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Jan 28, 2003, 08:14 AM
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Solar Pleaser


Hello,
I would like to tell you about my airplane project that started out as a Mini Pleaser and ended up a solar powered plane. You may wonder why I went to the effort and expense to build a solar plane when Li-ion/poly batteries are available that will fly a plane for over an hour. Well, I guess it・s just something I・ve always been fascinated with and wanted to do. This is my 3rd attempt and my first truly successful pure solar plane. My first solar plane was made with a Kolibri like wing and was a big :flop; in more ways than one. My second had a wing styled after an Elfi wing. This was a much better airplane but was slightly under powered because of the limited wing area to mount solar cells to. It had 32 cells.
On :Solar Pleaser; I built a balsa frame inside of the wing to mount the solar cells to. The cells are held in place with CA glue. I also eliminated most of the incidence in the wing.
There are no batteries or capacitors in the plane. The receiver, motor and servos are all driven by solar power.
I looked briefly at using flexible solar cells but found I would need a wing span of nearly 5 times of what I have.
I will try to post some pictures. Sorry the in-flight pics. aren・t too good. It was a little difficult taking pictures and flying at the same time. If I drag my wife to the flying field too many times she・ll probably make me go purse or shoe shopping with her!
During flight, if the sun goes behind dark clouds, the low voltage cut off on the ESC kicks in and kills power to the motor but the solar cells are still able to power the servos. In fact, I can turn the plane up side down (so the back of the cells are facing the sun) and still have enough power for the servos. This would of course be done while holding the plane on the ground, not attempting a loop while in flight. If the low voltage cut-off does kick in, I have to throttle all the way down, then back up and the motor will start again. This would not be necessary on a clear day.

So far I only have 3 flights on the plane, all during the same day. It was very cloudy and windy during the flights so they were limited to about 40 min. ea. I must say that I was absolutely thrilled with the way it flew. When the weather is better, I should be able to fly as long as the sun is shining or until the GWS motor burns up! It・s probably not the ideal motor for the job but for now it works well. Any suggestions on a motor/gearbox combo of the same weight? I have some current to spare so a slightly larger motor is not out of the question. I just don・t want to add too much more weight to the plane.

How the cells are wired:
There are 48 cells in total. Each cell generates 2.05V @ .214A. Cells are wired into groups of 4 in series. This group of 4 cells creates 8.2V @ .214A. There are then 12 of these groups. All the groups of 4 are then wired in parallel. This makes a total of 8.2V @ 2.568A or 21.0576W. Hopefully I explained this OK (and my math is right)!

Some Specs:
Wingspan 41;
Length 40;
RTF Weight 8.8oz
Solar Cells weigh 1.7g ea
The power plant is a good .ol GWS :A; IPS gearbox with a CB motor, turning a 10x4.7 prop.
Rcvr: Hitec 555
Servos: MPI MX-30
ESC: GWS 50
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Jan 28, 2003, 08:14 AM
Registered User

Pics.


Pics.
Jan 28, 2003, 08:15 AM
Registered User
pics.
Jan 28, 2003, 08:16 AM
Registered User
Pics
Jan 28, 2003, 08:17 AM
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pic
Jan 28, 2003, 08:22 AM
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pic
Jan 28, 2003, 08:24 AM
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Stregone's Avatar
Too cool Where did you get the cells and how much do they cost?
Jan 28, 2003, 08:27 AM
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pic
Jan 28, 2003, 08:40 AM
Hiigaran member
Lone Yankee's Avatar
WoW! This is the coolest thing I have seen in a very long time! I dabbled with the solar power question myself but could not solve the amperage problem. PLEASE tell us exactly what solar cells you used and where you found them. You are truly a pioneer of electric flight!
Jan 28, 2003, 09:46 AM
Live to ride... and fly!
Tres Wright's Avatar
That's awesome! What's your longest flight so far?
Jan 28, 2003, 09:54 AM
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Matt Chester's Avatar
That is VERY VERY COOL!!!

I love the idea of unlimited flight times.

Tell us more!!!!
Jan 28, 2003, 10:09 AM
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die fliedermaus's Avatar
More info please!!!

I've toyed with building a solar powered plane for years. The thing holding me back has been the lack of success of other modelers to build a reasonably small plane that will carry enough cells.

AstroBob made a solar powered plane in the '70s but the size and cost at that time were way to much for mere mortals. Of course there is Centurion and Helios and the Sky Tower built by Aerovironment with a huge pile of NASA money.

Solarflyer, who, what , where, why ,when?

Oh yeah, welcome to the 'Zone.
Jan 28, 2003, 11:24 AM
Registered User
Yes! More information please! There are a lot of us that would love to take solar power and apply it to parkfliers. Solar power is something easily accepted by the non-flying public which could be an advantage as the restrictions on flying space keep closing in. I'm amazed that you've managed to get 8 oz in the air using conventional radio/servo equipment. We have to know more about this!

JT
Jan 28, 2003, 11:26 AM
Motor Maniac
Interesting bird. With the warm and sunny weather we have had this winter I think you could get some great flights here in So Cal. I have one suggestion for you: get a lighter RX. Even with the case off the 555 is kind of heavy. On a plane like this even 7 or 8 grams could make it fly better, climb faster.

I like the looks of the clear covering, but does it get difficult to see at altitude? How high up have you flown it?

How about trying the Tipsy power system: 280 motor direct drive with a 4.7x2.4 in prop. This flies the Tipsy well on 6 cells @2A and the Tipsy is heavier than your plane.
Last edited by 10Thumbs; Jan 28, 2003 at 11:30 AM.
Jan 28, 2003, 11:53 AM
Leave me alone!
Martin Hunter's Avatar
Very very cool!

I had no idea you could even get solar cells that small or light! Please, more info!

Martin


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