In "Vol libre", September 96, page 9-11
The Flight Design B4 has just been crowned French National Champion in the paramotor cup! It is indeed a rousing first entry for this wing with its many qualities.
In Germany and many countries around the world, South America, for instance, the brand enjoys a definite leadership. The B3, A4, A5, A5 Sport and now this B4 are remarkable wings, easy to use, fast, and safe. The French importer, ECIF, is a true professional, as much for regular customers as for competitors to whom it provides wings, as it is when running its marketing campaigns or dealing with the press. The results in the sport world are there: previous to the B4 chosen by Philippe Jeorgeaguet and Alain Arnoux for the Paramotor World cup, the B3 was already France vice-champion in this category! All this with a pure free-flight wing. Those two guys probably understood that the true power of their machine lied first in the wing! Despite all this, Flight Design Germany offers little help to its French distributor...
The brand, born out of paragliding, has also known how to let go in time of the soft bag monoculture in order to diversify towards the "hard" world; for instance, it entered the ULM field with a very good looking composite-built multi-axis ULM it built with ASO, itself a manufacturer of "pendulaire" ULMs. Felix Ruhle, who spent time working at Lutz Drachenbau, is currently putting the final touches for the company to a folding free-flight rigid wing, a la John Lutz' Pegasus. Flight tests started last August.
The vivid yellow triangle and the Flight Design logo brighten up a simple black bag that carries a few white graphics representing stylized compasses. The cloth is rather thin, but appears to be quite sturdy. There is a big pocket in the front, a small one on top, the shoulder straps and the belt can be adjusted, but there is no padded back, and the volume can't be custom-fitted to the load.
The double coated T-9600 48g/m2 Teijin polyester wing is secured with a strap and stuffed in another nylon stuff bag, like most all other manufacturers do.
The wing is a combination of good ideas, with wide cells divided in halves and linked one to the other with diagonal reinforcements attached to ribs between the cells. According to the manufacturers and according to the theories of Dornier, the "TNT" system (for Tragflugel Neuer Technologie) lets the upper surface be perfectly bound to the inner surface, allowing no relative movement of one surface respective to the other. Lines are led to every other cell; the sewing on the rib that has no line is external, so it needs to be checked during the preflight inspection. The inner ribs sport extremely wide openings, which allows easy air flow inside the wing. Where the B lines attach, a hefty oval reinforcement picks up the forces applied to what's left of the ribs at the level of the line attachment. The luff and the ribs on the leading edge are reinforced with lengths of braid and are sewn with "double straight stitching". A dacron reinforcement rigidifies the main ribs to allow the wing to scoop well. Only 4 of the cells in the wing tips are closed, all the others offer degressive openings, and all are 20 cm wide.
The lines are 1.5 and 1.1 mm Dyneema. The layout is the classic 4 lines, branching out once. They gather at quick links that are covered with transparent shrink tubes, on 5 risers because the A risers are traditionally split at Flight Design. This configuration allows to easily pull ears by pulling down only on the outside risers, and to progressively inflate the wing if you only grab the inside A's in strong winds. They are marked in yellow, and the B's in red. The double-pulley speed system, with 22cm between the pulley axis (!), is permanently attached. It requires a double-rung speed bar to be able to reach max speed. The wing comes with one from the factory. The effectiveness of the system is tremendous ! It comes on top of a trim system on the D risers with 10 cm of travel. When used on its own, the trim system lets you reach comfortably 45 km/h just by loosening up the D risers, before you've even started using the speed bar. Very impressive ! The speed system pulls down the A, B and C risers (at 50 % pull) together, then, strangely, the D riser on the last 4 cm of pull, which gives the profile a little bit more curve...
With only a maximum chord of 2.45 m, a leading edge and a luff being almost parallel, the pilot hanging 8 m below the wing, a 5.8 aspect ratio, and the B4 has a killer look!
This 66-cell machine with TNT cross bracing, complicated to manufacture, is put together by the Chinese of Laminated Products. Manufacturing and finishing quality are excellent.
The risers with the trims are not the ones used for the certification. A little sticker floating in the wind, affixed on the A riser (you can't miss it) honestly reminds you of it! The position for the trims that correspond to the certification settings is fully pulled in. We found that the B4 was more friendly, lively and precise with the trims out 2 cm. A wing of that level, that is initially so stable in turbulence, can perfectly well sport this type of system, which is a real plus for advanced pilots, and which, if set to an average chosen position, doesn't bother the rest of the pilots. Denis Cortella even rigged trims on the A risers on his wing, so as not to get too tired pushing down on the speed bar during long runs between thermals!
The wing laid out in a horseshoe, both A risers held together at the quick links, hands at shoulder level, starting with the lines tight, the B4 scoops the air progressively and goes up smoothly. The pressure required on the brakes is light and the corrections are efficient, it flies straight and doesn't tend to fly over the pilot when accelerating. The overall feeling is one of smoothness during the take-off stage.
Yann Espinasse and a friend have just taken off for an out-and-back St-Hilaire/St-Eynard that is not a given. As they are flying Zen wings, it will be a good way to compare! I follow them right away, and we get together at Manival.
The B4 enters a turn with a slight yaw that tends to dampen. The pilot must help with a subtle weight shift to give it a little bit more roll than it produces by itself: this way, you get the very solid turn the wing knows how to produce. The pilots who like flat turns, that is, with little tilt to the wing, will be delighted. It is the natural tendency for the B4. There is little dampening on the roll axis: with weight shifting, the pilot can enter a thermal without hesitation, but on the other hand, it requires more pilot input when flying in rough air. The B4, with the chest strap on our Profeel harness tightened at 38 cm, "shakes" a little bit, but it never collapsed on us during the whole testing: the tips just folded a few times, with no bad effect, and reopened almost immediately. After inducing a 30 % asymmetric, the B4 is easy to control and the pilot can weight-shift to fly straight. When leaving a thermal its marked tendency is to center itself on its own! The outside wing accelerates frankly during a 1/4 turn to put the pilot back where s/he should have stayed! Quite surprising the first times it happened, because we had never experienced such a solid behavior in any other wing.
The brake pressure is rather light. They become more and more efficient the more you pull on them. They are very precise on 10 cm, which gives the pilot the whole piloting range. From this position, hands at chest level, you still have to pull another 20 cm before the wings stalls, quite gently, at 21 km/h with the test wing load!
We leave Manival at 1450 m, which is rather low, and are stepping on tree tops when we reach the other side. Figure eight in light lift bring us back into the flight pattern, that is at cliff level. The B4 really shines then, it is so efficient. With a turn here, a turn there, we end up at the fort, where we get to cloud base at 1700 m to fly back in all comfort, going 45 km/h trims off. We fly side by side with the Zen for 8 km, and arrive pretty much at the same time, pretty much at the same altitude, the advantage going to the Apco nevertheless. We each choose different options to fly up the Dent de Crolles, which won't let itself be conquered. We go back and forth over the Plateau des Petites Roches, flying in light lift. When going up, both wings seem to be on a par, with it seems a slight nod to the B4 in handling, as it centers itself more easily and seems more solid in the turns, despite its higher aspect ratio.
The B4 is well dampened in pitch. Still, it accelerates well when the pilot raises his or her hands; it reaches 35 km/h with the trims on (corresponding to the certified configuration) and 45 km/h with the trims off! With the speed bar, we measured 48 km/h trims on, 51 km/h trims off. It's been a long time since we last measured such speeds on a "Performance" wing!
The feeling when performing maneuvers like ears or B stalls is, just like when launching or braking, one of smoothness. Exits are quiet, with little surging. The B4 re-opens progressively by itself or instantaneously with brake input. It is a very self-sufficient wing!
Our measurements, taken in the morning, gave excellent results for a wing in this category, with a max glide of 8, but even more importantly of 7.19 at 45 km/h. It's on a par, a little better, with a standard Omega 3 w/ thick lines. We wonder why Flight Design looses credibility by claiming a glide of 9 in its spec sheets, as well as a max speed that is lower than it really is.
Flight Design manages once more to astonish us and to reach us. Aimed at pilots that already have a solid experience, this B4 offers a remarkable combination of easy flying, accessibility, safety and performance. The pleasure it offers and its efficiency in all conditions could for sure lead it to the podium in competition, without the extremes of handling and piloting required for "competition" wings! The price stays reasonable and is amply justified by the overall quality of the performance and of the construction of this machine.