In reply to Michel Jullian's message of Sat, 3 Feb 2007 15:50:20 +0100: Hi, [snip] >BTW I also have an untried design for an autonomous lifter (designed to take >off vertically and hover for a few mn while carrying it's own power supply, >would be a world first if it works), if anyone is interested in experimenting >it you're welcome. > >Be warned though that it requires thousands of euros worth of batteries >(about 5 last time I looked 3 years ago), the rest of the craft costing >virtually nothing except time and craftsmanship (a lot of each :). > >No HV power supply design experience required, the HVPS consisting >bruteforcely in a series string of about 1200 tiny lithium-polymer batteries >:))) [snip] A radioisotope power supply is ideally matched to this application. They can be designed such that energy is extracted by allowing the charged particles to travel "up hill" against a space charge, thus maintaining a high voltage (typically hundreds of kV to MV). The current is dependant upon the amount of isotope employed, and the half-life. The energy density of radioisotopes beats any chemical fuel hands down, so the power supply would be very light weight, and the fuel would last a long time. If a technique can be developed to dynamically alter the half-life of radioisotopes over a wide range, then this is a match made in heaven. Regards,
Robin van Spaandonk http://users.bigpond.net.au/rvanspaa/ Competition (capitalism) provides the motivation, Cooperation (communism) provides the means.
