A little quick math--Bicycle tire 28" o.d. Bicycle goes 10 miles an hour. wheel revolves {28x3.1416}/12=7.33 foot in one revolution. 10miles x 5280=52800 feet. 52800/7.33=7203 revolutions in 10 miles. Since we are going 10mph, that means 10 miles in 60 minutes, or 7203/60=120 revolutions per minute. Now, since the friction wheel is approximately 1" diameter, and the side of the wheel it bears against is about 26" diameter, that's a 26:1 ratio. So---The generator is turning at 120 x 26=3120 rpm. Let us assume out gas engine is running at 1200 rpm. 3120/1200=2.6:1 ratio. So---if we use a 2.6" pulley diameter on the engine, we only need a 1" diameter pulley on our generator. I don't know if they have enough power to do that or not. Now mind you, at 10 MPH you got a cone of pure white light that was pretty darn bright. I can remember turning my old J C Higgins upside down and shining the light over the lake, and pedaling it by hand and that light would be as bright as a search light . You wouldn't need that degree of light for a simple engine driven lighting plant.
