RE: Jet Glider
John,
The weight of ASW28 is about 5.5Kg with 4m wingspan.
The 4.25m Discus is about 6.5~7Kg.
Both of them do have retracble landing gears.
I think the most important thing is the adverse effect of heat impose on the vertical & horizontal stabilizers.
Since the length of the fuselage is about 1.75~1.8m.
Best regards,