Gas turbine engine with axial thrust balance

An aero gas turbine engine comprising:

• a rotor;
• a compressor;
• a combustor;
• a turbine, the turbine driving the compressor through the rotor from a hot gas stream produced in the combustor;
• a static housing, the static housing forming a forward pressure chamber and an aft pressure chamber, each of the forward pressure chamber and the aft pressure chamber having an upper variable restriction and a lower variable restriction;
• a source of compressed air, the source of compressed air supplying compressed air to each of the forward pressure chamber and the aft pressure chamber simultaneously;
• and
• an axial thrust balancing device associated with the rotor, the axial thrust balancing device including a rotating disk rotatable with the rotor and within the static housing, axial movement of the rotor increasing a pressure in one of the forward pressure chamber and the aft pressure chamber to balance the rotor in an axial direction.