During test flights at Esrange / Kiruna the small models have been dropped from weather balloons from altitudes up to 32km. During desent speeds close to the speed of sound have been achieved in stable flight, with no flutter at all. The maximum speed was 970km, and this with a small plane made out of EPP foam, and with a lenght of only 90cm.
The gliders got lifted with small weather balloons.
Shortly after launch
Just before release at 30mk altitude
Glider in controlled flight, flying back to Esrange
Glider making turns above Esrange for losing altitude
Closer look of Esrange with bottom camera
Glider in final just before touch down.
Successful landing after a long flight!