Construction has a very distinctive DaVinci touch: it's sobre but of decent quality and even with a certain blend of ambition and originality. Definitely this glider is not a subtle ultralight but rather a solid workhorse. The risers made of 22mm wide vebbing, metal connector, 4-liner with thick sheated bottom lines... The canopy is made of regular (not ultralight)Dokdo and Skytex cloth but the glider weight is however below expected due to well-optimized construction. The leading edge has huge intakes which have no mylar reinforcements but are always wife open due to relatively thick plastic rods spreading around 30 centimeters chordwise on both upper and lower surfaces, promising easy inflation and takeoff. The intakes have a pleasantly rounded shape giving certain flashbacks to Advance Bibetas, but the wing shape and the overall design are original with absolutely no doubt. The wingtip sections have small round valves made of ripstop -- maybe for better aerodynamics, maybe just for letting the garbage go out of the wing by itself.
Takeoff and ground handling. Good takeoff is crucial for tandems, and Duet did really shine in this test! Duet is amongst the best at the takeoff compared to other tandems i know. Even with the lightest wind the Duet goes to flight position in a gentle and calm manner and keeps overhead with minimal effort. It's even possible to bring it overhead applying no A-risers at all, a simple body drag is enough! Amazing for a big guy of 42 square meters!
Reaction to brakes. Amongst the best again! After some short flights Duet easily kept the honorable second place in my personal rating of maneuverability for tandems, preceded only by the outstanding Sup'Ait Sora (which has only a very small advantage in brake reactions). The brakes are light, it's like handling a solo wing up to 160-180 kgs of total flight weight. Amazingly, the brakes have almost no slack, the reaction to brake input begins from the very first centimeters of brake travel. The total brake travel is typical for biplaces, very long compared to colo wings.
This glider likes to turn rather flat, however entering the turn is unexpectedly fast. The turn radius can be easily adjusted by brake input, there's plenty of brake efficiency if you need to tighten the turn. Being a bit harsh on brakes may even result in almost-twist; this effect is rather typical for solo wings with high brake efficiency.
The bank changes occur in a calmer manner. You may force Duet to make a big bank, but this demands some time and some efforts since Duet is very well dampened. The big wingowers are however possible if you insist enough. I found the wingovers to be the most pleasant at 180 kg of total flight weight -- the brakes are still not too heavy but the reaction to brakes is well present. With heavier passengers (up to 220 kg of total flight weight) Duet moves faster on bank, but the brake efforts are less comfortable.
Pitch dampening is really impressive. Apparently Duet is one of the most pitch-dampened biplaces i've tried. High pitch stability is well appreciable even at the takeoff: Duet easily "stucks" above the pilot and demands only very minor corrections. Once airborne, it's also not too easy to build a big pitch, the glider always tends to keep it normal position above the pilot giving extra comfort for both pilot and passenger. It's interesting that, despite of high dampening, the Duet gives enough feedback in the slightly moving air of the before-spring. The brakes feedback is very well marked, the same for the airspeed changes. Entering the first spring bubbles produces gentle crunches and crackles of cloth, the pitch and banks feedback being very moderate. The risers feedback is well present but will not scare the passengers.
Landing. No problem throughout the whole weight range and even slightly above. The long brakes pull kills the speed very efficiently, making possible a zero-speed landing even in no wind (however this trick demands some training).
Concolusion. It appears that DaVinci made a nice biplace glider intended mainly for commercial use. Perfect takeoff, good landing, high pitch and bank dampening are perfectly suiting the demands of a typical commercial tandem flyer. The reactions to brakes are impressive, it appears that Duet is amongst the most brake-sensible biplaces. There's no limitation in use scenarios, the Duet can be flown in "pedagogic XC" mode or just to give some fun for your friends. It's also pleasant to mark that Duet is a well-elaborated and thouroghly developped wing which, for sure, will build a good reputation for DaVinci.
- Perfect takeoff in no wind conditions
- Good landing behaviour
- Very high brakes efficiency
- Not present
Special thanks to Rinat Sabitov and DaVinci Gliders for offering the glider for test flying!
Foto: I. Tarasova, A. Tarasov.