Complex sentence: On 11 October 1918, the fourth prototype flew from Joyce Green to Martlesham to conduct official trials; aside from being powered by the Eagle engine, it was otherwise identical to earlier prototypes aside from a greatly increased fuel capacity and reshaped and enlarged rudders.
Split into simpler sentences: On 11 October 1918, the fourth prototype flew from Joyce Green to Martlesham to conduct official trials. Aside from being powered by the Eagle engine, it was otherwise identical to earlier prototypes except for a greatly increased fuel capacity and reshaped and enlarged rudders.