(3) Stringers and Skin Stiffeners
(a)
The stringers are the longitudinal stiffeners of the fuselage shell. They are made of aluminum-alloy Z-section which are formed or machined. They are riveted between the frames and the skin panels.
(b)
The skin stiffeners make the skin stronger. They are riveted to the skin in areas of high stress (fuselage section and skin panel joints, cabin windows, emergency exits and door openings). Skin stiffeners are chemically milled or machined from forgings.
**ON A/C 301-399,
(1) Frames (Ref. Fig. 002B) Frames are the circular stiffeners around the fuselage shell. All but the two primary wing box frames are made of aluminum-alloy sections. The top part of each frame is formed from sheet and the lower part is machined from plate. The two wing box frames, FR36 and FR42, are machined from forgings. Clips, with cutouts for stringers, are riveted between the frames and the skin panels. The center fuselage is constructed of the following frames:
-FR35.8. A full ring frame which makes the joint between the forward and center fuselage. The forward pressure limit bulkhead is installed in the lower part of this frame. The keel beam also connects to the bottom of the frame,
R R Center Fuselage - Frame and Skin Panel Location Figure 002B
R EFF : 301-399, 53-31-00 Page 10 May 01/04
CES
R - FR36. This is the forward primary frame of the wing-to-fuselage
R joint and is part of the wing box assembly. The frame is made of
R two forged sections which are machined and installed back-to-back.
R The longer of the two sections extends to STGR1; the shorter
R section extends to STGR18. The frame is connected to the wing-box
R front spar,
R - FR37 thru FR41. Five frames which are connected to the left and
R right external attach points of the wing box root-ribs. These
R frames add to the structural strength of the center fuselage above
R the wing on each side,
R - FR42. This is the rear primary frame of the wing-to-fuselage joint
R and is part of the wing box assembly. The frame, almost the same as
R FR36, is two forged sections which are machined and installed
R back-to-back. The longer of the two sections extends to STGR1; the
R shorter section extends to STGR11. The frame is connected to the
R wing box rear spar,
R - FR43 thru FR45. These frames go around the shell and connect with
R the side box assemblies (left and right) and extend into the main
R landing-gear bay. Two slanting frames connect with the frame ends
R on each side to shape and strengthen the landing-gear wheel
R openings,
R - FR46. The rear pressure-limit bulkhead is installed in the lower
R part of this frame. The bulkhead completes the pressure limit zone
R of the center fuselage and makes the rear wall of the main
R landing-gear bay. The bulkhead slopes to the rear at the bottom to
R give the necessary wheel retraction area in the main landing-gear
R bay. The keel beam connects to the bottom of the frame,
R - FR47. A full ring frame which makes the joint between the center
R and rear fuselage sections.
R (2) Skin Panels
R (Ref. Fig. 002B)
R Five primary skin panels and four lower side panels make the center
R fuselage skin. The five primary panels extend the length of the
R center fuselage and include:
R - one top panel which extends across the width of the shell from
R STGR6 left to STGR6 right. The panel edges overlap the side panel
R edges and the panels are then riveted together,
R - two side panels, a top and middle on each side. The top side panel
R extends from STGR6 to STGR18 and includes ten passenger cabin
R windows. The middle side panel extends from STGR18 and attaches to
R the wing root cruciform-fitting and forward and rear lower side
R panels. The top side panel lower edges overlap the middle
R side-panel edges and are then riveted together at STGR18. Both side
R panel edges have a recess so that their outer faces are in line
R with each other when riveted together.
R The top panel and the top and middle side panels are chemically 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：A320飞机维护手册 AMM FUSELAGE 机身2(44)
