Like the reed, it bends but does not break. Here we will take the fable "The oak and the reed" to explain the subject.Ī pilot "at the bottom of the range" (of weight) will be like the reed: He will be more sensitive to turbulence, therefore his paraglider more inclined to close, but without too many consequences. I'll let you calculate how quickly Obelix will arrive. But Obelix will arrive sooner (higher sink rate), and faster (higher horizontal speed). We can therefore conclude, to come back to the initial question, that Obelix and Asterix will arrive at the same place (same finesse). Horizontal distance / Vertical distance.To note that all speeds increase, horizontal speed, like vertical speed (sink rate). In short, it would then go at 36.3 km / h, instead of 35. If Asterix's PTV is 65 kilos and it carries 5 kilos of ballast, its speed only increases by 0.37%. If the PTV doubles, as is the case in this example, assuming that Obelix weighs twice the weight of Asterix, the speed gain is “only” 41% greater (√2, ie 1.41). ( 1/2 C ρ S Vo 2)/( 1/2 C ρ S Go 2 ) = Po / PaĬonclusion: the speed of the sail varies with the square root (√) of its PTV.So, to come back to our Gauls, the difference in speed varies according to the variation in weight: Let us recall two equivalences making it possible to obtain the RFA (Resultant of the Aerodynamic Forces): If Obelix weighs twice the weight of Asterix, and Asterix flies at 35 km / h, what will Obelix's speed be, if he borrows his paraglider? Wing load and speedįor a given PUL (Ultra light glider, therefore delta Where paraglider), the manufacturer establishes a weight range.įor example, for a given paraglider model and a given size, it could be 75-95 kg.ĭepending on whether we are at the top of the weight range (here 95 kg) or at the bottom (75), the behavior of the wing will be different, because the wing load will vary, mainly due to the variation in weight. The hang glider creates less drag, so it doesn't need to create as much lift as a paraglider. The reason is simple: at the same weight of the pilot, the surface of the glider in hang-gliding is much less than in paragliding. In delta, it is even higher, from 5 and up to 10 for the most efficient models. If you fly in a two-seater, the wing load is then greater, around 5 kg / m2… and you can feel it in the controls, particularly if the passenger is heavy! The average wing load of a solo paraglider is around 3.5 kg / m2. It is therefore expressed in kilogram / m 2. The wing loading is a ratio between the PTV (total flying weight) and the area of the wing.
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December 2022
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