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Old May 10, 2011, 01:58 PM
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gsantos_pt's Avatar
Portugal
Joined Feb 2011
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My Solar Airplane

Hi everyone!

I started a project one year ago for build a electric airplane with solar cells. This plane is already built but the project is not finished .

The Solar Airplane:



FC 28-22 Brushless Outrunner 1200kv
TURNIGY Plush 18amp Speed Controller
Corona Synthesized Receiver 4Ch 35Mhz (v2)
ZIPPY Flightmax 1000mAh 3S1P 15C
HXT900 9g / 1.6kg / .12sec Micro Servo (2x)
GWS EP Propeller (RD-1047 254x119mm)
RC7.2-75 PSA Flexible Solar Panel 7.2V @ 100mA (10x)
12V Charger (made by me)

How it works?

The solar cells are connected in parallel and series. Five cells in parallel more five cells in parallel (5+5). This two groups are connected in series.



Theoretically the circuit gives 14.4V and 500mAh.


This cells have to charge a 3s lipo battery during the flight for extend the flight time. For charge the lipo I made the charger (L200 chip):



The circuit link: http://www.electronica-pt.com/circui...rger-l200.html

Some pics of building process:

Elevator and rudder:



wings:





More photos of the process:











Video of construction and flight tests:

Avião Solar / Solar Airplane (1 min 42 sec)


http://www.youtube.com/user/goncaloareias98

After testing the plane I checked that wasn't a good idea made it without ailerons. The weight of the plane is about 700gr (0,7kg). It's really hard fly it with wind.

In the next weeks I will try to flight it again but this time without wind

Test results comming soon.

Opinions, suggestions and questions are Welcome

Regards

gsantos_pt
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Last edited by gsantos_pt; May 10, 2011 at 02:48 PM.
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Old May 10, 2011, 05:35 PM
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GRASS GRINDER's Avatar
USA, DE, Townsend
Joined Aug 2009
126 Posts
looks like the cg is tail heavy, but the idea of a solar plane is great. cool plane. good luck on your build.

p.s. were did you get your solar cells from.
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Old May 10, 2011, 05:57 PM
Lost but making good time
Joined Nov 2008
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gsantos,

Impressive project to say the least! Check the horizontal stabilizer and rudder size with the proportions on the page I'm sending. Also, the CG location as Grass Grinder suggests.

http://adamone.rchomepage.com/cg_calc.htm

Again...very impressive!

Regards,

Hankg
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Old May 11, 2011, 12:18 AM
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Taiwan, 北市
Joined Dec 2010
1,215 Posts
Hi Gsantos,

A very good idea !

It might be a little tail heavy and the rudder seems to be not big enough for correcting back its attitude. Just my two cents.

Chen
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Old May 11, 2011, 01:34 PM
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Canada, BC, Squamish
Joined Jul 2002
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Quote:
Originally Posted by GRASS GRINDER View Post
looks like the cg is tail heavy,....
Or it's just heavy and not able to fly on the wing at the pitch speed. Seems to be hanging on the prop.
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Old May 12, 2011, 04:35 AM
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Old May 13, 2011, 03:05 AM
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gsantos_pt's Avatar
Portugal
Joined Feb 2011
67 Posts
Quote:
Originally Posted by GRASS GRINDER View Post
looks like the cg is tail heavy, but the idea of a solar plane is great. cool plane. good luck on your build.

p.s. were did you get your solar cells from.
Hi GRASS GRINDER. You can get the cells here: http://www.flexsolarcells.com/index_...C72_75_PSA.php

Quote:
Originally Posted by hankg View Post
gsantos,

Impressive project to say the least! Check the horizontal stabilizer and rudder size with the proportions on the page I'm sending. Also, the CG location as Grass Grinder suggests.

http://adamone.rchomepage.com/cg_calc.htm

Again...very impressive!

Regards,

Hankg
Hi hankg

Thanks for information. It's very usefull.

Ok guys I will check the position of CG before the next flight. I will try record a video of the flight.

Thanks everyone

Regards to all,
gsantos_pt
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Old May 13, 2011, 05:25 AM
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Norway, Akershus, Frogner
Joined Jun 2010
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Very nice project, and something that might prove quite usefull in places with allot of sun. Imagine a motorized glider with that. You would never have to come down on a good day

But there is one thing i wonder about. You say you use a 3s li-po. But from my knowlage they should not be trickle charged (slowly charging while slowli discharging at the same time). So do you collect the electricity in another battery first and then from there into the lipo at high speed or how do you do that?

And put some ailerons on it and as the others said, a more forward CG.
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Old May 13, 2011, 12:27 PM
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subscribed!
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Old May 13, 2011, 11:33 PM
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Prices have come down for this tech! Thanks for the link gsantos_pt
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Old May 14, 2011, 01:03 AM
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NSW, Australia
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Quote:
Originally Posted by Grejen View Post
Or it's just heavy and not able to fly on the wing at the pitch speed. Seems to be hanging on the prop.
My thoughts as well. Either reduce the weight if you can, or increase the pitch speed of the prop a bit.

Otherwise you've done a very good job!

Cheers - boingk
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Old May 17, 2011, 05:12 PM
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Portugal
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Quote:
Originally Posted by Coenraad View Post
Very nice project, and something that might prove quite usefull in places with allot of sun. Imagine a motorized glider with that. You would never have to come down on a good day

But there is one thing i wonder about. You say you use a 3s li-po. But from my knowlage they should not be trickle charged (slowly charging while slowli discharging at the same time). So do you collect the electricity in another battery first and then from there into the lipo at high speed or how do you do that?

And put some ailerons on it and as the others said, a more forward CG.
Hi Coenraad

The charger sends the power to the ESC. When the motor is not running and the servos too the the biggest part of the energy goes to the battery. When the motor are running and servos too just a part (or not) the energy it's used to recharge the battery. Why not charge the battery slowly? With a fast charge the battery will be warm. Warm means that the efficiency of the process was lower (would be nice if the efficiency was 100% but that is impossible when we charge a battery). Was this your question (I'm not really sure )?




This thing really needs the CG more forward.

Thanks again for the help guys

regards
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Old Dec 19, 2012, 02:44 AM
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Hello sir we are planning to build electric rc solar plane ....... Let me know about maximum investment.....
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Old Dec 19, 2012, 12:40 PM
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Blackstock, South Carolina
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Sort of offsides, but can solar cells be measured in milliwatt hours? I mean they produce power for as long as the sun shines on them at a rate dependent on the intensity of that light, and stop immediately after it doesn't. So a milliamp per lumen (or some other measurement on light intensity) measurement would be more accurate I would think.
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Old Dec 20, 2012, 02:25 PM
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that is really cool, i wish that i had the ability to make something like that!
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