According to one aspect, a clutch mechanism includes a control member. The control member is adapted to receive motive power and includes a first dry clutch member and a first viscous clutch member. The clutch mechanism further includes an output member that includes a second dry clutch member and a second viscous clutch member. The first and second dry clutch members form a dry clutch and the first and second viscous clutch members form a viscous clutch. The clutch mechanism further includes an actuation arm coupled to at least one of the control and output members. The actuation arm is selectively controllable to effect relative movement of the control and output members such that one of the dry and viscous clutches is selectively engaged.

An internal combustion engine includes an exhaust conduit having an exhaust port fluidically coupled to ambient fluid and having an internal cross-sectional area and an engine cylinder fluidically coupled to the exhaust conduit. A fluidic amplifier is disposed within the exhaust conduit and is fluidically coupled to the engine cylinder. The amplifier is further fluidically coupled to a source of primary fluid and is configured to introduce the primary fluid and at least a portion of fluid from the engine cylinder to the exhaust port.

There is described a method of operating a multi-engine system of an helicopter. The multi-engine system has a first turboshaft engine having a first shaft, a second turboshaft engine having a second shaft, a gearbox having a clutch system, and a range of rotation speeds defined as a placarded zone. The method generally has: rotating the first and second shafts at a flight rotation speed above the placarded zone when clutched to a load; decreasing a rotation speed of the first shaft from the flight rotation speed to a first idle rotation speed above the placarded zone; unclutching the first shaft from the load during the decreasing; and subsequently to the decreasing and the unclutching, simultaneously decreasing the rotation speeds of the first shaft and of the second shaft to a second idle rotation speed below the placarded zone, the simultaneously decreasing including clutching the first shaft to the load.

A gas turbine engine having: an engine core having, in serial flow communication, a low-pressure compressor, a high-pressure compressor, a high-pressure turbine drivingly connected to the high-pressure compressor, and a low-pressure turbine drivingly connected to an output shaft; and a clutch having a disengaged configuration in which the low-pressure turbine is drivingly disconnected from the low-pressure compressor such that, in the disengaged configuration, the clutch disengages the low-pressure turbine from the low-pressure compressor, and an engaged configuration in which the low-pressure turbine is drivingly connected to the low-pressure compressor, the low-pressure turbine drivingly connected to the output shaft in both of the engaged and disengaged configurations of the clutch.

An air turbine starter for starting an engine, comprising a housing defining an inlet, an outlet, and a flow path extending between the inlet and the outlet for communicating a flow of gas there through. A turbine member is journaled within the housing and disposed within the flow path for rotatably extracting mechanical power from the flow of gas and a gear train is drivingly coupled with the turbine member. A drive shaft is operably coupled with the gear train, and a decoupler is selectively coupled to the drive shaft for decoupling the air turbine starter from the engine.

A drive system for driving a load, such as a pump, a compressor or the like, is disclosed. The drive system comprises two clutches operable so that it is possible to exclude the load, so as to maximize the power transferred to the electric powered grid, when a peak of energy is required. Also disclosed is a method for operating a drive system for driving a load.

A method of operating a twin engine helicopter power plant, the power plant comprising: two turboshaft engines each having an engine shaft with a turbine at a distal end and a one-way clutch at a proximal end; a gear box having an input driven by the one way clutch of each engine and an output driving a helicopter rotor; a bypass clutch disposed between the proximal end of each engine shaft and the input of the gear box; and power plant management system controls for activating the bypass clutch; the method comprising: detecting when a rotary speed of an associated engine shaft is less than a rotary speed of the gear box input; activating the bypass clutch to drive the associated engine shaft using the rotation of the gear box input; and starting an associated engine by injecting fuel when the bypass clutch is activated.

A clutch for a lift fan with input and output shafts on a common rotational axis, connected by disc shaped output clutch plates oriented normal to the axis. A keyway extends radially inward from a mouth at an outer diameter of each output clutch plate to a seat at an inner diameter of the respective clutch plate. At least one output shaft lug key may be positioned in the keyway and extends axially from one output clutch plate to the other output clutch plate, which couples the rotation of the output clutch plates to the rotation the output shaft and allows axial movement of the two output clutch plates relative the output shaft lug key, the output shaft has an outer radial surface and an inner radial surface. At least one input clutch plate positioned axially between the two output clutch plates and rotationally fixed to the input shaft.

A gas turbine engine comprises a relatively high pressure compressor coupled to a relatively high pressure turbine by a relatively high pressure shaft; a relatively low pressure compressor coupled to a relatively low pressure turbine by a relatively low pressure shaft rotatable independently of the high pressure shaft; a first combustor located downstream of the high pressure compressor and upstream of the high pressure turbine; and a second combustor located downstream of the high pressure turbine, and upstream of the low pressure turbine. The engine further comprises a coupling arrangement configured to selectively transfer torque between the high pressure shaft and the low pressure shaft.

A method and system improving energy efficiency of a turbojet engine by optimizing rotating speed of a fan and operability of an engine, by freeing the fan from exclusive control of a low-pressure (LP) shaft by providing combined control with a high-pressure (HP) shaft when cruising power has been reached. The turbojet engine include at least one LP turbine and one HP turbine coupled to coaxial LP shafts and HP shafts, respectively, which can drive LP and HP compressors, respectively. The LP compressors include a fan that forms a first primary air-intake compression stage. The LP and HP shafts are mounted on one of two driving mechanisms, an inner ring gear, and a planet carrier for a planetary gear train for driving the fan, the HP shaft being mounted on a disengagement mechanism and the fan being coupled to the planetary gear train via an outer driven ring gear.