I`m a student form italy and last year (senior year) me and my best friend made 2.3 meters (something like 2.7 yard) solar powered aircraft, of course handled by ardupilot!
It has been more a journey than a project, making it we learnt -and still are learning- more than we ever did in some of our diy projects.
The planes actually flyes good, with an overall consumption of bout 28 watts/h, and an onboard solar production ranging from 33 watts at noon of an awesome summer day to 23/25 watts of you average summer day.
Still, we have a 33 watts/h LiPo on board so we can have that extra power for take of and give the plane that little 3/4 watt/h help it needs to fly :-)
Attached there is a picture of the beast, next 3 weeks are gonna be busy as hell in college so no tiem to translate and post the two technical relations we made about it (one include xflr5 simulation of the Thing), which were necessarily written in Italian because we incidentally used this aircraft as our "senior year personal project" too, but at the beginning of august we will feed you with all the telemetry data and so on you may want to see.
EDIT: PHOTOS HERE!!!!! ==> http://img52.imageshack.us/slideshow/webplayer.php?id=1001042k.jpg
Congratulations for your DIY solar ariplane LUSA
I hope to hear from you soon and get more informations about your plane
help needed here!! http://diydrones.com/forum/topics/i-need-a-pwm-output-controlled
pics coming this weekend :)
WE DID IT!!!! 142 MINUTES OF AUTONOMOUS, MOSTLY SOLAR, FLIGHT!!!!!
There is also a big margin of improvement, since in those 2 and a half hours it climbed from very low to almost out of sight 5 times, it was very windy and the plane was slightly out of balance.
Photos coming soon!
Could you give us some more detailed specifications about your plane such as what escs, motors, other parts you used.
Sure dude! We used an eco18 esc (hacker rebranded but I think its the same) with a hacked b20 15l + 4:1 maxxon gear planetary reduction. rx is futaba fasst, ardupilot is 2.6 w thermopiles.
Fuselage is fiberglass with carbon reinforcements, wing is carbon+balsa+fiberglass on the front part and its covered with oralite indoor.
Grade B solar panels with sharp edge (Yes, budget was VERY tight) without glass enclosure (only back part covered with polyurethane foam) are glued on carbon tube, left almost floating in the wing.
They are connected is a 14s 2p scheme, giving us about 4.5A at 5.3 V under load in an average nice day.
Guys I have been so "absent" about details beacuse the plany sadly suffered a crash (my bad! too much university library and too few airfield this year!) and we are working hard to get it fixed in a matter of days! I guarantee you a big update in 10days or so =)
We got the fibers and the resins from shaller composites (idk how it spells, the airframe was actually built by my project mate), the motor+balsa+ding`n`dents from our local hobby supplier and the battery+esc from another sponsor. Panels are from ebay but now there are already better performing things at decent prices so i cant really help there.budget was about 800 euro (1100 usd).
Designing the airframe is not an easy task at all, you need to be good with profili2 and xflr5, making such a big plane to fly with under 30W is really hard =)
Since many people are intrested in this project we may release all the documentation with a CC NON commercial license, I`ll discuss this with my firend soon ;)
Cheers ma friends :)
Congratulations, that is pretty impressive. I was wondering if your solar panels would be more efficient if you could somehow manage to mount them flush. Even though your outer cover is clear, you are probably losing some efficiency to reflection at certain angles. I'm not sure, but just a thought.
Keep up the good work. It sounds like with some adjustments/upgrades your flight times will quickly become even more impressive. I look forward to hearing your updates.
Hi! You are right, the covering is incredibly transapernt but at some angles (sadly, even 25 deg. is enough) the reflections gets very high... Only the guys working on Solar Impulse managed to make a covering film that doesnt have this problem but its a well kept secret. To achieve such a high efficency there was no room for big flat surfaces on the wings and putting them inside was our only bet.
Now the sun in Italy is already pretty lame (do not forget that northen italy is 45N from the equator) so well probably manage to see if our new improvements do work but we`ll have to wait for next year to pull something like 3 hours or more ;)
You`ll be able to see al the details of our project in its public release and share your thoughts with us in a few weeks!
Ok guys I added a slideshow with some pics in the main post! =) Also, I need hints in how to tune autopilot to fly an extreme light plane, 1.6 kg, in a strong wind considering its 2.3m wingspan. Tnks!!
I notice each of your main Solar cells is shadowed slightly by the wing struts.
I believe if you research Solar cell best practice, that even a little bit of shade on a cell will cause the shaded part of the cell to consume energy and bring down the rest of the cell.
Cells must be placed flush and at the same angle so they don't shadow each other IIRC.