L= SPAGES SPAGES d EACH TOTAL NO. OF RIVETS = 18(9 EACH SIDE OF SPLI A= ORIGINAL TUBE C = REP B= SLEEVE D USE AI7S ALUM. ALL
RIVETS, SMALL HEAD
HAMMER STANDARD SPLICES MAY BE USED ON LIGHTLY- ROUND HEAD LONGERONS OR WEB MEMBERS.
APPROX. THICKNESS CORRECT WAY OF BRAZIER HEAD. INCORRECT WAY A, C * 3/4 7/8 065 065 7/8 1-178 065 1-1/8 1-1/411-3/81-1/2 065 11-1/41-3/8 058 .058 d MUST NOT BE LESS THAN D/8.
ALL .058 THICK R= 3 d RIVET DIA 5 / 32 5/32 3/16 3/16 3/16 3 / 16 0000.0000 L 19-3/8|9-3/8111-1/4/11-1/4/11-1/4|11-1/4 0000: 0000 * INCLUDES ALL THICKNESSES UP TO AND IN MEACH. (USE BASIC ROUND SIZES IN TABLE STREAMLINE NOTE: USE SAME MATERIAL AS ORIGINAL FOR SLEE FOR SIZE OF RIVETS ETC.)
FIGURE 2.20.-Typical repair method for tubular members of aluminum allo;
AC 43.13 D CRACK 30 30 3020203030301 - D NOTE: FOR MINIMUM NUMBER OF RIVETS REQUIRED, SEE PARAGRAPH 100e. AND SUBSEQUENT.
AT LEAST AS THICK
AS ORIGINAL
ORIGINAL TER • REINFORCEMENT MATERIAL - DURAL. OR 2117-AD RIVETS ALUMINUM ALLOY USED IN 3/32" DIA. MIN.
ORIGINAL CONSTRUCTION.
SCALE - TWICE SIZE SECTION A-A
SCALE - TWICE SIZE 2017-T3 10000 SQ. ROD 3D 30 3D 3D _30 30 _ 3D • 2117-AD RIVETS 1/8" DIA: MIN FIGURE 2.21.-Typical repair for buckled or cracked formed metal wing rib capstrips.
Par 100
- 1A
SEE (C) SEE (D) 0000 OO10 (A)
• SEE (E) (B) D * RIVET DIA.
2 1.5 t (APPROX.) (MINIMUM 3/32")
BEND RADI TO FIT
ORIGINAL RIB.
(G) /I6PLYWOOD TO STIFFEr BENT RIBS.
- MACHINE SCREW D OR RIVET.
1.5 t l APPROX.
- PEEN (E) NOTE: FOR MINIMUM NUMBER
OF RIVETS REQUIRED, SEE PARAGRAPH 100e. AND 3030 30 20) (D) SUBSEQUENT.
FIGURE 2.22.—Typical metal rib repalrs (usually found on small and medium-size aircraft).
Par 100
Pago 58 AC "А" •040" 2017-T3 SPACER 20, 30, 30,2020,30 3D 20 "B" 2024-T3 SPLICE BAR "Д" "в" 2117-AD RIVETS 3/32" DIA, MIN. CRACK 2117-AD RIVETS 3/32i DIA. MIN.
- ЗА - ЗА
1. STRAIGHTEN CRIMPED OVER PORTION. • CRACK
2. INSERT HARDWOOD (ASH) INSERT SHAPED.
TO CONFORM TO T.E. PIECE.
2117-AD RIVETS 20 2D 2D 3/32" DIA. MIN.
FLATTEN HEADS (APPROX. 1.5t ) OUTSIDE I. STRAIGHTEN CRIMPED PORTION. •CRACK
2. USE SAME AL. ALLOY AS IN ORIGINAL.
NOTE: FOR MINIMUM NUMBER OF RIVETS REQUIRED, SEE PARAGRAPH 100e. AND SUBSEQUENT.
FroURE 2.28.- Typical repairs of trailing edges.
Per 100
(A) ADDED STIFFEN"
ERS TO BACK UP SEAM OF PATCH.
2 EACH PATOH PLATE TO 24-5/32" REQ'D BE OF SAME MAT- 12117-74 ¡RIVETS BY SAME BACKED ERIAL AS ORIGIN- AL AND SAME OR NEXT HEAVIER GAUGE. RIVET 3" HOLE MAX. DIA. SIZE, SPACING,
MAX DIA MATERIAL AND
PATTERN SAME 16-5/32 AS ORIGINAL AB.
PII7-T4 RIVETS DAMAGED SKIN
SHOULD BE
CLEANED OUT "G", "H", AND "K" SMOOTHLY AS
ARE INDICATED BY CIRCULAR PATCH PLATES. COEF.
DESIGNATION DIE SIONATION OF CIR. PATCH LATES H "G DIAMETER (OUTSIDE) 12-1/2" 7-1/2" DIA. INNER RIVET CIRCLE 1-3/4° DIA. OUTER RIVET CIRCLE 16-1/2
SAME RIVET SIZE, SPACING, MATERIAL
• PATTERN AS BO.. SAME RIVET SIZE, SPAGING, MATERIAL & PATTERN AS AD.
, PATGH PLATE 8-5/32"2112 RIVETS. MAX DIA I' HOLE TO BE OF SAME MATERIAL AS ORIGINAL AND SAME OR NEXT
HEAVIER BAUGE "K" - GRACA -NOT LESS THAN 2 TIMES, _PORTION OF SKIN REPLACED OF GRACK.-
- ORIGINAL SKIN SHEET. 4 RIVETS RECD EACH SIDE.
RIVET SPACING AT HOLES DRILLED TO LEAST 3 X RIVET DIA PREVENT CRACK SPREADING.
SKIN GAUGE = ,028 (B) RIVET DIA. "=" CRACK 2,5" LONG" FroURE 2.24-Typical repairs of stressed sheet metal covering.
Par 100
Раде 60 out the damaged area and then installing a conventional patch on the underneath side or back of the sheet being repaired. A plug patch plate of the same size as the opening may then be inserted and riveted to the patch plate.
Other types of flush patches similar to those used for patching plywood may be used (ref.
Chapter 1). The riveting pattern used, however, must follow standard practice to maintain satisfactory strength in the sheet.
In general, patches in metal skin are not restricted as to size or shape; however, those of rectangular, circular, square, oval, and rectangular with round ends usually are more desirable because of appearance and ease of installation.
e. Splicing of Sheets. The method of copying the seams at the edges of a sheet may not always be satisfactory; for example, when the sheet has cutouts, or doubler-plates at an edge-seam, or when other members transmit loads into the sheet, the splice must be designed as illustrated in the following exam-
(1) Material: Clad 2024 sheet, 0.032-inch thickness. Width of sheet (i.e., length at splice) - "W" = 10 inches.
(2) Determine rivet size and pattern for a single-lap joint similar to figure 2.18.
(a) Use rivet diameter of approximately three times the sheet thickness, 8 × 0.032 =
0.096-inch. Use 1/8-inch 2117 AD rivets (5/82- inch 2117-AD would be satisfactory).
(b) Use the number of rivets required per inch of width "W" from figure 2.29. (Number per inch 4.9 × .75 = 8.7 or the total number of rivets required = 10 × 8.7 or 87 rivets.)
(e) Lay out rivet pattern with spacing not less than shown in figure 2,18. Referring to figure 2.18(A), it seems that a double row pattern with the minimum spacing will give a total of 40 rivets. However, as only 87 rivets are required, two rows of 19 rivets each equally spaced over the 10 inches will result in a satisfactory splice.
f. Straightening of Stringers or Intermediate Framer. Members which are slightly bent may be straightened cold and examined with a mag- Far 100 AC 43.13-1 197 nifying glass for injury to the material. Rein force the straightened parts to an extent, de pending upon the condition of the material an the magnitude of any remaining kinks or buc kles. If any strain cracks are apparent, mak complete reinforcement in sound metal beyon the damaged portion.
(1) Local Heating. Do not apply local heat ing to facilitate bending, swaging, flattening or expanding operations of heat-treated alumi num alloy members, as it is difficult to contro the temperatures closely enough to prevent possible damage to the metal, and it may im pair its corrosion resistance.
g. Splicing of Stringers and Flanges. Make splices in accordance with the manufacturer's recommendations, which are usually contained in a repair manual.
Typical splices for various shapes of sections are shown in figures 2.25 and 2.26. Design splices to carry both tension and compression and use the splice shown in figure 2.26 as an ex ample illustrating the following principles:
(1) Statement of Principles:
(a) To avoid eccentric loading and conse quent buckling in compression, place splicin or reinforcing parts as symmetrically as poss ble about the centerline of the member, and a tach to as many elements as necessary to pr vent bending in any direction;
(b) To avoid reducing the strength tension of the original bulb angle the rive holes at the ends of the splice are made sma (no larger than the original skin attaching riv ets), and the second row of holes (thos through the bulbed leg) are staggered bi from the ends. In general arrange the rivet the splice so that the design tensile load for member and spliceplate can be carried into splice without failing the member at the most rivet holes;
(c) To avoid concentration of loa end rivet and consequent tendency tow gressive rivet failure, the splice is ta the ends, in this case, by tapering the angle and by making it shorter than th bar (ref. figure 2.26) ; and
(d) The preceding principles are
3.13-1A Page 61 00000000000000000 NOTE: FOR MINIMUM NUMBER TAPERED
OF RIVETS REQUIRED, SEE SPLICE PARAGRAPH 100e. AND SUBSEQUENT. MEMBER NOTE: UNSHADED SECTIONS ARE ORIGINAL AND/OR REPLACEMENT SECTIONS. SHADED SECTIONS ARE CONNECTING OR REINFORCING SECTIONS.
per W, a Wz FIGURE 2.25.-Typical stringer and flange splices.
Par 100
Page 62 AC 43
CUT IN STRINGER TAPERED SPLICE MEMBER o 0-0
ON LOWER SURFACE OF WING, MAKE END RIVET SAME SIZE AS SKIN ATTACHING RIVETS.
A → 2d2,MINIMUM - ід* 3 de, MINIMUM
- THE NUMBER OF BOLTS REQUIRED IN THE "BULB" LEG OF THE STRINGER IS DETERMINED FROM FIG. 2.29 FOR 2017-T3 AS FOLLOWS:
+= 1/16" (Use .064") de= ,190" (AN3 bolt) NO. OF BOLTS PER INCH OF WIDTH FROM TABLE = 3.3.
ACTUAL NO. OF BOLTS ON EACH SIDE OF CUI = WX 3.3 * (1.0)x 3.3 = 3.3 BOLTS USE 4BOLTS
WHEN BOTH RIVETS AND BOLTS
ARE USED, BOLT HOLES SHOULD BE REAMED TO SIZE.
We
(1.O) SPLICE ANGLE "A"
SHADED AREA GREATER THAN Wexte.
SECTION A-A -KEEP LARGE HOLES BACK FROM END OF SPLICE.
THE NUMBER OF RIVETS REQUIRED IN
THE UPPER LEG OF THE STRINGER IS DETERMINED FROM FIG. 2.29 FOR 2017-T3 AS FOLLOWS:
t, = 1/16" (Use "064") d,= 1/8" (2117-AD rivet) NO. OF RIVETS PER INCH OF WIDTH FROM TABLE = 9.9 ACTUAL NO. OF RIVETS ON EACH SIDE OF CUT = WIx 9.9 = (.5),× 9.9 :4.95 RIVETS. USE SRIVETS.
d, (1/8), RIVET DIA. PREFERABLY 2tTO 3t, BUT NOT GREATER THAN W/4.
"B"SPLICE BAR. SHADED AREA GREATER THAN W, Xt..
STRINGER
AREA REPRESENTING BULB FIOURE 2.26.--Example of stringer splice (material-2017 alloy).
Par 100
NOTE: FOR MINIMUM NUMBER OF RIVETS REQUIRED, SEE PARAGRAPH 100e. AND SUBSEQUENT.
NOTE: STRENGTH INVESTIGATION USUALLY REQUIRED FOR THIS TYPE OF REPAIR.
FIGURE 2.27.-Application of typical flange splices and reinforcement.
Par 100
Pae 64 AC 43.13 cially important in splicing stringers on the lower surface of stressed skin wings, where high tension stresses may exist, When several adjacent stringers are spliced, stagger the splices if possible.
h. Size of Splicing Members. When the same material is used for the splicing members as for the original member, the next cross-section area (i.e., the shaded areas in figure 2.25) of the splicing member will be greater than the area of the section element which it splices. The area of a section element (e.g., each leg of an angle or channel) is equal to the width multipled by the thickness, For example, the bar "B" in figure 2.26 is assumed to splice the upper leg of the stringer, and the angle "A" to splice the bulbed leg of the stringer. Since the splice bar "B" is not as wide as the adjace leg, and since the rivet diameter is also at tracted from the width, the bar is made tw as thick in order to obtain sufficient net area.
I. The Diameter of Rivels in Stringers. The i ameter of rivets in stringers might preferal be between 2 and 8 times the thickness "+" the leg, but must not be more than 1/4 t width "W" of the leg. Thus, 1/8-inch rivets a chosen in the example, figure 2.26. If t splices were in the lower surface of a wing, t end rivets would be made the same size as t skin-attaching rivets or 8/32 inch.
I. The Number of Rivets. The number of rive required on each side of the cut in & stringer flange may be determined from standard tex FIGURE 2.28.- -Number of rivets required for splices (single-lap joint) in bare 2011-T6, 2024-T8, 2024-T96, al 7075-T6 sheet, clad 2014-T6, 2024-T8, 2024-T86, and 7075-T6 sheet, 2024-T4, and 7075-T6 plate, bar, rod, tut and extrusions, 2014-T6 extrusiona.
No. of 3117-AD protruding bead No. of Thicknese reets required per inch of width "py" botta in inches 8/82 1/8 5/82 8/16 1/4 A7-8
0.016 4.0 .020 4.9
4.9
0.2 .086 7.0 .040 18 7.3 .051 9.8 „084 12.8 .081 .OĐ1 .102 .128 NOTES :
a. For stringers in the upper surface of a wing, or in a fuselage, 80 percent of the number of rivets whown io table may be used.
b. For intermediate frames, 60 percent of the number shown may be used.
c. For single lap sheet Joints, 75 percent of the number shown may be used.
EMoINEEBING NOTES: The above table was computed as follows:
1. The load per inch of width of material was calculated by assuming a strip one inch wide in tension.
2. Number of rivets required was calculated for 2117-AD rivets, baaed on a rivet allowable shear stre 40 percent of the sheet alloweble tensile stress, and a sheet allowable bearing stress aqual to 160 percent o allowable tensile stress, using nominal hole diameters for riveta.
3. Combinations of sheet thickness and rivet size above the heavy line are critical in (1. e., will fail by) the sheet; those below are critical in shearing of the rivets.
4. The number of AN-8 bolts required below the heavy line was calculated based on a sheet affowable ton of 70,000 p.s.l. and a bolt allowable single shear load of 2,128 pounds.
Par 100
43.13-1A Раде 65 oks on aircraft structures, or may be found figures 2.28, 2.29, and 2.30. In determining c number of rivets required in the example, ure 2.26, for attaching the splice bar "B" to e upper leg, the thickness "+" of the element area being spliced is 1/16 inch (use 0.064), e rivet size is 1/8 inch, and figure 2.29 shows at 9.9 rivets are required per inch of width.
nce the width "W" is 1/2 inch, the actual imber of rivets required to attach the spliceir to the upper leg on each side of the cut is 9 (rivets per inch) × 0.5 (inch width) = 95 (use & rivets).
or the bulbed leg of the stringer "+" = 1/16 ch (use 0.064); AN-3 bolts are chosen and e number of bolts required per inch of width
3.8. The width "W" for this leg, however, is inch and the actual number of bolts required 1 each side of the cut is 1 × 3.8 = 8.8 (use 4 ›lts). When both rivets and bolts are used in the same splice, the boltholes must be accurately reamed to size. It is preferable to use only one type of attachment, but in the above example, the dimensions of the legs of the bulb angle indicated rivets for the upper leg and bolts for the bulb leg.
1) Splicing of Intermediate Frames. The same principles used for stringer-splicing may be applied to intermediate frames, when the following point is considered:
(a) Conventional frames of channel or Z section are relatively deep and thin compared to stringers, and usually fail by twisting or by buckling of the free flange. Reinforce the splice-joint against this type of failure by using a splice plate heavier than the frame and by splicing the free flange of the frame with a flange of the spliceplate, as illustrated in figure
2.31. Since a frame is likely to be subjected to bending loads, make the length of spliceplate |GURE 2.29.-Number of rivets required for splices (single-lap joint) in 2017, 2017 ALCLAD, 2021-T86 and 2021- T36 ALCLAD sheet, plate, bar, rod, tube, and extrusions.
No. of 2117-AD protruding bead rivets required per inch of width "W" No. of bolts kness "t" In inches AN-3
6. 5 4. 9
6. 5 < 9 3. 9
6. 9 4. 9 3. 9
8. 9 4. 9 3. 9
10. 0 5. 6
11. 1 8. 2
7.0 coco so co Tea co co co co
9. 9
12. 5
10. 3 7.1 3. 9
12. 9 8. 9 1 9 3. 3 or stringers in the upper surface of a wing, or in a fuselage, 80 percent of the number of rivets shown in the be used r intermediate framee, 60 percent of the number shown may be used.
ingle lap sheet joints, 75 percent of the number shown may be used.
NOTES: The above table was computed as follows:
id per inch of width of material was calculated by assuming a strip one inch wide in tension.
er of rivets required was caloulated for 2117-AD rivete, based on a rivet allowable shear stress equal to i the sheet allowable tensile etress, and a sheet allowable bearing stress equal to 160 percent of the sheet usile stress, using nominal hole diametera for rivets.
binations of sheet thickness and rivet size above the heavy line are critical in (i.e., will fail by) bearing on hose below are critical in shearing of the rivets.
› number of AN-3 bolts required below the heavy line was caloulated based on s sheet allowable tensile stress .s.i. and a bolt allowable single shear load of 2,126 pounds.
Per 100
Page 66 АС 43.13- "I" more than twice the width "W," and the rivets spread out to cover the plate.
101. REPAIRING CRACKED MEMBERS. Acceptable methods of repairing various types of cracks in structural elements are shown in figures 2.82 to 2.35. The following general procedures apply in repairing such defecta:
a. Drill small holes 3/82 inch (or 1/8 inch) at the extreme ends of the cracks to minimize the possibility of their spreading further.
b. Add reinforcement to carry the stresses across the damaged portion and to stiffen the joints (as shown in figures 2.82 to 2.35).
The condition causing cracks to develop at a particular point is stress concentration at that point in conjunction with repetition of stress, such as produced by vibration of the structure.
The stress concentration may be due to the q sign or to defects such as nicks, scratches, to marks, and initial stresses or cracks fro forming or heat-treating operations. It shou be noted, that an increase in sheet thickne alone is usually beneficial, but does not nece sarily remedy the conditions leading to crac ing.
102. STEEL AND ALUMINUM FITTINGS.
a. Steel Fittings-Inspection for Defects.
(1) Finings are to be free from scratche vise and nibbler marks, and sharp bends ‹ edges. A careful examination of the fitting wit a medium power (at least 10 power) magnif ing glass is acceptable as an inspection.
(2) When repairing aircraft after an accide or in the course of a major overhaul, inspe FIGURE 2.30.-Number of rivets required for splices (single-lap joint) in 5052 (all hardnesses) sheet.
Thictness "t" in inches No. of 2117-AD protruding head rivets required per inch of width "p" No. of bolt AN-31
0.016-. 6. 3 1, 7 .020_. В. з 4.7 3. 8 .025__ 6. 8 3. 8 .032_. 6. 3 4, 7 3. 8 3. 2 .036__. 7.1 4.7 8. 8 3. 2 2.4 .040__ 7. 0 4. 7 3. 8 3. 2 2.4 .051-. 10. 1 5. 6 3. 8 3. 2 2,4 .064_ 12.7 7.0 46 3. 2 .081_. & 9 5. 8 2 .091-- 10. 0 6. 5 .102_ 11. 2 7. 3 .128_ 9. 2 NOTES:
a. For stringers in the upper surface of a wing, or in a fuselage, 80 percent of the number of rivets shor table may be used.
b. For intermediate frames, 60 percent of the number shown may be used.
c. For single lap sheet jointe, 75 percent of the number shown may be used.
ENGINEERINO NOTES: The above table was compuled as follows:
1. The load per inch of width of material was calculated by assuming a strip one inch wide in tension.
2. Number of rivets required was calculated for 2117-AD rivets, based on & rivet allowable shear stre.
70 percent of the sheet allowable tensile stress, and a sheet allowable bearing stress equal to 165 percent of allowable tensile stress, using nominal hole diameters for rivete
3. Combinations of sheet thickness and rivet size above the heavy line are critical in (l.e., will fall by) be the sheet; those below are critical in shearing of the rivets.
Par 100