US Patent 9709136 Aircraft and planetary gear systems

Planetary gear systems, transmissions, and apparatuses include a plurality of compound planet gears, each having three gear stages, a first non-fixed annular gear, a second non-fixed annular gear, a fixed annular gear, and a non-fixed sun gear. A rotational input to the non-fixed sun gear results in opposite rotational outputs of the first non-fixed annular gear and the second non-fixed annular gear. Compound planet gears and carriers for planetary gear systems are also disclosed.