Paragliding
U-Turn U2
Monday, 23 February 2009 17:36
High performance with maximum passive security in a tandem has, until now, been an unsolvable conflict. Now is the start of a new age: The U2, the new Tandem glider from U-Turn GmbH, has agile flying characteristics as well as a very high degree of security thanks to the revolutionary AFS-System (Automatic Flight Stabilization).
AFS technology, invented by U-Turn chief designer Ernst Strobl, represents a basic change in glider construction. Until now all measures to improve security resulted in a loss of performance, and vice versa. With AFS technology the issue of design compromises is no-more.
The brilliant, basic principle of AFS is based on pre-tensioning of the under surface at the trailing edge. A special sewing method at the brake attachment points provides the desired effect. In calm air there is enough pressure inside the cells to neutralise the pre-tensioning at the brake attachment points, i.e. the pressure inside the wing is stronger than the pre-tensioning and the trailing edge of the glider stays aerodynamically perfect just like a conventional glider.
When entering turbulent air with an AFS equipped glider, the system adjusts immediately; even the slightest drop of internal pressure allows the system to react and the pre-tensioning at the trailing edge effectively “pulls on” the brakes. A canopy featuring the AFS-system reacts without any steering or braking action from the pilot. This is exactly what the safety experts of the DHV recommend: The wing itself flies actively and therefore more safely. More detailed information about the AFS system can be found 
here . Of course the U2 uses the advantages of the dynamic cell-width reduction and the geometric setting of the profiles as well.
Thanks to the increase of security provided by the AFS system, Ernst Strobl was able to choose a profile with a more ambitious aspect ratio and shape. Andi Siebenhofer proved the concepts behind this system by making his record breaking flight across the Mediterranean from Greece to Egypt by paramotor on an AFS equipped U2. Andi’s paramotor equipment setup allowed not only a top speed of 62km/h, but also the durability and extraordinary stability to cope with a hail storm! Here you can find the riveting report from Andi Siebenhofer about his amazing experiences on our homepage.
Besides high performance and integrated automatic security the U2 offers everything you can expect as a professional or hobby pilot including a descent rate down to 1.1 m/sec; thus far unknown agility for a tandem glider; the landing behaviour of a solo glider. Unlike most other tandem gliders, the U2 offers a trimming riser which is approved by the DHV. Utilising the trimmers the glider can be adjusted perfectly to the prevailing wind and above all, the speed can be changed by up to 7 km/h. Accordingly a slow set-up of the trimmers allow an extreme slow lift-off speed making it possible to have a take off with old or disabled people. Launching the U2 is very easy, because the wing neither sticks nor surges forward.
To be able to concentrate fully on the passenger whilst flying the U2 has two other features built in to the risers to make the pilot’s job easier: B-stall-assistance; and a separate A-riser for “Big-Ears”. “Big-Ears” increases both the angle of attack and the surface load leading to a very stable flight attitude whilst the glider remains fully controllable. Whilst flying with “Big-Ears” the descent rate varies between 3 to 5 meters per second depending on the number of cells folded in. The “Big-Ears” A-riser feature has been borrowed from the U-Turn beginner’s glider, the BODYGUARD, where this feature serves as a security device to help inexperienced pilots to distinguish outer A-lines from the inners. Of course this kind of mistake doesn’t happen to experienced tandem pilots but Ernst Strobl nevertheless decided to add this feature to the U2, “Because it improves the ease of use allowing the pilot to put his attention to other things.”
The B-stall-assistance acts in a similar way. B-Stall is initiated by pulling the b-strap, this causes the current to break away from the top surface of the aerofoil and the canopy folds in the direction of the aerofoil effectively becoming a parachute. The glider then starts sinking at a rate of about 5 to 8 meters per second without moving forward. If the C-risers were pulled accidentally to initiate the B-line stall the whole flight attitude becomes instable, the glider tilts back and gathers backward speed shortly followed by heavy swinging. This is impossible with the distinctive B-stall-assistance feature. With a conventional glider a very strong effort is needed to pull the first 5 to 10 centimetres sometimes this effort is so great that it proves impossible for some pilots. By using a pulley system the beginning of the B-Stall on the U2 does not need much effort and can be done sensitively.
A special feature of the U2 is the ingenious line schema. The load bearing requirements of every riser was calculated specially by Ernst Strobl leading to the reduction at certain points of the diameter of the lines. This in turn realised an added potential in handling and performance, which is often underestimated. Effectively the line diameters vary according to the requirements of the different parts of the wing. According to Ernst Strobl: “In the U2, we use high-tech fibers which can hold up to 400 Kilo on each line.”
U-Turn Free Force II
Monday, 23 February 2009 17:34
Villingen-Schwenningen. The FREE FORCE by U-Turn is now available as “new edition” in a fresh, trendy design and the new U-Turn-claw. Furthermore, the canopy is now equipped with the newest Dyneema lines, which optimized extension behavior gives the glider an extra portion agility. Therefore the very agile canopy is more than ever a must-have for those trying to practise acro-figures.
With the new design the FREE FORCE appears even more dynamic. The FREE FORCE has the identical ground plan as its successful, elder brother G-FORCE, but its aspect ratio is so far subdued by the designer Ernst Strobl, that the conferral of the seal of quality was assured.
There is even more: due to the employment of the automatic flight stabilisation (AFS) the canopy was awarded, despite tremendous performance in many fields, the safety of the DHV-assessment 1-2.
"FREE FORCE stands for a lot of fun whilst flying. By means of the manoeuvrability and agility, similar to the G-FORCE, connected with safety supplies of the AFS, the FREE FORCE is the perfect glider for all those who want to start acro-gliding" Strobl marks an area of employment.
At the same time the long-haul pilot can look forward to this first DHV-2 glider with AFS-system. Although the FREE FORCE has only a small cap, it craves for altitude in the thermal. With a top speed of more than 56 kilometres per hour one is very agile en route and the AFS-system makes sure with many little, automatic corrections that FREE-FORCE pilots always achieve the maximum altitude on trips.
The FREE FORCE new edition is available in sizes 22, 24, and 26 in the attractive colour combinations. The canopy is in stock
Of course there had been long discussions whether to employ the AFS-system in a DHV-2-wing or not when the new canopy was introduced. But now, after the prove of value, as expected, the AFS is still on board in the new edition. Because the system offers a lot of advantages.
To talk about acro-gliding: The FREE FORCE is available in sizes 22, 24 and 26, and thanks to the ground plan that is identical to the G-Force, this canopy also goes about it with tremendous dynamics.
Dynamic figures such as spirals and loops work in an easy way; here the unrivalled performance equipment is set to activate when and if required. "The AFS-system is not activated during dynamic manoeuvres, as the pressure inside the wing prevents an intervention" Strobl explains.
With regard to figures such as the MacTwist, it is a different matter. If the pilot misses the break moment, the AFS starts slowing down the canopy automatically, so the shooting forward and with this the reaching of a potentially dangerous flying situation are prevented. "Because of the very sporty interpretation of the guidelines I could boost the pre-tensioning much better with the FREE FORCE in contrast to our beginners glider the BODYGUARD" Strobl illustrates. The effect is equivalently noticeable. However at no time does the system prevent the pilot from learning the figures: Someone who brakes on time feels nothing from the AFS and this does not only apply to the MacTwist, but also to further figures.
"All 44 cells of the FREE FORCE are endowed with the AFS-system" Strobl explains. To draw a comparison one can say that with the BODYGUARD only the ten outer cells are automatically slowed down at a time. "Here it is not so much a question of the folding stability than of the prevention of the shooting forward."
To summarise, a pilot who is looking for a glider with which will give him a taste of real acro-gliding like the professional pilots while still giving a mainly mistake-forgiving flight need look no further than the FREE FORCE.
To talk about long-haul-flight one can say that although the glider has a relatively small area, there is always something going on with it in the thermal. Ascending is no problem for the FREE FORCE and once up there the canopy has a minimum sink of 1.1 metres per second. During long-haul-flight the AFS-system also becomes positively apparent, the system constantly corrects small turbulences by braking automatically. Theoretically this occurs with some at reduction of speed, however the FREE FORCE is amply blessed with velocity. With 38-39 kilometres per hour (trim) an 53 – 56 km/h accelerated (full area load), the canopy cannot deny its origins i.e. the very dynamic G-FORCE. With the FREE FORCE it is no problem for pilots to decelerate because the minimum speed comes to 23 kilometres per hour on average.
To sum up, the use of the AFS-system benefits in regard to the air safety by means of an improved collapse stability for beginners, even the constructors of powerful gliders are impressed by the system. FREE FORCE means having lots of fun and performance coupled with a high level of security.
U-Turn Obsession
Monday, 23 February 2009 17:33
The long awaited High End 1-2 paraglider from U-Turn generates extraordinary levels of performance with an aspect ratio of 5.55 and offers significant security with the further developed AFS system.
Is there a better feeling than flying high over the earth with a paraglider? This experience of freedom and closeness to nature is now even more attractive with the OBSESSION from U-Turn. And faster. And safer. The latest innovation from designer Ernst Strobl is now available. The OBSESSION has an aspect ratio of 5.55 and is brimming with performance but thanks to the optimized construction technique and the automatic flight stabilization system (AFS), also has the safety of a DHV 1-2 paraglider.
The OBSESSION is situated right on the border between DHV 1-2 and DHV 2. It defines the cross-over point between maximum performance and the security level of DHV 1-2. The fantastic glide ratio, available even at full speed, is one of the significant properties of the glider. The OBSESSION possesses the typical U-Turn long accelerator travel for exact control and high final speed. In addition the agility and manoeverability are second to none. All of the know-how from the development of the Acro-reference G-FORCE 360 has been applied to the very dynamic and direct handling of the OBSESSION. Very flat yet confined thermalling is the glider’s trademark and the OBSESSION's turning sink rate is extremely low. The pilot will notice that there are without doubt genes in the OBSESSION which where previously reserved for higher paraglider categories.
The OBSESSION has a high inherent stability despite the remarkable performance and aspect ratio of 5.55. This is mainly due to the further optimized AFS-system. The dynamic basic design of the glider canopy allows room for an increase in the AFS effectivity – without the danger of losing enjoyment or performance potential. The wing area upon which the AFS system is effective has been increased by 20% in comparison to the INFINITY II. This increase in the effectivity and further enhanced stability in turbulent conditions is successfully realized without degrading the fine tuned reactivity of the system.
Interestingly, the OBSESSION has a large number of upper cascade lines. The upper cascades are 40cm long, extremely thin 0.6mm Liros lines. This causes a better distribution of the forces across the paraglider canopy and a reduction of the single force per line and connection point. Ernst Stroble explains, "This higher count of topmost lines costs some slight performance reduction because of their air resistance, nevertheless by their employment I was able to construct the wing to have significantly higher performance with the same good resistance to collapse, so that these losses are more than overcompensated”. Because of this design feature the OBSESSION is particularly resistant to collapses. Should a dangerous situation arise and the large secure performance region be exceeded then the canopy will give a corresponding feedback beforehand.
Strobl decided to use the glider fabric for the series production which had been tested so convincingly during the Trans Speed Europe by Mad Mike Kng at highest stress rates. It was clear after exhausting tests with several prototypes of different sizes: "An even lighter material did not show improvements neither during start, flying or landing" Strobl says. The selected material from Porcher Marine offers superior UV-resistance and overall mechanical stress resistance. In order to ensure the longevity of the paraglider and its second-hand value, not to mention the easy start behaviour, the OBSESSION also has the Mylar Fix System, which is implemented in the INFNITY II and which has been universally applauded. Any unwanted creasing of the leading edges is prevented with a fixing loop system – the paraglider stays in form and keeps within the original performance criteria.
"It was our aim to get a very high performance paraglider with the high security standard of a DHV 1-2 category to the market", states U-Turn co-founder Thomas Vosseler. He is very satisfied with the results. "Despite this it has to be stated clearly: that the Obsession is not intended for beginners and it is not suitable for learning/beginners training purposes." Newly qualified pilots who want to be more ambitious than U-Turn’s DHV-1-BODYGUARD, should select the INFINITY II with AFS. "Indeed the INFINITY II is also a DHV 1-2 paraglider but it is significantly closer to the 1 level and suitable for beginners training purposes."
The OBSESSION is available in the sizes S (65-90 kg – to be confirmed during the DHV-tests that are scheduled in the next weeks), M (80-110 kg) and L (100-130 kg). The characteristic U-Turn motif has been restyled and this gives the paraglider a very sporty, dynamic appearance.
U-Turn Emotion
Monday, 23 February 2009 17:30
Performance meets safety: This is the headline about the EMOTION. This DHV-1-canopy not only provides lots of fun in the air, but also much, much passive safety due to the AFS-system. In brief: Good emotions.
The aspect ratio of the EMOTION has been slightly reduced in comparison to the BODYGUARD, the reference model among the safest category 1 paragliders. Nevertheless constructor Ernst Strobl has decreased the curvature at the wing ends. The EMOTION gains agility and improved handling reaction because of this. The AFS system provides the safety and security: The Automatic Flight Stabilization influences all cells and prevents in the majority of all cases unpleasant asymmetric deflations already during their initial phase.
The EMOTION is delivered from the factory with a conventional harness.
In this way we can fulfill the wish of those flying students who wish to start in the "normal" fashion with the corresponding start procedure. Additionally the B-stall as a method to lose height quickly can be instructed and practised. The EMOTION can be made available optionally with the well known divided riser system. With this the EMOTION can perform the B-stall safely, that is sinking at a rate of around 5m/s while still being fully manoeuverable with a glide ratio of 1:3,5. This for example makes it easier for inexperienced pilots to land on small landing areas which is more dificult to manage when the maximum gliding ratio has to be used without the B-stall technique. In any case the EMOTION is very suitable for instruction purposes with both harness systems.
Another feature is available for the EMOTION as well: It is fitted out with the MYLAR-FIX-system, the unique folding system to protect the sensitive leading edges and air intakes.
The EMOTION is available in four colors and in the sizes XS (55 – 80kg), S (70 - 90kg), M (85 - 110kg) and L (100 -130kg). This excellent performing 1-category paraglider closes the gap which lies between the BODYGUARD and the INFINITY II.
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