Abstract: A rotary-wing aircraft includes a retractable port movable between a closed position and an open position to selectively control flow of combustion gases into a bypass passage to change a power distribution between a rotor system and a secondary propulsion system.

Abstract: An example method of assessing a component of a gas turbine engine includes monitoring debris in at least a portion of an engine and establishing an estimated thermal energy level for a component of the engine based on the monitoring. The method may use gas path parameters to establish the estimated thermal energy level. An example gas turbine engine component assessment system includes a debris monitoring system configured to monitor debris moving through a portion of an engine and a controller programmed to execute an engine deterioration model that assesses a thermal energy level of at least one component of the engine based on information from the debris monitoring system.

Abstract: An example method of estimating gas turbine engine performance deterioration includes monitoring debris in at least a portion of an engine and estimating performance deterioration of at least one component of the engine using information from the monitoring. The method may use gas path parameters, such as pressures, temperatures, and speeds to establish the estimated performance deterioration. An example gas turbine engine performance assessment system includes a debris monitoring system configured to monitor debris moving through a portion of an engine and a controller programmed to estimate performance deterioration of at least one component of the engine based on information from the debris monitoring system.

Abstract: An example method of assessing a component of a gas turbine engine includes monitoring debris in at least a portion of an engine and establishing an estimated thermal energy level for a component of the engine based on the monitoring. The method may use gas path parameters to establish the estimated thermal energy level. An example gas turbine engine component assessment system includes a debris monitoring system configured to monitor debris moving through a portion of an engine and a controller programmed to execute an engine deterioration model that assesses a thermal energy level of at least one component of the engine based on information from the debris monitoring system.

Abstract: An example method of estimating a gas turbine engine surge margin and surge margin deterioration includes monitoring debris in at least a portion of an engine and establishing an estimated surge margin for the engine using information from the monitoring The method may use gas path parameters, such as pressures, temperatures, and speeds to establish the estimated surge margin. An example gas turbine engine surge margin assessment system includes a debris monitoring system configured to monitor debris moving through a portion of an engine, and a controller programmed to execute an engine deterioration model that establishes an estimated surge margin and loss in surge margin of the engine based on information from the debris monitoring system.

Abstract: A convertible gas turbine propulsion system operates in multiple output modes. The convertible gas turbine propulsion system comprises a gas generator, a first power turbine, a secondary propulsion system and an exhaust duct. The gas generator is configured to produce exhaust gas. The first power turbine is aligned with the gas generator to receive the exhaust gas. The secondary propulsion system is in series with the gas generator and the first power turbine. The exhaust duct coaxially extends from the first power turbine to the secondary propulsion system. The exhaust duct includes an exhaust port for opening the exhaust duct to ambient air pressure and permitting exhaust gas to bypass the secondary propulsion system. In various embodiments of the invention, the first power turbine is connected to a first rotary propulsion system, and the secondary propulsion system comprises a second power turbine or a nozzle.

Abstract: A carbon dioxide/cofluid mixture is provided for use in a refrigeration cycle in which the carbon dioxide is alternately absorbed and desorbed from the cofluid. The mixture includes from 50% to 95% cofluid and from 5% to 50% carbon dioxide. The cofluid is selected so that the mixture falls within region A of the plot of pvap versus &Dgr;hsoln shown in FIG. 3. The &Dgr;hsoln of the mixture is the differential heat of solution of the carbon dioxide in the cofluid at 5 wt % and 0° C. The pvap of the mixture is the vapor pressure of the carbon dioxide over the solution at 20 wt % and 40° C.