Micro (or personal) wind turbines are sprouting on the rooftops of many UK homes in an effort to defeat our addiction to fossil fuels and reduce greenhouse gas emissions. Laudable goals, but most of these 'off-the-shelf' roof-mounted wind turbines struggle to generate enough electricity to power a single light bulb.

While clusters of horizontal-axis wind turbines are our primary weapon in the war to reduce greenhouse gas emissions to save the planet from the effects of global warming, there are other interesting wind turbine designs. Vertical-axis wind turbines (VAWT) come in a variety of shapes and sizes for those keen to take the path less travelled.

Darrieus Vertical-Axis Wind Turbine

Today the most cost-effective means of capturing wind energy is a horizontal-axis wind turbine positioned on land or at sea in a proven windy area. Whether micro, personal or industrial – modern horizontal-axis wind turbines share the same basic features.

Wind Turbine

Global warming concerns have launched a renewable electricity-generation boom with sleek wind-turbine farms on land and at sea playing a leading role. Yet capturing wind energy using windmills is an ancient science that pre-dates the use of electricity. The invention of the windmill is variously attributed to the Babylonians (circa 1700BC) and the Persians (circa 600-900AD); either way it is still an ancient machine.

The democratization of technology isn't just about making things for less, to line the already full pockets of CEOs. The ubiquity of technology also allows hobbyists and students to build more for less. Nowhere is this truer than for aerodynamic gadgets such as cars, planes and even wind turbines!

The United States Postal Service (USPS) on March 17, 2007 issued 2 stamps that feature Computational Fluid Dynamics (CFD) generated images of the North American X-15 rocket plane in flight.

The inaugural Formula Hybrid International Competition was held May 1-3, 2007 at the New Hampshire International Speedway, Loudon, NH, USA. College and university students from the US and Canada took up the challenge to construct and race gasoline-hybrid powered, open-wheel racecars.

Underbody tunnels, rear diffusers and venturis are common terms used to describe the contouring of a racing car's underbody. While largely hidden from view, these devices are the secret weapons in an arsenal of aerodynamic features for generating downforce on racing cars.

The Automotive X Prize will award substantial cash prizes to the winning teams of a long-distance stage race. So is it replicating the World Rally Championship then? Not quite. The vehicles competing for the Automotive X Prize have to be environmentally friendly, production-capable and exceed 100mpg. I doubt any World Rally Cars will qualify!

Merriam-Webster's online dictionary definition for aerodynamics is "a branch of dynamics that deals with the motion of air and other gaseous fluids and with the forces acting on bodies in motion relative to such fluids." So what is aerodynamics again?