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Review of Windtech Serak
Test pilot: Norbert Aprissnig
Review courtesy of Gleitschirm Magazine
Translated from German by Verena Jurthe,
with thanks.
(*Corrections, comments & updates
by UK importer Carlo Borsattino - CB)
Slowly but surely the Spanish manufacturer Windtech, based in the northern province of Asturias in the city of Gijon, is getting a firm hold in the hard fought paragliding market in Germany, Switzerland and Austria. Respected distribution partners like Robair (In Switzerland) and Skyline (In Germany and Austria) are on the one hand partly responsible for that. On the other hand the best distributors don't get anywhere if the product isn't good. But Windtech has already fully convinced everyone about the great quality of their products with paragliders like the performance wing Quarx.
The newest creation by this Spanish company is the intermediate Serak, which got DHV 1-2 rating.
As with many other well known paraglider manufacturers, we find a unique owner structure within this firm, too. Gabriel Canada, who studied Business economy in the USA is the impulsive manager of Windtech. The other owner, Alvaro Valdes, is the quiet man in the background, responsible for the designs of the wing. To put Alvaro's construction philosophy into one sentence it is "Bringing approval to the point of perfection". He managed that, I will say beforehand, with the Serak magnificently.
Construction & Design
Whoever thinks that the Serak was a development from the 1-2 Ambar though could not be more wrong. The Ambar stays in the market as a basic intermediate, suitable for first time buyers, whilst the Serak attempts to reach the top of what is possible in the DHV 1-2 class.
With an aspect ratio of just 5 the Serak does not seem a spectacular intermediate. The revolution is to be found inside the wing: Alvaro Valdes combines 3 different concepts of diagonal cell ribbing, across the span of the glider, together with cell widths decreasing towards the wingtip. This is necessary because the different curvatures and tensions / strains inside the wing, due to the cell width decreasing, do not allow the more basic construction technique of just equal cell width and diagonal ribs. The visible effect of this very fines tuned development: The wing is incredibly clean and crease free in the air! The different cell width and diagonal rib concepts do of course affect the leinenpläne. In the centre of the wing the relatively long upper lines cover two cells, whilst in the outer area they cover three, and at the wingtip there are even three extra stabilo lines worked in. Apart from some cross ribs there are no other special constructions visible. In the perfil one finds that there is a small amount of 'arrow' form ('Arrow' form means that the trailing edge is more straight and the leading edge is curved forwards). The risers are straight forward 4 level risers with speed system and no Big Ear pulleys.
Quality and Finish
The quality and finish of the wing are altogether excellent, and all of the materials used of very high quality. The entirety of the wing's sewing (zigzag), the strong tension relief of the hangpoints (reinforcement tabs) inside the wing and at the wingtip, the finish of the line stitching, etc. are all an obvious sign of the excellent attention to detail and high quality standards that Windtech maintain. On the stitching of the line ends, the Kevlar lining is slightly shortened at the end which ensures soft transition and minimises entanglement . The high quality material is documented as the new Skytex material from Porcher Marine as well as Vollmetalrollen from AustriAlpin to name just two of them. There is little to be found to complain about in the quality of the Serak. The only thing I did not like were the plastic clips on the riser maillons that were not very secure.
Launch características
The launch características are totally well- balanced. No tricks are necessary, and the wing comes up reliably and neutral above the pilot. This is also true for strong wind launch.
Flight behaviour
After just a few metres of flying straight and a couple of turns the pilot will find the Serak's handling already familiar even on a first flight. It's like a return to the virtues of a particularly pleasant wing. The attempt to justify this rather subjective statement ends in the realisation that it is probably the exceptionally well- balanced nature of this wing that provokes this emotion.
Flying the Serak there is nothing too much and nothing too little. The whole tuning is just perfect for an intermediate. This is particularly noticeable in turns, where the Serak reacts promptly to any pilot input. Pitch, roll, the turning circle and break pressure behave in a constantly well-balanced relationship. The pilot therefore has a good feedback of these parameters and can adjust to them accordingly. The brakes are light and gradually increase in pressure, making it easy to adjust to a thermal core to gain maximum height. The wing requires a little bit of sensitivity to turn efficiently in weak thermals.
I tested the Serak in everything up to strong and very strong conditions and found it to be extraordinary stable, hardly ever collapsing, not even a wingtip and hardly pitching or rolling either. So much so that I seriously wondered when the conditions got very turbulent how on earth the Serak managed to stay so solid. It was really quite impressive.
However, this does not mean the wing was unresponsive or dull at all. Quite the opposite- the Serak gave feedback of the smallest changes (superb for finding thermals) and never leaves the pilot in doubt of turbulence.
Asy mmetric tucks are a rare occasion and simulating them one soon knows why. The Serak is literally fighting to stay inflated. Only a very hard pull on the A- riser initiates a 60% asy mmetric tuck. The Serak then closes a little at the leading edge but opens again very quick without turning very much at all. Holding the asy mmetric in, the Serak is easily stabilised and controlled to fly dead straight.
Descent manoeuvres
Big Ears: The outside A- lines work well even without Big Ear pulleys. The wing's high stability does however make it a little harder work. On a longer flight in Big Ears it is necessary to re- adjust one's grip. The wing opens on its own.
B- Stall: Test pilots have quite often remarked on the problems and inefficiency of this manoeuvre. Because of the high cell pressure that needs to be overcome and the short riser length it is difficult to get the Serak into a B- Stall. Once you have managed it, by climbing up the riser, you can then get the wing to go into B- Stall. The sink rate is about 7m/sec. The Serak comes out of this manoeuvre dynamically and has no tendency to deep stall.
Spiral dive: The spiral dive with this Spanish wing is very efficient. The sink rate quickly goes to 18 m/sec. and the wing is still easily controllable by adjusting the outside break. Extreme sink rates like this should of course always be recovered actively. Without opposite break pressure the Serak comes out of the spiral after a few 360's. Even then I did not find that it pitched much.
Suitability
My compliments to Alvaro Valdes and his test pilot Jose- Ramon Sainz. The Windtech team have succeeded in making the Serak an outstanding intermediate wing in the DHV 1-2 class. Although extreme manoeuvres (SIV) are predictable and manageable and the recoveries brilliant I would not advise this wing for a beginner / novice pilot.
This wing aims for a pilot looking for a wing with outstanding security and maximum performance potential. With a trim speed of 38 km/h and a maximum speed of 50 km/h the Serak is advisable to a pilot with some experience. This well- balanced wing enables the XC pilot to reach his goals stress free.
Test Conditions
Altogether I made 14 fights on the Serak, including some small XC flights. These were made in the time of May and June in the Austrian Alps, in some very strong thermals and some very broken and choppy conditions. 8m/s -up was not that unusual. I used a Right Stuff harness from Aerosport.
Technical Data
|
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| size |
25 |
27 |
30 |
| area (m2) |
25.81 |
27.55 |
30.80 |
| projected area (m2) |
22.73 |
24.26 |
26.50 |
| span (m) |
11.42 |
11.80 |
12.33 |
| projected span (m) |
9.47 |
9.78 |
10.22 |
| aspect ratio |
5.05 |
5.05 |
5.05 |
| nº cells |
52 |
52 |
52 |
| line length (m) |
6.94 |
7.17 |
7.49 |
| pilot weight (kg) |
50-70 |
65-85 |
80-105 |
| all-up weight (kg) |
70-90 |
85-105 |
100-125 |
| min-max speed* (km/h) |
22-50 |
22-50 |
22-50 |
| max speed trim* |
37 |
37 |
37 |
| DHV certification |
Pend. |
1-2 |
Pend. |
| DM Prize |
5.390 |
5.590 |
5.790 |
| FR Prize |
- |
- |
- |
| Euros Prize |
2.755,68 |
2,858,12 |
2960,38 |
| cloth: |
Nylon Porcher Marine Skytex 44 g/m2 |
| lines: |
Kevlar |
| kit: |
Bag, accelerator |
Test Log
| measuring instrument |
Brauniger IQ Basis II, GPS |
| take off height (m MSL) |
800 |
| min speed (km/h) |
22 |
| max speed trim* (km/h) |
38 |
| max speed (km/h) |
50 |
| Test pilot weight (Kg) |
95 |
| Flat load (k g/m2) |
3,45 |
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