Around the World in a Solar Plane

Coati writes "Bertrand Piccard, the guy that flew around the world in a balloon, wants to do it again, this time in a solar plane."

Comments

Sunny skies

[Jumper99]

Guess he won't be flying at night.....

Re:Sunny skies

[kinnell]

Guess he won't be flying at night.....

As long as he can design a solar plane which can fly at mach 2, this shouldn't be a problem.

Re:Sunny skies

[isorox]

You need to make 700mph to fly arround the world in complete sunlight, starting at sunrise on the equator, and taking 36 hours arriving at your departure point at sunset the next day.

Re:Sunny skies

[swillden]

As long as he can design a solar plane which can fly at mach 2, this shouldn't be a problem.

Nahh, 700 mph is all he needs. If he flies with the sun, night will gain on him at a velocity of v_s - v, where v_s is the speed of the light's edge and v is his speed. If he takes off at dawn, and flies along the equator, he has to get all the way around (25,000 miles) before night, which starts out at 12,500 miles away, catches up.

So, he has to achieve a velocity v that satisfies both:

(v_s - v) t = c/2

and

v t = c

where t is the travel time and c is the circumference of the earth. Isolating t in each and setting them equal gives:

c / [ 2 (v_s - v) ] = c / v
==> 2 (v_s - v) = v
==> 2 v_s = 3 v
==> v = 2/3 v_s

Plugging in the numbers, that means he needs a velocity of about 694 mph, assuming the earth's circumference is 25000 miles.

no sun = no fly

[ikoleverhate]

he'd better not fly over the UK then.. no sun here ;)

eco friendly?

[A1tha1us]

So after a few years of r&D half a dozen custom built protoypes (to be discarded as non-biodegradable junk) and other discarded parts they can have something that probably took more energy to make than a small town uses in a year, but then fly it around the world using only energy from the sun...I suppose it will be a cool engineering achievement.

Re:eco friendly?

[gobbo]

So after a few years of r&D half a dozen custom built protoypes (to be discarded as non-biodegradable junk) and other discarded parts they can have something that probably took more energy to make than a small town uses in a year, but then fly it around the world using only energy from the sun...

A Proof of Concept product is always more costly. You can think of R&D costs not concentrated in a single product, but amortized across the series of product lines inspired by the new engineering, whether those costs are money or calories or a balance of available resources. The long-term savings (in all economic senses) represented by efficient design suggests a real bargain for global society.

The publicity stunt aspect of this is really a kind of marketing for sustainable tech in the long view.

Re:eco friendly?

[Urkki]

Do you truly not see why developing solar energy technology to the level that makes this kind of plane possible is eco-friendly proejct, or are you just trying to troll?

And it's not just developing better solar cells to enhance current applications of solar energy.

Consider for example that if a lot of oribital satellites could be replaced with purely solar-powered autonomous planes that could stay up theoretically indefinitely. Just think how much "non-biodegradable junk" can this project produce to match the environmental impact of just a single space rocket launch...

Or imagine a hydrogen fuel-cell car that could partly refuel itself in a sunny parking lot during the workday, and could keep moving (slowly) even if you run out of fuel. Not much use in higher latitudes maybe, but imagine southern China, India and entire SE Asia with 2 billion cars like this instead of 2 billion cars using fossil fuels.

Power storage

[GeckoFood]

So, assuming he has clear skies for most of that trip, no problem. However, if he hits "inclement weather," how much energy does that plane store up before it runs out of juice? Or can it be assumed he will be above the cloud cover for the whole trip? And, is it assumed the trip is continuous or will he be able to stop at "jump points" (this makes more sense for obvious reasons). If he can stop even briefly, this idea becomes a lot more feasible.

Re:Power storage

[Zocalo]

I was wondering that too. I'd assume that the plane would essentially be a glider and would use the solar power to provide lift as required and thrust only if sufficient spare energy was available. I'd also assume any onboard batteries would be fully charged at takeoff too to give things a head start.

Even so, doing this in one hop seems a little unlikely, unless circumnavigation near the pole in summer is in order, and it's not in my book! Ignoring the tilt of the Earth, then taking off at dawn and flying west to maximise the amount of daylight would require a circumnavigation within 36 hours before night would fall. That's in the region of an average speed of 1,000mph. Fully charged batteries at takeoff, flying on battery through pre-dawn and recharging through the day and finishing off on battery at night would reduce that some, but enough for one hop?

Re:Power storage

[Coelacanth]

An aircraft of this type will certainly be cruising above the clouds, and will be steering well clear of any convective activity (thunderstorms) for safety reasons. The real power storage challenge is to get through the night.

This is the reason you don't see all that many solar-powered UAVs, never mind piloted aircraft. The economics of solar flight would change radically if battery technology improved.

Glider

[penguinoid]

People can stay in the air for several days in a glider. They use upward currents to gain height. You know, fly over a desert in the day, and over a forest at night.

Get off the cross

[Gothmolly]

We need the wood.

Spare me the "any mention of ecology gets a lukewarm response from the public because their comfortable existence is threatened".

The problem with many so-called 'ecologists' is that they frame everything in terms of 'saving the Planet'. Here's a clue - the Planet will survive long after we're all dead. The Earth will be there when the sun becomes a red giant and eats it. We shouldn't save the Planet, we should save ourselves. Does the Earth 'care' if biodiversity diminishes due to pollution? Does the Earth 'care' if the light pollution causes algae disruptions in the Great Lakes? No. but we should.

This project is great at raising visibility and research focus in the fields of energy capture, storage and motor design, but these folks aren't the Messaihs.

Everyone asking 'can it fly at night'

[hookedup]

If you had clicked the article link, you'd see a picture of it flying at dusk, right on the front page!.

Also from the press release

The Solar Impulse aircraft will have an extremely long wingspan, advanced aerodynamics, and a revolutionary structure in order to capture and store sufficient solar energy during the day and to be able to maintain itself in flight during the night.

Re:Everyone asking 'can it fly at night'

[Robert Osfield]

My guess is that they will probably climb during the day and charge batteries then glide all night with a small power draw to the batteries extending the glide. If they can climb enough during the day then they might not need to use batteries, and just glide until the morning. It should be possible to build such a machine with less than 100ft/min sink rate, perhaps even 50ft/min. Thanks 3000-6000 ft lost per hour, 8 hours is 24000-48000ft height loss. Manned flight makes this more complicated though with needing oxygen and heating the pilot at high altitudes.

That's not cool

[Anonymous Coward]

They should go around the world in a solar-powered submarine.

We're not alone...

[WIAKywbfatw]

Perhaps we have a right to wipe humanity of the face of the planet, perhaps we don't. But I don't see how we have a right to wipe out all the countless other species and to poison the earth, sky and the seas.

To use a famous quote, this is a beautiful planet, it's a miracle and we're destroying it.

(Cue a dozen posts from people who think environmental awareness is for only for hippies high as a kite.)

Remember Helios?

[adun]

NASA's little darling solar plane flew at about 90,000 feet, well above any potential cloud cover. You can assume that these guys are planning on the same strategy. But if you plan to send a manned flight up to 90k feet, doesn't that raise a whole slew of logistics questions? i.e., the amount of oxygen needed, the weight ratios to follow, etc...

Re:No, the son of Jacques & grand-son of Augus

[rduke15]

Who is Jean-Luc Piccard anyway?

Bertrand is the son of Jacques and the grand-son of Auguste. See his biography.

"His grandfather, Auguste (1884-1962), [...invented] the principle of the pressurised cockpit and the stratospheric balloon. In making the first exploration of the stratosphere [...] in 1931, he [...] became the first man to see the curvature of the earth's surface with his own eyes."

"His father, Jacques, continued the work of Auguste [...] the world's deepest dive (-10916 metres in the Marianas Trench, the greatest known ocean depth)."

A better link, explaining the technology

[rduke15]

The EPFL explains much more about the technological aspects. It's in French of course: here.

But for those who cannot read :-), they also have nice pictures

One technological aspect is that by flying very high, they can take advantage of the cold (-55C), which can improve efficiency of electro-magnetic motors.

There are other interesting bits. I guess the page will be translated in English in a few days. (Forget computer translations, unless you want a cheap laugh)

Awareness my Ass

[rocker_wannabe]

Just repeat after me:

"It's all about money."

"It's all about money."

I have a 2kw solar system on my roof so I'm certainly not anti-renewable energy. I just think people should realize that the problem has nothing to do with technology or people's desire maintain their lifestyle because it's not even allowed to come down to that. It's about greed and established infrastructure. I don't think it's any coincidence that the major solar panel manufacturers are all owned by oil companies. I can't prove it but it doesn't seem unreasonable to assume that they are controlling the price of solar panels to keep the usage at a level that is comfortable to them.

We have reached the level of corporate control in this world that is reminicent of the movie Rollerball (for those of you old enough to remember it). The U.S. courts and the EU and make a good show of protecting their citizens but corporations don't need to do anything illegal to get what they want. With enough money and lawyers you can blunt any reform that comes down the pike. Movies have to be more dramatic but the truth is much more banal.

I'm glad Mr. Piccard has the ability to put together these inspiring projects. I wish he'd invite me to be on his team. I just don't think for a minute that it's going to address the real problem.

"I tried solar power but it just made my skin peel. I'll stick with food, thank you."