Basically aft of fuselage station 265.1 a structural production break the fuselage is new. One major internal change is the changing from a central shear panel (formerly between the two engines) to two shear panels (one on either side of the engine) to absorb fuselage bending loads and fuel inertial loads.
All the changes to the fuselage still enable the same wing root rib to be used with the slight exception at the tail cone.
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| Clip from CVS-37356 V-389 Engine Installation Profile View |
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| Clip from CVS-37356 V-389 Engine Installation Plan View |
Changes to the wing center section was fairly mild. The center-section pylons are moved 9.7 inches aft of the A2U location. The pylons attached to the main wing beam and aft beam instead of the front beam and main beam.
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| CVS-37358 V-389 Comparison of V-389 and A2U-1 Plan View |
In addition to the pylons the aft end of the wing root was to be changed to adapt to the new aft fuselage cone for the single exhaust.
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| CVS-37358 V-389 Comparison of V-389 and A2U-1 Plan View |
Under the skin lighter electrical and hydraulic systems were incorporated. The electrical system would incorporate a separate AC and DC circuits with AC generation taking place by a bleed air turbine generator. Weight would be saved by removing one DC generator, internal battery, and two inverters.
The hydraulic system incorporated an emergency ram-air-turbine driven hydraulic pump and alternator. The utility system reservoir was redesigned to accommodate the lower fluid volume requirements. One utility system pump was eliminated due to a new higher efficiency pump and the hydraulic oil cooler was eliminated.
Another subtle change was the installation of only two MK12 guns above the right-hand inlet duct with provisions for a second set over the left-hand inlet duct.
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| CVS-37360 V-389 Gun Installation Profile View |
The gun muzzles are staggered and located aft of the duct lip instead of in the air duct lip like the A2U-1.
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| CVS-37360 V-389 Gun Installation Plan View |
Source Chance Vought Engineering Report 8847 V-389 Attack Airplane Design Report, NARA II
