On December 21, 2011, Samy Dupland test flew Electravia’s latest adaptation of its electric power systems. The Electrolight 2, a Fauconnet A60 on which Electravia head Anne Lavrand and Dupland mounted their 26 hp motor and power pack, is a French version of the Scheibe L-Spatz (Sparrow) standard class sailplane. With a 5.55 kilowatt hour lithium polymer battery pack, the electric microlight glider can stay up for one hour, 45 minutes or gain up to 3,000 meters (9,842 feet). Its cruising speed is between 100 kilometers per hour (62 miles per hour) and 150 km/h (93 mph), with its range doubtless dropping at higher speeds. Its maximum weight is 315 kilograms (693 pounds) with a recovery parachute, right at the limit for French ultralight rules. Electravia sells the complete system of electric propulsion (motors, controller, batteries, instruments, propeller), and provides integration of the system into light sailplanes like the Fauconnet. Several vintage sailplanes could be easily adapted to such a system. …
Concentrating Sunlight
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 …
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 …
Small car, Small motor, Big Launch
This recent video from FES (Front Electric Sustainer) in Slovenia shows a relatively low-budget way to launch and sustain a sailplane in flight. This was uploaded to YouTube by Lumakaja on September 27, with the following commentary. “This way of sailplane start, can make gliding much cheaper! Idea is simple: Use of FES after being airborne with help of auto-tow. Only a few sailplanes have high enough landing gear, so that propeller clearance on grass is not too small for safe self-launch. With minimal help of auto-tow than all FES equipped sailplanes would not need towing plane or winch any more to become airborne. All you need is FES equipped sailplane, usual car and about 120 meters (384 feet) of Dyneema rope. Such start could be used also on relatively short, let say 750 meter (2,460 feet) long airfields, which are otherwise too short for usual winch or car launch! If only short runway is available, then more powerful car is needed for …