Sustainable Skies in San Francisco

Dean Sigler Batteries, Electric Powerplants, GFC, Hybrid Aircraft, SAS, Sky Taxis, Solar Power, Sustainable Aviation Leave a Comment

I’m writing this in the first person, rather than the usual third-person voice that allows me to remain objective about things on which I report.  In this case, I have been the recipient of much joy over the last ten years from being an observer of the ongoing progress in electric aviation. Dr. Brien Seeley, founder of the Sustainable Aviation Foundation, asked me to begin writing a blog about electric aviation in 2009.  One of my original postings concerned a Kitplanes Magazine contributor, David Ullman – who was this year’s Sustainable Aviation Symposium’s keynote speaker.  In 2009, he predicted a great future for electric aviation – most of which has come to pass, and some of which he is creating in his hangar with his fully-instrumented wind tunnel and ambitious blown-wing design.  He proposes something called USTOL, Ultimate Short Takeoff and Landing, aircraft that will use a dynamic relationship between their power and lift systems.  His vehicle for demonstrating this …

Alta Devices – From UAVs to Hanergy Solar Powered Cars

Dean Sigler Solar Power, Sustainable Aviation 2 Comments

Alta Devices has been trading places with the National Renewable Energy Laboratories (NREL) in holding world record efficiencies for single- and dual-junction solar cells at one sun (not concentrated).  Their gallium-arsenide technology includes a layer of indium gallium phosphide (InGaPh), which the firm says utilizes photons more efficiently. According to Alta Devices, “Alta has achieved this breakthrough by modifying its basic ‘single-junction’ gallium arsenide (GaAs) material. The company’s dual junction technology builds on the basic GaAs approach, but implements a second junction (or layer) with Indium Gallium Phosphide (InGaP). Because InGaP uses high-energy photons more efficiently, the new dual-junction cell generates more electricity from the same amount of light than a single-junction device. With this breakthrough, Alta currently holds both the dual-junction and single-junction records at 31.6% and 28.8%, respectively.” Alta claims, that for a typical HALE (high altitude long endurance) UAV aircraft, their solar material requires less than half of the surface area and weighs one-fourth as much while …