We had a Dagling in the club at Andover many moons ago.
On good thermal days when everything else was staying up we would drag it out and have spot landing competitions.
It would barely make 600ft on the winch, and then it would only just make it back to the launch point !
Good fun on a nice summers day, no instruments, so one judged the speed by the feel of the wind on the face and comparing the undersurface of the wing to the horizon to asssess the angle of attack.