Abstract: A tethered unmanned aerial vehicle firefighting system includes a firefighting drone, a lifting drone and a tether line coupling the firefighting drone to a control station through the lifting drone. The control station includes a control unit for controlling the firefighting drone and the lifting drone, a fire retardant supply, a pump coupled to the fire retardant supply, and a power supply. The tether line includes a power line coupling the power source to and powering the firefighting drone and a fire retardant hose coupled between the pump and a nozzle carried by the firefighting drone. A lifting tower hold the tether from the control station at a height above ground level, and the lifting drone maintains the tether above obstruction for the firefighter drone. The firefighter drone disperses fire retardant from the nozzle for firefighting purposes and with a substantially unlimited supply of retardant and power.

Abstract: A tethered unmanned aerial vehicle firefighting system includes a firefighting drone, a lifting drone and a tether line coupling the firefighting drone to a control station through the lifting drone. The control station includes a control unit for controlling the firefighting drone and the lifting drone, a fire retardant supply, a pump coupled to the fire retardant supply, and a power supply. The tether line includes a power line coupling the power source to and powering the firefighting drone and a fire retardant hose coupled between the pump and a nozzle carried by the firefighting drone. A lifting tower hold the tether from the control station at a height above ground level, and the lifting drone maintains the tether above obstruction for the firefighter drone. The firefighter drone disperses fire retardant from the nozzle for firefighting purposes and with a substantially unlimited supply of retardant and power.

Abstract: A system for starting a gas turbine engine includes an engine controller and a fuel controller. The engine controller varies the engine speed between a minimum start speed and a maximum start speed until light-off of the engine occurs. The fuel controller operates a fuel command to vary fuel provided to a combustion chamber of the engine until light-off of the engine occurs.

Abstract: An exemplary containment structure includes an annular wall configured to receive a rotatable portion of a turbomachine. A plurality of apertures extend radially through the annular wall. The apertures have a varying circumferential width.

Abstract: An exemplary containment structure includes an annular wall configured to receive a rotatable portion of a turbomachine. A plurality of apertures extend radially through the annular wall. The apertures have a varying circumferential width.

Abstract: A system for starting a gas turbine engine includes an engine controller and a fuel controller. The engine controller varies the engine speed between a minimum start speed and a maximum start speed until light-off of the engine occurs. The fuel controller operates a fuel command to vary fuel provided to a combustion chamber of the engine until light-off of the engine occurs.

Abstract: A spectroscopic detector for identifying the presence of a first substance in the presence of another substance includes a laser for illuminating the substances at a plurality of wavelengths to induce the emission of radiation characteristic of the substance; a spectrometer for measuring the emitted radiation to obtain a plurality of spectral measurement data; and a processor for processing the data. An algorithm combines the data into a composite spectrum and a parameter characteristic of the first substance is identified while information in the composite spectrum contributed by emission of radiation from the other substance is removed to identify the presence of the first substance and obtain a characteristic spectral signature of the first substance. The signature is compared to signatures in a spectral library database, wherein at least some of the library signatures have spectral characteristics differentiated from each other by identifiable spectral characteristics caused by environmental factors.