If you squint your eyes it could pass for a private jet

May 11, 2008 8:03 AM

Is solar-powered flight getting any nearer? As noted previously on Metafilter, solar powered aviation has travelled a long way since the heady days of the Gossamer Penguin. But could it actually one day power commerical flight?

Trouble is, a quick look at the prototypes reveals that most solar-powered planes remain a world away from passenger aviation. But that could be subject to change. Although we are not quite at the stage of the easyJet ecojet just yet, what might be just over the horizon is something like the Hy-Bird, a hybrid of hydrogen, solar-power and lithium-polymer batteries. The Hy-bird still looks like a bit like a prototype, but it is beginning to look more like a proper plane. If you squint your eyes, it could pass for a private jet. Lisa Airplanes, the Hy-bird's manufacturer, is planning to take the plane on a voyage that will circumnavigate the planet later this summer.

According to Inhabitat, the Hy-bird gets just 10% of its power from solar, but that's still a significant contribution. Yes, we should all fly less if we want to reduce CO2. But the prospect of a truly green-powered aeroplane is enough to spark the imagination. Could we both save the planet and still be able to fly?

posted by MrMerlot (25 comments total)

I don't like saying never, but it's a real long shot that you'll have a 100% solar aircraft outside of sport aircraft. Weather is really the issue - airplanes need to get places, and aircraft that can only fly in clear blue skies won't get sold. Small airplanes can't fly above the weather. Bizjets and commercial aircraft won't be able to take off, which will make an already cranky flying public even angrier.

Yes, you can put batteries or other propulsion systems on to get the airplane to altitude, but that's extra weight and expense that's unnecessary. Batteries (and even solar cells) are heavy, and the amount of energy needed to get a hundred-thousand-pound jet (and this is Embraer size - Boeings and Airbuses are quite a bit heavier) to altitude is not insignificant.

Keep in mind, too, that the world's entire fleet of aircraft produce only some small fraction of the carbon emissions of the US's automobiles. If you want to cut greenhouse gases, I'd start with something other than airplanes.
posted by backseatpilot at 8:38 AM on May 11, 2008

Oh, and to address this Hy-brid specifically - don't hold your breath. A very high fraction of announcements in the aviation world turn into vaporware; if they're lucky, they'll build one or two prototypes before the company goes bankrupt.

Where did you get "later this summer" from their website? As far as I can tell, they don't even have a real airplane yet. It's a bad sign when there's a lot of hype and the only images are computer renderings. If they can get an aircraft built from the ground up with new, relatively unproven technology, and fly it around the world by the end of summer I would die from shock.
posted by backseatpilot at 8:43 AM on May 11, 2008

Keep in mind, too, that the world's entire fleet of aircraft produce only some small fraction of the carbon emissions of the US's automobiles. If you want to cut greenhouse gases, I'd start with something other than airplanes.
posted by backseatpilot

That's only because more people drive than fly. Should we ignore the fact that individual flyers pollute much more than individual drivers because there are fewer flyers? Here--calculate your emissions on a per-person basis.
posted by weapons-grade pandemonium at 9:04 AM on May 11, 2008

I agree with your point, but there are two reasons that I can see to focus on cutting greenhouse gases in, say, automobiles, instead of aircraft. First is that more people drive than fly. Second is that you'll never see equivalent ridership in aircraft and automobiles. So, I think having more marginal gains in a larger number of vehicles - by increasing mileage ratings in cars, for example - will provide a cheaper and more substantial impact than focusing on fuel economy in aircraft.

I'm not saying we should ignore fuel economy in aircraft; there's been some interesting work lately making planes more efficient. GE's GENx engine has some innovative improvements; granted, you're only getting a few percent extra efficiency, but it's a start. Also, over the past decade or so airlines have been retrofitting their fleets with winglets, which is another relatively cheap way to get a little extra economy out of their airplanes.

The whole aviation industry has a strong incentive to make more efficient aircraft, since the airlines are realizing that their solvency is tied to the price of fuel. That situation hasn't hit individuals yet, so I think you'll see more advances in aircraft efficiency.
posted by backseatpilot at 9:25 AM on May 11, 2008

I'd like to think that they've built a few prototypes along the lines since they're projecting this 'round the world journey to take place this summer. Of course I'd also like a harem of beautiful women, a palace, and a bucket of ice. Not gunna happen though.

Well. . . I do have the harem.

Nonetheless, the idea is great, although overshadowed by Ed Begley Jr.s means of conveyance:

"I prefer a vehicle that doesn't hurt Mother Earth. It's a go-cart, powered by my own sense of self-satisfaction"
posted by Inversehelix at 9:36 AM on May 11, 2008

Keep in mind, too, that the world's entire fleet of aircraft produce only some small fraction of the carbon emissions of the US's automobiles. If you want to cut greenhouse gases, I'd start with something other than airplanes.

This is simply not true. US CO² emissions are about 20% of the world total. Total US carbon emissions for transportation are 33% of this total, but cars and light trucks only account for 57% (PDF, 3-7) of that. So, in total US car and light truck carbon emissions are about 3.8% of the world's total carbon emissions.

World aviation CO² emissions are 2.4% of world total emissions. Sixty-three percent is not a small fraction.

However, the question at hand is the climate change effects, not the CO² emissions. Because of the effects of burning fuel at high altitude, the climate change effects of aviation are about 3 times as large as they would be just from the CO² emissions.
posted by ssg at 9:50 AM on May 11, 2008 [1 favorite]

10% of it's power? that's pathetic. would 10% even cover the extra weight of having solar cells in the first place? i wish we could come up with real solutions instead of these stupid things that are only done to get venture capital.
posted by bhnyc at 10:31 AM on May 11, 2008

Solar-powered commercial flight is impossible.
posted by Mr. President Dr. Steve Elvis America at 10:32 AM on May 11, 2008

I think that practical, consumer-palatable solar powered automobiles are more probable, and that's saying something. You'd need planes built out of stuff that would make balsa wood look like lead, some very tiny people, and possibly parachutes to save on the costs of landing and taking off again.
posted by adipocere at 10:57 AM on May 11, 2008

I think you'd have to squint the eyes a great deal to have the Hy-Bird pass as for a private jet. Also, its configuration, with that off-axis propeller, seems pretty suboptimal: when the motor runs, its thrust will create a significant nose-down pitching torque, whereas then it stops its drag will pull the nose upwards. Moreover, with the propeller there, right behind the cockpit, you definitely do not want to have to bail out. The only aircraft I know with similar configurations are a bunch of seaplanes, which need to keep the propellers as far from the water as possible, and the Trislander trimotor, which just needed some place to put that third engine...

Looks like venture capital bait to me.
posted by Skeptic at 11:01 AM on May 11, 2008

If everyone thought that the smallest advances wouldnt make a difference, we would have no more innovation.
posted by subaruwrx at 11:15 AM on May 11, 2008

There is probably more energy to be tapped by making passengers pedal for battery or propeller power. And as long as every future energy solution assumes that the consumer spends no energy, we're still in a luxury zone, and farther from a solution.
posted by Brian B. at 11:16 AM on May 11, 2008

From the website:

An electric engine (more silent than heat engines) will propel Hy-Bird.

Yeah, you might be changing your minds on those heat engines when you're flying over the arctic circle.
posted by Civil_Disobedient at 11:22 AM on May 11, 2008

That's only because more people drive than fly. Should we ignore the fact that individual flyers pollute much more than individual drivers because there are fewer flyers? Here--calculate your emissions on a per-person basis.
posted by weapons-grade pandemonium


I used the site to calculate a coast-to-coast US flight. It said my percentage of fuel would be 97 gallons.

Driving covers a longer distance since you can't drive in a straight line, so it would be about 3000 miles. With a 30mpg car, that would be 100 gallons.

So a car uses more gas than a plane in this common example.
posted by eye of newt at 11:42 AM on May 11, 2008

My mistake--I forgot to click on-way. So the flight uses less than half the fuel as a car (assuming you trust the sites calculations).
posted by eye of newt at 11:45 AM on May 11, 2008

Driving covers a longer distance since you can't drive in a straight line, so it would be about 3000 miles. With a 30mpg car, that would be 100 gallons.

Technically, though, to compare individual flyers with individual drivers, one would assume a near empty plane to compare with a near empty car, but you have a point here. People choose flying because it is cheaper for them in terms of hourly productivity, but as fuel costs double, this would not be the case for very many. I would assume that nothing beats a crowded charter bus per passenger hour, except perhaps high speed trains, if even that.
posted by Brian B. at 12:01 PM on May 11, 2008

If everyone thought that the smallest advances wouldnt make a difference, we would have no more innovation.

I'm saying this isn't an advance at all. Take off the solar panels and it would weigh less, fly further and use less energy. There are so many goofy things at the moment that are pretending to be green. It's because it's easy to get funding and publicity in this stuff. it has nothing to do with whether they are useful ideas. It's just feel-good nonsense.
posted by bhnyc at 12:09 PM on May 11, 2008

I used the site to calculate a coast-to-coast US flight. It said my percentage of fuel would be 97 gallons. Driving covers a longer distance since you can't drive in a straight line, so it would be about 3000 miles. With a 30mpg car, that would be 100 gallons. So a car uses more gas than a plane in this common example.
My mistake--I forgot to click on-way. So the flight uses less than half the fuel as a car (assuming you trust the sites calculations).

Except that the climate change impact of the flight is about three times the effect of the carbon emissions on their own. So the climate change impact of flying will be about one and a half times as much as the impact of driving. If you put two people in the car, the impact will be about a third as much as flying. Of course, a full bus or train will reduce your impact much further.
posted by ssg at 12:24 PM on May 11, 2008

The only kind of solar-powered aircraft that has some chance to one day be commercially useful for transportation is the kind that doesn't require all that energy for lift. So, let's build a dirigible covered with solar panels. As with just about any crazy idea, there's already someone working on it:

Strato Cruiser is a concept for a “lifestyle zeppelin”. It's a bit unclear whether its propulsion is actually intended to come from the photovoltaics.

Hyperblimp has the advantage of actually existing, but the disadvantage of being too small to carry much more than its own weight.
posted by sfenders at 12:40 PM on May 11, 2008

According to Greyhound sources, their newer buses hold 54 passengers and get about 168 passenger miles to the gallon. This does not exceed the average full car or minivan, and when factoring in operational costs like filling up the seats, it doesn't come close. The car is still the efficiency king of the road. If there was an easy way to charge a federal highway tax on the empty seats in a car, it would encourage wiser use.
posted by Brian B. at 1:22 PM on May 11, 2008

Plus, if riding Greyhound buses is the only way to keep New Jersey above the water, well, it's been real, New Jersey, but we both knew this wasn't forever.
posted by Mr. President Dr. Steve Elvis America at 1:28 PM on May 11, 2008

the world's entire fleet of aircraft produce only some small fraction of the carbon emissions of the US's automobiles.

Bear in mind that some people don't give a shit about carbon, but are still looking for ways around the predicted price of liquid fossil fuels a few years from now. Right now, the future of aviation is bound more tightly than even cars, to liquid fuels.
posted by -harlequin- at 2:40 PM on May 11, 2008

I'm saying this isn't an advance at all. Take off the solar panels and it would weigh less, fly further and use less energy.

I seriously doubt the solar panels would account for 10% of the weight of the plane. I mean, that's just a bizarre thing to think.
posted by delmoi at 6:39 PM on May 11, 2008

This 10% figure they quote is just pulled out of the air. This plane is CGI vaporware.

The panels are going to weigh something and the "Ri&Flex" wings are going to have to be compromised in some way (drag) to accommodate them. I'm just guessing, but more than a 10% penalty in performance seems reasonable.
posted by bhnyc at 7:36 PM on May 11, 2008

This plane is CGI vaporware.

Yeah, after looking at the abomination that fucking NASA built, you've got to be skeptical of anything claiming solar with less than, like, 12 engines. And that's unmanned. The take-off and landing strip, by the way, have to be miles long before you get any real altitude. Fuck that, I think I'll keep sucking off the petroleum teet for a little while longer, thanks.

Those wee-wings might power the instrument cluster. If you're lucky. And it's day time. Right.
posted by Civil_Disobedient at 4:11 PM on May 12, 2008