Science May 23, '97, p. 1211 has an exciting article, "Macro Power
from Micro Machinery", which says that scaling laws work in favor of
making small turbines, using close to existing technology. In fact,
"a complete gas-turbine generator of under 1cm^3 can be realized
delivering as much as 50W of electric power or 0.2 N of thrust. ... A
mm-size engine would have a thrust-to-weight ration of about 100:1,
compared to 10:1 for the best modern aircraft engines. ... 1400 of
them working in parallel could elevate his skateboard."
Robin D. Hanson hanson@hss.caltech.edu http://hss.caltech.edu/~hanson/