Many Happy Hours in Sunny Skies

Dean Sigler Uncategorized 1 Comment

Eric Raymond, over the last 20 years, has accumulated more solar-powered flying hours than any other pilot. And what hours these have been. Having met Gunther Rochelt and flown Rochelt’s Musculair human-powered airplane in 1986, Eric was inspired to apply the light construction techniques to the building of a solar-powered airplane. In 1990, he flew Sunseeker I across the United State in 21 hops totaling 121 hours in the air, going from California to Kitty Hawk, North Carolina, the birthplace of powered flight. He upgraded Sunseeker over the years, improving the powerplant and aerodynamics of the amazingly light aircraft. Even with solar cells, batteries, and a 2.5 kW motor, the airplane weighed little more than a legal ultralight. Sunseeker II …

An American ReVolt

Dean Sigler Uncategorized 0 Comments

ReVolt Technologies LLC, a Swiss battery company founded in 2004 as a spin-off of SINTEF, Norway, is moving its headquarters to Portland, Oregon. Initially targeting the consumer electronics market with their zinc/air battery (compare to the lithium/air batteries IBM is researching – see “Big Blue and Blue Sky Thinking” October 25, 2009) in a grant request to the U. S. Department of Energy for $30 million for research on making large format versions of the battery for vehicles.  The company has an alliance with chemical giant BASF. ReVolt claims the following advantages over lithium batteries: A theoretical potential of up to 4 times the energy density of lithium-ion batteries at a comparable or lower production cost. Extended battery life due …

The Prodigious and the Petite

Dean Sigler Uncategorized 0 Comments

We are endlessly fascinated by the largest, most powerful, or smallest and most infinitesimal of anything. Here we look at two extremes in electric propulsion. The Prodigious American Superconductor produces superconducting wires, and from those, winds a very large motor, that if not the biggest thing to power ships, is the most powerful for its size, and the most powerful to be used in a Navy ship. The company promotes the following benefits for its 36.5 MW (49,000 horsepower) HTS (high temperature superconductor) motor: high power density (compared to traditional copper-wound motors), high partial load efficiency, low noise, harmonic-free voltage, low synchronous reactance, cyclic load insensitivity, and low maintenance. The Petite Lad, living in St. Petersburg, Russia, has constructed the …

Growing Your Own Battery

Dean Sigler Uncategorized 0 Comments

While Dr. Cui at Stanford works on perfecting his painted paper battery, reseachers in Sweden are growing algae that does well as a paper battery. Maria Stomme of the University of Uppsala says that the growth of Cladophora, an otherwise stinky beach slime, “Creates new possibilities for large-scale production of environmentally friendly, cost-effective, lightweight energy storage systems.” The algae, according to, “makes an unusual kind of cellulose typified by a very large surface area, 100 times that of the cellulose found in paper. This allowed researchers to dramatically increase the amount of conducting polymer available for use in the new device, enabling it to better recharge, hold and discharge electricity. Despite the relative ease of making this rechargeable paper, …

The Painted Battery

Dean Sigler Uncategorized 0 Comments

Dr. Yi Cui, assistant professor of materials science and engineering at Stanford University, is a battery scientist extraordinaire, and a presenter at last April’s Third Annual Electric Aircraft Symposium. His paper was well received, one in which he discussed how breakthroughs in his lab could lead to an 80-percent improvement in battery capacity for the same weight as current units. He has topped himself with an extraordinary approach to manufacturing batteries. Imagine painting an ordinary piece of paper with a coating of carbon nanotubes and silver nanowires, and ending up with a very thin battery or supercapacitor. This video, courtesy of Stanford University, shows that process, and includes Dr. Cui lighting an LED with a small square of paper. He and his …

Largest-Battery Powered Airplane Takes Flight

Dean Sigler Uncategorized 0 Comments

Two weeks ahead of the 106th anniversary of controlled powered flight by the Wright Brothers, the Solar Impulse, HB-SIA broke its earthly bounds and flew 350 meters (about a quarter mile) at a height of about one meter.  Because the airplane does not yet have its solar panels mounted, the flight was made on battery power. Graphic © Solar Impulse/EPFL Claudio Leonardi The project’s press release leaves no doubt as to the importance, and the thrill, of the flight. “The results of the ground tests conducted these last few weeks to verify numerous parameters (the prototype’s controllability, acceleration, braking paths and, engine power) had been overwhelming positive, thereby leading the team to give the go-ahead to Markus Scherdel, the test pilot, to take the …

Isn’t It Ionic?

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Only a few months after the first heavier-than-air hydrogen-fueled crossing of the English Channel (See Man of La Manche, October 29), the Naval Research Laboratory flew its hydrogen fuel cell-powered Ion Tiger for an endurance record of 26 hours and one minute.  The flight took place on November 16th through November 17th. The Navy press release claims, “Fuel cells create an electrical current when they convert hydrogen and oxygen into water and heat.  The 550 Watt (0.75 horsepower) fuel cell onboard the Ion Tiger has about four times the efficiency of a comparable internal combustion engine and the system provides seven times the energy in the equivalent weight of batteries. The Ion Tiger weighs approximately 37 pounds and carries a …

Powerful Pancakes

Dean Sigler Uncategorized 1 Comment

AST, Automation Source Technologies, has a line of compact “pancake” motors that are of interest to those designing electric aircraft. Their CDS Series have power outputs ranging up to 21 kW, efficiencies up to 93.2 percent, and weights of no more than 21 kg. The CDS 150, largest in the line, can be either water or air-cooled, handles inputs from 24 to 96 Volts DC, and operates at 1,000 to 6,000 rpm. High torque peaks, and a three to four times overload capacity might make this eight-pole series worthy of consideration.  

Sanyo Starting Mass Production of EV Batteries

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Sanyo Electric Co., Ltd.  has announced that mass production of its EVB-101 battery package will begin in 2010.  This compact package – 366 × 213 × 66 mm – or 14.4 x 8.39 x 2.60 inches, wraps a group of 18650-size computer batteries in a water-resistant aluminum housing, complete with a standard communication plug for battery management and monitoring.  The 14 in series, six in parallel package stores 10.8 Amp hours of energy and weighs about seven kilograms (15.4 pounds).  It has a maximum discharge current of 120 Amps and a continuous output of 35 Amps. The batteries got a good workout in Yokohama Rubber’s E-V Buggy at Pike’s Peak on July 19, posting the second best time by an electric …

A Tale of Three Pauls

Dean Sigler Uncategorized 3 Comments

Dr. Paul Robertson lectures at Cambridge University’s Engineering Department, and Paul Dewhurst serves as Director and Chief Flying Instructor at Flylight Airsports, Ltd.  The two Pauls made simultaneous takeoffs March 1, 2009 in Britain’s first two electric aircraft.   A third Paul, Welsh by name, acted as certification engineer for the effort. Dr. Robertson took to the skies in a Dragonfly hang glider powered by a Geiger/Eck 10kW motor/controller/propeller combination, while Dewhurst became skyborne in a Lazair ultralight propelled by a pair of Plettenberg Predator 12 kW (peak output) model airplane motors.  This testbed in particular reflects Dr. Roberton’s studies toward the constuction of a sub-115 kg electric twin called Hummingbird.  His PowerPoint presentation shows the mathematics of powering such a craft on …