Thanks for being interested. I am thinking that power in is a variable because I can scale-up the turbine. In other words, I'm starting with the alternator and then figuring a way to drive it. As to cut-in, my best guess based on the models would be around 70 rpm. I found that I could apply a load at that speed without stalling. I know that I'm upside down in figuring this thing, but it seems to me a more direct approach to build the alternator, then fit the turbine. Being a newbie, I need some direction in determining a "load point." Thanks for your patience.