Or at least an approach to provide angst-free cross-country flying, as Michael Friend explained in his Electric Aircraft Symposium presentation last April at Rohnert Park, California. Friend, a Boeing engineer closely tied to the company’s early fuel cell work, is the owner and pilot of N787M, one of the earliest production kit Silence Twisters. The Twister is a Spitfire-like, retractable-gear light aircraft capable of cruising 146 on its Jabiru 80-horsepower engine. It’s capable of full aerobatic flight, and was converted to electric power in Germany for possible airshow demonstrations. The Twister’s designers also plan a lengthened wing that would make motor gliding possible. Friend noted the difference in energy density between available batteries and gasoline, explaining that 10 kilograms of gasoline (22 pounds – or about 3.75 gallons) had the energy of 450 kilograms (990 pounds) of lithium batteries. The gasoline cost $10 (April prices) while the battery pack cost $36,000. Despite the fact that the batteries will run through …
CAFE News: Comparing Apples, Bananas, Oranges and Doughnuts
One of the problems facing judges in the July Green Flight Challenge the CAFE Foundation is managing for NASA is that of determining fairly who gets the best fuel mileage. Since “fuel” in this case can be traditional aviation gasoline, bio-diesel, electricity from batteries or solar panels, or some other energy storage medium, wildly different energy densities have to be taken into account. If TSA “freedom feels” seem intrusive, the scrutiny applied to GFC entrants and their craft will be even more onerous. Aircraft will be impounded once inspected and registered, and the only contact pilots may have with their planes before taking off will be to “top off” their fuel tanks or batteries just before the start of their flight – all under constant monitoring. The widely and wildly differing energy densities for the different forms of motive power require careful definition of energy equivalencies. One pound of gasoline, for instance, equals about 20,000 BTU, or 5.8 kilowatt hours, …
Eco-Marathon an Echo of the Green Flight Challenge
Think of the Green Flight Challenge flown on a much smaller course, but allowing hydrogen fuel cell powered balloons to compete against liquified natural gas powered ultralight aircraft, or solar-powered autogyros. You might get a small idea of the creativity and innovation that sponsors hope to unleash in an upcoming event. In the town of Vichy, France, at the Vichy-Charmiel airfield, on July 9-11, the Eco Marathon ULM (Ultra Light Machines) will be held to test the limits of how little energy can be used to fly an aerial craft around a closed-circuit course three times. The rules are simple. The craft using the least energy wins – like the CAFE Foundation’s 2011 Green Flight Challenge, and inspired by the Shell Marathons for high school students who build extreme vehicles that get extreme mileage. There are no speed or weight requirements outside those imposed by the French Civil Aircraft Authority (the DGAC) on the various types of aircraft. Since participants …