According to an aspect, a bowed rotor sensor system for a gas turbine engine is provided. The bowed rotor sensor system includes a bowed rotor sensor operable to transmit a sensing field in an observation region and receive a signal indicative of a gap between an air seal and a blade tip within the gas turbine engine. The bowed rotor sensor system also includes a controller operable to monitor a plurality of gap data from the bowed rotor sensor indicative of the gap between the air seal and the blade tip of a plurality of blades passing through the observation region and determine a bowed rotor status of the gas turbine engine based on the gap data.

According to an aspect, a bowed rotor sensor system for a gas turbine engine is provided. The bowed rotor sensor system includes a bowed rotor sensor operable to transmit a sensing field in an observation region and receive a signal indicative of a gap between an air seal and a blade tip within the gas turbine engine. The bowed rotor sensor system also includes a controller operable to monitor a plurality of gap data from the bowed rotor sensor indicative of the gap between the air seal and the blade tip of a plurality of blades passing through the observation region and determine a bowed rotor status of the gas turbine engine based on the gap data.

A system for light-off detection in a gas turbine engine according to an example of the present disclosure includes, among other things, a computing device that has memory and a processor. The computing device is configured to execute a data module and a comparison module. The data module is programmed to access data that corresponds to a present rotational speed of a gas turbine engine component. The comparison module is programmed to cause an indicator to be generated in response to determining that an acceleration rate relating to the present rotational speed meets at least one predetermined acceleration threshold, the indicator relating to an engine light-off condition.

An example turbofan engine starting system includes a core nacelle housing a compressor and a turbine. The core nacelle is disposed within a fan nacelle. The fan nacelle includes a turbofan. A bypass flow path downstream from the turbofan is arranged between the two nacelles. A controller is programmed to manipulate the nozzle exit area to facilitate startup of the engine. In one example, manipulates the nozzle exit area using nozzles, in response to an engine shutdown condition. The nozzles open and close to adjust the nozzle exit area.

An example turbofan engine starting system includes a core nacelle housing a compressor and a turbine. The core nacelle is disposed within a fan nacelle. The fan nacelle includes a turbofan. A bypass flow path downstream from the turbofan is arranged between the two nacelles. A controller is programmed to manipulate the nozzle exit area to facilitate startup of the engine. In one example, manipulates the nozzle exit area using nozzles, in response to an engine shutdown condition. The nozzles open and close to adjust the nozzle exit area.

There is provided a method of operating a gas turbine engine. The gas turbine engine comprises a staged combustor comprising an arrangement of fuel spray nozzles in which fuel flow is biased to a subset of the nozzles adjacent one or more ignitors during a re-light procedure. The method comprises providing fuel to the combustor having a calorific value of at least 43.5 MJ/kg. Also disclosed is a gas turbine engine.

There is disclosed an aero gas turbine engine comprising a compressor and an array of variable inlet guide vanes for the compressor. The angle of the variable inlet guide vanes is controlled by scheduling, the scheduling comprising a first component invoked for engine ground start and a second component invoked for engine in-flight windmill start at least under particular flight conditions. The angle of the variable inlet guide vanes required by at least a portion of the second component is greater than the angle of the variable inlet guide vanes required by at least a portion of the first component.

There is disclosed an aero gas turbine engine comprising a compressor and an array of variable inlet guide vanes for the compressor. The angle of the variable inlet guide vanes is controlled by scheduling, the scheduling comprising a first component invoked for engine ground start and a second component invoked for engine in-flight windmill start at least under particular flight conditions. The angle of the variable inlet guide vanes required by at least a portion of the second component is greater than the angle of the variable inlet guide vanes required by at least a portion of the first component.

The invention relates to an architecture of a propulsion system of a multi-engine helicopter, comprising turboshaft engines (1, 2) that are connected to a power transmission gearbox (3), and comprising a low DC voltage onboard network (7) for supplying helicopter equipment during flight, characterized in that it comprises: a hybrid turboshaft engine (1) that is capable of operating in at least one standby mode during a stable flight of the helicopter; an electrotechnical pack (20) for quickly restarting said hybrid turboshaft engine in order to bring said engine out of said standby mode and to reach a mode in which it provides mechanical power, said restart pack (20) being connected to said onboard network (7); and at least two sources (4, 16, 18) of electrical power for said onboard network (7).

The invention relates to an architecture of a propulsion system of a multi-engine helicopter, comprising turboshaft engines (1, 2) that are connected to a power transmission gearbox (3), and comprising a low DC voltage onboard network (7) for supplying helicopter equipment during flight, characterized in that it comprises: a hybrid turboshaft engine (1) that is capable of operating in at least one standby mode during a stable flight of the helicopter; an electrotechnical pack (20) for quickly restarting said hybrid turboshaft engine in order to bring said engine out of said standby mode and to reach a mode in which it provides mechanical power, said restart pack (20) being connected to said onboard network (7); and at least two sources (4, 16, 18) of electrical power for said onboard network (7).