Ultra high overall pessure ratio gas turbine engine

A gas turbine engine comprising:

• a first turbine rotor positioned upstream of a second intermediate turbine rotor and a third turbine rotor being positioned downstream of the first and second turbine rotors;
• a fan rotor and three compressor rotors, with an upstream one of said three compressor rotors being connected to rotate on a shaft with the third turbine rotor, and said third rotor also driving said fan rotor through a gear reduction, and an intermediate one of said three compressor rotors for being driven by said second intermediate turbine rotor, and a third one of said three compressor rotor downstream of said upstream and intermediate compressor rotors and being driven by said first turbine rotor;
• said fan rotor for delivering air into a bypass duct as propulsion air and for delivering air to said upstream compressor rotor as core air flow and a ratio of said bypass air flow to said core air flow being greater than or equal to about 10.0;
• and
• a variable turbine vane positioned upstream of said first turbine rotor to allow the selective control of an overall pressure ratio, said variable turbine vane is utilized to reduce an overall pressure ratio at take-off conditions.