A plane that weighs 8.5 kilograms will need a wing of much more than 1.7 meters span, assuming the wing has an aspect ratio of 5 or 6. Either the weight will have to be reduced by a factor of two or the span will have to be increased to about 2.4 meters with an aspect ratio of 5 or 6 in order to get the wing loading down to that of a trainer.