Complex sentence: The Kaman design was the only one in early 1972 which was to reach the hardware stage and come close to being tested with a special landing gear platform attached to the AERCAB ejection seat for a first stage ground take offs and landings with a test pilot.
Split into simpler sentences: The Kaman design, in early 1972, was the only one which was to reach the hardware stage. It came come close to being tested with a special landing-gear platform attached to the AERCAB ejection seat for first-stage ground take offs and landings with a test pilot.