The 188 was originally intended to have the Rolls - Royce Avon but the Gyron Junior was substituted in June 1957 .
Two Gyron Juniors , with afterburners , were also used on the Bristol 188 Mach 2 supersonic research aircraft .
The 188 was originally intended to have the Rolls - Royce Avon but the Gyron Juniors   was substituted in June 1957 .
Two Gyron Juniors , with afterburners , were also used on the Bristol 188 Mach 2 supersonic research aircraft .