DC-9 flight demonstration program with refanned JT8D engines. Volume 2: Design and construction

The nacelle configuration selected for the DC-9 had a 1595.6 mm Refan length inlet and an 1811.8 mm exhaust duct. The inlet had 1234.4 mm of acoustic treatment and the tailpipe had 1305.5 mm of equivalent length acoustic treatment. The pylon was reduced in width from 425.5 mm to 204.5 mm. Fuselage frames and titanium skin panels in the area of the pylon were reinforced or replaced to support the higher loads and engine thrust. Experimental type tooling, fabrication and assembly were used on all hardware. The design is considered certifiable and representative of the hardware that would be built as retrofit kits.