I think the way to pure water hydrophobic windows is to design/build a new tool into the industry. I don’t have the money to drag this into exsistance so here is the idea.
Rather then one big brush, 2 circular rotating brushes focusing all water, dirt and whatever flowing between the circular brushes between them. Left circular brush rotates clockwise and right rotates counter clockwise. Keeping the water flowing from the top or wherever thats best.
Powered by lithium ion battery or some high quality power source. F the weight, I think this should work on hydrophobic windows.
There’s actuall a solution you can spray on to help make a window go from hydrophobic to hydrophilic. It’s very early on though from what Mike Draper at AWC Mag told me. Not sure when it will be able on the market.
I’ve been thinking about this myself. The cordless brushes are just too heavy to effectively use at heights, and there isn’t enough pressure in a WFP to run the brushes in a water driven one.
Perhaps it is possible to get some rotation to the brushes from the up and down motion we would normally use to adjetate. That could eliminate the need for moving parts dependant on power sources.