George you always look as though you are really having a blast.
Watching that blade flexing does remind me why I am not allowed to taxi the instructors Bensen without the rotor turning. He maintains that not only is the turning rotor carrying the weight of it's blades but also achieving the extra strength and rigidity derived from centrifugal force.
That Goped set-up of yours continues to impress every time I see it in action particularly after your observations Jon on the friction effect of grass strips.
We have a huge grass area at Rissington and have to taxii on grass in some spots, luckily a number of hard paved runway areas to take off from as well. Intended strip in Kenya for the Hornet though is grass and sometimes it gets a bit long. Getting the owner to mow sometimes bit slow.