RamAir Reviews by Mark Stucky and Paul Voight

RamAir Reviews by Mark Stucky and Paul Voight

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Glider Review: Wills Wing RamAir 146

By Mark Stucky
Originally published in Hang Gliding Magazine, June 1994. © 1994 United States Hang Gliding Association. Reproduced with permission.

This review reflects the author's personal experience and assessment at the time of publication.

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A few years ago I got an idea. As a trained test pilot, I felt I could use classical flight test techniques to quantify the performance and flying qualities of a hang glider. Although this went against conventional wisdom, I felt that with modern instrumentation I would be able to successfully accomplish my goal. I approached Wills Wing with the project and they agreed to loan me an HP AT 145 for testing.

The results of the test excited the Society of Experimental Test Pilots enough that Wills Wing and I were invited to provide a presentation of our results at their annual symposium in Beverly Hills. The briefing was very well received and we were awarded first runner-up, losing out to a joint NASA/USAF paper dealing with controlling the boundary layer of the forward-swept-wing X-29 at beyond stall angles of attack. I hoped that Wills Wing would view the test results as a baseline for future testing. They did, and recently invited me to repeat these tests on their new RamAir 146, this time for publication in Hang Gliding.

Replacing the venerable line of HP gliders, the RamAir, as the name suggests, makes use of a major innovation in that it uses ram air pressure to variably define the entire airfoil as a function of speed and angle of attack. The RamAir is the culmination of the longest product development project in the history of Wills Wing.

Improving upon the highly successful HP AT was not an easy task, and Wills Wing explored several different avenues before deciding that the RamAir concept offered the greatest promise.

Air enters the double surface via a single plastic scoop velcroed to the bottom surface to the right of the keel. There are no other openings on the glider and all tube protuberances are sealed with a thin layer of neoprene. Airfoil shape is controlled with internal fabric ribs joining the upper and lower surfaces (like those used in paragliders). Unlike a paraglider, the fabric ribs do not extend the full length of the chord, but are limited in length by the cross bar and breakdown considerations. The RamAir features a very defined airfoil with increasing undercamber toward the tips. The inflated sail eliminates the requirement for all but a single undersurface batten per side.

Setup

The RamAir sports an entirely new array of hardware designed for ease of setup and breakdown. For several years Wills Wing had been studying ways to improve the process. What started as a European requirement for easy setup or lay-down with the wings spread evolved into a mechanization that is almost as easy as pushing a button to open an umbrella.

Assembling the RamAir does not involve installing a single bolt, pip pin, nut or safety ring — even all flying wires stay permanently attached! The folding control bar is assembled by simply aligning the basetube halves and sliding a sleeve into place. The track-mounted apex slides into position by pulling a flush-mounted cable on the keel and placing a swan lever into a spring-loaded catch that snaps shut automatically. The glider is then rotated onto the basetube and the wings are spread. All of the top-surface battens are now installed except for the last three per side (this keeps the wing tips off the ground). Moving to the rear of the keel, a single easy pull on another flush-mounted rope and the keyhole rear kingpost tang is placed over its grooved restraining bolt. That single motion locks the cross bar into place and raises the kingpost, passively activating the bridles, VG system and VG compensator without any further action!

Next, the tip battens and the two undersurface battens (which pop into place without any rear holdback) are inserted. Rotating the swan lever to the second catch tensions the glider. Now press on the velcro-attached nose cone, air scoop and wing tips and you are ready to fly. If it's windy you can quickly and easily fold the control bar up by releasing the swan catch and lowering the glider to the ground — again without releasing any flying wires.

Wills Wing estimates that the RamAir setup procedure is about 30% quicker than the HP AT. I was able to assemble the RamAir in less than 10 minutes with practice, which is about six minutes faster than I could assemble an AT.

Speed Range

The RamAir has a Vne of 60 mph versus 55 for the HP AT. With a hook-in weight of 180 pounds I could pull the bar smoothly all the way in and the RamAir would accelerate stabilizing just under Vne. It is very easy to exceed Vne if you slip into it out of a wingover. The factory realizes the speed potential of the RamAir and includes an airspeed indicator with each glider purchase.

Speed Stability

Exact pitch pressures are dependent upon CG position and VG setting but are significantly lighter (about half as much force) at higher speeds than those of the HP AT. In a full arm extension dive the 10-20 pound pressure is light enough that you can push an extra couple of inches by using your fingertips. The lightly increasing pitch pressures were rated excellent for this class of glider, since adequate speed feedback exists through the use of control bar position.

I was amazed the first time I pulled the bar in on the RamAir and accelerated out. "Stiletto," was the name that came to mind as I screamed along. The RamAir cuts through the air like a knife through butter — fast and clean. There is absolutely no tendency to inadvertently dutch roll. The RamAir simply goes where you point it and will easily go 10+ mph faster than an HP AT regardless of VG setting.

Yaw Stability

At higher speeds the HP AT suffered from nose wandering with the VG tight and was directionally unstable, requiring constant pilot compensation with the VG loose. The RamAir is roll neutral. The glider just doesn't want to wind in or roll out.

Roll Rate

From wings level, the RamAir has light roll control forces and initiating a turn is easy. The RamAir has stiffer leading edges than the HP AT and the effects of this are evident during roll reversals. The RamAir has about two-thirds the roll performance of the HP AT. Any delay in roll rate also manifests itself as increased pilot effort, since you must hold your body displaced "uphill" for a longer period.

Spiral Stability

Both the RamAir and the AT have neutral spiral stability with the VG loose. Tightening the VG increases the nose angle which in effect shortens the fixed-length side wires. This decreases the dihedral, thereby reducing the spiral stability. With the VG tight, the RamAir has twice the spiral stability of the AT.

Glide Performance

Wills Wing claims that the RamAir has performance equal to the HP AT at low speeds and gets an increasing advantage at speeds above 30 mph. They back up their claims by having performed a series of side-by-side comparison flights in stable air. My results appear to validate Wills Wing's statement that VG loose is not performance degrading, and that VG tight is only required for a sink rate advantage at high cruise airspeeds or to attain maximum steady-state airspeed. Such good VG loose performance means you do not have to give up any handling performance (roll rate and spiral stability) while trying to maximize your soaring potential.

It is probably reasonable to assume that the stiff leading edges of the RamAir will deform less under the loads of a tight bank, and therefore be more efficient than an AT when cranked up in a small thermal.

Stalls and Departures

During a slow, wings-level deceleration the first indication noted is a loss of roll control authority. Like the AT, small lateral inputs are ineffective below 20 mph. Unlike the AT, a complete loss of turning authority occurs prior to stall with the VG tight. The glider was responsive to small pitch inputs all the way to stall at 16-17 mph indicated airspeed. I rated the RamAir to be extremely resistant to spinning, since the glider could be stalled with full roll and pitch control input for 15 seconds without spin entry. The RamAir has honest departure characteristics and I rated them excellent.

Landing

The HP AT 145 was known as a relatively easy-landing glider, but the RamAir is significantly easier to land consistently well. Flare authority is excellent and timing less critical. The majority of my flights were in light to no-wind conditions, and all landings save one were clean flares without any running or dropping of the nose or control bar.

Tow Considerations

The entire RamAir 146 evaluation was conducted using tow launches. I found the RamAir to be an outstanding tow glider. It required only fingertip pitch pressure to control angle of attack, as compared to a constant ten-pound pull-in required on the HP AT. More significant was the lateral stability under tow. The RamAir feels solid and is devoid of any of the lateral looseness seen in the AT. I consider the RamAir to be easier and safer to tow than many intermediate class gliders.

Conclusions

If your flying mainly involves hanging out at Torrey Pines then you might not need to trade in your HP AT-class glider for a RamAir. If you want to outrace your opponents in an Owens Valley meet then the RamAir can help. Since the roll performance of the RamAir is not quite as good as that of the AT, I recommend that you fly a RamAir well suited to your weight. I am convinced that the better strength, speed range, yaw stability, spiral stability and landing ease can make the RamAir safer in many situations. Last, but certainly not least, is the trick hardware and ease of setup. Wills Wing deserves a lot of credit for their innovative design.

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RamAir 146 Specifications

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Pilot Report: Wills Wing RamAir 154

By Paul Voight
Originally published in Hang Gliding Magazine, November 1994. © 1994 United States Hang Gliding Association. Reproduced with permission. Photos by Paul Voight.

This review reflects the author's personal experience and assessment at the time of publication.

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Ever since its official release at the 1993 U.S. Nationals (where it swept the top four places) the RamAir 154 has been riding a veritable roller coaster of popularity, competition successes and controversy. Being attracted to controversy like a magnet, I decided that the complete story of this glider needed to be told, and I was the man to do it. I use the term "story" because that's the format best suited for a review of this particular design. The fact that the 154's short one-year history is so colorful (and pertinent) dictates that any discussion of this design, at this point, has to include the background to fully appreciate the end result.

Besides, I have the luxury of deferring to the excellent review of the RamAir 146 authored by Mark Stucky, which appeared in the June issue of Hang Gliding. That article very thoroughly covered the technical aspects of the RamAir design concept. A lot has happened since that article appeared, however, and there are enough subtle differences in the two sizes of the glider to warrant this discussion.

First Impressions

I flew for about 15 minutes and had a full hour's worth of fun. I never really wired into it, but I certainly put it through its paces. My only reaction was awe and exhilaration. At speed, my helmet lifted off my head! You could go whistling along, straight and level, pounding through those Crestline thermals at 70 mph. It turned nicely, climbed well and felt different. The L/D seemed to hold constant well into the speed range, up to or past 35 mph! Holding a speed of 35 was a joy, and with the bar positioned at my collarbone a long race to goal would be a breeze.

Some History and Controversy

Wills Wing strategically released the RamAir a few days before the 1993 Nationals held in Lakeview, Oregon. Even with several days of tuning problems and flying technique readjustments, the four top places in the meet went to pilots flying RamAir 154's. Needless to say, however, the design made an awesome opening statement. As a result, sales were off to a brisk start, with all of Wills Wing's loyal followers scrambling to get their names on the ever-growing production list.

As customers began receiving and flying their new 154's there was an interesting reaction by some — they didn't like them! Historically, Wills Wing gliders had a very similar-handling quality from design to design. These RamAirs, however, were quite different. They were very easily flown too fast and seemed to prefer steeper bank angles while thermaling. Compared to an HP AT, which was quite easy to fly VG tight (lever down), the Rams were considerably stiffer VG tight. These combined factors required a longer learning curve to become comfortable flying the new glider.

The Grounding

On May 12, Wills Wing temporarily grounded the RamAir 154. Earlier that spring, over a period of a few weeks, there had been three reports of 154's tumbling in Europe (two since verified). Wills Wing modified a 154 with some ideas they thought would help it pass different DHV pitch standards, and went out to test it. During this testing they also retested what they thought was the stock configuration, and got results showing non-compliance with HGMA standards. Wills Wing grounded the glider immediately.

The project goal then shifted to regaining HGMA compliance. After reexamination of the test glider, and returning it to the actual stock configuration, Wills determined that the stock glider did pass HGMA standards with full loose and full tight VG, but that there was one middle VG setting, at one leading edge sail tension setting, where two data points fell below the HGMA minimum curve by about two pounds of control bar force. Wills decided to develop a retrofittable modification which would make the glider pass both sets of standards, in all VG settings, by an increased margin. Afterwards, they contracted with Mark West to verify their test results of the modified configuration on his test rig, which he did.

The Modification

The modification kit that Wills Wing provided to every owner included a new root batten reflex curve, a new CG forward adjustment, a different luff line compensation adjustment, and a new set of bifurcated luff lines. Bifurcated, a favorite new word of mine, refers to the splitting of a pair of lines into four lines. Two luff lines serving one wing divide midway, so as to connect to the trailing edge in four places. Obviously, the intended result of a much more compliant pitch curve was realized, as verified by gobs of certification at many VG settings.

Surprisingly, the modification also resulted in some very pleasant (albeit accidental) improvements in the glider's handling qualities, with almost no detectable deterioration in performance.

How the 154 Flies

On launch you'll notice that the glider needs to be held at a slightly higher angle of attack than previous Wills Wing gliders. When you hold the nose too low, the glider gets heavy. Otherwise, it launches like a hang glider. The heaviness of the glider (72 lbs.) is a non-issue because of the good balance.

Once airborne, the "new" 154 has a fairly conventional feel. VG full loose affords light roll pressures with a reasonable roll rate. Gone is the tendency (of the unmodified 154's) to bank steeply in thermals. In addition, the glider has a greater tendency to find trim. It is much easier to fly the glider effectively now, and thus benefit from its performance.

Thermaling these things takes some practice. What you have to practice is the art of doing as little as possible. Set the bank, and try to be a bag of cement. These things will go around flat and effortlessly — if you let them.

The bar pressure of the 154 is still light, about half that of an AT. The pressure builds progressively, unlike the original, but never gets annoyingly high.

Landing the 154 is (and always was) a piece of cake. I don't know how or why, but when you flare these guys they stop, stand up on the keel, and plop you on your feet. Flare early, late, downwind, crosswind — it doesn't matter much.

Performance

At low speeds, I find the performance to be only very slightly better than an HP AT. We have a very well-flown flying site here in Ellenville, New York, and on the good days I get to comparison-fly with 50 or 60 pilots, many of whom I know well (performance-wise). I have definitely noticed an effective improvement in sink rate and climb since the modification, which I'm sure is partly due to the new user friendliness.

At higher speeds (27-40 mph), the performance advantage of the RamAir concept really shows. I notice "the puff" kicking in at around 27 mph, and truly believe the idea works. We get conditions here in the East that lend themselves to high-speed comparisons; wonderwinds, with smooth winds aloft often in excess of 35 mph. On these days, the RamAir pilots are laughing! They're not just getting considerably higher, but maintaining the ability to move around as well. Forty miles per hour is a usable speed in a RamAir.

Conclusions

Obviously, I like the glider. I had to adjust a bit, but I like it a lot. Is it the glider for you? I don't know. If your style of flying is mostly boating around, getting high and landing in the LZ, you shouldn't be looking at any company's high-end glider. A Super Sport (another of my favorites) will do everything you want and need, and make you look good to boot. But if performance is a big consideration and you're shopping the high-end gliders, you really need a demo flight on a RamAir. They're safe, stable and strong, and the experience will be eye-watering.

With its most recent victory (Chris Arai's first place finish in the 1994 U.S. Nationals), I have to wonder how long it will be before we see pressurized hang gliders from other manufacturers. Until then, I believe this glider's got the edge.