=20 I think anyone who's ever played with the concept of multicopters has had the passing though of if/how/when they could be "man-sized"; just a matter of cost and flight-time. Efficient doesn't really come into it, how about "FUN"!! ; )=20 I could easily envision military use of single-person multicopters, with the pilot lying flat, you could get EXTREME manouverability, but obviously there's a limit (at the moment) of how much a human can take, as well as structural stresses. Of course you could just go the remote method instead.=20 Non-electric and collective pitch would probably be the way for longer flight times, a single central internal combustion engine feeding drive belts/shafts for an array of collective-pitch blade assemblies.=20 I think sensor and microprocessing technology/cost has come low enough that these things are going to be popping up in the average hobbyists backyard shed fairly shortly. What would have cost tens of thousands a few years ago can now be done with an arduino and a wii controller! (with motion plus, of course!)=20 Moller had his Skycar back in '03, which was essentially an ethanol quadcopter, but to me it looked unstable. Wonder if he's been upgrading the control systems since then (doesn't seem to be much new info). That said, a bit of a search seems to indicate quite a bit of money going in for not much results showing...=20 Lee --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .