Yup Rem, the first time I viewed this vid I was shaking my head in wonderment about nearly every launch. But seems I always have some sort of negative comment to share, so I abstained. I'm with ya Rem, better to keep 'er down and haul assets until you can't run any faster, then run faster, and only after that should you let 'er fly. I've seen too many near-botched launches in seemingly nice breezes where the pilots did a "two-step-Tony" launch and the breeze subsided a second later. Oops.
I believe too many pilots transition to a bottle grip far too soon in their launching. Like as soon as the glider lifts off their shoulders. Then inevitably the pilot allows the AoA to increase too much ( nose pop or nearly so) and they lift off with barely enough airspeed.
I find it nearly fool-proof to hold a vine-grip all the way through the launch, then transition to the control bar with barely a hint of a bottle grip within the transition movement. I have much more pitch and roll control with the vine grip while on the launch run and have never had a weak launch with it. Certainly can't say the same when I used to transition too early.
Take a another look at the first rigid launch at 2:29. The pilot clearly holds the DTs with a vine-grip past his launch, then only after clearing the landing gear he transitions to a bottle-grip, then to the CB. Of course, he keeps a reasonable AoA on his initial run... until after launching.... appearing as though he nearly stalls it.
At 4:06, a flexy pilot transitions to the bottle after lift-off, and the launch was not bad, but still he didn't keep the AoA down well enough to really get a fair amount of groundspeed via leg-power and gravity.
Most of the pilots seemed to try to pull through the control frame with their upper body while unwittingly inputing much too much positive pitch on launch. I've seen this at multiple flying sites, especially where the launch ramp or slope is short. The pilots are actually
pulling near the bottoms of the DTs and therefor pushing the nose up at a high pitch angle.
Too much drag from the wing to achieve more-than-adequate groundspeed from leg-power.
The second rigid (5:34) to launch had a typical high AoA, bottle grip launch, and launched slow.
The launch at 6:17 had a vine-grip through launch, but again had too much AoA right from the git-go. So one can see it's not
all about the vine-grip. But it can certainly help if the pilot is aware.
I think it is easier (for body mechanics) and more intuitive to transition to the bottle grip too soon. It sometimes takes a big leap of faith and a strong constitution to hold that nose down well and long and remain in the grape-vine grip until well above terra firma.
But then, those boys down there do things their own way.
Take a look at the launch at 1:22. Ouch. Glad he pulled it off.
I think this is a great vid. At least if the viewer understands that most every launch shown should
not be replicated.
So there... there's my negative comment for today.
Merry Christmas!