Dual speed planetary gear system for convertible engines

An aircraft comprising:

• a fuselage and wings, and a gas turbine engine;
• the gas turbine engine having a propulsor having a propulsor input shaft;
• a turbine rotor driving a turbine shaft, said turbine shaft driving said propulsor input shaft through a gear reduction, the gear reduction being a planetary gear system having a sun gear rotating with the turbine shaft and engaging and driving a plurality of planet gears, said planet gears rotating with a gear carrier, the gear carrier driving the propulsor input shaft;
• and
• there being at least two ring gears in engagement with a respective one of two tooth locations on said planet gears;
• and
• a ring lock having a pair of gear tooth sets, a first of said gear tooth sets on said ring lock selectively engaged with a first ring gear tooth set and a second of said gear tooth sets on said lock ring selectively engageable with a second ring gear tooth set, said ring lock constrained against rotation, such that when said first gear tooth set on said ring lock engages said first ring gear tooth set, rotation of said first ring gear is stopped, and said planet gear drives said carrier at a first speed to in turn rotate said propulsor, and when said second ring lock gear tooth set engages said second ring gear tooth set, rotation of said second ring gear stops and said planet gear drives said carrier to in turn rotate the propulsor at a second speed which is different than the first speed.

A method comprising:

• driving a turbine shaft, and said turbine rotor driving a propulsor input shaft through a gear reduction, the gear reduction having a sun gear rotating with the turbine shaft and engaging and driving a plurality of planet gears, said planet gears rotating with a gear carrier and the gear carrier driving the propulsor input shaft;
• and
• there being at least two ring gears in engagement with a respective one of two tooth locations on said planet gears;
• and
• moving a ring lock having a first ring lock gear tooth set such that said ring lock is engaged with a first ring gear tooth set, moving said ring lock such that a second lock ring gear tooth set is engaged with a second ring gear tooth set, constraining the ring lock against rotation such that when said first ring lock gear tooth set engages said first ring gear tooth set, rotation of said first ring gear is stopped, and said planet gear drives said carrier at a first speed to in turn rotate said propulsor, and when said second ring lock gear tooth set engages said second ring gear tooth set, rotating of said second ring gear is stopped and said planet gear drives said carrier to in turn rotate the propulsor at a second speed which is different than the first speed.