Complex sentence: Six Model 10As were evaluated by the United States Army as the YO-54, the successful testing led to an order for a slightly larger and heavier O-62, later designated the L-5 Sentinel.
Split into simpler sentences: Six Model 10As were evaluated by the United States Army as the YO-54. The successful testing led to an order for the slightly larger and heavier O-62, later designated the L-5 Sentinel.