Rolls-Royce Corporation

Derick A Perry

James P Angus

An improved arrangement of a turbofan engine comprises a core engine, an upstream fan, a downstream fan and a booster compressor. The upstream fan and downstream fan are both positioned upstream of the core engine, and are arranged to be driven in opposite directions by a gear assembly. The gear assembly is positioned axially between the upstream fan and downstream fan. The booster compressor is positioned upstream of the upstream fan and downstream fan, and comprises a first rotor carrying blades and a second rotor carrying blades. The first rotor is driven with the upstream fan and the second rotor is driven by the turbine of the core engine in opposite direction to the first rotor.

Turbofan gas turbine engine

A fan casing of a turbofan gas turbine engine has a slot which extends generally in a circumferential direction and which has an aerofoil section. A variable pitch fan blade may be removed from the turbofan by rotating the fan blade about its axis of rotation to fine pitch setting, and rotating the fan rotor so as to align the tip of the fan blade with the slot. The fan blade is detached from the fan rotor and the tip of the fan blade is inserted radially into the slot. The root portion of the fan blade is then moved in a radially outwards and axial direction to remove the fan blade. The slot in the casing allows the fan blade to be loaded by the reverse procedure. Loading/unloading of a fan blade is made possible without removing the fan casing.

Fan casing and fan blade loading/unloading

A hollow aerofoil cross-section aircraft propeller blade is provided with a tow of KEVLAR fibres internally thereof. The fibres which are anchored to the blade root and tip portions are arranged to be passive under all normal operating conditions of the blade. However in the event of a structural failure of the blade between its root and tip portions the fibres serve to contain the blade tip together with any portion of the blade attached thereto. The invention is additionally applicable to prop-fan and fan blades for gas turbine engines.

Hollow aerofoil blade

A hollow prop-fan aerofoil blade is covered by a woven containment sheath which is bonded to the aerofoil surface of the blade and operationally anchored to the blade root. The sheath is arranged to be of sufficient strength to contain any of the aerofoil cross-section portion of the blade in the event of any structural failure thereof.

Rotor aerofoil blade containment

A hollow propfan aerofoil blade is provided with grooves which extend between its root and tip portions. The grooves contain filaments which are enclosed within a resin matrix material and are anchored to the root and tip portions. The filaments are arranged to be of sufficient strength to contain any of aerofoil portion of the blade in the event of any structural failure thereof.

A casing support structure for a gas turbine engine is provided with means for reducing the effect of distortions such as are produced by differential heating of the structure on shut-down. To this end the casing is mounted from supporting structure by links which are arranged to be individually heated by associated heaters. The degree of heating of the links is arranged to provide differential expansion which moves the casing so as to reduce the effect of eccentricities on the clearance between the casing and its associated rotor structure.

Casing support for a gas turbine engine

This invention relates to a bladed rotor for a gas turbine engine which comprises a disc having blade carrying slots in its periphery. In order to seal the spaces between the blade platforms and the disc an annular array of sealing plates is provided. The plates are supported directly from the disc by a rivet, pin or the like which passes through the disc in between the blade carrying slots, in this way avoiding any additional loading on the blades themselves.

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Derby, United Kingdom

Derick A Perry