Quiet Nacelle's (QNC's) earlier JT3D Stage 2 hushkit for 707-100s and OC-135Bs forms the basis of its Stage 3 upgrade package. To achieve Stage 3 compliance, an inner acoustic ring is located co-axially within the engine intake. The inner ring will be fully anti-iced and certificated for bird strikes. Additional acoustic changes are included at the fan-exhaust ejector shroud, and the thrust-reverser translating sleeve and engine diaphragm, are also modified. To provide maintenance access, the ejector shroud consists of two hinged doors, which can be opened to allow access to the standard engine-cowl doors.
Source: Flight International
