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 …
Ready to Launch
LaunchPoint Technologies, Inc. announces the highest power to weight ratio of any known electric motor – seven horsepower for 1.4 pounds (635 grams) or five pounds per horsepower. As a comparison, the tiny Neutrino outrunner by Steve Neu of Neumotors weighs 14 grams and puts out 125 watts, peak. That would add up to 784 grams at 7 horsepower if that motor were scaled up to match the output of the LaunchPoint unit. The LaunchPoint motor is not only lightweight, but surprisingly small, scaling only six inches in diameter and one inch in thickness. It is composed of a great deal of carbon fiber in its plate-like structure. Behind this astonishing power output is the use of a Halbach array, “an arrangement of permanent magnets that augments the magnetic field on one side of the array while cancelling the field to near zero on the other side,” according to Wikipedia. The effect of the array is powerful enough to permit its use …