Why are solar aircraft projects not funded heavily?

[manoj r patil]

I was just browsing on this topic and found that people have tried implementing this concept since a decade but it seems (based on whatever I browsed) that there is no much global funding coming for such projects resulting in a slow progress.

Are the biggies biased and don't want to loose their oil monopoly or there is something else?

In fact hybrid model would be well suited in today's oil crisis and everybody's interests would be preserved...

[Maneesh Godbole]

Manoj,
Don't disclose this to anyone, but it's a conspiracy by the oil companies. They do not want any alternative to crude.
Somebody I know told me that he heard from somebody who knows someone who used to know somebody whose neighbor was murdered. It was rumored he had invented a carburetor which would give fantastic mileage.

These oil companies are so powerful that they have even managed to somehow make the sun start loosing its energy.
Check this out on how they managed that.

[Joe Ess]

manoj r patil wrote:Are the biggies biased and don't want to loose their oil monopoly or there is something else?

No conspiracy. All things aircraft are slave to a single factor: power-to-weight ratio. The power-to-weight ratio of a solar drive train just isn't good enough for much more than a really big solar panel shaped like a wing.

[Pat Farrell]

Joe Ess wrote:All things aircraft are slave to a single factor: power-to-weight ratio

They also care about power to drag ratios, and since the power to weight is so bad, it becomes big and that has lots of drag with is doubly bad.

[John Bengler]

Well, at least the DARPA is founding a solar plane project:

Vulture II

But I suppose you were thinking of a civil use.


John

[Pat Farrell]

John Bengler wrote:at least the DARPA is founding a solar plane project

DARPA/ARPA funds all sorts of stuff. They do less pure science these days, and more in the "has application" stuff, but they are always thinking ten years out. Cool stuff.

[John Smith]

With the current technology, my wild guess is that a solar-powered aircraft able to transport 300 passengers would have to have wing span of about 5 miles.

[Frank Silbermann]

John Bengler wrote:Well, at least the DARPA is founding a solar plane project:

Vulture II

But I suppose you were thinking of a civil use.


John

More to the point, DARPA is probably researching solar powered drones that would serve as alternatives to satellites for recording images from sky and radioing them to earth. Electronic images don't weigh much; that's how you deal with the power-to-weight ratio.

[Pat Farrell]

Frank Silbermann wrote:DARPA is probably researching solar powered drones that would serve as alternatives to satellites for recording images from sky and radioing them to earth.

There is a lot of interest in solar powered drones that gather enough power during the day to stay up all night. The intel services much prefer planes over satellites since they can hang over the target, not be on the other side of the world for 98% of the time.

[manoj r patil]

Joe Ess wrote:
All things aircraft are slave to a single factor: power-to-weight ratio. The power-to-weight ratio of a solar drive train just isn't good enough for much more than a really big solar panel shaped like a wing.

Wouldn't this be good idea to focus on hybrid model initially and even if we save 10% ATF using this model, that would be great help to conserve the energy resources on the earth?

[Pat Farrell]

manoj r patil wrote:Wouldn't this be good idea to focus on hybrid model initially and even if we save 10% ATF using this model, that would be great help to conserve the energy resources on the earth?

That is so far down the priority list that I bet it doesn't enter the engineer's discussions.

Plus, "hybrids" are only useful for things that have varying loads in their normal usage, like a car driving in a city. Planes and ships don't follow that, and they are normally designed to run at optimal efficiency at a fixed speed.

With a drone, you launch it, and it flys at a constant speed for nearly the whole flight. Hybrids like the Toyota Prius just add complexity in this usage model.

There the hybrid cars win is in city traffic. They are not particularly good at constant speed highway miles on the freeway/interstate/autobahn.

[manoj r patil]

Pat, appreciate your knowledge!

...may be instead of aircraft where power-to-weight ratio is highly important, finding optimal solution for the vehicles/rail cars running on the ground with solar as one hybrid option would be useful where even if weight is increased, technology can use its higher inertia and can use solar more when running in a constant speed with lowest acceleration required.

...or how about adding dynamo to wheels which will switch on when running at constant speed and that loss of energy (energy of wheel motion converted to electric energy) will be fed by the conventional fuel?

[Pat Farrell]

manoj r patil wrote: finding optimal solution for the vehicles/rail cars running on the ground with solar as one hybrid option

There was work on using Flywheels to store energy, much as current hybrids use regenerative braking, back in the 60s. I don't think the energy storage density was high enough to be interesting back then. You had to really spin the flywheel, and that raised the possibility of the wheel exploding.

Trains are already very efficient, probably 100 times more efficient than automobiles. They use a diesel motor to drive a generator, and the generator drives electric motors that drive the wheels. No transmission, lots of torque.

I could see a car using the same concept, a tiny diesel powered generator to recharge the battery, and otherwise be an all electric car. The diesel could be far more efficient at that then trying to run it through gears to drive the car directly. Nearly all internal combustion engines run most efficiently at one speed, for cars, its a compromise, needs transmissions, etc. But if you drive the generator, you can match the speed perfectly.