Test - Windtech Tempest
The Spanish paraglider manufacturer Windtech, celebrating their 12th anniversary this year, has surprised us with this new advanced intermediate model, the Tempest, a DHV2 glider that replaces both their intermediate Quarx 2 (DHV2) and their high performance model Syncro (DHV2-3).
The reason for this unusual double succession can be found in the significant performance of this paraglider for its level of security, and the design solutions introduced in it to achieve such balance. Among these, we can mention the floating ribs and the small pockets inside the inner sail of the leading edge, to grant better performance and resistance to collapses, especially at speeds.
The Tempest is a completely new glider, with a relatively deep profile and open cells. The planform and aerofoil sections have been computer designed with “a perfect aerodynamic tension” for the best possible glide throughout the speed range, according to Windtech.
The aspect ratio of this glider is 5.66, one of the highest in its category. It feels fast at trim speed and stepping on the speedbar we can reach more than 55k/h, depending on the conditions and the load.
Windtech expects to cover the needs of a wide scope of pilots with this glider. We believe that many will like its stability, the handling and the ease of use of the speedbar.
We received a Tempest M for this test, just on time to take it with us to Chile. It was there where we flew it, in diverse conditions and places: From a smooth soaring flight in front of the sea in Valdivia, Andean thermals in Santiago, strong windy conditions in La Serena, or the famous thermal-soaring of Iquique, in the Atacama desert.
One of the qualities we liked the most in the Tempest concerning dynamic behavior was its great pitch stability. It is a solid glider, with a healthy tendency to recover normal flight with no big surges or dives.
We induced many collapses for testing. Pulling down an A riser the glider tends to stay open until the hand is very low, then the leading edge folds down but the wing remains half inflated. It requires a strong input to fully collapse one side of the wing. The entrance in the turn is gentle, with no tendency to accelerate. Just by using weight shift we could maintain our course. Once we released the riser, the glider re-opened on its own.
During the test flights we had the opportunity to fly in different types of thermals, some smooth flights and some not so smooth, with narrow thermals and strong cores. In such conditions we noticed that if one side of the wing suffers a loss of pressure it rarely collapses. The loss of pressure comes as an ‘accordion-like’ shape, which means that the wing does not collapse but seems to contract on itself along the span, to quickly recover its internal pressure and shape. A few times we had some small wing-tip tucks that reopened almost immediately without pilot input. Apart from that we did not suffer any significant involuntary collapses.
Big ears are easy to pull thanks to the split As. They remain in, allowing the pilot to use weight shift. They don’t come out without pilot input, but with a pair of gentle turn reversals they re-open.
Using weight-shift and the brakes together, you can be spiralling down in just one 360, achieving high descent rates although with a significant physical force, like all high-g manoeuvres. Thanks to the profile’s own ability to recover flight without big surges or pitching, the exit can be quite gradual.
Trying ‘dolphins’ we again noticed the pitch control of the Tempest: We found it hard to make the glider dive more than 45º and we never felt that the leading edge lost pressure; the glider stayed solid and fully inflated all the time.
The B-stall enters after a good effort, but it is quite stable and the sink rate goes between -5 and -8 m/s, with no tendency to make a "croissant" of the glider. The exit is benign; the glider quickly recovers its shape, gaining speed, and recovers flight without any sudden dive.
The speedbar of the Tempest is easy to use throughout the speed-range, not heavy at all, which helps the pilot get the most out of all of the virtues of this paraglider. At high speeds, it keeps its stability and a good sink rate.
Construction wise the Tempest is a flawless glider. We did not find any wrinkles in the sail and it has a clean brake-fan. The definition of the leading edge and the internal definition of the cell-structure is remarkable. The openings are small, with floating ribs or profiles (part of Windtech’s SSS or Security Speed System) to maintain a very regular leading edge in flight. It has internal pockets inside the inner sail of the leading edge to prevent it from "fluttering" in accelerated flight, and to get optimal performance throughout the polar. This seems to work just as claimed.
The lines and the internal diagonal ribs (two types of diagonal ribs depending on the thickness and width of the cell, without intermediate cells) help obtain a very clean outer sail, specially at the leading edge, which translates into a greater efficiency of the profile and better overall performance.
As a counterpoint to these technological solutions of design, we have to mention that the leading edge is a bit heavier than usual, so the pilot needs to learn how to handle this extra weight, especially in reverse inflations in light wind. When you set the glider on the ground the cells already show the starting shape, ready to be filled with air. But if there’s no defined wind you will need to pull the risers strongly to prevent the leading edge from falling ahead under its own weight. Once the air has entered in the cells, however, the weight of the leading edge no longer affects the process and the Tempest rises evenly and consistently, with no tendency to overshoot or hang back.
Handling and senses
The Tempest has a relatively short brake travel. In about 20 cm we have almost all the dynamic control of the glider, for “happy” turns or to take the most out of the thermal cores, before reaching acro flying. The brake has a moderate pressure not too hard, not too soft precise enough to "feel" everything going on in the glider.
Of all the Windtech gliders we’ve had the chance to test fly, the Tempest seems to be the best all round and the most fun to fly, with a direct handling and a good feeling of control over the canopy. With the first third of brake we could make flat turns and seek the best sink rate. To make steeper / acrobatic turns the Tempest demands more brake, especially to round-up more aggressive wingovers or to find the stall point. Otherwise, 95% of the time we will stay within the first 20cm.
A peculiar detail: the Tempest comes from factory with very long brakes and we had to shorten them more than 10 cm to be comfortable with them.
Performance and references.
This is a glider with an auto-stable profile that works very well across a wide speed range. It can be flown smoothly to climb in weak lift and it can also turn dynamically to center narrow cores. Performance wise, the Tempest is one of the fastest and highest performing gliders we have flown in its class.
Our test pilot Nacho Montoro, who flew the Tempest 27 at 98kg all up, found it fast, dynamic and solid. Compared to his usual glider, a UP Trango (DHV2-3), he thinks that the Tempest has better performance, is faster and offers greater solidity and stability.
The manufacturer claims more than 9 points as best glide, which corresponds with our conclusions (to achieve this glide we need to fly efficiently, using an aerodynamic harness and a bit of speedbar). The best sink rate is near 1m/s with about 3-4 kg of brake, at 30 k/h approx. At trim speed we reached 38k/h, as quoted by the manufacturer.
The max speed of 58 k/h claimed by Windtech seems realistic to us, as long as the glider is flown near the top of the weight range. The sink rate at high speeds is very good, which makes the Tempest a fast and surely very competitive glider in the DHV2 category.
The Tempest is accessible to pilots who are already experienced with a DHV1-2 glider, and who wish to take the step up to the higher category. This glider is dynamic and responds well to the controls, so they will have to be careful about over-reactions. Inflation requires some skill in light wind.
Pilots used to DHV2 gliders will find that the Tempest is at the top of the class regarding performance, but it’s still not difficult to handle. For them it would probably be a “natural”.
Pilots coming from higher categories (AFNOR Performance or DHV2-3) will probably get more performance from the Tempest than from their higher rated gliders of more than one year ago, but with a safer behavior. For them it would be a good change if they are looking for safer flights without sacrificing the performance they are used to.
Its qualities make it a good option for pilots who want to compete in serial class / DHV2.