Sunday, August 22, 2010

parachute Launching.

(a) Forward launch: in low wind the wing is inflatal with a forward launch, where the pilot tuns forward so that the air pressure generated by the forward movement inflates the wing.
(b) Reverse launch: In higher winds particularly ridge soaring, a reverse launch is used with the pilot facing the wing to bring it up into flying position then turning under the wing to complete the launch. Reverse launches have a number of advantages over a forward launch. It is more straight forward to inspect the wing and check the lines are free as it leaves the ground. In the presence of wing\d, the pilot can be tugged toward the wing and facing the wing makes it easier to resist this force and safer in case the pilot slips as opposed to being dragged backwards. These launches are making the ground speed required to pressurise the wind much lower the pilot is initially launching while walking forwards as opposed to running backward.
(c) Towed launch: In flatter countryside pilots can also be launched with a tow. Once at full height the pilot pulls a release cord and the towline falls away. This requires separate training as flying on winch has quite different characteristics from free flying. There are two major ways to tow. Pay in and pay out towing. Pay in towing involves a stationary winch that pays in the towline and thereby pulls the pilot in the air. The distance between winch and pilot at the start is around 500 meter or more. Pay out towing involves a moving object like a car or a boat that pays out line slower than the speed of the object thereby pulling the pilot up in the air. In both cases ,it is very important to have a gauge indicating daN to avoid pulling the pilot out of the air. There is one other form of towing , static towing. This involves a moving object, like a car or boat attached to a paraglider or hand glider with a fixed length line. This is very dangerous because now the forces on the line have to be controlled by the moving object itself which is almost impossible to do.

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