Various embodiments include a system having: at least one computing device configured to tune a set of gas turbines (GTs) by performing actions including: commanding each GT in the set of GTs to a base load level, based upon a measured ambient condition for each GT; commanding each GT in the set of GTs to adjust a respective output to match a nominal mega-watt power output value, and subsequently measuring an actual emissions value for each GT; adjusting an operating condition of each GT in the set of GTs based upon a difference between the respective measured actual emissions value and a nominal emissions value at the ambient condition; and further adjusting an operating condition of each GT in the set of GTs based upon a determined emissions measurement error.

Various embodiments include a system having: at least one computing device configured to tune a set of gas turbines (GTs) by performing actions including: commanding each GT in the set of GTs to a base load level, based upon a measured ambient condition for each GT; commanding each GT in the set of GTs to adjust a respective output to match a nominal mega-watt power output value, and subsequently measuring an actual emissions value for each GT; adjusting an operating condition of each GT in the set of GTs based upon a difference between the respective measured actual emissions value and a nominal emissions value at the ambient condition; and further adjusting an operating condition of each GT in the set of GTs based upon a determined emissions measurement error.

Techniques are described for using an electrical motor to slow down or stop a propulsor during an operation mode where the engine is to be otherwise running but the speed of the propulsor should be low or the propulsor should be stopped.

Techniques are described for using an electrical motor to slow down or stop a propulsor during an operation mode where the engine is to be otherwise running but the speed of the propulsor should be low or the propulsor should be stopped.

Embodiments of the invention are shown in the figures, where a method for manufacturing a gearbox, the method comprising: providing a predefined interval around an integer; providing a gearbox setup; determining a speed ratio of at least two components of the gearbox setup; comparing the speed ratio with the predefined interval around the integer; and manufacturing a gearbox in accordance with the gearbox setup in dependence on the comparison.

An exemplary aircraft includes a turbine engine having a gas generator spool and a power spool, the power spool operational to drive a rotor, a first generator coupled to the gas generator spool, and a controller operable to increase a load on the gas generator spool when the gas generator spool is on a speed limit thereby increasing a speed limit margin in order to increase power available from the turbine engine.

A gas turbine engine for an aircraft comprises a high-pressure (HP) spool comprising an HP compressor and a first electric machine driven by an HP turbine; a low-pressure (LP) spool comprising an LP compressor and a second electric machine driven by an LP turbine; a combustion system comprising a fuel metering unit; and an engine controller configured to, in response to a change of a power lever angle setting indicative of a deceleration event, reduce fuel flow to the combustion system by the fuel metering unit, and to operate the first electric machine in a generator mode to reduce the HP spool rotational speed and engine core mass flow.

A gas turbine engine for an aircraft comprises a high-pressure (HP) spool comprising an HP compressor and a first electric machine driven by an HP turbine; a low-pressure (LP) spool comprising an LP compressor and a second electric machine driven by an LP turbine; a combustion system comprising a fuel metering unit; and an engine controller configured to, in response to a change of a power lever angle setting indicative of a deceleration event, reduce fuel flow to the combustion system by the fuel metering unit, and to operate the first electric machine in a generator mode to reduce the HP spool rotational speed and engine core mass flow.

The disclosure describes a system that includes an engine having a shaft that rotates around an axis of rotation, an engine controller configured to control the engine, an electric machine mechanically coupled to the shaft of the engine, and an electrical controller. The engine controller is configured to control the engine using control techniques configured for a mechanical device having a target moment of inertia around the axis of rotation. The electric machine has an actual moment of inertia around the axis of rotation that is different from the target moment of inertia. To supplement control of the engine due to the difference in moments of inertia, the electrical controller is configured to receive a rotational speed of the shaft, determine a torque for the shaft based on the speed of the shaft, and control the electric machine to apply the torque to the shaft.

The disclosure describes a system that includes an engine having a shaft that rotates around an axis of rotation, an engine controller configured to control the engine, an electric machine mechanically coupled to the shaft of the engine, and an electrical controller. The engine controller is configured to control the engine using control techniques configured for a mechanical device having a target moment of inertia around the axis of rotation. The electric machine has an actual moment of inertia around the axis of rotation that is different from the target moment of inertia. To supplement control of the engine due to the difference in moments of inertia, the electrical controller is configured to receive a rotational speed of the shaft, determine a torque for the shaft based on the speed of the shaft, and control the electric machine to apply the torque to the shaft.