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Is it technically feasible to make a sailplane from transparent carbon fiber? I am looking for an answer based on the specifications' comparison of the 2 different fibers.

And can it be made self-launch capable with an electric motor ? ie. the difference in the design considerations while positioning and designing an electric motor for a normal glider vs a carbon fiber glider; Eg. Sparrowhawk.

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    $\begingroup$ Sorry to disappoint, but the product you are referring to is just a fake stick-on plastic laminate with no fibre content or structural use whatsoever. Carbon fibers (whatever type) are inherently black (in the visual spectrum, X-ray e.g. is different though). $\endgroup$ – yankeekilo Apr 2 '14 at 6:00
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    $\begingroup$ Sure, but any structurally useful amount of carbon will be opaque. And completely transparent structural GFRP (with suitably high fiber content) is not yet available. $\endgroup$ – yankeekilo Apr 2 '14 at 6:10
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    $\begingroup$ Most assuredly not - both make heavy (pun intended) use of CFRP. But I meant this Antares and this e-Genius :D Note: If you want to message someone, add a @username in the comment, then username gets noticed. $\endgroup$ – yankeekilo Apr 2 '14 at 7:25
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    $\begingroup$ Please see the link below. Some gliders were upgraded/had a carbon fibre variant. The carbon fibre would be far stiffer than the glass fibre, resulting in a higher performance (especially at speed), or indeed in any scenario in which the wings flex. As the wings flex you're altering the angle of attack which in turn could cause more drag reducing the performance of the glider. Please read the wikipedia page, the Nimbus 2c was upgraded to a partial carbon fibre construction. en.wikipedia.org/wiki/Schempp-Hirth_Nimbus-2 $\endgroup$ – Joe Harper Apr 2 '14 at 7:39
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    $\begingroup$ The motor can be built into any kind of fuselage, only optically clear GFRP is not available. $\endgroup$ – yankeekilo Apr 2 '14 at 17:25
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As long as there are load-bearing structures beneath the fiber (I don't know how strong that fiber is so I will assume it is fabric-like), it will most likely fly if designed properly. If the fiber is smooth, it shouldn't be much different than regular fabric or other composite skins.

And yes, there are plenty of sailplanes that self launch with electric or gas motors. You would just have to take into account the weight and position of the motor when you add it in. This could mean that you need to lengthen the tail section for more tail down force, move the seats further back, place the engine in a more neutral CG position above the fuselage on a pylon, or any number of other methods. You might then also need to increase the wing surface area a bit, to lift the extra weight. Also take into account the weight and position of the batteries. The design effects and considerations are pretty straightforward, but dealing with them may or may not be complicated.

The Soviets tried in the 1930's to make an invisible spy plane (an AIR-6 I believe) by replacing the cloth skin with a cellophane-like material so that its entire was transparent. At just a few thousand feet the engine could be heard but the plane was almost completely invisible. Unfortunately the cellophane-like material would rapidly degrade after a few flights or several days out in the sun. It seems like your idea would be the modern version of that endeavor.

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  • $\begingroup$ That plane used acrylic. Carbon fiber is a far superior material. And that would give additional structural benefits. The Sparrowhawk is a monocoque structure. $\endgroup$ – Ayan Mullick Apr 2 '14 at 5:13
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    $\begingroup$ But all carbon fiber monocoque structures that I know of are composites, layers of fiber with epoxy between them. I would think that each layer of material and epoxy would make your skin more opaque, and the clear fiber you're asking about isn't all that transparent to begin with. So yes, you could certainly build a monocoque fuselage with the transparent fiber as long as it is strong enough and you layer it correctly. But I think you would lose most of your transparency in the process. $\endgroup$ – StallSpin Apr 2 '14 at 5:58

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