Wills Wing U2 160 Demo Flight

2010-01-08T16:44:00.000-08:00

Wills Wing U2 160 Demo #35645 follow-up flight

The forecast on the morning of Tuesday, August 25, 2009 for the Sylmar area looked good for an out and return flight from our 3,500’ launch point at Kagel Mountain to the 2,900’ West Towers turn point above Stetson Ranch Park then East to 5,000’ Mt Lukens above La Crescenta and back to our 1,400’ LZ by the Pacoima Wash. I exchanged emails with Joe Greblo at Windsports to secure a ride up the hill. I was initially considering attempting the flight on my new Falcon 3 195 until I got a call from Rob, the gopher reaper. Rob flies a Litespeed RS-4 and so I thought I’d better bring the T2 144 and get ready for a workout. At the last minute I called Joe and asked whether the U2 160 demo glider was available and called “dibs” on it. One less thing to pack on my car plus I get to see what the glider will really do. I had previous flown this 2009 U2 160 in very marginal conditions and posted my impressions on the Oz Report here.

Rob and I were joined by Andy the thermal ninja who also flies an RS. We were all off the hill by 2:00 PM. Andy and Rob were working over Trash Mtn and radio coaching Janyce the comeback kid on her Falcon while I worked over at the third bowl and climbed to 5,600’ and decided to go tag West Towers while Team RS was otherwise occupied. I was a couple of miles West and losing altitude when Rob announced they were climbing out fast and getting ready to head to Lukens. I doubled back in a vain effort to play catch up and just wasn’t finding any good thermals so I decided to do my best to try and catch them come what may.

I had my trusty Canon Powershot mounted on my right leading edge/wire junction running CHDK and set to shoot one still photo every 14 seconds. I was hoping to capture at least a few stills that would so this U2 justice and maybe illustrate the flight a little better than my text and tracklog. I also had a lot of things I wanted to do on this flight to really evaluate the U2 including: thermalling in more robust lift, extended glides and at least one speed run. I also wanted to fly the glider in as many combinations of VG setting, speed and turning as I’m normally likely to do.

I fly with the same Wills Wing aluminum base tube that I have equipped with 6” streamlined wheels, fitted with custom-machined aluminum hubs. I swapped my base tube in for the stock base tube, equipped with the Delrin “Davis” skids. I’m 5’ 7” and this glider has 68” downtubes that, when combined with the extra 3” of the wheel radius, makes for very little ground clearance but I’d already gotten accustomed to that on my previous flight. Also, the 33’ span and slightly heavier feeling than my T2 144 with its Dacron sail were also quickly out of mind as well. In other words, the glider now felt fine on launch rather than somewhat awkward as it did on my first demo flight.

Thermals were cycling in at Kagel launch and the 8-10 mph wind was somewhat gusty and switchy. I hooked in today at 198# and the 160 square feet of UVM10T full Mylar upper surface felt just right as I powered off the ramp and smoothly transitioned to prone in my 2001 Rotor Kickass single suspension harness at 2:00 PM.

The climb out to 5,600’ in the first thermal felt pretty good. My vario was showing 5-600 fpm and I kept the VG off during the climb. Centering seemed fairly easy and I thought I was doing great until I spotted Fat Fred and his tandem passenger out-climbing me on his North Wing tandem in a nearby core. I found it very easy to adjust my turn to drift into Fred’s core and then re-center myself in some better lift. It wasn’t long before I was watching Fred and company start shrinking and the world once again seemed in order. I once flew tandem in one of those North Wing monstrosities and they climb very well with a steady hand. I don’t know whether my camera picked Fred up or not, as I haven’t had time to review all 780 photos.

Once I topped out, I went on my first extended glide across the Pacoima Wash and off towards West Towers. I pulled the VG cord until it stopped about 6 inches past the ‘full' mark. It’s a shorter throw than on my T2 144 and a bit longer than my Sport 2 155. And it’s surprisingly easy to pull and set the cord in the cleat. All this makes me want to use the VG as needed rather than just setting to full on or full off when in or out of thermals. Did I mention that this is a big glider and I’m at the low end of the hook-in range? That easy VG system is like having a well engineered 5-speed manual transmission. You look forward to shifting gears and it becomes part of the driving experience. I really enjoyed it too.

And then there’s the acceleration that accompanies the VG gear shifting. This glider trims at about 22 mph for me at zero VG and has an almost linear increase in trim speed as the VG reaches the stop, 6” past the full mark where it trims anywhere from 28 to 44 mph depending upon the air I’m in. You heard me right. At full VG, this U2 160 with my 198# mass attached to it, was giving me neutral bar pressure at anywhere from 28 to 44 mph depending on the type of air. Luckily, it was trimming faster while in sink and slower while in lift. In dead air it was trimming in the 35 mph range. I can’t explain this phenomenon and it’s not unique to this glider. When I was a boy and flew flee-flight model gliders and rubber-powered aircraft I often noticed that the apparent airspeed of my gliders would change, depending on the type of air it was in. And a well trimmed and balanced glider would react to changing air in a way that gave it a longer flight. So from that standpoint alone and notwithstanding any academic debate to the contrary, this is to me an indication that a glider is well balanced and well trimmed. It’s not magic. It’s merely a matter of good tuning.

My 208-hour old T2 144 with it’s Dacron sail doesn’t do this. No matter where I have the VG set from zero to 110% it always trims at 22 mph. Does it fly poorly? Hell no! But it usually has some bar pressure, whereas this U2 160 has no bar pressure at the airspeeds which tend to correspond to the VG settings that match the intended glide. What this means to me is that this is the kind of glider that I can fly all day long over long distances and in a wide variety of air and the pitch inputs from me are minimal, thus saving my strength for coring thermals, and that is exactly what I did during today’s 2-hour and 53-minute flight.

Late in the flight, I even managed to get in a speed run for one minute at an average airspeed of 54 mph that computed out to and L/D of 5.3. Considering this glider has a kingpost and vinyl-coated top rigging, that ain’t too shabby! Did I mention that I’m also at the low end of the hook-in range? I topped out at 60 mph on this run and found the glider to be surprisingly easy to keep on a straight track. Here I am at 60:

It doesn’t show up in the photo, but at 60 mph there was a slight buzz in the trailing edge between the #2 and #3 battens which was identical on both sides of the sale. Below 55 mph, I didn’t notice any sail flutter or irregularity at any time. Overall, the sail appeared to be extremely clean looking.

Getting back to my pursuit of Rob and Andy, I found myself below launch height after I’d turned around and flew past Kagel. I headed out in front of Trash Mtn and started scratching. I let Rob know I wasn’t likely to be joining them any time soon but he encouraged me to use the gap as a motivation for me to fly my best. By now I was getting my familiar and comfortable with this big double-surface glider and didn’t mind scratching in close to the hill. On my T2 144, I am accustomed to working in very close and in somewhat rowdy conditions. It’s a responsive glider and suffers from adverse yaw when initiating rapid turns as well as high tip inertia. Both of these factors require that I always be at least a second or two ahead of the glider in order to stay safe when working in close and to climb more efficiently. Oddly but happily, the U2 160 did not exhibit any noticeable adverse yaw like my T2 and its longer and larger wings actually seemed to feel lighter.

I finally worked up enough altitude to head East from Trash Mtn toward the large gap at Little Tujunga Cyn Rd that leads to Little Tujunga Peak on the opposite side. The last piece of hillside before this gap is known as Lance’s Ridge and 4,000’ on a Litespeed is generally considered a safe altitude to cross with enough height to arrive at Little T with enough height to work up and climb out above Big Tujunga Peak a mile or so downrange. I hit sink on my glide toward the gap and left Lances lower than I had hoped at 3,700’. I continued to hit sink on my crossing and arrived at Little T without much altitude to spare. Again, I notified Rob of my position and began scratching in close in earnest. Had this glider not already inspired my confidence I would have turned back after I arrived low at Lances and would have been preparing to land out rather than working on one of many low saves during this flight.

I got a really good chance to see how the big U2 maneuvers and handles in transient bubbles of lift popping off of the knolls and spines along Little T. I just couldn’t get more than a few hundred feet over and was feeling discouraged. There’s a large bailout LZ in the Big Tujunga Canyon Wash about 3 miles to my East and I knew I could get there in glide, but my purpose was to climb out and tag Mt Lukens some 2,000’ higher and 6 miles to my East. I headed along the canyons and spines of the Tujunga ridge line and worked in very close until I came out in front of 'Big T', no higher than where I started on the West end. I had to be patient and focused while Rob and Andy were tagging Lukens and I was announcing that I may need a retrieve. Rob has heard me make this announcement so many times that it’s gotten to sound like the boy who cried wolf. He’s even watched me climb out from a bigger hole and with no instruments on my T2.

By this point in my flight the U2 was beginning to take on the same sort of familiarity as my T2 except that it feels like an entirely different glider the control bar, which was in fact the one I borrowed off of my T2. Patience finally paid off and I climbed out to the mid-5s above Big T and started to cross the broad wash toward Little Lukens while Rob and Andy were on glide for home directly below me. I hit more sink crossing the wash and arrived at Little Lukens with just enough height to get to work hunting for lift. I’d been paying attention to Rob’s radio dialogue with Andy and knew there was not going to be any free lunch today. Again, I had to work in close and in bubbles of lift until something finally turned on. And again, my confidence and comfort with the U2 160 was on the rise as I pushed far back along to ridge as low as I’d ever attempted on my T2. By now I had a pretty good feel for how far I could glide and how fast I could glide to run from sink.

I failed in my first assault on the Lukens turn point above the transmission towers and turned back towards Little Lukens overlooking the wash. I was about a spine back from Little Lukens when I caught a strong column that carried me to 5,900’ for the high point of my flight. At first, I entered the lift in a right-hand turn and eventually reversed directions in order to keep the camera pointed at more interesting subjects than just the sky.

The glider was feeling more and confidence inspiring and my ability to core and center the lift felt natural. I peeled off and headed for the towers and hit more sink along the way and arriving a hundred feet below the summit. I worked my way around the far side and encountered many bubbles of lift boiling off of the canyon on the East side of the summit. The U2 demo handled with ease and predictability in the somewhat turbulent and uneven air. I finally prevailed and rose above the towers.

I pressed another mile or so Eastward in hopes of possibly tagging Mt Wilson if there was good lift, but none was to be found and I headed back toward Sylmar. It was a beautiful, clear day and I held the glider steady in hopes that my camera might capture a few good frames during its 14-second intervals.

Downtown Los Angeles between my nose wires and Catalina Island just above that:

On my way back from Big T I had the VG past full while on glide toward Little T and the long gap toward Lance’s Ridge. I hit some broad and some smooth lift and rather than letting off the VG, I left it alone and soon discovered that if I got used to the modest bar pressure of pushing out to keep the glider at 25 mph (when it was trimmed for ~35 mph) that it handled just fine with the sail fully tight. This was a nice trick since it allowed me to slow down in patches of lift without bothering to change the VG and then I could just relax and let the glider speed up to its trim speed on my way out. I don’t know whether this is an efficient cross-country technique but it did show me that the glider was very well balanced in roll and had no notable tendency to wind up in turns at any VG setting. In other words, I did not have to high side this glider like I do on my Sport 2 and my T2. This was an added plus for anyone considering using the U2 160 for extended cross country flights.

Returning from Big T:

I cruised back to Sylmar then tagged West Towers which gave me a circuit of about 15 miles from end to end. In order to set up the speed run I wanted to bank up a few hundred more feet and worked and area that is known for some pretty rough air. Even though it was later in the afternoon, there was no exception for this point adjacent to Towers Launch. By now, I’d been in the air two hours and my confidence if the glider felt very solid to me and I was able to effectively work the extremely choppy and rapidly drifting bubbles and gain the needed altitude. My camera caught a nice image of the locale:

After I did the speed run I was hoping to do a few spins if I could get enough height. The first of these was over the third bowl at Kagel while I was turning in smooth and gentle late afternoon lift. I found that I could control the glider all the way down to 20 mph in full VG so I slowed it down to 17 mph and the inside wing stalled and away we went. The nose immediately dropped and the glider wound up more rapidly than my T2 has ever done. It felt like I did two or three rotations in about 6 seconds. My track log showed that I only lost about 150’ but it happened fast. I relaxed my arms and the nose dropped further while it did another half-rotation before zooming out. This is not a glider you want to be doing spins in at full+ VG without plenty of ground clearance. On the other hand it didn't initiate a spin until I was going much slower than anyone would deliberately fly the glider and spun only after I prodded it.

I actually spent a fair amount of time flying the U2 160 in the low 20’s including working smooth thermals and it never felt anything but predictable and confidence inspiring responses. Bear in mind also that the glider trims at about 35 mph in full+ VG so that the likelihood of accidentally initiating a spin is pretty remote. I also attempted a spin at zero VG and just couldn’t do it. All I got was stalling spiral turn but no snap and break. I next tried a spin at ½ VG and that felt just right to me from start to finish.

Setting up a spin at ½ VG

Mid-spin at ½ VG and post-spin pull up:

The U2 has a reputation for being easy to land and off-hand I have no reason to argue with that. I find that this U2 160 is even easier to land than my Sport 2 155. I landed with a 5 mph crosswind coming nearly perpendicular from my left. I inadvertently left the VG on at ½ and found no problem or surprises as I did a full-flare, no-step landing which left a big ole grin on my face. My camera caught me just moments before the crescendo:

In summary, I was extremely pleased and delighted with the performance or handling of this glider. I could easily see myself owning and getting a great deal of cross-country and recreational flying from the current U2 160 even though I’m at the low end of the hook-in range. The glider was a pleasure and a joy to fly. The materials and workmanship all appeared excellent as well.

Computed performance using SeeYou, based upon my track log data: http://www.paraglidingforum.com/leonardo/flight/259628

@ 198# hook-in

L/D @ mph
11.1 @ 24
14.3 @ 28
12.6 @ 34
5.0 @ 54

In contrast, my T2 144 generally calculates out to 14.7 @ 30 mph and 5.5 @ 70 mph

Wills Wing U2 160 Demo #35645 Color scheme:

Views with full VG on:

Here is the photo album w/ full resolution images for a better look at Sylmar and Los Angeles.

Note: The views expressed in this article are strictly my own and do not necessarily reflect those of Wills Wing or anyone else.

NMERider

Wills Wing U2 160 Demo Flight