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The Wills Wing U2: A Glider for You, Too
By Dennis Pagen
Originally published in Hang Gliding & Paragliding Magazine, June 2004. © 2004 Dennis Pagen. Reproduced with permission.
This review reflects the author's personal experience and assessment at the time of publication.
This is a good time to be alive. Not only can we watch 120 TV channels in the comfort of our recliners while eating Godiva chocolates and drinking endless lattes, but we also have the luck to be able to choose from a number of great intermediate gliders that perform like thoroughbreds and obey like well-trained ponies. These gliders are only a slight step down from the top topless racers. With a the addition of a kingpost for lighter weight and lowered cost, then a slight bit of detuning for friendliness, the designers have achieved the gliders 98.6% of us warm bodies have been waiting for since that first Australian pilot took a leap of faith into the air.
Wills Wing has offered the public their version of this class of gliders with the U2. Certainly this venerable company has been in the mix since the beginning of time as we pilots know it. Anyone who has flown the various incarnations of their Sport will recognize that they have had a great run of success with their intermediate gliders. But in this new era, nobody can rest satisfied with past success, for this is a competitive and constantly evolving market. The bar has been ratcheted up again in the never-ending quest for perfection. How does Wills Wing's U2 compare?
I set out to answer this question when I met Rob Kells, Wills's point man, at the Finger Lakes Aerosports Park near Rochester, New York last fall. After several flights involving cruising the area with a host of other gliders, twirling up in thermals scattered all over the power spectrum and flying little out-and-returns, I think I have an answer: very favorably.
The Overall U2
Let's take a look at the layout of the U2. The first thing to notice is that it has curved tips. It seems that the new bloom of intermediate gliders, even more than the topless gliders, is settling on curved tips as being the ideal for the best combination of performance and handling. If all else were equal, I think I would choose curved tips every time. Maybe I am just a fan of curves, but in my mind it renders a shape to a glider that is sensual, graceful and birdlike.
The U2 has a kingpost which is readily apparent in the photos, and in keeping with the philosophy of reducing weight on intermediate gliders. (It is interesting to note that we obsessive racer flyers are willing to add 10 to 15 pounds for a mere nudge of performance.) With a kingpost and upper wires, the crossbar and central fittings don't have to be strong enough to support the wing in the negative load. So instead of a carbon (read expensive) conduit (read heavy), a reasonably light-weight aluminum tube can be used for the crossbar. Lighter weight sometimes adds a handling bonus as well, because there is not as much outboard weight to fling around in a roll.
The U2 incorporates two sprogs per side that support transverse battens to hold a minimum amount of twist in the wing, just like the topless gliders or even the rigid wings. The result is less drag (no wires slicing through the firmament) and perhaps even more pitch stability (it is my supposition that gliders with a good sprog system are more resistant to a pitchover event because more of the outboard wing is held with rigid twist and more dampening occurs). The penalty may be a tad more weight, but the U2 is admirably light for a glider of its class (see the specs below). I think that designers in general and Wills Wing in particular have taken advantage of the many little tricks learned over the years to make glider forms efficient in terms of performance and weight.
If you ignore the kingpost, the U2 appears very similar to Wills Wing's popular topless Talon. But the span for a given area isn't as large on the U2, and the nose angle is a couple degrees less. Also, the variation of nose angle with the VG line pull isn't as great on the U2 as it is on the Talon, so the crossbar doesn't have to be oversize (very tight VG settings increase the compression load on the crossbar). This is the detuning referred to earlier. The results are really great handling on the U2 with performance about equal to anything topless at thermaling speeds. Many intermediate gliders thermal with the big boys because handling and slow speed are two of the main requisites for thermal efficiency. Where they fall off is during long glides between thermals or at racing speeds. But you would expect to buy an intermediate glider to buoy up to the top of the stack, not enter the Golden Eagle Award XC Championships.
The Little Picture
Let's toss away our telescope and get out the microscope. We should look at hardware and other little Wills Wing touches. One of the first things I noticed is that the U2 got the Talon's slick appointments in the cleanliness department. We don't need to linger on those curved tips, since you already know how I feel. But look at the undersurface near the top of the uprights. The lower surface continues on back and fairs in the hang strap, the top upright fittings and any other unsightly mechanical items threatening to create turbulence. This under section has a flap closed by zippers for easy access to the innards for your preflight, or even your lunch if you choose to store it there.
The lighter weight, lower cost and possibly handling sweetness are what we gave up when we went topless, but Wills Wing has gone one more step in the right direction: They have gotten rid of the reflex bridles that on the older kingposted gliders routed from the top of the kingpost to the trailing edge. Their purpose is to hold up the trailing edge in the event of a nose-down rotation, and thereby assist in pitch stability. But the last 10 years have taught us something and one of those somethings is that internal rigid dive sticks (sprogs) do a fine job of providing pitch stability.
Now turn your attention to the trailing edge and notice the batten ends. They are levers that easily insert in the sail hem and straighten out to tighten the batten in the sail with a minimum of stress, work or error (early versions of this type of batten ends involved springs which were unkind on your fingers and patience). There always seems to be a better way and in this case the U2 shows it.
Much of the hardware on the U2 is new compared to Wills's earlier offerings. The clearest example is the control bar system. The U2 is the only glider of its class that comes stock with a faired base tube. This base tube is an aluminum bar and is the same one that comes with the Talon. The uprights are known as Litestream tubes with an easy-grip flat back and a faired body 2 1/2 inches front to back. The corner fittings are made of machined aluminum and have been redesigned to reduce drag. The calculations show a full point in glide over the older-style Fusion setup.
The other details we should mention are the sail construction and haulback system. The sail comes with a Mylar leading edge transitioning to a Hydranet main body. This latter cloth is a good durable material with a spectra line in it for strength. It is lighter and more convenient (folds smaller) than the Mylar sails of the topless gliders. The haulback system attaches and detaches with a new spring-activated detent button. It is similar to what Icaro has used in the past, and is perhaps the easiest system going. While we are at the tail end of the glider, we should mention the kickstand which lets you lift the tail up to hold the tips off the ground. This comes into play during setup and breakdown.
All in all, I give Wills Wing accolades for the hardware appointments on the glider and I think in these details they have excelled. The attention to detail is apparent and I have learned over the years that anything that looks good just feels good.
Getting Set
Open the bag, triangulate the control bar, then flip the glider upright, and spread the wings as efficiently as you can so as not to miss the thermal of the day. Then insert the transverse battens all the way. They were pulled out a bit in breakdown to allow the sail to fold neatly. Next, Wills wants you to insert the tip wands (fiberglass curved ends) and put on the cams, but don't tension them. Follow this by attaching the nose battens (doing this later makes it a much harder job) and inserting the innermost four battens per side and levering them up tight. Now the crossbar haulback should be pulled and attached at the rear of the keel, followed by an erection of the kingpost. It is held up by attaching the rear upper wire at the haulback attach point.
Next, if the wind isn't too powerful or wayward, lift the keel, pull out the kickstand and set it up so the tips are lifted. Now you can crank in the tip cams easily. Here's the important point: Pull the VG on to tighten the sail and then insert the rest of the battens. If you don't pull the VG, battens #5 and #6 are very compressed as you slide them in. Follow this by folding the sprogs to their working position and zipper them in. The idea is that the tightened sail allows the sprogs to fit into the lower surface without stretching or ripping the sail. Finally, do the nose cone, pre-flight, harness up, do a walk around then go catch some quality airtime.
Flying Performance
We have been calling the U2 (and others in its class) an intermediate glider, only because it handles and lands so well that any intermediate pilot worth his, her or its Hang 3 can fly it with confidence and competence. In truth, this glider as well as the Litesport and Discus, for example, could be called intervanced or admediate designs because their performance is nearly that of a hawk, with the docility of a pet parakeet. They are true all-around gliders for everyman (or omniwoman).
I towed the U2 aloft on every flight I took (four). I found it to be very easy to track on aerotow. This aspect reflects its yaw stability and its predictable response to an input. I am used to towing tuned-up blade wings, and these intermediate gliders are a welcome refreshment. Once the line was popped, I headed off to the nearest thermal to try my luck. Well, luck didn't have much to do with it since the thermal was marked by a tall stack of gliders of various performance, guided by pilots of various skill. I soon found the U2 would respond to my every whim. It was nice to be able to think "turn" and turn with the speed of thought. OK, I may be exaggerating a little, but I sure grew fond of the glider's quick follow-through to my roll commands. I was able to fly very slowly because I didn't need as much control airspeed as on a topless glider. I believe that made me very efficient in the climb department. I soon found myself at the top of the thermals with the better pilots no matter what they were flying. I seriously believe that a glider such as the U2 will improve most pilot's thermaling skills, for unless you can put your wing exactly where you want it, you will not only be missing some climb, but will not learn as quickly because you won't be able to feel the opportunities or the little mistakes. Enough said.
I grabbed a handful of line and pulled the VG on tight. I felt the glider accelerate to my command with a reasonable reserve of bar pressure when fully stuffed. That pressure is assuring, I can assure you. My eyes didn't water as much as with a speeding bullet wing, but the velocity was ample for all but a competition race. The glider tracked fine in this mode and could be made to respond with a bit of persuasion. In fact, I typically glide between thermals with the VG 3/4 on in a topless glider. Often if I hit a thermal I want really badly, I have to turn before I can get the VG off. The result is sometimes a wandering around before I can center up. With the U2 I was able to hook right into the thermals I blundered into without delay or miscue. In other words, the response with full VG was adequate for the initial catch and coordination of a thermal climb.
In a thermal I would back off the U2 to about 1/4 VG since it handled well enough and slowed well enough to make this efficient. I expect if I had a bit more airtime to compare with other climbers I would find that absolute sweet VG settings for different conditions (strength, roughness and width of thermals). It is nice to fly a glider which allows you this latitude.
The landing of the U2 was a non-event. No nebulous flare timing, no extraneous roll/yawing, no seismological endings. I like to do a diving turn to final to gather speed and to control my height. After flying more gliders than I can name, I have learned to do this cautiously on a new glider. But the U2 took to the maneuver like an old pro, or rather a young ace. There was nothing unpredictable about its acceleration and it yawed to the new heading right on track. I think this little test sums up the glider in flight: It is responsive and predictable.
In general sink rate and all-around performance, the U2 is as good as Wills's former topless glider, the Fusion. That glider (the Fusion) was pleasant enough and climbed well, but it was not a blazer. So the U2 glides as well as the first generation topless gliders, and it does it with better handling and 10 (or more) fewer pounds. It is worth noting that particular spec: the smaller U2 weighs 63 lbs. (!) while the larger size is a reasonable 68 lbs.
I had a chance to fly both sizes of U2s. The 145 (representing nominal area in square feet) felt like a little rocket in my grasp. I could go anywhere and do anything. I am at the upper end of the ideal range for this size (see spec chart), so would not expect to have a world-busting climb with it, but in fact I did climb as well as most gliders plying the air. On the larger size (160), I felt right at home and this would be what I would normally fly, so my comparisons here were most pertinent. The comments above were based on this glider. Both gliders felt like they came from the same mold with the same feel and balance. Landings were similar, despite the one being smaller, because they are so forgiving and slow landing.
I'm not the only one who likes the glider, for I have heard two former world team pilots (not Wills factory pilots) raving about the fun and performance of this glider. I think that after a while those of us trying to live life in the fast glide forget how simply effortless flight can be. A glider like the U2 can bring back all the fun to jaded pilots or offer a newly-arrived thermal pilot an unlimited wealth of experiences.
You get all this performance and kindness with every U2. There are no options to worry about except sail colors. Every one has the faired control bar and the lever battens. Oh, yeah, there is one other thing: you can get Wills's wheels, which consist of a neat machined fitting that slides over the basetube and extends down to form an axle for a small wheel for the temporally challenged (those who struggle with flare timing). A pair of those items will cost you $140.00 retail.
Ending
In the end we find that the U2 offers plenty of likeable qualities and no unpleasant surprises. But that shouldn't be surprising. Wills & Co. have been at this game a long time. There is no doubt that Wills has exposed the falsehood that we are at the end of hang gliding evolution. We hear this bemoaned about every decade. The U2 is one of the examples of bringing the latest design techniques together in one package. I see the U2 as an exercise in ergonomics, efficiency and elegance. If you long for any or all of those Es, I suggest you find the closest place to take a test dive, then get in line. I'm sure it will be love at first flight. Feel privileged, and consider giving up those 120 channels and going flying more.
Manufacturer's Specifications
| Specification | U2 160 | U2 145 |
|---|---|---|
| Area (ft²) | 160 | 145 |
| Span (ft) | 33.1 | 31.3 |
| Aspect Ratio | 6.8 | 6.8 |
| Glider Weight (lbs) | 68 | 63 |
| Hook-In Weight (lbs) | 160–260 | 140–220 |
| Optimum Body Weight (lbs) | 170–210 | 140–170 |
| Nose Angle (deg) | 125–128 | 125–128 |
| Double Surface (%) | 84 | 84 |
| USHGA Rating | 3 | 3 |
| Vne (mph) | 53 | 53 |
| Va (mph) | 46 | 46 |
| Vms (mph) | 20 | 20 |
The U2 Story
By Steve Pearson, Wills Wing designer
Originally published as a sidebar to Dennis Pagen's U2 review in Hang Gliding & Paragliding Magazine, June 2004.
Developing a new hang glider design in the performance-intermediate class is a deceptively ambitious task. Any new design in this class faces its largest competition from an abundant supply of relatively inexpensive, used high-performance and competition gliders. These gliders set a benchmark for performance that is just marginally less than current competition wings. A pilot flying in this performance category expects to be able to match the best-performing current generation gliders in anything except an all-out racing task. To be successful, a new glider design has to offer not only this level of performance, but also a compelling advantage in flight characteristics and other features. Simply put, it has to perform as well, and be lighter, better-looking and much more fun to fly.
In the U2 development program, I also intended to target another group of pilots that normally wouldn't consider this type of glider as a new purchase. I often joked that my goal was to develop a glider that my partner Mike Meier would want to purchase. Despite the fact that Mike is an extraordinarily experienced and skilled pilot, if he were to purchase a new glider, it would more likely be a simple, fun-to-fly glider — even a Falcon — rather than something like a Talon, which offers dramatically increased performance, but at a cost in weight, complexity, and more demanding flight characteristics. If Mike already owned a good performing, easy handling glider like a Sport, he'd likely be a hard sell on a new glider. I haven't asked Mike if I succeeded in making a glider he would want to buy, but judging from his expression after a production test flight on a new U2, I'm sure that I came close.
The Litestream Performance control bar with streamlined basetube was designed expressly for the U2 and is included as standard equipment on every glider. The aerodynamic design of the Litestream bar builds on technology that started at Wills Wing in 1983 with the first angle-of-attack optimized control bar assembly with integral streamlined basetube. More recently, the World Team Carbon Control Bar was the industry's first high-temperature carbon-composite ultra-low-drag control bar. It was followed by the Slipstream aluminum profile, which is the most common high-performance downtube available on competition class gliders today. The Litestream design improves on the Slipstream bar for the non-competition pilot by offering a smaller and easier-to-grip profile and lighter weight with almost no loss of performance. The Litestream fittings are CNC machined from solid wrought aluminum for maximum strength and durability.
The U2 airframe tubing, except for the control bar and kingpost, is completely 7075-T6. Wills Wing introduced the use of 7075 on a mainstream production glider with the original Sport 167 in 1986. For many years afterwards our use of 7075 was subject to scrutiny and criticism from others in the industry. The "controversy" has taken almost 20 years to resolve but 7075 is now universally recognized as the premium choice for airframe tubing. The U2's exceptional light weight certainly wouldn't be possible without this high-strength material.
Two other factors that contribute to the U2's performance are the large percentage double surface and the completely-enclosed 4-sprog stability system. The large percentage double surface is supported by internal paraglider-type ribs, which were introduced to hang gliding by Wills Wing and were quickly adopted by the rest of the industry. The cable-supported sprog configuration with a universal joint mounted to a bracket on the back of the leading edge is another Wills Wing innovation that has been widely adopted by other manufacturers. The pitch and roll control pressures are reduced by a kingpost hang system, another design feature introduced on the original Sport. These features, together with a wide-range VG system, contribute to the U2's light and responsive handling characteristics.
I recommend that pilots considering a U2 go to www.willswing.com and other online forums to read comments about the aerotow, landing and other handling qualities of the U2. Better yet, check the calendar section of our Web site for an upcoming demo day in your area and test fly one yourself.