Bayboos Well, there are places in the world where LIDL gliders are more expensive, or even not available at all... Besides, this glider is only roughly similar to the LIDL one; it's much lighter (but also less rigid), making it better for free flight and_or low power (slow) RC conversion.

Bayboos Most likely yes, but you will need to cut some foam out. And also you will loose the gyro stabilization.

Bayboos Yes, I bet the dimensions are flipped. I built my own DIY Gripen quite close to the original (in scale) and it turned out 1200mm in length and 820mm wingspan.

Bayboos Single 18650 Li-ion is 3.7v nominal; thus 2x18650 (connected in series) is 8.4v and 4x18650 is 16.8v - still nominal. But the nominal voltage is not the max one for any given battery. Li-ion baterries have (in most cases) max safe voltage limit around... 4.2v. That means this light is designed to work on single cell Li-ion battery. But that's not the whole story. The other thing is battery's current capability; which in high-current applications may not be enough. To allow high current draws from low current cell, you may want to connect more than one cell in PARALLEL - that way you will increase the current capability (and as a side effect: the capacity) without increasing the output voltage. All this means this particular light is designed to work on four Li-ion cells connected in parallel to meed the amp draw requirement while staying under the max voltage limit. Which tells a lot about this light's design; enough to try to avoid it whenever possible.