Google Makani – Wind Energy Kites • Hacker News Board

Re: Google Makani – Wind Energy Kites

#131

Post by INTPenis » Wed, Mar 18, 2015, 4:47 AM UTC

Call me skeptical.

I live in the land of many wind turbines, the Øresund region of southern sweden, and I know that they can break down or even catch fire from time to time. Who is going to service this aeroplane when it breaks down?

It just seems to me that this idea has too many possible problems that could go horribly wrong from trying to fly a plane around on a teather in strong winds.

To be honest, before I saw the G+ page and read the top HN comments, my first thought was that april 1st is right around the corner. ;)

Re: Google Makani – Wind Energy Kites

#132

Post by tim333 » Wed, Mar 18, 2015, 4:57 AM UTC

Looks kind of cool. I just looked up the cost of regular turbines are "about $1.3 million to $2.2 million per MW of nameplate capacity installed." So I guess for a 600kw kite to be economic you'd have to build them for about $1 - 3m given the kite produces more constant power. Dunno what happens when the wind drops and all your kites have to land.

Re: Google Makani – Wind Energy Kites

#133

Post by tim333 » Wed, Mar 18, 2015, 5:07 AM UTC

mkl wrote: post #129

TylerE wrote: post #5

Earlier quoted context omitted.

I think that's more or less it. I think what they're doing is a milder version of dynamic soaring, which is a popular technique used among RC glider pilots (and some birds). The speeds attainable are pretty insane, the current RC record is 505 MPH, which in a rather fascinating twist is faster than the fastest POWERED RC aircraft. This a video that shows a pretty good idea of what it looks like, at compartively slowe…

This video explained dynamic soaring for me: https://www.youtube.com/watch?v=SVN-oF6tPLc The key thing seems to be having different wind speeds available at different heights so you can do the upwind part through slower moving air.

Cool. I never knew that stuff. There's a vid here of a guy getting his glider to 320kph with wind speeds of only 25-30kph before crashing it into a rock face. Reminds me of my own efforts with a RC glider which crashed into a concrete pillar at ~50mph quite promptly due to my lack of pilot skills.

https://www.youtube.com/watch?v=QjWFcYqdgA4

Re: Google Makani – Wind Energy Kites

#134

Post by digitalzombie » Wed, Mar 18, 2015, 5:10 AM UTC

I want Kinetic Energy Puppies.

Re: Google Makani – Wind Energy Kites

#135

Post by msutherl » Wed, Mar 18, 2015, 5:14 AM UTC

untog wrote: post #44

scholia wrote: post #37

Earlier quoted context omitted.

It's always worth complaining about this sort of crap, even if it doesn't have any impact on the ardent followers of web design fashion....

Is it? What does it achieve? I think anyone browsing HN knows the opinion of the average HN user on scrolljacking. If they're still doing it it's because either they don't read HN or they have data that proves it works.

Honestly, I think it might help. I design websites sometimes and I'm on here. At first I was kind of into it, but HN helped me see the error in my initial excitement.

This implementation especially is incredibly obnoxious.

Re: Google Makani – Wind Energy Kites

#136

Post by Untit1ed » Wed, Mar 18, 2015, 5:23 AM UTC

ChuckMcM wrote: post #28

I think this is pretty cool, but several questions spring to mind which I haven't found good answers for. The first is what sort of density can you get out of these? How many per acre/hectare? 1? 3? California has a number of wind installations and some of them are pretty dense [1]. The second is what sort of radar signature does this thing have? Probably not a navigation hazard but should be interesting on the weath…

They do mention density in terms of kw / sqm as being slightly higher than conventional turbines, but don't give a lot of details beyond that. I can only hope it's not based on parking them all right next to each other and hoping they don't get tangled up :p

Re: Google Makani – Wind Energy Kites

#137

Post by bduerst » Wed, Mar 18, 2015, 5:35 AM UTC

Untit1ed wrote: post #136

ChuckMcM wrote: post #28

I think this is pretty cool, but several questions spring to mind which I haven't found good answers for. The first is what sort of density can you get out of these? How many per acre/hectare? 1? 3? California has a number of wind installations and some of them are pretty dense [1]. The second is what sort of radar signature does this thing have? Probably not a navigation hazard but should be interesting on the weath…

They do mention density in terms of kw / sqm as being slightly higher than conventional turbines, but don't give a lot of details beyond that. I can only hope it's not based on parking them all right next to each other and hoping they don't get tangled up :p

Imagine if they were aware of each other's locations and made micro adjustments to their timing to sync each other. They could cross flight paths.

On the other hand, wind isn't uniform enough to really allow this.

Re: Google Makani – Wind Energy Kites

#138

Post by swatow » Wed, Mar 18, 2015, 5:38 AM UTC

avn2109 wrote: post #128

elevensies wrote: post #3

I'm still a bit confused about how the forces line up for the flight path. If I'm understanding: - the wing flies in a circle which is perpendicular to the wind (oriented the same way an ordinary wind turbine would be) - the tether is up-wind from the wing, so the force from the tether pulls the wing into the wind which generates lift, which is used to propel the wing along the circular path - the propellers are driv…

We need a free-body diagram here, talking about the balance of forces in English is madness.

One way to describe it in words is that it's like a normal wind turbine, but instead of 3 blades, you have one wing that moves in a circle like a blade. And instead of the energy being extracted by a generator where the 3 blades meet, the energy is extracted at the wing itself, by many small turbines.

Re: Google Makani – Wind Energy Kites

#139

Post by techdrone » Wed, Mar 18, 2015, 6:43 AM UTC

looks like a fun project, but unfortunately wind will unlikely to make the impact needed on the shift from fossil to renewables.

Re: Google Makani – Wind Energy Kites

#140

Post by ovi256 » Wed, Mar 18, 2015, 6:45 AM UTC

PakG1 wrote: post #127

My friend worked for Makani for quite some time. I remember at the time, they were in financial difficulty and, in his words, laid off all the people who viewed it only as a science project in order to get lean. Not enough people were focused on what would be necessary to bring the tech to market. He ended up finally leaving after some time, but I think before Google took them. A Google X type of environment probably…

I guess they did very well to lay off the people who thought of it as a science project, because it's obviously an engineering project! All the science needed to make it work already exists, it's just a question of hammering it together. Disclaimer: engineer here.