Solar Plane Successfully Completes Maiden International Flight

That was a great accomplishment but the upside is very limited for normal aircraft use. There is only so much solar energy falling on a given area. It will never be a practical replacement for normal aircraft.

Where a solar powered aircraft really shine (pun intended) is as an unnamed scientific or military data acquisition platform with a loooong loiter time.

 

....as long as oil is cheap.

 

Or expensive.

 

What kind of motors did this plane use ?

 

Sounds like Wonder Woman's invisible jet. Except you can't collect solar energy with transparent solar panels.

As for it being impractical because of limited solar energy, future advances might make it practical. The solar cells right now are not efficient. But future solar panels might put out 3X as much power. Then, design a plane that intentionally has a large surface area facing the sun, and you're onto something!

 

I think for any application moving cargo or people (it works perfectly as a spyplane now, i'm sure they said when they did the night flight that it could stay up indefinitely in the summer months) the solar is a bit of a "nice to have" that extends flight time/reduces battery weight, but it will be heavily battery reliant. I'm fine with that. Make the body out of that material Volvo were testing which has similar properties to high strength steel but also acts as a battery. i flew quite a bit for work last year and didn't like it, i'd have been much happier in an electric plane

 

Even if the solar panels could be made 100% efficient, they would still lack the necessary power to move a plane at high speed. Solar powered aircraft, by the very nature of energy density, must remain niche vehicles.

For high speed flight, solar power only works if it is off of the plane, where it is used to generate some sort of high energy density fuel.

Tom

 

You're assuming that high speed planes of the future require the same amount of power as today's planes. There is no law that says it takes x power to fly at y speed.

 

I assume you are making a joke? The laws governing this are the most basic of all: the laws of physics. Physical law in this area is simple and well understood, and it doesn't allow for high speed flight at those power densities.

I suppose we could allow for a wholesale overthrow of physics as we know it, but in that case we can equally allow for free energy from the vacuum of space. In the realm of science fiction anything is possible.

Tom

 

Which house of Congress can oveturn the laws of physics?
Or will this discussion need to be moved to FHof Politics?

 

For classical physics, action must be initiated by the House, but the final vote is made by the Senate. For modern physics, essentially anything involving quantum effects, it is a bit more involved, requiring a super-majority of both houses.

Tom

 

You forgot to add "and an act of God."

 

Sure there is (at optimum velocity):

Energy / unit weight / unit distance = (((CdA)^1/2) / E)g
where Cd = coefficient of drag (already pretty optimized)
A = frontal area
E = efficiency of motor
g = Gravitational constant

Since you can express the energy from solar panels in terms of energy density (MJ/kg), they are no different (conceptually) from carrying kerosene.

 

If humans could stand more acceleration, a big rubber band would come in really handy for launching planes. An electric rail launch would be even better.

And when Arthur C Clarke's dream of a space elevator is realised, the plane could be launched from a great height and glide to its destination. Of course, travelling all the way to the geostationary satellite would be further than the surface distance between departure and arrival points...

 

Not really, kerosene doesn't recharge or get its efficiency decreased by cloud cover. Since a good pilot flies with a safety margin, solar necessarily requires a much bigger reserve. Even if we run out of oil, other processes will allow us to make ethanol or jet-a, so this is really just a feel good demonstration. For anything carrying payload or passengers on a schedule solar is not a viable option. For recreation or spyplanes the tech has merit.

 

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