Differentially geared reversible fan for ducted fan gas turbine engines
AssigneeRolls-Royce (1971) Limited
InventorsAlexander Scott, Peter Eric Peck
Life of this patent
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Abstract
A ducted fan gas turbine engine comprises a pair of turbines in flow series which are contra-rotating and which drive shafts which in turn drive into an epicyclic gear. The output from the epicyclic gear drives a fan which normally provides forward thrust from the engine. The fan can be made to rotate in the opposite direction to provide reverse thrust by varying the relative speeds of rotation of the two turbines by bleeding working fluid from between them.
Claims8
A ducted fan gas turbine engine comprising a fan, two shafts, a turbine drivingly connected to each shaft for driving the shafts in opposite rotational directions, and a gear mechanism, wherein the two shafts are connected with the gear mechanism, the output of the gear mechanism being connected to drive the fan, the gears of the gear mechanism being arranged so that a given change of the relative speeds of rotation of the two shafts causes a reversal of the direction of rotation of said output, and means for varying the relative speeds of rotation of the shafts for achieving said given change of relative speeds of rotation thereof.
A ductd fan gas turbine engine as claimed in claim 8 and in which the teeth of the annulus gear are formed on an internal surface of the second of the two shafts, and the teeth of the sun gear are formed on an external surface of an extension of the first of the two shafts.
Dependencies are inferred from the claim text.