.

[kevinmccune]

Just a SWAG, What about a small wind turbine?,
they come in several sizes, and since we are moving thru the air under leg power, there would be a constant source of air movement while moving and could also have the natural wind flow, as here in NV, we very seldom have a day without the wind blowing, usually a minimum of 5-6 mph every day, (info coming from my home weather station.)
I have never looked into these small wind turbines, but will,
I see several around, at the Kitty Litter plant, between Lovelock and Fernley, there is a huge one, blade span is around 8-12' and it is always turning when I go by it to Reno,
I think it is connected to the NDOT billboard sign. YMMV,
Don

No the drag it creates will soon change your mind now if you feather it and engage downhill it will act as a brake and give you a little juice, an inoperable engine on a prop plane has its "airfoil" feathered because of the incredible amount of drag when its turning( some liken it to a flat disc, its probably a little worse)