[thedoc (OP)]

Paul asked the Naked Scientists:
   
If I walk down the street on a windy day wearing a brimmed hat ,the wind is likely to blow it off. If on
top of my hat I had two rotating blades on the same spindle rotating in the horizontal plane in opposite directions, would this cancel out the effect of the wind and keep my hat on my head? No doubt it would be important to keep the blades rotating at the same speed and this needs a bit more thought to figure out how that might be achieved. If this idea works, could it be applied to the roof of a house which is situated in the path of frequent hurricanes and typhoons? Ifd it cold be hooked up to generate electricity, that would be a further benefit, but someone is going to say that they will not have hurricanes all year!

What do you think?

[Colin2B]

If on top of my hat I had two rotating blades on the same spindle rotating in the horizontal plane in opposite directions, would this cancel out the effect of the wind and keep my hat on my head?

No
I assume Paul that you are thinking of blades like paddle wheels rather than aircraft propellers. Such paddles would throw air out in all horizontal directions and suck air in from above and below. So no net effect on the wind blowing from ahead - or indeed on a head.