Keep your face to the sunshine and you can never see the shadow.

July 26, 2016 3:48 AM

Solar Impulse 2, a sun-powered plane many times lighter than the lightest glider, has completed a round-the-world flight. The craft landed early Tuesday in Abu Dhabi, ending a journey that took some 558 hours (more than 23 days). The wingspan of the fuelless craft is the size of a 747, yet the unpressurised, unheated cockpit is not much bigger than a phone booth. Towards the end of the trip it was escorted by Spanish Jets. The landing (and all 17 legs of the journey) were streamed live.

Education opportunities weren't missed; there is a long list of handouts for schools, as well as a TedEd Lesson on How to fly around the world without fuel.  The pilots, Bertrand Piccard and André Borschberg are not shy about sharing their vision with young minds curious about the science behind the project. They've run Connected Classrooms to share their passion with students, and participated in Google Hangouts for select schools.

Its creators, patrons and partners hope the current plane's technology will be a springboard to solar-powered passenger planes in ten years, and have begun plans to capitalize on the material science advances made during the 13-year project. The battery tech alone is a fascinating series of innovations.

While in flight, Piccard finalized efforts to establish the International Committee of Clean Technology (ICCT). The committee is intended to regroup the main global actors in the field of clean technologies to bring independent and credible guidance on energy policy to governments and corporations. This builds on another of the founders' creations, the #futureisclean initiative which will push for the replacement of old polluting devices by existing clean technologies.

Previously.

posted by Hardcore Poser (33 comments total)

Note: The 'many times lighter' refers to the plane's incredibly low wing loading. Solar Impulse 2 has 269.5 m² wing area to carry its 2.3 tons of mass, giving it a wing loading of about 8.5 kg/m² (many times less wing loading than gliders).
posted by Hardcore Poser at 4:06 AM on July 26, 2016 [1 favorite]

Even though his name's one c out, it's made me smile every time I've read the news of this flight to think of a real Piccard boldy going where noone's gone before.

Epony-artforeshadowinglife-ical.
posted by protorp at 4:28 AM on July 26, 2016 [2 favorites]

How close could (theoretically, and/or plausibly using familiar technologies) electric energy storage get to the energy density of A1 kerosene?
posted by acb at 4:44 AM on July 26, 2016

acb, the battery test link suggests that the batteries are currently about 1/10 the density of kerosene and that attaining parity will take about 20 years.
posted by Autumn Leaf at 5:03 AM on July 26, 2016 [2 favorites]

Random observation: at ~70hp (4x17.4hp) it flew around the world with 30% less engine power than a Fokker Eindecker made in 1915.
posted by vanar sena at 5:05 AM on July 26, 2016 [4 favorites]

The video of it coming in to land is unworldly - it just flies so slowly ("Increase speed to 30 knots...") and the long string of landing lights hanging in the nighjt sky apparently motionless was pure Close Encounters. A feeling intensified by the sight of the local dignitaries in hijab and burqa bustling around on the runway laying out an enormous flag.

And then the band struck up...
posted by Devonian at 5:17 AM on July 26, 2016 [1 favorite]

I wish someone would make a solar powered unpiloted drone that would just keep flying forever and ever. I think the mere idea of it being up there would be irresistibly soothing.
posted by Joe in Australia at 5:22 AM on July 26, 2016 [9 favorites]

Getting there, Joe
posted by Devonian at 5:32 AM on July 26, 2016 [2 favorites]

Even though his name's one c out, it's made me smile every time I've read the news of this flight to think of a real Piccard boldy going where noone's gone before.


The Piccard family has a long history of going where no man has gone before. I believe Gene Roddenberry got the idea for the name from them.
posted by TedW at 5:36 AM on July 26, 2016 [10 favorites]

Towards the end of the trip it was escorted by Spanish Jets.

This is a great technological acheivement and all, but this detail just made me think of this.
posted by Johnny Assay at 5:46 AM on July 26, 2016 [2 favorites]

Like travelling around the world by horse-drawn carriage, or climbing mount Everest while carrying a large jar of pickles, it's a technically impressive accomplishment that I'm not sure why anyone would attempt.
posted by sfenders at 6:01 AM on July 26, 2016

On RTFA: "it has become the first solar lane to cross the Pacific Ocean, spending 5 consecrative days and nights in the air."

Oh I see, it's a religious thing.
posted by sfenders at 6:07 AM on July 26, 2016 [4 favorites]

many times lighter than the lightest glider

Argh...it is not possible to be many times lighter than the lightest glider, or the heaviest glider, or that giagantic megaplane Boeing made, or anything else. /pedant

(oh who whom am I kidding, I'm never going to /pedant)

I wish someone would make a solar powered unpiloted drone that would just keep flying forever and ever. I think the mere idea of it being up there would be irresistibly soothing.

I think that's the space station. I mean there are people there, but I don't think they pilot it. I think they just ride it.

The plane and the trip are impressive, but given how slow it is (I hope the pilots are being screened for DVT) and how light the airplane had to be, it doesn't seem like it would even qualify as proof of concept for purposes of eventual commercial flight. The article says that part of the point was to show that solar energy could provide for our energy needs on the ground, so I would have liked to see more about that. Is this new solar technology that makes it easier to power our ground-based things by solar or other renewable power? Also, since this thing travels about as fast as a car, is there no route to adapt this technology to make solar [flying] cars instead of trying to make airplanes?
posted by If only I had a penguin... at 6:07 AM on July 26, 2016

Oh I see, it's a religious thing.

I confess I find this point of view incomprehensible. You really can't understand why someone might want to do this type of pioneering engineering and design effort? Really?
posted by vanar sena at 6:29 AM on July 26, 2016 [2 favorites]

The hype just seems excessive, and the idea that it's going to be useful to industry somewhat silly. I suppose solar powered air travel is today what flying cars are thought to have been in the 1950's, a future people can get excited about no matter how little sense it makes.
posted by sfenders at 6:40 AM on July 26, 2016 [1 favorite]

I confess I find this point of view incomprehensible.

Look at the words again.
posted by pompomtom at 6:45 AM on July 26, 2016 [1 favorite]

Yeah I get it. I was responding more to the comment above it.
posted by vanar sena at 6:46 AM on July 26, 2016

Ahaa... in which case we are in complete agreement.

It shits me, but I'd've thought military aerostats would be the first and most profitable application for this sort of effort.
posted by pompomtom at 6:51 AM on July 26, 2016

I wish someone would make a solar powered unpiloted drone that would just keep flying forever and ever. I think the mere idea of it being up there would be irresistibly soothing.

Until Matthew McConaughey hacks it out of the sky in an moment of inspiring but perhaps irresponsible parenting.
posted by sparklemotion at 7:28 AM on July 26, 2016

Well love'em or hate'em, Facebook generally does not invest in technologies just for fun.

Facebook on July 21 said the first flight of its full-scale Aquila solar-powered aircraft designed for regional internet connectivity was a success, lasting longer than expected despite an unspecified “structural failure” just before landing.
posted by sammyo at 7:32 AM on July 26, 2016 [1 favorite]

attaining parity will take about 20 years.

No doubt batteries still have the potential for a great deal of improvement yet, but I suspect that "20 years" will be rather longer than the "20 years" before fusion power plants are operating.
posted by bonehead at 7:49 AM on July 26, 2016 [1 favorite]

While this may not even qualify as a proof of concept (we'll leave that argument up to others...) It'll be a while, if ever, before we're booking flights on solar powered aircraft. But everything starts somewhere and this is a first step.
posted by azpenguin at 7:50 AM on July 26, 2016 [1 favorite]

The plane and the trip are impressive, but given how slow it is (I hope the pilots are being screened for DVT) and how light the airplane had to be, it doesn't seem like it would even qualify as proof of concept for purposes of eventual commercial flight.


"When the going gets weird, the weird turn pro." - HST
posted by Slap*Happy at 7:54 AM on July 26, 2016 [2 favorites]

I really don't understand how anyone isn't impressed by this.
posted by aspersioncast at 8:01 AM on July 26, 2016 [3 favorites]

hope the pilots are being screened for DVT) and how light the airplane had to be, it doesn't seem like it would even qualify as proof of concept for purposes of eventual commercial flight.


For delivering valuable freight to sensitive regions, however, this could be awesome.

Remove the pilot and let the thing fly by GPS/LORAN.

Add helium or hydrogen to make it semi-bouyant and it will only need even less power.

Now it can hover in place to provide better telecom than a satellite. Or deliver goodies.

Shit. Igor Sikorski talked like this about his helicopters. I better shut up.
posted by ocschwar at 8:11 AM on July 26, 2016 [3 favorites]

The Facebook thing demonstrates the niche where solar powered heavier than air flight might have a chance of being the right choice: When the aircraft doesn't need to carry any passengers, or freight, or go anywhere. Even so it's still not clear if it's a better investment than Google's similar idea, or a constellation of LEO satellites.

On the other hand, I do want a ticket for the first trans-Atlantic solar-powered zeppelin passenger flight.
posted by sfenders at 8:37 AM on July 26, 2016 [1 favorite]

Slow, stable airborne platforms with a lot of endurance are desirable for a LOT of reasons - military and commercial. I've read more than one sci-fi novel that had solar powered drones that absorbed energy by day and descended gently by night.

Y'know - just like this.

I am utterly fascinated by this and think it's terrific.
posted by Thistledown at 10:42 AM on July 26, 2016 [1 favorite]

Anyone who is inclined to be all like "well, it's not THAT impressive, because [reason]" - we went from biplanes made of bicycle parts that could stay in the air for like 12 seconds to jet airliners that could fly across the ocean in less then 50 years.
posted by showbiz_liz at 10:56 AM on July 26, 2016 [3 favorites]

One thing that I learned when reading up on human-powered flight was that the brainpower that was being put into making flight more efficient during the first couple of decades of flight was almost entirely redirected with the invention of the jet engine, WWII, and the quest for supersonic flight. Smart people just weren't thinking about how to make flight more efficient. They were figuring out how to make planes as fast as possible. Most of the cutting-edge research on efficient flight, even as late as the 1980s, had been done in the 1930s.

The Daedalus human-powered flight project didn't lead to a world filled with people pedaling their planes from destination to destination. What it did do was get a bunch of young engineers fired up about the most efficient possible airplanes. Those engineers created computer programs to design high-efficiency low-speed airfoils, propellers with the most efficient possible twist and taper, and carbon fibre spars with maximum strength and minimum weight. None of those things turned out to be particularly useful for airplane flight, but they were all important for the creation of efficient modern wind turbines. That useless flight had a big impact on the engineering and financial viability of wind power.

Engineers get excited about weird things, and sometimes the long-term results aren't easy to predict. As long as they're not working on something that's actively harmful, I say let 'em go at it.
posted by clawsoon at 11:22 AM on July 26, 2016 [5 favorites]

it is more flash than substance - things like the battery technology is being developed anyway, and I get more excited by stuff like this, which is solving a real, practical need, in this case an electric version of a light aircraft that can be used for training, with an endurance of about an hour at a power cost of a couple of euros and a replenishment regime of five minutes.

So, pretty but pretty pointless. You can normally spot these things by the sponsors. The best I think I can say for it is that if it enthuses people to get involved in engineering or thinking about the future of aviation, then that's no bad thing.
posted by Devonian at 1:15 PM on July 26, 2016 [1 favorite]

It's easy enough to be impressed by this. I am. But relevant to the future of transcontinental travel? Naaah.
posted by wilful at 3:03 AM on July 27, 2016

I really don't understand how anyone isn't impressed by this.

It's part of our post-science age. We no longer really believe that anything good can come from research and development, so we tend to look skeptically at people doing it.

ow, if this had been an art project we'd be all over it.
posted by happyroach at 9:25 AM on July 27, 2016 [2 favorites]

The "post-science" aspect of this is best illustrated by the text of that "battery tech" link. Note that it's a publication nominally all about batteries, so they don't have much excuse. If you skimmed it and it all seemed really impressive, perhaps try thinking more critically about the various battery-related claims and comparisons made there. That's what they'd do at NASA.
posted by sfenders at 4:44 PM on July 27, 2016