That is superb.
A SS has always had more than enough speed to take off as long as you can gain lift and get airborne.
Speed is only a small part of the equation...a sailplane can lift off at 50 mph.
It's a combination of wing load, length of wing/airfoil design ( he chose a good one for his purpose ).
He makes it look simple but he's flying that like a hang glider with his weight shifting turns and to some degree climbing or descending in combination with the prop speed.
He has to be very careful of stall speed and angle.
And you still need to know how to fly ( which is not so hard ) but take off and in particular landing would be tricky.
Good thing is flying it that way with weight shifts and throttle control it is closer to the motorcycle riding experience.
I notice he did not flair on landing - that's where the mcycle suspension is handy - he just planted it.
But guys....for $2k including all your flights and lessons you can become a sail plane pilot and be pulling 4Gs in 3 dimensions within a summer or two in one of these
My fav plane and I was quite pleased to see on hanging in Smithsonian along with the SR71, the Shuttle and a bunch of other classic planes.
only a hour from the GTA either one
http://www.yorksoaring.com/
http://www.sosaglidingclub.com/
mcycling in 3D