Did anyone else read this as Google Mankini?
http://www.amazon.com/Smiffys-Mens-Borat-Mankini-Dress/dp/B0...
Google Makani – Wind Energy Kites
111–120 of 165 posts
Re: Google Makani – Wind Energy Kites
#112Off topic but I have been toying with building a small catamaran powered by a Darrieus turbine or a kite setup such as depicted. The point is wind powered navigation of busy rivers and the east coast intracostal waterway. Obviously this makes zero sense on the open sea or in wide bays, where long tacks are easy and more efficient. Tacking on the intracoastal is practically infeasible in today's world, yet there is loads of wind. Can anyone refer me to to prior art on this?
Re: Google Makani – Wind Energy Kites
#113Interesting tech. I wonder if these have lower impacts on avian and bat populations. Also, it's interesting that tech companies love using Hawaiian words for things (Wiki, akamai).
The research I've seen says bats are mostly affected by low frequency pressure waves from conventional turbines, so these won't have that problem.
They may also spin fast enough to make enough noise to scare birds away, but they are also moving pretty fast, so could pose a problem for birds at the low end of their loop, which is somewhat under 150 m.
Putting them on a migration route would be a very bad thing for birds.
Re: Google Makani – Wind Energy Kites
#114Earlier quoted context omitted.
There's also autorotation, which means you need very little power for a controlled descent (still need some power to steer). http://en.wikipedia.org/wiki/Autorotation
Autorotation only really works for large heavy propellers, like the ones on helicopters.
I don't know. It works for RC helicopters of 500 size or so. I haven't seen autorotation performed with multicopters, though, so not sure how it maps to this application. I'm guessing these are fixed-blade machines. RC heli's manage autorotation via their collective pitch, which RC quadcopters (or hexacopters) don't have (collective). So it might not be relevant. But on the other hand, if the value of avoiding a crash is high enough, they could make the blades collective just for that purpose. Or maybe make one or two of the multiple props collective... I'd assume they already have a working solution to avoid falling out of the sky, but then, it isn't mentioned in the copy.
EDIT: There are quadcopters that can fly inverted, but I think they use powered servos with a reverse polarity. The value of autorotation is that it works when your main power source dies. So it all depends on the context and parameters (is there a backup battery of lower capacity available for emergency situations, say).
Re: Google Makani – Wind Energy Kites
#115Good, could people just stop messing with how scrolling works.
Block cookies and it scrolls normally.
Browsing without cookies means tons of things are broken — including things that break other things.
Re: Google Makani – Wind Energy Kites
#116> The energy kite simulates the tip of a wind turbine blade, which is the part of a turbine that makes most of the energy. The kite is launched from the ground station by the rotors, which act like propellers on a helicopter. Once in the air, the kite generates power by flying in large circles where the wind is strong and consistent. Air moving across rotors mounted on the kite forces them to rotate, driving a genera…
Yes. The generators turn into motors if you turn the electricity around.
Re: Google Makani – Wind Energy Kites
#117http://kitepowercoop.org/
Looks like there is an open-source community around energy kites. They're largely focused soft form kites, rather than fast moving rigid wings.
And another rigid wing competitor: http://www.ampyxpower.com/
Re: Google Makani – Wind Energy Kites
#118Direct link to video for those frustrated by the scrolling:
Re: Google Makani – Wind Energy Kites
#119I'm happy to see experimentation in new wind technologies, but it makes me sad to see things like this grabbing headlines when floating offshore is such a strong contender that just needs some more funding for the engineering effort (mostly because it's pushing the currently tested limits of carbon composites). http://bangordailynews.com/2014/05/07/news/bangor/umaine-get...
I don't think they mutually exclusive, but great link.
Re: Google Makani – Wind Energy Kites
#120Earlier quoted context omitted.
I'm fairly certain you're wrong about that. A quick googling suggests that a commercial wind turbine produces about 1M kWh/year, more or less. That's a great deal more energy than it would require to manufacture and install. By comparison, it takes about a pound of coal to produce 1 kWh of electricity, more or less. So a single wind turbine produces the equivalent energy of a MILLION pounds of coal every year! How mu…
A MILLION pounds (which really should be said in a "Dr Evil" voice :-)) is 500 tons. A rail car carries 120 tons of coal. A typical 2 GWe thermal plant burns a rail car of coal every ~20 minutes (coal has ~30 MJ/kg, and there are ~1000 kg/ton, so 120 1000 30E6 = 3.6E12 J/rail car, and 2 GWe ~ 4 GWth, which over 1000 seconds = 4E12 J) So by your figures, a windmill's yearly output is equivalent to a little over an hou…
I don't understand the focus on how many windmills it takes to replace one coal plant. It's not like there's some limit to how many you can build. If the costs are comparable, that's what matters, no?