilot (quite easily if you were under 90kts) by a c.18" long bar, using perhaps 20lbs of force.

Upon landing the hang glider pilot would simply move the lever, swing his legs down and land normally.

It doesn't sound impossible,....

:crazy:

Leo Jones
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