Original sentence: The Rolls-Royce Avon has also been considered, but only the Gyron Junior was used in practice.Two afterburning versions of the Gyron Junior were also used to power the Bristol 188 Mach 2 supersonic research aircraft
Edited sentence: The Rolls-Royce Avon had been considered, but only the Gyron Junior was used in practice.Twin Gyron Juniors, with afterburners, were also used to power the Bristol 188 Mach 2 supersonic research aircraft