Complex sentence: The Type 173 was a tandem rotor development of the earlier Type 171 Sycamore single-rotor helicopter, it used two sets of Leonides Major engine and rotor that had been used on the Sycamore with a new fuselage.
Split into simpler sentences: The Type 173 was a tandem rotor development of the earlier Type 171 Sycamore single-rotor helicopter. It used two sets of Leonides Major engine and rotor that had been used on the Sycamore with a new fuselage.