The promise of solar energy is that, for all practical purposes, solar energy is unlimited and eternal (if the sun goes away, we go away). Despite this, only four percent of the world’s energy needs are supplied by solar resources today. Part of this is the relatively high cost of solar cells, their limited efficiency, and sometimes limited lifespans, which makes expensive replacements a regular necessity. The total amount of solar energy striking the earth is a strikingly high figure, something in the way of terajoules, according to one site. About 1,000 Watts of energy hit every square meter of the earth’s surface, varying by the angle at which the surface is tilted relative to the parallel rays from the sun. Most solar cells fall into a 12-to-40-percent efficiency range, though, limiting a photovoltaic array’s output to about 120 to 400 watts per square meter (10.76 square feet) at the best angle. That’s part of what makes solar aircraft problematical. …
Horizontal or Vertical, in the Air or on the Water
A 2008 ScienceDaily story was brought to light recently in the Minimalist Airplane Study Group, a Yahoo group dedicated to academic research on small aircraft. “In an advance toward introduction of an amazing new kind of internal combustion engine, researchers in China are reporting development and use of a new and more accurate computer model to assess performance of the so-called free-piston linear alternator (FPLA).” Their study of the FPLA, which could provide a low-emission, fuel efficient engine for future hybrid electric vehicles, was published in the August 27, 2008 issue of The American Chemical Society’s Energy & Fuels, a bi-monthly, peer-reviewed journal. Qingfeng Li, Jin Xiao and Zhen Huang explain in their paper that the FPLA has only one moving part and is an engine designed to generate electricity. “In the device, a piston in a cylinder shuttles between two combustion chambers. Permanent magnets on the piston generate electricity by passing through the coils of an alternator centered on …
Paint Me – Win 1,000 Euros
Tine Tomazic sends the following invitation. Pipistrel has published a unique design contest for Design of Livery for the Panthera, our brand new aeroplane to be presented in 2012. Anybody can participate! Prize is 1000 EUR ($1,350) and author’s signature on the aeroplane itself! The recognition may well be worth more than the prize money for the budding artist. The airplane will be featured at major airshows worldwide and in masses of mass media. All an aspiring illustrator has to do is capture the spirit of the sleek craft and create a livery “which will enhance Pantera’s unique lines and characteristics.” Connect with Pipistrel’s Facebook page to get all the particulars. There, you’ll learn about the luxury, sportiness, speed, efficiency/environmental friendliness and safety of Pantera, and doubtless be inspired to get out the magic markers. Here are some inspirational warmups.
Better Batteries: Fluoride – Not Just for Toothpaste Anymore
At Germany’s Karlsruhe Institute of Technology (KIT), researchers have developed a new concept for rechargeable batteries. Based on a fluoride shuttle – the transfer of fluoride anions between the electrodes – it promises to enhance the storage capacity reached by lithium-ion batteries by several factors. Operational safety is also increased, as it can be done without lithium. The fluoride-ion battery is presented for the first time in a paper in the Journal of Materials Chemistry by Dr. Maximilian Fichtner, Head of the Energy Storage Systems Group, and Dr. Munnangi Anji Reddy. “In search of new concepts to build batteries with high energy densities, electrochemical cells based on metal fluorides may be promising. Herein, we report the demonstration of secondary battery cells based on fluoride shuttle. In fluoride ion batteries, [a] fluoride anion (negatively-charged ions moving toward the positive electrode) acts as charge transfer ion between a metal/metal fluoride pair where it will react with metal or evolve from metal fluoride depending on the flow of current.” Presenting on day two of the …
99.99 Percent Air, Thinner Than a Human Hair
ScienceDaily reports that, “A team of researchers from UC Irvine, HRL Laboratories and the California Institute of Technology have developed the world’s lightest material — with a density of 0.9 mg/cc — about one hundred times lighter than Styrofoam™.” Their findings appear in the Nov. 18 issue of Science. Looking a bit like a jacks matrix, this “micro-lattice” cellular architecture consists of 99.99 percent air and a lattice of interconnected hollow tubes with a wall thickness 1,000 times thinner than a human hair, according to Dr. Tobias Schaedler of HRL. Despite its extreme lightness, the advanced material is not flimsy. Squeezing it to 50 percent of its original dimensions does not destroy the lattice. Instead, it handles the high strain and resumes its original size and shape, the ultimate memory metal. Energy absorption capabilities are also high, as are its possibilities for use in “battery electrodes and acoustic, vibration or shock energy absorption,” according to Science Daily. The new material …
Better Batteries: Powers of Ten
The CAFE Foundation in its Electric Aircraft Symposia has put forth the idea of the 10X battery for many years. Dr. Seeley therefore found a great deal of excitement in the following news. Researchers at Northwestern University in Evanston, Illinois have perhaps achieved part of that dream, with a graphene and silicon anode that yields a 10-times-faster charge and can hold a charge 10 times greater than that of a typical lithium-ion battery. Claiming their technology will be on the market in three to five years, the researchers have published a paper describing the research in the journal Advanced Energy Materials. A University press release explains. “’We have found a way to extend a new lithium-ion battery’s charge life by 10 times,’ said Harold H. Kung, lead author of the paper. ‘Even after 150 charges, which would be one year or more of operation, the battery is still five times more effective than lithium-ion batteries on the market today.’ (Meaning …
Big Birds Flying Green Economy Class (Part Three): Environmental Politics or Revenue Source?
Recent disputes among the many national and regional players in the emerging biofuel/jet fuel markets may slow acceptance and development of hese promising alternatives to fossil fuels. The European Union’s emissions trading system (ETS) seems to be central to contentions by China and the United States. The scheme would impose caps on carbon emissions from airlines flying into Europe, unleashing charges from China that the proposed rules discriminate against carriers from developing countries. A one cent per liter tax on jet fuel, part of the system, is at least partially responsible for the international dispute. According to Flight Global, “The airlines likely to be involved are the nation’s flag carrier Air China, China Southern Airlines and China Eastern Airlines, said an official from the China Air Transport Association.” America has weighed in with court challenges from American Airlines and United Continental, represented by the Air Transport Association (ATA), and Congress has added its voice, opposing what it perceives as European threats to American sovereignty and defending domestic jobs, which it …
What Has 16 Motors, a Pilates Ball, and Flies?
Your editor would rest easier at night knowing that the intrepid test pilot of this stalky creation were strapped onto a proper seat with a proper restraint system, but the current impromptu nature of keeping the operator out of the multiple twirling blades has worked – so far. Despite its gangly, random appearance, the E-Volo is not just tossed together. The 16 Hacker motors (editor’s best guess – or they might be budget Asian copies), controllers, and large diameter propellers need to be modulated with great finesse to maintain level flight, and that suggests a sophisticated control system, as designed by Stephan Wolf underlying the design. It must work exceedingly well, since pilot Thomas Senkel reported that, “The flight characteristics are good natured. Without any steering input it would just hover there on the spot”. The 80 kilogram (176 pound) device can “land safely” with 12 motors running, indicating that it might be able to remain aloft with three motors …
Alpaero’s Exel Goes Electric
Alpaero, a small firm in the southern French alps (hence its name?) created an ultralight sailplane/motorglider about 10 years ago that was originally powered by a two-stroke engine. Recently, though, it’s gone green with a four-stroke, Briggs & Stratton engine and even greener with an electric motor version. Claude Noin, the designer, wanted to answer the request for a “light autonomous sailplane at a reasonable cost,” able to meet ULM (ultralight) qualifications. The fixed engine behind the cockpit configuration avoids the complexity of the retractable engine configuration, which Alpaero says can increase drag two or even three times over that of the “clean” sailplane when the engine or motor is extended. As Dick Van Grunsven has pointed out, the need for motor extension usually occurs at some low point in the flight, when other options have been exhausted. Even the clean design of his Antares motor system produces a noticeable drop in gliding performance, he notes. The large cockpit has …
Big Birds Flying Green Economy Class (Part Two): Inspire and Aspire
Strategy was almost as important as design in the recent Green Flight Challenge, with near flawless planning and execution of carefully-crafted flight paths by the winning teams. This same precision and use of resources will become more important in a future constrained by increasingly precious fuels. According to Greenaironline.com, “The Indian Ocean Strategic Partnership to Reduce Emissions (Inspire) partnership achieved fuel savings of 3,482kilograms (29,723lb) and carbon dioxide savings of 42,469kg on five flights operated between Australia and the Middle East and South Africa.” These green demonstration flights, according to Greenair, show, “what is what is possible when air navigation service providers (ANSP), airlines and airports work together to remove operational constraints.” Begun in 2010 to “develop gate-to-gate procedures, practice and services” with the goal of reducing fuel use and emissions “across all phases of flight,” Inspire follows Aspire – the Asia and Pacific Initiative to Reduce Emissions – established in February 2008 by Airservices Australia, Airways New Zealand and the U. …