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KaiMartin wrote:And there you have it: The PG wing is flying with an increased pitch at a lower speed even though the pilot is still hanging straight under the wing.
In addition, PG pilots can pull the on a contraption they suggestively call "accelerator". This selectively shortens the front lines more than the middle ones, effectively pitching the wing down.
---<)kaimartin(>---
Thanks for posting.
You are, of course, technically correct that PG pilots do have some limited control of their pitch and airspeed. But the key word is limited (note that despite my participation in the founding of the US Hawks Hang Gliding Association, I do hold an Advanced Paragliding rating).
In the U.S. we have a slightly different name for what you called an "accelerator". We call it a "speed bar". Just as you described, it proportionally shortens the lines from front to back causing a slight decrease in the angle of attack. I have used it many times when I was desperate for penetration into the wind. The mechanism is very clever, and it can pull the "nose" down by a few inches. But the difference in speed is pretty negligible when compared to balling up and diving a hang glider (see any of John Heiney's flight videos where he is picking up speed for a loop).
You are similarly correct that pulling both "brakes" does have an effect on airspeed - especially for landing. But again, it is negligible when compared to the dramatic nose-to-the-sky "hard flare" that can be accomplished in a hang glider.
But more importantly, both of those two limited airspeed controls on a paraglider also introduce considerable danger. The speed bar (accelerator) lowers the pitch only a few degrees, but even that small amount is sufficient to greatly increase the possibility of a frontal collapse - especially in turbulent air. This is drilled into every student's head during training. On the other end of the speed range, pulling too much brake can stall the wing. Anyone who's stalled an airplane or a hang glider knows to expect a "stall break" where the nose drops automatically and the aircraft begins a natural recovery. Sometimes (as in a "power on stall") these effects can be somewhat more dramatic. But they are NOTHING compared to the full stall and recovery of a paraglider. The stalled paraglider wing first disappears behind the pilot as a ball of "loose laundry" leaving the pilot in free fall for a few moments. Then as the pilot hits the limits of the lines, the paraglider re-inflates and shoots forward over the top and out in front (assuming it isn't self-entangled, but that's another story). Sometimes this forward surge is enough to send the glider out front and eventually down below the pilot. In these cases, pilots have actually fallen into their wing - "gift wrapped" for their rapid to return to earth. In the best cases, the pilot can control this surge without stalling again and after a few moments of terror return to normal flight.
So while you might technically argue that paragliders DO actually have some speed control, it is generally both negligible ... and risky.
