Alt-BEAM Archive

Message #10440



To: beam@sgiblab.sgi.com
From: "Timothy Flytch" flytch@hotmail.com
Date: Fri, 18 Feb 2000 22:25:50 PST
Subject: [alt-beam] Re: solarbotics pager mtr+fan


>At 06:11 PM 2/18/00 , jester96beam@iname.com wrote:
>>I don't think you would need two fans spinning in opposite
>>directions. What would happen if you had two spinning in the same
>>direction? Would it still spin, or would it move in a line? Or would it
>>spin slower?
>
>
>It would still spin, just not as much because the center of rotation is
>shared (guessing here). Opposite fans would be idea.
>
>-Dave
No...NO ...NO... It would NOT spin... It has been done if full size
helicopters! The only reason for using counter rotating blades is
interference between the blades not tork...
Try this... take two dinner plates and lay them on the table... now turn the
plates in the same direction and notice which way the edges are moving in
relation to each other... then try turning them in opposite directions...
just like gers messing??? Sikorsky first flying bananas had blades that
rotated in the same direction... later when production started they
switched to counter rotating blades to eliminate the risk of blade strike
(that is when a violent maneuver would cause the blade disks to
intermesh)...
Timothy...

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10441 Fri, 18 Feb 2000 23:30:29 -0700 [alt-beam] Re: solarbotics pager mtr+fan beam@sgiblab.sgi.com Jean auBois At 03:58 PM 2/18/00 -0700, Dave wrote:

>The "Mesicopter". 'tis neat. Have talked to the researcher there about
>trying the TPMs, but don't know if they have.
>http://www-rpl.stanford.edu/RPL/htmls/mesoscopic/mesicopter/mesicopter.html

Sigh. It really really looks neat. And I bet it works just fine. But
there are a few things that are real bummers:

external power
Initial tests stabilized on a pivot arm

This is why I've never been much impressed with the M.I.T. walkers (except
somewhat for that pogo thingy). ALL of them take external power and most
of them are stabilized by some external mechanical structure.

'tis why I've always been impressed with Mark Tilden's robots: they walk
autonomously and with a degree of agility. And like you say on your
Solarbotics page, some of them don't have an on/off switch 'cuz they don't
need any power but the sun. I depend on THAT tether every day!


jab

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