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May 13, 2017, 07:40 PM
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Special MXC


Not for traditional XC but based on the MXC that we know.
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May 13, 2017, 11:25 PM
If it flies - I want one!
Petem's Avatar
Drool!
May 14, 2017, 01:23 PM
Balsa breaks better
Thermaler's Avatar
More info!! and what Pete said. . . ;>)

Joe
May 16, 2017, 09:36 PM
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Just found this thread. Dean's team built this for us as part of a continuing project in an effort to achieve near perpetual flight with a swarm of cooperating gliders. The project started nearly a decade ago as a student's PhD topic to develop cooperative autonomous thermaling with a flock of gliders. At that time we used some very old SBXC airframes that had been modified for electric propulsion, and equipped with autopilots, some additional computing capability and WiFi. There's a rather old video of our first shared thermal here:

Cooperative Autonomous Soaring (3 min 35 sec)


At that time the gliders were not equipped with solar and we ran separate batteries for avionics and propulsion. On a day with good thermals we would just use the motor at launch, and the avionics batteries were good for several hours. When either battery got low, we would land. With the addition of solar we can now recharge batteries in flight. The ultimate goal will be to find an appropriate balance of solar capacity and battery storage, matched to a suitable airframe (in terms of wing loading, aspect ratio, and min sink), in order to be able to keep individual gliders up 24/7. Others have already achieved that goal, but what we plan additionally makes use of local lift, and local, shared knowledge of the environment. Operating as a team, members of the flock share information about where lift and sink are in real time, and can efficiently divide up the efforts to support mission goals, whatever those might be.

If you are interested in the project, we have quite a few papers available online for further reading. Key names are Andersson, Kaminer, Dobrokhodov and Jones.
May 19, 2017, 06:01 PM
Master of the Wind
G Norsworthy's Avatar
What kind of cells are those, and did you mold them in the skin in the initial layup?

I designed a solar powered plane to showcase some CIGS thin film cells on stainless steel foil but the company tanked before they could fund it. I was certain it would fly, for how long I'm not sure. Would have been a fun project but for some reason I didn't save all the work on a thumb drive before I bailed.
May 19, 2017, 06:19 PM
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Quote:
Originally Posted by G Norsworthy
What kind of cells are those, and did you mold them in the skin in the initial layup?

I designed a solar powered plane to showcase some CIGS thin film cells on stainless steel foil but the company tanked before they could fund it. I was certain it would fly, for how long I'm not sure. Would have been a fun project but for some reason I didn't save all the work on a thumb drive before I bailed.
These are SunPower E60 cells (not the sort that goes on your roof). I think they call them semi-rigid cells. They are mono-crystalline Si, and can be broken quite easily, however, if you are careful, you can get them to conform to slightly curved surfaces. I think SunPower claims they have got them onto a cylinder with 12" diameter. We don't challenge them quite so much. Interestingly, you can fracture them without actually damaging them. The way they are constructed, cracks in the front Si layer usually don't cause problems for the actual collection circuitry.

Efficiency is about 24%, giving us a nominal power of around 190W in perfect exposure. The arrays are installed in the mold during layup. You can detect the seam between the painted skin and the laminate film, but it is quite a small defect. This is just the second airframe they have built for us with embedded solar, and I have to say, they have it down to an art.
Jul 05, 2017, 08:08 PM
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Ifixtoomuch's Avatar
Beautiful glider! Where are people finding and purchasing MXCs today? From what i understand its RnR but they dont offer them on their website.
Chris


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