Solar Cells And Electric Motors

Hi All,
Has anyone experimented with using solar cells on electric R/C planes either in running the motors or in recharging the batteries while in
flight?
I am looking for your experiences and what you had to do to get the solar cells to work with standard nicad batteries. I like to hear your success and failures too.
I am prepairing to build an electric plane that will carry a camera and hopefully will be powered fully or partially by solar cells.
Thanks for your help. You have a body of experience and knowledge that is fantastic and all of you have helped me in the past with good advice.
Happy Flying, Bill Verge
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Ceti @comcast.net wrote:

Plenty have tried, but the fact of the matter is that a wing large enough to produce enough power, is too heavy to fly with that power. Just about. I think if you spend megabucks its possible to produce a fragile nightmare that may ghost along at head height at midday in the atacama sesert...
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Here's probably the ultimate of what you're looking for.
http://www1.dfrc.nasa.gov/gallery/photo/Helios /
Helios! Developed for NASA. It holds the altitude record for non-rocket powered flight. Beating out the SR-71 by several thousand feet.
It uses a system of solar cells and rechargeable power cells. The solar cells, some 65,000 of them, do the recharging during the day and the power cells take up the load at night.
One goal for this vehicle is to function as a poor mans satellite. Circling over a city at 60,000 feet for up to six months at a time. A replacement comes up to take over services and the original lands to be refitted for whatever mission is next. Could do wonders for the cell phone industry.
Several prototypes of various sizes have been built. The smallest I've seen had around a 15-20 foot wing. It flew on the solar cells and if I recall correctly, used Astro motors.
So in spite of what D.H. may think, the wing is not too heavy nor fragile for the job. And though not cheap, it doesn't require mega bucks or NASA couldn't sponsor it.
Chuck
wrote:

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The full scale item (100+ foot span) had a mid air structural failure during testing. IIRC, they were testing in the Hawaiian islands (great test site, eh?) and got into more turbulence than they anticpated. If memory serves, this happened within the past year.
KB
wrote:

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Kyle Boatright wrote:

As I said.
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The one did crash but, the project continues none the less. A new one is being built.
The one that crashed did have structural failure. It had been overstressed on a previous flight! As in taken beyond the design limits. Then it was over stressed again on the final flight. Show me a type that won't crash when this sort of thing happens!
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Chuck Jones wrote:

Yes, but it i slightly beyind the reach of the avearge modeller,
Asshole.
And a mega buck is only a million bucks. Why that's scarcely 550,000 uk pounds, in todays money at todays exchange rate.

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And the true D.H. shines through! Go sober up you twit!
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Why did you have to respond like that? Megabucks is a term like Megasale, not intended to be finite. But being a Brit, you probably can't understand the concept.
The aircraft was a design concept and proved that it could be done with CURRENT technology. While it may be beyond the average modeler, it is certainly not beyond SOME modelers!
-- Paul McIntosh http://www.rc-bearings.com
wrote:

enough
about.
nightmare
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Certainly beyond D.H. It was nice of him however to acknowledge his betters!
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| Why did you have to respond like that? Megabucks is a term like | Megasale, not intended to be finite. But being a Brit, you probably | can't understand the concept.
Actually, the British are probably quite familiar with prefixes like `mega', as they use the metric system over there. (I certainly wish we did over here -- my daughter needs 1 tsp of medicine. Is that a tea spoon or a table spoon? How many ml? (answer? teaspoon, approximately 5 ml.)
Since `mega' has a specific meaning, and `buck' has several specific meanings (one of which refers to money, where one buck is one dollar), defining a megabuck as one million dollars seems entirely appropriate, and that is definately a finite amount of money. (A cost of `one million antelope' seems less appropriate.)
If you don't want somebody to misunderstand you, you may wish to consider your terms more carefully. Rather than say `megabucks' try `a zillion dollars' instead.
This place even has megabuck defined!
http://dictionary.reference.com/search?q=megabuck&rg
... and you'll find both definitions there.
| The aircraft was a design concept and proved that it could be done with | CURRENT technology. While it may be beyond the average modeler, it is | certainly not beyond SOME modelers!
... and it's budget probably was not more than a few megabucks. The estimated cost of the Helio-like satellites was 10 megabucks each. I believe the total cost of the plane that crashed was about 15 megabucks.
http://www.engineering.uiowa.edu/~hawkeng/fall01/helios.shtml
It was certainly an impressive project. I can't think of a cooler job for a modeler to get -- if only I'd studied aerospace engineering in college! | > Yes, but it i slightly beyind the reach of the avearge modeller,
To be fair, turbine powered jets are slightly beyond the reach of the average modeller too.
A simple solar powered plane, one that can fly under only solar power under ideal conditions, probably could be done for less money than a moderate sized turbine powered jet ...
| > And a mega buck is only a million bucks. Why that's scarcely 550,000 uk | > pounds, in todays money at todays exchange rate.
--
Doug McLaren, snipped-for-privacy@frenzy.com
I may agree with everything you said. But I will stab you in the face
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| Plenty have tried, but the fact of the matter is that a wing large | enough to produce enough power, is too heavy to fly with that power. | Just about. I think if you spend megabucks its possible to produce a | fragile nightmare that may ghost along at head height at midday in the | atacama sesert...
As others have said, it has been done.
Helios is the extreme example, but others have done it too.
Ultimately what you have is a powered glider (because they're efficient) with lots of solar cells. They generally fly poorly, having very little power, but they do fly.
http://personalpages.tds.net/~dbeck / http://rz-home.de/~sieghard.dienlin/ { German, no idea what it says }
I could have sworn I saw a page on a solar powered plane in the back of a R/C magazine within the last year too. I recall that he'd started with a coreless motor, then went to an Astroflight 010 when the original motor kept burning out ...
In any event, it's not cheap, and it generally turns out to be incredibly fragile.
--
Doug McLaren, snipped-for-privacy@frenzy.com
There is no monument dedicated to the memory of a committee.
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snipped-for-privacy@frenzy.com (Doug McLaren) wrote:

Extreme silliness.

And lots of weight.

Apparently that was given up a long time ago. All of the links are dead.
I would like to find out what cell is used in order to determine how much weight for the power. Then some knowledgeable people could opine on the potential reality. There are allusions to various cells, but no one ever states a name or part number.
http://www.plastecs.com/solar_cells.htm
That appears to have the cell, but there is no weight given.
I would think something that great would be filmed. The photo gallery doesn't have any pictures of the thing in flight.
Extraordinary claims require extraordinary proof.

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| >As others have said, it has been done. | >Helios is the extreme example, | | Extreme silliness.
eh? | >but others have done it too. | >Ultimately what you have is a powered glider (because they're | >efficient) with lots of solar cells. They generally fly poorly, | >having very little power, | | And lots of weight.
Weight and power go hand in hand. Low power is OK if you have low weight. And high weight is often OK if you have lots of power.
I doubt the planes are that heavy.
| >but they do fly. | > http://personalpages.tds.net/~dbeck / | | Apparently that was given up a long time ago. All of the links are | dead.
Ok ... not my site.
| I would think something that great would be filmed. The photo | gallery doesn't have any pictures of the thing in flight. | | Extraordinary claims require extraordinary proof.
There's nothing extraordinary about this. It's tricky, but not rocket science. (And even rocket science usually isn't rocket science.)
I found the magazine I was talking about. June 2004 `Fly RC', Issue 7. Page 162. The plane is `Solarus', builder is Jonas Romblad.
Wingspan is 2.3 m. Weight is 480 grams. Power is provided by 16 10x10 cm silicon solar cells. Nominal output is 3A at 0.5V each. Motor is an Astroflight 010 with a 8.5:1 gear box.
Apparantly it maintains altitude with only 10 watts of power -- pretty impressive.
And yes, there is a picture of the plane in flight. With solar cells.
It wouldn't be kosher of me to scan the article for you, but you could probably buy it at http://flyrc.com/toc_06-04.shtml .
Or you can just read this --
http://64.233.161.104/search?q che:i5uYLOTgpy0J:www.astroflight.com/e/env/00013pK8Ko0Gkc8Yw48R584/%3Flink%3D/whatsnew.html+Jonas+Romblad+solar&hl=en
(Had to go to google cache for it ...)
In any event, Fly RC is a pretty good general R/C magazine.
| >Path: | newssvr12.news.prodigy.com!newsdbm05.news.prodigy.com!newscon03.news.prodigy.com!newsmst01a.news.prodigy.com!prodigy.com!newscon06.news.prodigy.com!prodigy.net!border1.nntp.dca.giganews.com!border2.nntp.dca.giganews.com!nntp.giganews.com!cyclone.austin.rr.com!fe2.texas.rr.com.POSTED!not-for-mail | >Newsgroups: rec.models.rc.air | >Subject: Re: Solar Cells And Electric Motors
There you go again ...
--
Doug McLaren, snipped-for-privacy@frenzy.com
Anyone who isn't confused really doesn't understand the situation.
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Ceti @comcast.net wrote:

I think the current produced by solar cell is a very tiny fraction of the current required to run a motor.
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Ceti @comcast.net wrote in

Yes it's been done, take a look at the following webpage, next to the last airplane at the bottom:
http://www.parmodels.com/ralphs_models.htm
- HPT
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That's the claim.
Searching the Internet, the only reference to "Sol Mite" is on that page.
Notice the wing covering reflects some light. That's not good for solar cells.
I am trying to find a solar cell which sources 1/10 the power required and weighs less than the total plane weight of 144 grams.
Does anybody know what (available) solar cell might be used in that? I guess not.
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John Doe wrote:

I think silicon cells - he most efficicent - are heavy.
There are som new phosphors coming along - rare earth ligands - that look promising, burt iff yu dio the watts per square meter calculations, you wll find that even at 100%, its a very low power model indeeed you will have.
The physics off fligt mean that what you need up with must be large, and very slow. And very light. Not surprsingly, ecen with themost odernmaterials, rthats very fragile.
As I said.

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As you said: "a wing large enough to produce enough power, is too heavy to fly with that power"
As I said: Sober up you drunken slob!
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Thanks for the information. It was what I had found out for the most part. The solar cells are too heavy to do the job that I am looking for. Still the same I appreciate all your help.
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