3.13-1A Page 89
DOUBLE LOOP LACING, SEE FIG. 3.8 FOR DETAILS OF KNOT.
— CAPSTRIP
CAPSTRIP
STARTING STITCH, SEE FIG. 3.6 FOR DETAILS.
9* NORMAL STITCH SPACING FIGURE 3.7.-Standard double loop lacing.
пр 3 Par 136
Page 90 AC •
- PULL NO.4 PULL NO. 4- 10 L8.
TO COMPLETE KNOT.
EDGE OF
CAPSTRIP
DIRECTION OF LACING PULL NO. 2 - 6 6B
TO TIGHTEN STITCH
COMPLETED KNOT
EDGE OF CAPSTRIP PULL NO.3
PULL SNUG OPERATION NO. 2 -STITCH LOOPS
AROUND CAPSTRIP PULL NO. 1 - 10 LB. FROM PREGEEDING
TO TIGHTEN LOOPS STITCH OPERATION NO. I FIGURE 8.8.-Standard knot for double loop lacing.
Par 136
43.13~1A MAXIMUM SPACING OF RIB LACING - INCHES I. IF ORIGINAL RIB STITCH SPACING CANNOT BE DETERMINED, NOTES USE SPACING INDICATED IN THESE CURVES.
2. LACING TO BE CARRIED TO LEADING EDGE WHEN VELOCITY EXCEEDS 275 M.P.H.
• SPACING OTHER THAN IN SLIPSTREAM-
SPACING IN SLIPSTREAM- PLACARD NEVER EXCEEDS SPEEDS-M.P.H. (INDICATED) (CURVES PRESUME LEADING EDGE SUPPORT REINFORCEMENT
SUCH AS PLYWOOD, METAL) FIGURE 8.9.-Fabric attachment spacing.
37.-147. RESERVED.
1г 136 Chap 3
Page 92 AC 43,13 Section 2. DOPING
148. APPLICATION OF AIRCRAFT DOPE, EPOXY, it be done properly. Since local atmosphe AND RESINS. Determine that dope and fabric conditions affect the doping process, determ materials are compatible by consulting the the amount of thinner necessary at the ti product manufacturer's instructions before the finishing material is to be applied by fi applying finish to aircraft surfaces. Compati- using it on experimental panels.
bility of products may also be determined by wetting samples of the fabric with the impreg- 149. BLUSHING AND USE OF BLUSH-RETARDI nating materials and thorough examination of THINNER. Blushing of dopes is very comm the material after it has dried. The following when doping is accomplished under humid c military specifications, or later revisions ditions. The condition is caused by the ral thereof, apply to aircraft dope, epoxy, and poly- evaporation of thinners and solvents, wh ester resins: lowers the témperature on the surface, causi MIL-D-5549A-1 condensation of moisture and producing 1 white appearance known as "blush. Blushi MIL-D-7850 tendencies are also increased, if strong ci rents of air flow over the surface when app MIL-D-6550A-1 ing dope or immediately thereafter.
MIL-D-5551A-2 A blushed finish has very little protective tautening value. When the relative humidity MIL-D-5558A-2 such that only a small amount of blushing MIL~D-5552A-1 encountered, the condition may be eliminat MIL-D-5554A-1 by thinning the dope with a blush-retardi MIL-D-5555-1 MIL-R-9800A thinner and slightly increasing the room te perature. If it is not possible to correct humi MIL-R-25042A ity conditions in the dope room, suspend dopi operations until more favorable atmosphe MIL-R-7575B conditions prevail. The use of large amounts blush-retarding thinner is not advisable 1 cause of the undesirable drying properties ¿ companying the use of this material.
150. NUMBER OF COATS. Apply as many coats dope as are necessary to result in a taut al well-filled finish job. A guide for finishing fa ric-covered aircraft follows:
a. Two coats of clear dope, brushed on al sanded after the second coat,
b. One coat of clear dope, either brushed sprayed, and sanded.
c. Two coats of aluminum pigmented dop sanded after each coat.
Par 148 Chap
43.13-1A Page 95 72 Section 3. REPAIRS TO FABRIC COVERING
55. GENERAL, Make repairs to fabric-covered irfaces in a manner that will return the origial strength and tautness to the fabric. Sewed spairs and unsewed (doped-on patches or pan-
ato a surface which contains aluminum or ¡her color coats. Whenever it is necessary to id fabric reinforcement, remove the old dope ther by softening and scraping or by sanding own to the point where the base coat or clear ›at is exposed. Use clear dope in doping the abric to the surface. After reinforcement is lade, normal finishing procedures may be fol- ›wed.
66. REPAIR OF TEARS IN FABRIC. Repair tears & shown in figure 8.10 by sewing the torn edges together using a baseball stitch and doping a piece of pinked-edge fabric over the tear.
If the tear is a straight rip, the sewing is started at one end so that, as the seam is made, the edges will be drawn tightly together throughout its entire length. If the openings are cut in wings to inspect the internal structure, start the sewing at the corner or point so that the edges of the cover will be held in place while the seams are being made. The sewing is done with a curved needle and well-waxed thread. Clean the surface to be covered by the patch by rubbing the surface with a rag dipped in dope, wiping dry with a clean rag, or by scraping the surface with a putty knife after it has been softened with fresh dope. Dope solvent or acetone may be used for the same pur- 1" MIN. LOCK EVERY 8 OR IO STITCHES → 1.51 АЛАЛ
- START SEWING
AT THE POINT
LOCK STITCHING
AT ENDS WITH
1.5 MODIFIED SEINE KNOT
MATERIALS SHOULD →1.5 BE AT LEAST AS GOOD
AS ORIGINAL FIGURE 8.10.-Repair of tears in fabric.
hap 3 Par 165
pose, but care should be taken that it does not drop through on the inside of the opposite surface, causing the dope to blister. Cut a patch of sufficient size from airplane cloth to cover the tear and extend at least 1 1/2 inches beyond the tear in all directions. The edges of the patch should either be pinked similar to surface tape or frayed out about 1/4 inch on all edges.
167. SEWED PATCH REPAIR. When the damage is wing than go in such that it will not permit sewing the edges together, a sewed-in repair patch may be used if the damage is not longer than 16 inches in any one direction (see figure 8.10). Cut out the damaged section, making a round or ovalshaped opening trimmed to a smooth contour.
Clean the area of the old fabric to be doped as indicated in paragraph 166. Turn the edges of the patch 1/2 inch and sew to the edges of the opening. Before sewing, fasten the patch at several points with a few temporary stitches to facilitate sewing the seams. After the sewing is completed, clean the area of the old fabric to be doped as indicated for small repairs and then dope the patch in the regular manner.
Apply surface tape over the seam with the second coat of dope. If the opening extends over or closer than 1 inch to a rib or other laced member, extend the patch 3 inches beyond the member. After sewing has been completed, rib lace the patch to the rib over a new section of reinforcing tape, using the method explained in paragraph 133. Do not remove the old rib lacing and reinforcing tape.
168. UNSEWED (DOPED-ON) REPAIRS. Unsewed (doped-on) repairs may be made on all aircraft fabric-covered surfaces provided the never-exceed speed is not greater than 150 miles per hour. A doped patch repair may be used if the damage does not exceed 16 inches in any direction. Cut out the damaged section making a round or oval shaped opening, trimmed to a smooth contour. Clean the edges of the opening which are to be covered by the patch with a grease solvent. Sand or wash off the dope from the area around the patch with dope thinner.
Support the fabric from underneath while sanding.
Par 166 AC 43.1:
For holes up to 8 inches in size, make fabric patch of sufficient size to provide a of at least 2 inches around the hole. On h over 8 inches in size, make the overlap of fabric around the hole at least 1/4 the hole ameter with a maximum limit of lap o inches. If the hole extends over a rib or cl than the required overlap to a rib or ot laced member, extend the patch at leas inches beyond the rib. In this case, after edges of the patch have been doped in pl and the dope has dried, lace the patch to rib over a new section of reinforcing tape the usual manner. Do not remove the old lacing and reinforcing tape. All patches sho have pinked edges or, if smooth, should be:
ished with pinked-edge surface tape.
169. REPAIR BY A DOPED-IN PANEL. When 1 damage exceeds 16 inches in any directi make the repair by doping in a new panel. T.
type of repair may be extended to cover bi the upper and lower surfaces and to cover s eral rib bays if necessary. Lace the panel to the ribs covered, and dope or sew as in t blanket method.
a. Remove the surface tape from the ribs i jacent to the damaged area and from the tri ing and leading edges of the section being paired. Leave the old reinforcing tape a lacing in place. Next, cut the fabric along a li approximately 1 inch from the ribs on t sides nearest the injury and continue the ci to completely remove the damaged section. !
not remove the old fabric from the leading a trailing edges, unless both upper and low surfaces are being re-covered.
b. Cut a patch to run around the trailing ed 1 inch and to extend from the trailing edge to and around the leading edge and back a proximately to the front beam. Extend t patch approximately 3 inches beyond the ri adjacent to the damage.
As an alternative attachment on metalwood-covered leading edges, the patch may lapped over the old fabric at least 4 inches the nose of the leading edge, doped, and fi ished with at least 4 inches of pinked-edge su face tape.
Chap
: 43.13-1A 72
c. Clean the area of the old fabric that is to be vered by the patch and apply a generous coat ' dope to this area. Put the new panel in ace, pull as taut as possible, and apply a coat I dope to that portion of the panel which overps the old fabric. After this coat has dried, pply a second coat of dope to the overlapped rea and let dry.
d. Place reinforcing tape over the ribs under Chap 3 Page 97 moderate tension and lace down in the approved manner.
e. Give the panel a coat of clear dope and allow to dry. Install surface tape with the second coat of dope over the reinforcing tape and over the edges of the panel. Finish the dope scheme, using the regular doping procedure.
170.-180. RESERVED.
Par 169
Page 98 AC 43.13- Section 4. FABRIC TESTING
181. TESTING OF FABRIC COVERING. Field test ber of tests in 30 percent. Fabric which h instruments that are commonly used to test the less than 70 percent of the original requir tensile strength of aircraft fabric covering tensile strength would not be considered a:
give only approximate indications of the fabric worthy. Figure 3.1 contains the minimum te condition. Since the accuracy of field test in- sile strength values for deteriorated fabric struments is affected by climatic and environ- tested in the undoped condition.
mental conditions, a laboratory test is recom- (3) Grade A fabric may be used whe mended when aircraft fabric covering is found only intermediate fabric is required. Wh to be marginal by field test methods. Labora- testing for deteriorated condition, 46 poun tory test procedures are set forth in Federal (70 percent of original requirements for inte Specification CCC-T-191B, methods 5122, mediate fabric) is considered airworthy.
olo2, 5184, or 5136; American Society of Test. (4) Failures may occur in fiberglass cove ing Materials (ASTM) Method D89-61 or ing where rib stitching has worn through tl D39-49, and others. In all cases, test fabric reinforcing tape and covering material witho specimens in the undoped condition. Use ace- being detected through visual inspection. Su tone, dope thinner, or other appropriate thin- failures can be located by using a suitable su ning agents for the removal of finishing mate- tion cup and lifting the fabric in the r stitched area. If the fabric pulls away from tl
a. Strength Criteria for Aircraft Fabric.
(1) Present minimum strength values for new aircraft fabric covering are contained in figure 8.1.
ribs, new stitching will need to be applie using additional reinforcing tape and doublin the number of stitches throughout the affecte area. Five particular attention to the are:
within the propeller slipstream area.
(2) The maximum permissible deterioration for used aircraft fabric based on a large num- 182.-192. RESERVED.
Par 181 Chap 3
: 43.13-1A Page 99 172 Chapter 4. CONTROL CABLES AND TERMINALS Section 1. INSPECTION AND REPAIR
93. GENERAL. Aircraft control cables are genrally fabricated from carbon steel or corroion-resistant steel wire and may consist of eiher flexible or nonflexible type construction.
Contents of this section may be used for conrol cable installations pertaining to both prinary and secondary system applications.
a. Cable Definitions. Construction features of arious cables are shown in figure 4.1. The folowing terms define components used in airraft control cables.
(1) Wire-Each individual cylindrical steel 'od or thread.
(2) Strand-Each group of wires helically Avisted or laid.
(3) Core Strand--The central strand about which the remaining strands of the cable are elically laid.
(4) Coble-A group of stranda helically ¡wisted or laid about a central core.
(5) Preformed Cable-Cable in which the wires and strands are shaped prior to fabrication of the cable.
(6) Diameter-The diameter of cable is the diameter of the circumscribed circle.
(7) Lay or Twist-The helical form taken by the wires and strands in a cable. A cable is said to have a right-hand lay if the wires and strands twist in the same direction as the thread on a right-hand screw.
(8) Pitch-The distance in which a strand or wire makes one complete revolution about the axis of the cable or strand respectively.
194. CABLE SPECIFICATIONS. Cable size and strength data are given in figure 4.2. These values are acceptable for repair and modification of civil aircraft.
a. Cable Proof Loads. Cable terminals and Chap 4 T
CHAMETER DIAMETER
NONFLEXIBLE 7X7 7X19
FLEXIBLE EXTRA FLEXIBLE FIGURE 4.1.--Cable cross section.
splices should be tested for proper strength prior to installation. Gradually apply a test load equal to 60 percent of the cable breaking strengths given in figure 4.2 for a period of 3 minutes. Place a suitable guard over the cable during the test to prevent injury to personnel in the event of cable failure.
195. REPLACEMENT OF CABLES. Replace control cables when they become worn, distorted, corroded, or otherwise injured. If spare cables are not available, prepare exact duplicates of the damaged cable. Use materials of the same size and quality as the original. Standard swaged cable terminals develop the full cable strength and may be substituted for the original terminals wherever practical. However, if facilities and supplies are limited and immediate corrective action is necessary, repairs may be made by using cable bushings, eye splices, and the proper combination of turnbuckles in place of the original installation. (See figure 4.6c.)
a. Location of Splices. Locate splices so that no portion of the splice comes closer than two Par 193
Page 100 AC 43.13-14 1971 1X7 and 1X10 7X7, 7X19, and 6X19 (1WRC) Nonflexible, carbon Corrosion resisting Flexible, carbon Flexible, corrosion resisting Diameter (Inch) MIL-W-6910 MIL-C-5699 MIL-W-1511 MIL-C-5424 Weight, Breaking Weight, Breaking Weight, Breaking Weight, Breaking pound: strength, pounds strength, pounds strength, pounds strength, per 100 feet- pounds per 100 feet pounds per 100 feet pounds per 100 feet pounds ½a- 0. 25 185 0. 25 150
564. • 65 375 • 55 875 Ko- . 85 500 - 85 500 0. 75 480 0. 75 480 561- 1. 40 800 1. 40 800
2. 00 1, 200 2, 00 1, 200 I. 60 920 1. 60 020
2.70 1, 600 2.70 1, 600
3. 50 2, 100 3. 50 2, 100 2. 90 2, 000 2. 90 1, 760
5. 50 3, 300 5. 50 3, 300 4. 50 2, 800 4. 50 2, 400
7. 70 4, 700 7. 70 4, 700 6. 50 4, 200 6. 50 3, 700
10. 20 6, 300 10. 20 6, 300 8. 60 5, 600 8. 60 5, 000 ¼ 13. 50 8, 200 18. 50 8, 200 11. 00 7, 000 11. 00 6, 400 Ysa 13. 90 8, 000 13. 90 7, 800
21. 00 12, 500 21. 00 12, 500 17. 30 9, 800 17. 80 9, 000
20. 70 12, 500
21. 30 14, 400 24. 30 12, 000
35. 60 17, 600 35. 60 16, 300
45. 80 22, 800 45.80 22, 800 *The strength values listed were obtained from straight tension tests and do not include the effects of wrapped ends.
FIGURE 4.2.-Strength of steel cable.
inches to any fair-lead or pulley. Locate connections at points where jamming cannot occur during any portion of the travel of either the loaded cable or the slack cable in the deflected position.
b. Cutting and Heating. Cut cables to length by mechanical means. The use of a torch in any manner is not permitted. Do not subject wires and cables to excessive temperature. Soldering bonding braid to control cable will not be considered satisfactory.
c. Ball-and-Socket Type Terminals. Do not use pall-and-socket type terminals or other types for general replacement that do not positively prevent cable untwisting, except where they were utilized on the original installation by the aircraft manufacturer.
d. Substitution of Cable. Substitution of cable for hard or streamlined wires will not be acceptable unless specifically approved by a representative of the Federal Aviation Administration.
Par 195
196. MECHANICALLY FABRICATED CABLE AS- SEMBLIES.
a. Swage Type Terminals. Swage type terminals, manufactured in accordance with Air Force-Navy Aeronautical Standard Specifications, are suitable for use in civil aircraft up to and including maximum cable loads. When swaging tools are used, it is important that all the manufacturers' instructions, including "go and no-go" dimensions, be followed in detail to avoid defective and inferior swaging. Observ.
ance of all instructions should result in a terminal developing the full rated strength of the cable. Critical dimensions, both before and after swaging, are shown in figure 4.8.
(1) Terminals. When swaging terminals onto cable ends, observe the following procedure:
(a) Cut the cable to the proper length, allowing for growth during swaging. Apply a preservative compound to the cable ends before insertion into the terminal barrel.
NorE: Never solder cable ends to prevent fraying Chap 4
AC 43,13-1A Page 101 1972 Before swaging After swaging Cable size (Inches) Wire strands Minimum Outside Bore Bore Swaging breaking Shank diameter diameter length length strength diameter* (роипав) 7×7 0. 160 0. 078 1. 042 0. 969 480 0. 188 352 7X7 • 218 - 109 1. 261 1. 188 920 . 190 7×19 . 250 . 141 1. 511 1. 488 2, 000 - 219 7×10 . 297 . 172 1. 761 1. 688 2, 800 , 250 7×10 359 • 208 2. 011 1. 988 4, 200 . 813 7×10 427 • 234 2. 261 2. 188 8, 600 - 875 7X10 494 . 265 2.511 2. 438 7, 000 438 7×19 563 . 297 2. 761 2.688 8, 000 500 F10-. 7×10 635 - 328 8. 011 2. 938 9, 800 563 7×19 4 708 - 890 3. 510 3. 438 14, 400 . 625 * Use gages in kit for checking diameters.
FIGURE 4.8.-Straight-shank terminal dimensions (AN-666, 687, 668, and 669).
since the presence of the solder will greatly increase the tendency of the cable to pull out of the terminal.
(b) Insert the cable into the terminal aproximately one inch, and bend toward the terminal; straighten the cable back to normal position and then push the cable end entirely into the terminal barrel. The bending action puts a kink or bend in the cable end and provides enough friction to hold the terminal in place until the swaging operation can be performed.
Bending also tends to separate the stranda inside the barrel, thereby reducing the strain on them.
NorE: If the terminal ia drilled completely through, push the cable into the terminal until it reaches the approximate position shown in figure 4.4. If the hole is FIGURE 4.5.-Gauging terminal shank after swaging.
BEND CABLE THEN PUSH
IN TO SWAGING POSITION FIGURE 4.4.-Insertion of cable into terminal.
Chap 4 not drilled through, insert the cable until the end rests against the bottom of the hole.
(c) Accomplish the swaging operation in accordance with the instructions furnished by the manufacturer of the swaging equipment.
(d) Inspect the terminal after swaging to determine that it is free from die marks and splits, and is not out-of-round. Check for cable slippage in the terminal and for cut or broken wire strands.
lel Using a "go no-go" gauge or a mi- Par 196
crometer, check the terminal barrel diameter as shown in figure 4.5.
(f) Test the cable by proof-loading it to 60 percent of its rated breaking strength.
(2) Splicing, Completely severed cables, or those badly damaged in a localized area, may be repaired by the use of an eye terminal bolted to a clevis terminal. (See figure 4.6a.)
However, this type of splice can only be used in free lengths of cable which do not pass over pulleys or through fair-leads.
(3) Swaged Ball Terminals. On some aircraft cables, swaged ball terminals are used for attaching cables to quadrants and special connections where space is limited. Single shank terminals are generally used at the cable ends, and double shank fittings may be used at either the end or in the center of the cable. Dies are supplied with the swaging machines for attaching these terminals to cables in the following manner:
(a) The steel balls and shanks have a hole through the center, and are slipped over the cable and positioned in the desired location.
(b) Perform the swaging operation in accordance with the instructions furnished by the manufacturer of the swaging equipment.
(c) Check the swaged fitting with a "go no-go" gauge to see that the fitting is properly AM 668 TERMINAL
(c) FIGURE 4.6.- Typical cable splices.
Par 196 AC 43.13-1 197
MEASURE SHANK
- AFTER SWAGING 1/16 CABLE 3/32 MEASURE SHANK
BEFORE SWAGING
SLEEVES
MEASURE BALL
• BEFORE SWAGING
MEASURE BALL
AFTER SWAGING FIGURE 4.7.-Typical terminal gauge.
compressed. (See figure 4.7.) Also inspect the physical condition of the finished terminal.
(4) Cable Slippage in Terminal. Ensure that the cable is properly inserted in the terminal after the swaging operation is completed. Instances have been noted wherein only 1/4 inch of the cable was swaged in the terminal. Observance of the following precautions should minimize this possibility:
(a) Measure the length of the terming end of the fitting to determine the prop length of cable to be inserted into the barrel of the fitting.
(b) Lay off this length at the end of the cable and mark with masking tape. Since the tape will not slip, it will provide a positive marking during the swaging process.
(c) After swaging, check the tape marker to make certain that the cable did not slip during the swaging operation.
(d) Remove the tape and, using red paint, paint the junction of the swaged fitting and cable.
(e) At all subsequent service inspections of the swaged fittings, check for a gap in the painted section to see if cable slippage has occurred.
b. Nicopress Process. A patented process using copper sleeves may be used up to the full rated strength of the cable when the cable is looped around a thimble. This process may also be used in place of the five-tuck splice on cables up to and including 8/8-inch diameter. The use of sleeves that are fabricated of materials other than copper will require engineering approval of the specific application by a representative of the Federal Aviation Administration.
Chap 4