UAV powered by solar energy

[cadet5120]

Hello everyone
At this time I am continually working on the project UAV powered by solar energy. In this moment I am trying to find someone who has such experiences with solar panels(cells) and their plug in into the circuit. And also if someone know which of the solar panels are the most suitable for electric engine of 35A. Is there someone who can help me?

[Arp]

I considered trying (and reconsidered).

Solar panels measuring about 20 x 17 centimeters. offered me something like 13 volts at 100 milliamps, while weighing almost 100 grams. Meanwhile, a battery of 100 grams gives the same voltage and 10 amps.

Therefore, panels of the type I tested would be *absolutely* too heavy for sustained flight. For sustained flight, one would need decisively lighter panels (and quite possibly, autonomous thermal-finding).

A kludgy solution would be having an UAV fly at night and recharge during day, but to have it fly non-stop... is currently possible only with a really big budget (which only bigger research projects can afford).

[rjet]

Check out PowerFilm they make paper thin photovoltaics for RC aircraft. I am not sure what the price is, but enough to fly a plane would probably be very expensive. A research university student was sponsored by one of the photovoltaic companies and used the craft to provide aerial video coverage of a sporting event. I think it was a huge glider with over 10 square feet of wing area covered in solar panels and still it was running less power than most of our small planes.

[PHaze]

Check out this thread (http://www.rcgroups.com/forums/showthread.php?t=378861) about a solar powered UAV (http://www.acpropulsion.com/ACP_PDFs/ACP_SoLong_Solar_UAV_2005-06-05.pdf) that recently completed a continuous 48 hour flight. It used 76 Sunpower A300 solar cells.

[radiohound]

That was a great article (solong)

which shows some of the planes specifications. It got me very interested in the solar cells he used which look very thin and light. They are also 20% efficient which brings them up to par with what Nasa is using in space. Most consumer available cells get about 12 to 15% efficiency.

I called to get a price, just to see if the prices were astronomical, but it turns out they are $12 a piece if you buy the minimum 50 cells. That's actually a lot more reasonable than I thought they would be. This plane used 76 cells.

Here is their spec sheet, just in case anyone else was curios.

http://www.sunpowercorp.com/html/Products/datasheet/A-300/A-300.pdf

One thing to keep in mind if you are designing your wings for solar, is you want to keep the solar cells as cool as possible. The cooler they are, the more efficient they are.

Also, the Solong used an aluminum mold in the construction of the wings. I am not sure about the other details, but I bet this provided a very smooth outer surface. I wonder if vacuum bagging would also produce a similar affect (though not quite as smooth).

There have been many who just build the cells onto the upper surface of a typical construction balsa wing too.

http://www.chrisgood.com/rcplanes/solar/

http://personalpages.tds.net/~dbeck/

The power film cells mentioned in an earlier post are not near as efficient per area, but they are light!

[cadet5120]

Thanks a lot guys. Your info helps me a lot. In recent time I will start on it. If i will get somwhere i will get you to know. Thanks

[gnz]

I wonder why there isn't any solar powered flying wing designs used? Isn't it the ultimate solution -> Big wing area which helps to add more and more solar cells. Beside that you get good L/D ratio.

Just my 2 cents...

[kd7ost]

I'm sure this isn't specifically what you mean, but it is being done.

http://www.uavforum.com/library/photo/pathfinder.htm
http://www.aerovironment.com/

Dan

[gnz]

I'm sure this isn't specifically what you mean, but it is being done.


Yes. I meant hobbyist scene.

[kd7ost]

Yep, I know what you mean. I think solar cells need to experience a break through (A big one) before we can use them to power reasonable hobby planes. They just have such a poor power to weight ratio it's much easier to use other power systems.

Dan