Using solar panels on electric plane

I know this has been posted before but is anyone using solar panels on their plane to keep the battery charged in flight? You can buy thin film flexible panels (http://store.sundancesolar.com/powulflexthi.html ) but I don't know if it will work.
Silicon Solar makes a couple of solar charged planes. The Night Vulture (wierd name for a solar plane) can stay aloft for several hours or so they claim. http://www.siliconsolar.com/solar_powered_rc_planes.htm
I've got a little cheapo foam plane with a 6 cell 7.2v 300mah MiMH battery and was wondering if I could slap a couple solar film panels on it and fly forever ro at least until the sun goes down!
Thanks!

You can't get enough power density in solar panels to fly planes as small as we fly. The panels to generate that kind of current would weigh much more than the plane! Looking at the web sites you have, it would take 5 of the PowerFilm 7.2v, 200mA sets to get just 1 amp. That is almost the size of a .40 sport plane wing with no where near the capacity to fly it!
I think that if it were possible, it would be done already.

| You can't get enough power density in solar panels to fly planes as small as | we fly. The panels to generate that kind of current would weigh much more | than the plane! Looking at the web sites you have, it would take 5 of the | PowerFilm 7.2v, 200mA sets to get just 1 amp. That is almost the size of a | .40 sport plane wing with no where near the capacity to fly it! | | I think that if it were possible, it would be done already.
It has. It's just not easy.
Here's one guy who has done it --
http://personalpages.tds.net/~dbeck /
Here's another guy who may have done it, but it's all in German so maybe he never succeeded :)
http://rz-home.de/~sieghard.dienlin

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I was thinking of the solar panels keeping the onboard battery charged and not actually running the motor.

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It depends on how much current your motor draws and how much wing area you have available.
Let's hypothesise for a moment:
If your plane flies for 5 minutes - for example - it's drawing around 4 amps. The Sundance bunch sell a 7.2v 200mA panel - you'd only want 20 of the suckers to generate the required amps. The panels are pretty small, only about 11" x 7", so all you'd need was 1540 square inches of wing area to stick them to - what's the wingspan of your plane? Let's say it's an 11" chord, it'd only need to be 12ft or so. The panels would add about 36 oz, which might then require a bigger motor to get off the ground, needing more amps, so you'd need to throw a few dozen or so extra panels on.
That'll need a tad more wing area, and might add a little weight, so you could be looking at a bigger motor, which will need more amps...

| I've got a little cheapo foam plane with a 6 cell 7.2v 300mah MiMH | battery and was wondering if I could slap a couple solar film panels | on it and fly forever ro at least until the sun goes down!
This sort of thing has been done ... both with R/C gliders and with larger planes (think of NASA's Helios, RIP.)
However, it's *much* more difficult than `slap a couple solar film panels on it'. You could probably add enough solar cells to keep the receiver battery charged without too much trouble, but enough to actually power the motor will require a very carefully thought out and efficient airplane. And it will be expensive and fragile.

If your foamy will lift 3 pounds, your in business!
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The specs on their website don't make sense. It says the operating current is 4 amps, the battery capacity is 280mah, and the solar array provides 600ma. I don't see how you can fly for several hours unless you are doing a lot of thermaling. At full throttle you'd only get 4 minutes of flight on the 280mah battery. Assuming you were really good at throttle control, you could double that to 8-10 minutes. In that 10 minutes of flight you've only gained about 100mah from the solar panels. And the whopping 100ft transmitter range doesn't sound like you are going to be thermaling this thing very high.

Looks like a little POS toy. That is, what you CAN see of it.

NASA's UAV Helios uses some 64,000 panels mounted to the top of the wing. That's for daytime and rechargable power packs run it at night. Intended to stay up for six months or more.
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A guy in San Fernando Valley Electric Flyers flys an electric with solar cells and no internal battery except one for the receiver for safety. 100" and uses a geared Astro 020. Flys as long as the sun's high in the sky.
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