Complex sentence: The upper wing was much smaller than the lower wing, having a wingspan 5 feet less, with the wings braced by a single "N"-strut and an inverted "V"-strut on each side.
Split into simpler sentences: The upper wing was much smaller than the lower wing, having a wingspan 5 feet shorter. The wings were braced by a single "N"-strut and an inverted "V"-strut on each side.