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Old Sep 10, 2014, 03:02 PM
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solar aircraft?

hey people,
for a science fair I am going to try to make a solar powered airplane that flies all day. I was wondering if anyone had experience with this sort of thing (the last post on this subject that I could find was in 2003)
thanks!
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Old Sep 10, 2014, 03:23 PM
Micro and Beyond!
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From what I understand, if you can accomplish this you will be a rich man... No sarcasm intended.
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Old Sep 10, 2014, 03:38 PM
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Unfortunately you need to be a rich man already (or have backers with deep pockets) to achieve realistic solar powered flight.

What you might want to try is a solar-powered lighter-than-air craft (an airship), where the power required is a fraction of what's needed for a regular fixed-wing aircraft.
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Old Sep 10, 2014, 03:51 PM
yank and bank!!
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Your search skills need refinement;

http://www.rcgroups.com/forums/searc...67&query=solar
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Old Sep 10, 2014, 04:20 PM
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Originally Posted by failboat View Post
Your search skills need refinement;

http://www.rcgroups.com/forums/searc...67&query=solar
careful now. people may get upset at you for suggesting the use of the Search feature.
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Old Sep 10, 2014, 04:21 PM
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I kinda already searched there.....I was thinking get up to altitude then ride thermals until the battery charged again then head back up to the previous hight....Idk...when I was searching around I found a really cheap solar store (silicon solar) where I could probably load up on solar panels...
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Old Sep 10, 2014, 04:39 PM
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1. it will take a long time for your batts to charge off solar panels. i assume you are aware of your charge and discharge rates.

2. more interestingly, how do you plan to power the aircraft when it is charging?

3. the weight added by the solar panels is likely more than just carrying a bigger battery to have longer flights. this point doesn't matter as much since #1 and #2 will keep you quite busy.
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Old Sep 10, 2014, 05:24 PM
yank and bank!!
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A quick and cynical summary.... most people fail.
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Old Sep 10, 2014, 07:32 PM
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Solar Plane Aims for New Record: 3 Months Aloft Without a Pilot or Fuel

In July 2008 QinetiQ's Zephyr unofficially set the record for the most time aloft by a solar-powered plane. Now, the company is trying again, hoping to break that record by a factor of 10. Here's how they hope to do it.



By Rob Goodier









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three men push a solar plane into the air


Three men launch the 2008 version of QinetiQ’s solar-powered Zephyr unmanned aircraft. The new version is heavier with a larger wingspan and requires five people to launch. (Photo courtesy of QinetiQ)







July 7, 2010 12:09 PM Text Size: A . A . A


Any day now, five people will toss one of the world's most sophisticated remote-control planes into the air at the U.S. Army's proving ground in Yuma, Ariz. It's the latest incarnation of QinetiQ's Zephyr, a solar-powered, high-altitude unmanned machine that unofficially set the record for the most time aloft in July 2008. It flew for 3.5 days. Now, its creators hope to break that record with the latest design tweaks. Their end goal is to fly for three months. But for this new version's first test flight, Zephyr's crew is aiming for two weeks in the sky.

The bulk of the Zephyr is ultralight carbon fiber, banks of lithium-sulphur batteries and wings papered with thin-film photovoltaic arrays. The new version has a longer wingspan—74 feet compared to 56 feet on the previous model—with 50 percent greater area overall and wings that are deeper at the fuselage than at the tips. The bigger frame and more batteries make the aircraft over 40 percent heavier—it weighs in at 115 pounds, compared to its former 66.

"The real challenge has been pushing every element of the technology, from the efficiency of the engines to the efficiency of the aerodynamics to make sure it stays aloft for a long time," says John Saltmarsh, the program director for Zephyr's trials in Yuma.
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Old Sep 10, 2014, 08:46 PM
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Originally Posted by abenn View Post
Unfortunately you need to be a rich man already (or have backers with deep pockets) to achieve realistic solar powered flight.
from: http://defense-update.com/features/2...es_180509.html
"Overall, each platform will cost about $1.7 million to produce"

i rest my case.
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Old Sep 10, 2014, 08:51 PM
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United States, WA, Woodinville
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My most efficient plane can maintain altitude with a draw of about 45 Watts. With careful construction of a glider type plane you may be able to get this down to around 20-30 Watts. Now calculate the area and weight of 30 Watts of solar panels and you'll quickly see the problem. It's a lot like human powered flight, it can and has been done, but you have to push every limit to achieve it as the power density of current solar panels is just not very high. A 100 Watt panel is around 2'x3' and weighs more than 10 pounds.

Honestly you would probably be able to stay up longer by ditching the solar entirely and going with a pure glider. The power you get from the photovoltaic panels is not likely to offset the weight they add.
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Old Sep 10, 2014, 09:45 PM
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The power you get from the photovoltaic panels is not likely to offset the weight they add.
This is the key, cheap solar cells are heavy and have terrible efficiency. Good ones cost a fortune (and are still pretty heavy).
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Old Sep 11, 2014, 05:20 PM
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Maybe you can try a mix of natural resources add a belt and gear to another motor and have that outputting power while you also have a prop being spun by the wind passing by and solar. I mean you are basically trying to accomplish something that defies physics and something scientists and physicists have been trying to do. People with expensive educations. I don't know your educational background. So good luck.
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Old Sep 11, 2014, 06:18 PM
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Joined Oct 2010
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The naysayers make me laugh.

"They" said man would never fly, never exceed 100 mph - let alone the sound barrier, or go to the moon. Computers are just a fad and smoking is actually good for your health.

Dog may not do it for the science fair this year, but why all the negativity? What if we dismissed Einstein because he had bad hair, or Martin Luther King because he had a dream?

Never say never IMHO.

RF
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Old Sep 11, 2014, 07:14 PM
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this isn't theoretical physics. we're not talking E=mc^2 or an academic epiphany. its been done so its not a major scientific breakthroughs. btw, on Einstein's practical side, he helped make an A-bomb with US government backing.

we're talking about making a model fly given products available to the mainstream consumer. of course, if you have $1.7 million to blow on a model plane then you wouldn't be a mainstream consumer.

i dream that i want to fly a full-scale Spitfire around. will it happen? no. i'm too cheap for that.
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