Abstract: A separating inlet duct (14) is provided with a reduced arm, bypass throat section (46) to restrict the bypass flow (18b) during periods of high speed aircraft flight. An ejector (34) ensures a minimum bypass flow (18b) during hover or low speed flight. An icing resistance baffle (40) having a rounded leading edge (42) defines the sized throat section (46).

Abstract: A method and apparatus for eliminating vortex whistle noise in a radial-to-axial compressor intake uses a plurality of flow fences (36) disposed along the radially inner gas passage boundary (10). The fences (36) disrupt a portion of the swirling gas flow (32) resulting from the position of a plurality of pivotal inlet guide vanes (28) disposed about the radially outward facing inlet (18).

Abstract: A method and apparatus for utilizing bleed air taken interstage from a multi-stage compressor and passing the bleed air through hollow engine support struts in the inlet area of the compressor, the struts being formed such that a jet flap will be provided by the bleed air discharging from the strut to induce a pre-swirl in the air drawn into the compressor at low operating modes.

Abstract: An exhaust stub for a turbo-prop engine which exits from the aircraft nacelle at a location other than the aft end. A fairing is attached to the exhaust stub to minimize frontal area for a given exhaust stub exit area, but free of the nacelle, because of the requirement for the exhaust stub to move relative to the nacelle. An end plate is secured about the exhaust stub and fairing, substantially parallel to and at close proximity to the nacelle. The end plate effectively improves the performance of the fairing, by eliminating the effect of the gap in the nacelle around the stub and also the gap between the fairing and the nacelle. Improving the performance of the fairing reduces the magnitude of the exhaust duct wake which in turn reduces the momentum definiency in the wake flow; reduces exhaust duct drag; reduces mixing of the exhaust gases into the wake region; and reduces nacelle sooting by exhaust gases.