This was a very successful project, I used an off the shelf 3 bladed propeller, beautifully balanced and extremely strong, made from glass filled nylon, they are designed as ‘pusher’ props and can spin at up to an amazing 13 000 rpm when driven by a radio control plane engine. I suspect just 1500 rpm [...]
A Chinese farmer has made his own solar-powered water heater out of beer bottles and hosepipes.
“I invented this for my mother. I wanted her to shower comfortably,” says Ma Yanjun, of Qiqiao village, Shaanxi province.
Ma’s invention features 66 beer bottles attached to a board. The bottles are connected to each other so that water flows [...]