With the ever expanding and affordable array of 3D printers (also known as rapid prototyping machines) new opportunities abound. I first covered 3D printing back in 2007. Since that time The New York Times has run a number of articles on 3D printing (Don't believe me? Then try searching Google for 3d printing site:nytimes.com) - an indication if ever it were needed that 3D printing has gone mainstream and entered the public's consciousness. So enough with all this virtual engineering, at some point you have to get physical and the 3D printing revolution is a great place to start.

Yet another roadable aircraft or flying car? Yes, but the Model 367 BiPod [source: gizmag] is different because of who designed and built it. Burt Rutan - of SpaceShipOne fame - retired earlier this year from legendary prototype aircraft maker Scaled Composites. His last project was a hybrid-powered road and air vehicle. The twin fuselage, a signature design feature of many Scaled Composites airplanes, makes for a uniquely odd looking car design. One cockpit controls the vehicle while on the ground and the other cockpit controls the vehicle while in flight.

The world's largest, scientific quality, boundary-layer wind tunnel was recently declared operational at the University of New Hampshire (UNH). The new wind tunnel known as the Flow Physics Facility (FPF) serves as a great example of how a wind tunnel and Computational Fluid Dynamics (CFD) can form a mutually beneficial relationship.

Flow Physics Facility Building, UNH

The movies Innerspace and Fantastic Voyage both featured miniature submarines, piloted by miniaturized humans, roaming around inside a live patient. As the trend continues towards unmanned autonomous vehicles (UAVs) both in the air and in the water it seems the movies had half the story right – that of the miniature vehicle. For example, researchers in Japan have developed a self-propelled endoscope [source: Popular Science] that can swim mermaid-like through our digestive system.

Mermaid Endoscope

I just came across an interesting study [source: Gizmag] on the total efficiency of wind turbine clusters that compared vertical-axis wind turbines with the more popular horizontal-axis wind turbines. The study compared the efficiency of a cluster of wind turbines rather than individual machines. The measure of efficiency was related to the area occupied by the clusters.

Wind Farm

Is your next car going to be powered by compressed air? Probably not, but there are groups working with compressed air as an energy source for the usual transport suspects, i.e., cars and bikes, and also for energy storage in general. Though the energy density of compressed air is poor relative to fossil fuels, it scores well in terms of efficiency – if, and it’s a big if, you can raise its pressure to store energy and lower its pressure to recover energy at constant temperature (isothermal process) and with no heat transfer to the surroundings (adiabatic process).

Air Compressor

A recent proposal of a streamlined truck designed using Computational Fluid Dynamics (CFD) holds the promise of reducing drag by 63%, which would translate into huge fuel savings. The relentless rise of oil prices has placed increasing importance on truck fuel and aerodynamic efficiency. However, as best as I can tell from pictures of the streamlined design it looks more like a train. It's not obvious to me how this design would maneuver around sharp corners. There is mention of morphing body work but it's not evident in the models presented.

I couldn’t resist writing about a real-world transparent car [source: Jalopnik], especially after already covering real-world cutaway and wireframe models. So you know the score, which is real and which is fake?

Fake Transparent Car: Courtesy of RM Auctions

A recent CFD study into the exhaust concentration in car wakes has revealed that certain rear car spoilers (or airfoils) can either disperse or concentrate pollutants at the same height as a following cyclist's head. The study "Spoiling Air Pollution Dispersion: A Numerical Investigation of Exhaust Plume Dispersion from Cars with Rear Spoilers" authored by A. McNabola, implies possible health implications for cyclists and pedestrians that follow behind cars.

Car Wake: Streamlines released from a tailpipe

In the press release announcing the report "Rooftop Solar Arrays and Wind Loading: A Primer on Using Wind Tunnel Testing as a Basis for Code Compliant Design per ASCE 7 (pdf)," there is the phrase:

"It also addresses the applicability of Computational Fluid Dynamics (CFD), which is sometimes proposed as an alternative to testing."

With eager anticipation I read the report and found a quite damning assessment of CFD.