Solar-powered model planes

Anything you like!
Martin
Posts: 744
Joined: 16 Feb 2018, 14:11
Location: Warwickshire

Re: Solar-powered model planes

Post by Martin »

I've added the Arduino sketch to the opening post of this thread. Anyone interested in how it works, there are lots of comments in the source code. Please ask if anything is unclear.
Ralkbirdy
Posts: 44
Joined: 25 Feb 2018, 13:10

Re: Solar-powered model planes

Post by Ralkbirdy »

The cells are 125mm, so 8 give 1000mm, and then needs to be about 300mm at the middle with 160mm tip. I probably will do a straight front by the 4 cells with a curved LE to the tip. I may have full length elevons or just have them on the outer 50%. The wing needs to be 1040mm to accommodate the cells and some spacing.
I would have tip fins underneath again for a shadow free upper surface.
20180710_141320.jpg
I am trying to use a folding prop on the 12c wing but this would need a normal power prop.

Carbon, like this?
20180710_141941.jpg
Carbon, Mylar, RCModellers glue/Cyrano.
Last edited by Ralkbirdy on 10 Jul 2018, 14:56, edited 1 time in total.
Ralkbirdy
Posts: 44
Joined: 25 Feb 2018, 13:10

Re: Solar-powered model planes

Post by Ralkbirdy »

I have just tested my 12c model, using a Pololu the Rx and 2 servos were using 4W, a robotbirds ESC and Rx used 6W, both on 2s, similar voltage. The solar cells were up to 30W, so loosing 2W is about 8% less power.

Using the arduino you need either a Simonk or Blheli ESC as they do not have any initial programming which may get confused with the arduino.
User avatar
Shaun
Posts: 1049
Joined: 15 Feb 2018, 21:49
Location: West Yorkshire

Re: Solar-powered model planes

Post by Shaun »

Hi Mike,
My indoor aerobatics are made from 6mm EPP with localised strengthening. Depron wouldn't last long with 6 - 10 models up in a triple squash court hall. Lots of white confetti would rain down. EPP just tends to tear and fixes easily in mins with POR.
I have a plan somewhere for a built up delta originally designed for indoor use , geared brushed motor and small NiMH cells. It was feather light and would scale well.

Shaun
User avatar
tiptipflyer
Posts: 393
Joined: 16 Feb 2018, 22:49
Location: Germany

Re: Solar-powered model planes

Post by tiptipflyer »

A great project, I follow it with interest.

Frank
Ralkbirdy
Posts: 44
Joined: 25 Feb 2018, 13:10

Re: Solar-powered model planes

Post by Ralkbirdy »

I have been putting together a semi delta 12 cell model, finished today, weighing in at 344g, with possibly another 20g weight loss if i change the motor / prop. I am starting off with a 2212 1450kv and a folding prop to give forwrd cog, but can move to lighter items if the cog can go backwards.

It was quite cloudy this afternoon when ready but on 9W of power it was able to maintain height, so should be good when up to 28W.

20180721_190413.jpg
20180721_190504.jpg
User avatar
Phil_G
Posts: 597
Joined: 15 Feb 2018, 23:32
Contact:

Re: Solar-powered model planes

Post by Phil_G »

Is each panel actually 3 cells in one that are paralelled by a common connection down each edge?

And the plain blue side is the active side? Do they solder easily?
The plan is to go for a simple KFM wing, so all the cell mounts are perfectly flat, span & chord dictated by 12 cells, and avoiding return wires by using two rows on each wing:

12cells.jpg
What do you think?
Cheers
Phil

Edit: found this:

Image


Image
jmp_blackfoot
Posts: 15
Joined: 24 Feb 2018, 23:53

Re: Solar-powered model planes

Post by jmp_blackfoot »

Phil,
On the German site RC-network, there are some exciting findings, namely that the C60 cells can be divided electrically (no cutting) and rewired as shown here and detailed in the subsequent posts #959, 960 and 963:
http://www.rc-network.de/forum/showthre ... ost4587404
What do you think?
Martin
Posts: 744
Joined: 16 Feb 2018, 14:11
Location: Warwickshire

Re: Solar-powered model planes

Post by Martin »

As they come the three + connections are internally joined on each cell, as are the three - connections: but you're supposed to use all three as the internal connecting 'tracks' are pretty thin and not really suited to handling the four amps plus that the cells can deliver. The idea is that the current is shared across the three connectors to provide lower resistance and some redundancy.
Ralkbirdy
Posts: 44
Joined: 25 Feb 2018, 13:10

Re: Solar-powered model planes

Post by Ralkbirdy »

While having 2x6 has shorter cabling, I think that the 12x1 has better aerodynamics, glider wings are high aspect ratio not low aspect. Which is why I moved to a 8x4 to avoid the very low aspect ratio wing.

I flew the semi delta today on a slope which confirmed that the cog needs to go backwards, will move onto the 2208 1800kv & 6x4 prop. Perhaps move the motor mount backwards if I want to go onto the 2212 motor again.

Mike
Post Reply