Patent ID: 9726186
Date: 2017-08-08
CPC Classifications: F02C,F02K,F04D,F05D,Y02T

Claim:
1. A method for optimizing rotational speeds of an at least two-flow and twin-spool turbofan engine, comprising at least one low pressure (LP) compressor/turbine assembly and one high pressure (HP) compressor/turbine assembly respectively comprising coaxial LP and HP transmission shafts for transmitting power from a turbine to the compressor of the assembly, and in which a fan forms a first primary air intake compression stage, the method comprising: providing a planetary gear train for driving the fan, the planetary gear train including driving means and driven means, and the HP transmission shaft being engageable and disengagable with the driving means of the planetary gear train; at a first operating condition, engaging the HP transmission shaft such that the fan is driven by the LP transmission shaft and the HP transmission shaft; and at a second operating condition, disengaging the HP transmission shaft such that the fan is driven only by the LP transmission shaft.