Direct down wind faster than the wind my first experiment

I was very impressed by the cart of Rick Cavalero, which could go faster than the wind with straight down wind. Than some years ago i tried to replicate the small cart for testing with a treadmill. But i have no treadmill and my cart was much too heavy to work outdoor with wind, so i simply fergot the idea.
But yestrerday i stumbled upon an other experiment from Tony Andrew who , back in 2008, made almost the treadmill exp but with a turning table. So the cart and prop can really go from direct down wind up to front wind.
So now as it work for me, i am sure that there is no faking in this experiment. I am very fascinated by how the cart can go faster than the motoring wheel. So i am asking if it could be possibble to improve the experiment.
So for today my built is very crude with a lot of friction, (no bearing in the center axle, the curved transmission spring between the roller and the prop etc.., but it works and i thought it was interesting enough to show this test, and perhaps reanimate the DDFTTW subject.
Laurent