How do i make a small horizontal wind turbine for a school project using affordable materials?

not a blue print, but fairly clear instructions (with pictures) on how to do it: http://www.instructables.com/id/A-Paper-Plate-and-Pop-Bottle-Savonius-Wind-Turbine/

You obviously made your vertical turbine by cutting a bottle down the centre line, splitting it & mounting the 2 halves on opposite sides of a vertical shaft. I've never seen a horizontal mill made from bottles but I have seen one made from plastic pipe spilt down the centre in a similar fashion to your vertical mill so there were two blades each made from one half of the plastic pipe. They were bolted together somehow in the middle & offset so that each blade was inclined to the windmills plane of rotation, i.e., blade pitch. It made a very effective windmill with a very simple arrangement. You could do something similar with a couple of plastic bottles. They would have to be joined at the neck so that they were neck to neck at the hub & they would have to be angled to each other to give some pitch on the blades. You might have to have several attempts before you get exactly what you want but then how many discarded plastic bottles are there in the world? I can't see any problem finding another one.

You obviously made your vertical turbine by cutting a bottle down the centre line, splitting it & mounting the 2 halves on opposite sides of a vertical shaft. I've never seen a horizontal mill made from bottles but I have seen one made from plastic pipe spilt down the centre in a similar fashion to your vertical mill so there were two blades each made from one half of the plastic pipe. They were bolted together somehow in the middle & offset so that each blade was inclined to the windmills plane of rotation, i.e., blade pitch. It made a very effective windmill with a very simple arrangement. You could do something similar with a couple of plastic bottles. They would have to be joined at the neck so that they were neck to neck at the hub & they would have to be angled to each other to give some pitch on the blades. You might have to have several attempts before you get exactly what you want but then how many discarded plastic bottles are there in the world? I can't see any problem finding another one.

It would be more efficient to power a flywheel while going down hill to have some power to get up the next hill or travel on the level at the bottom of the hill. Now cars with gas engines will have a flywheel to keep the engine spinning between power strokes, and this is just the same principle. But it would not be economically feasible, and the wind machine would act mostly as a flywheel propelled by the wind then returning part of the energy lost previously. You might be better to use some kind of sail to get power from cross winds and tail winds, but you can not use it on a public roadway. I can just imagine you surfing down the interstate using the wind off the front corner of a big truck. A car with a parachute deployed might be able to be pulled along with another vehicle's wind. I use the principle on the interstate to cut my fuel consumption. It does not add to the fuel consumption of the truck, but as we approach a hill I pull just ahead of the truck, a lane over, and provide turbulence to help the truck over the hill. Symbiosis.