I am the first to admit there is absolutely no point in this except for my own personal curiosity. I already have an electric powered plane that can fly longer than I can so why go for longer still?
This plane had 4 LiFe cells built into its wing. They were charged insitu.
Although a sound technical solution that allowed the plane to carry batteries that weighed 60% of its total the widely spread load did result in some stability issues which were never completely resolved. Its wayward flying characteristics prevented it from getting anywhere near demonstrating its potential 2 hour endurance.
In its final version the LiFe cells were replaced with Li-ion. Of exactly the same dimensions they had 3 times the capacity, delivered 3.7V instead of 3V and were 5% lighter but they have a very limited 1.5C rating. However for endurance flying such a low C is not really a problem as at cruise the current required is very small, 0.5C or less.
My Endurance plane carries a 5000mAh 2s LiPo that weighs 7.2oz and it flies on 1A.
6 Li-ion cells in a 2s3p arrangement would give 9000mAh capacity and weigh just 8oz. If they could be housed in a plane that could also fly on 1A its duration would be.......silly!
Tubular cells can be efficiently arranged in a triangle and if stacked 2 deep it would neatly give a 2s3p arrangement.
A test section of a triangular Depron fuselage to demonstrate the layout.
As the Li-ion cells have to charged individually they have to be removable. A single cell sized hatch is one possibility.
Would this even work or ever show the potential endurance?
I have no idea, but there is really only one way to find out!