Solar powered paraglider

 Hello everyone. Anybody who knows if the following is possible?
I am a Paraglider Pilot (Glorified parachute) and I am busy with my
Paramotor license. (A Paramotor is a paraglider with a small engine+prop
(0.8m - 1.3m) carried on the pilot's back which gives 40-50Kg force with a
12-20KW engine. The whole thing weights about 20-25Kg). My idea is to
replace the internal combustion engine with a electric one of similar weight
and power. Now If you don't know anything about paramotors - I only need
12+Kw (and 40 or so Kg of push) for a minute or so during take off. In
normal flight 4-8Kg of force is enough to keep me in the air ! Because of
this the internal combustion engine is build very light with no proper
cooling (does not need to anyway). I have found a suitable engine within
minutes on google (15KW max for a few minutes 7KW continuous at 36v (48v)
and only weights 10Kg !) Also the propeller can be made bigger to increase
efficiency (a 1.5m - 1.8m max which will give approx. 6Kg - 8Kg force per
Kw) I intend on using a super cap for the 30 seconds or so of extra take off
power (they are plenty within the weight limit which stores enough for the
short time) . The only thing I don't have is a light, flexible solar panel
aprox. 3x9m to work into the upper surface of the glider/wing. I thought the
power can be carried thru the control lines to the engine/cap. It must be
around 12% to 15% efficient to give me the 2.5Kw or so I need for the
electric motor which in turn will convert 90% or so to mechanical energy
(turning motion for the prop). Any ideas?

  Go under a cloud and your thermals and your power goes away.

Have you compensated for the increased weight of the solar panels? How
about the breakage factor of rigid ones?

  Huh buddy, first thanks for bothering to answer. Secondly if I manage to
get under a cloud I won't bother about solar anyway :-) That's the beauty
about the system. The 2 energy sources (wind and solar) complement each
other perfectly when used like described. Cloud above means thermal
underneath (most of the time) - so no worry there. Here in South Africa's
semidesert region where I (un)fortunately reside, clouds are scarce, to say
the least, that's why I am thinking solar (more then plenty) I have found
all the 'ingredients' on the Internet to build a hopefully flyable thing -
apart of the solar generator part. I've found that too (flexible and enough
power believe it or not) the problem is weight ! I can 'absorb' 10-15 Kg on
the top side of the wing, but the flexible solar cells I've found are more
like 85Kg ! ! !
Here is the one link
http://www.siliconsolar.com/shop/catalog/Flexible-Solar-Panel-10-Watt-p-54.html  
if this (weight) can be somehow sorted out then I don't see any other
problems to build my 'Dream-Machine'. I have also come across a French site
which builds Electric paramotors using Nicd/Ni-mh batt.(good for about 15min
power)
 By the way I am a qualified electronic technician and paraglider pilot :-)
so I have a good Idea what I am talking about. Please help me with a link or
something to a lighter flexible solar panel.
Greetings from South Africa,
Mario

 

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  These people specialize in flexible thin film, along with other =
companies.
http://www.globalsolar.com/
  The power output is less than silicon wafer type and the cost is quite =
high,
but they are flexible and can be light if you can do without the heavy =
backing
on the panels for mounting and prolonged weatherproofing.
  But if you only have say 10 square meters of area, you could only get =
maybe
500 watts. Not enough to power your 10kw motor. So now you have =
batteries
and the solar is just to prolong flight.
   Batteries could be 30 pounds per kilowatt hour, so you might need 150 =
pounds
of batteries for 1/2 hour of flight and the solar would only extend that =
for a bit.
If you can handle 150 pounds of batteries, it might be better to go with =
batteries
alone rather than an expensive solar array, that can only assist just a =
bit.

 Maybe a little ducted fan brushless dc motor like the model jet planes
use on a glider? I used to see that little BD5 Silver Bullet jet at air
shows... it seemed to really get around on a 75 pound thrust turbine.
How much thrust would you need to climg in a glider?