You probably don’t want our opinion on the 13.5 meter class. So far it is a waste of time and resources. For light weight gliders the GP15 will be nearly as light as the 11 or 14 with better performance for very little extra cost. The 13.5 meter class should have never been approved by the FAI and has never attracted any real interest. It is similar to the failed World Class gliders and the newly proposed e-glider.

Back to gliders less than 15m, there is a minimum mass required for a fuselage and pilot, with modern materials the difference in weight for a 13.5 or 15m wing makes very little difference but impact of wingloading and performance are significant.