ACRES Basic SLEEVE BOLT g) SLEEVE SLEEVE TYPE Part Number PART NO. SIZE LENGTH JK5511 ()04 (X) 100° 509 Tension JK5512( )04 ()() 85516(04 (% 1/8 Head Plus JK5610 K5517()04 () Flange JK5511()45 (X) JK5512 K5516()45 ( #6 Protruding Head (Shear) JK5511 K5517()45 () JK5511()05 (X) 100° Low Profile Head JK5512 JK5512( )05 (X) JK5517()05 (X) JK5516( )05 (X) 5/32 10 JK5511()55 (X) JK5512( )55 (X 100° Standard JK5516()55 ()() #8 10 Profile Head JK5516 JK5517()55 (X) (509 Type) JK5610()55 ()() JK5511()06 (X) JK5512()06 ()) JK5516()06 (X) #10 12 Protruding Head (Tension) JK5517 JK5610()06 ()() JK5511()08 ()) JK5512()08 ()) 100° Oversize JK5516()08 (X) 1/4 16 Tension Head JK5517()08 (X) (1/64 Oversize JK5533 JK5610 08 ( )() Bolt) JK5511()10 ()() 1K5512()10 ( )( ) JK5516()10 (X) 5/16 16 PART NUMBER BREAKDOWN JK5517()10 (X) JK5511 04 N 08 JK5610()10 ( )() "L" at end of part number indicates cetyl alchol lubricant JK5511()12 ()() IK5512()12 (X) Length in sixteenth inch increments. (Required installation length by JK5516()12 (X) K5517()12 ()() 3/8 16 breaking off at proper groove) JK5610()12 (X) | Surface Finish N = No finish ACRES SLEEVE FOR 1/64 OVERSIZE BOLT C = Chemical film per MIL-C-554) SLEEVE PART NO. SIZE BOLT (2) SLEEVE LENGTH Fastener shank diameter in 32nds. K5533(06 ( )) K5533(108 (Y) 13/64 17/64 12 16 Material code JK5533()12 ( )) JK5533()10 (X) 25/24 21/64 16 16
• Basic part number NOTES MATERIAL MATERIAL CODE Acres sleeve, JK5533 1/64 oversize available in A286 steel only.
5052 Aluminum alloy (1/2 hard) 6061 Aluminum alloy (T6 condition) Acres sleeve length in sixteenth inch increments.
A286 Stainless steel (passivate) FIGURE 6-16A. Acres sleeve identification.
HOLE PREPARATION FOR 1/64 OVERSIZE BOLT
BOLT DRILL DRILL SIZE NO. DIA. Existing Fastener 13/64 7/32 0.2187 17/64 9/32 0.2812 21/64 11/32 0.3437 25/64 13/32 0.4062
- Acres Sieeve
HOLE PREPARATION
STANDARD CLOSE FIT FIT 1/64 Oversize Hole BOLT DRILL DRILL DRILL DRILL Structure SIZE NO. DIA. NO DIA.
1/8 9/64 0.1406 28 0.1405 #6 23 0.1540 24 0.1520 5/32 11/64 0.1719 18 0.1695 #8 15 0.1800 16 0.1770 #10 5 0.2055 0.2040 1/4 14 0.2660 17/64 0.2656 5/16 21/64 0.3281 3/8 25/64 0.3908
LINSTALLATION PROCEDURE A. DRILL OUT CORROSION OR DAMAGE TO EXISTING HOLE TO 1/64 OVERSIZE.
B. SELECT PROPER TYPE AND LENGTH
ACRES SLEEVE FOR EXISTING FASTENER ACRES SLEEVE INSTALLATION C. BOND SLEEVE IN STRUCTURE HOLE WITH MIL-S-8802 CLASS A 1/2 SEALANT.
FIGURE 6-16B. Acres sleeve identification.
Hole Preparation See figure 6-16 for drill number for standard or close fit holes. Inspect hole after drilling to assure all corrosion is removed before installing the sleeve. The hole must also be the correct shape and free from burrs. The countersink must be enlarged to receive the flare of the sleeve so the sleeve is flush with the surrounding surface.
Installation After the correct type and diameter sleeve have been selected, use the 6501 sleeve breakoff tool for final installation length. See figure 6-16B for the sleeve breakoff procedure. The sleeve may be installed with or without being bonded in the hole.
When bonding the sleeve in a hole, use MIL-S- 8802A1/2 sealant. Reinstall original size fastener and torque as required.
Sleeve Removal Sleeves not bonded in the hole may be removed by either driving them out with a drift pin of the same diameter as the outside diameter of the sleeve or they may be deformed and removed with a pointed tool. Bonded sleeves may be removed by this method, but care should be used not to damage the structure hole. If this method cannot be used, drill the sleeves out with a drill 0.004 to 0.008 smaller than the installation drill size. The remaining portion of the sleeve after drilling can be removed using a pointed tool and applying an adhesive solvent to the sealant.
Stud Detachable part Stud assembly Grommet Cut-away view of complete Fixed Dzus assembly part spring and Spring assembly rivets FIGURE 6-17. Dzus fastener.
TURNLOCK FASTENERS Turnlock fasteners are used to secure inspection plates, doors, and other removable panels on aircraft. Turnlock fasteners are also referred to by such terms as quick-opening, quick-action, and stressed-panel fasteners. The most desirable feature of these fasteners is that they permit quick and easy removal of access panels for inspection and servicing purposes.
Turnlock fasteners are manufactured and supplied by a number of manufacturers under various trade names. Some of the most commonly used are the Dzus, Camloc, and Airloc.
Dzus Fasteners prevent corrosion. The spring supplies the force that locks or secures the stud in place when two assemblies are joined.
The studs are fabricated from steel and are cadmium plated. They are available in three head styles; wing, flush, and oval. Body diameter, length, and head type may be identified or determined by the markings found on the head of the stud. (See figure 6-18.) The diameter is always measured in sixteenths of an inch. Stud length is measured in hundredths of an inch and is the distance from the head of the stud to the bottom of the spring hole.
A quarter of a turn of the stud (clockwise) locks the fastener. The fastener may be unlocked only by turning the stud counterclockwise. A The Dzus turnlock fastener consists of a stud, DZUS grommet, and receptacle. Figure 6-17 illustrates an installed Dzus fastener and the various parts. 6½ .50 The grommet is made of aluminum or aluminum F - Flush head alloy material. It acts as a holding device for the stud. Grommets can be fabricated from 1100 aluminum tubing, if none are available from normal sources.
The spring is made of steel, cadmium plated to 6½-Body diameter in 16th's of an inch 50 - Length (50/100th's of an inch) FIGURE 6-18. Dzus identification.
sunk, or counterbored hole, depending upon the location and thickness of the material involved.
A quarter turn (clockwise) of the stud locks the fastener. The fastener can be unlocked only by turning the stud counterclockwise.
Airloc Fasteners The Airloc fastener shown in figure 6-20 consists of three parts, a stud, a cross pin, and a stud Stud receptacle. The studs are manufactured from steel assembly and case hardened to prevent excessive wear. The stud hole is reamed for a press fit of the cross pin.
The total amount of material thickness to be secured with the Airloc fastener must be known before the correct length of stud can be selected for installation. The total thickness of material Grommet that each stud will satisfactorily lock together is Receptacle stamped on the head of the stud in thousandths of an inch (.040, .070, .190, etc.). Studs are manufactured in three head styles; flush, oval, and wing.
FIGURE 6-19. Camloc fastener. Installed fastener Dzus key or a specially ground screwdriver locks or unlocks the fastener.
Camloc Fasteners Camloc fasteners are made in a variety of styles and designs. Included among the most commonly used are the 2600, 2700, 40551, and 4002 series in the regular line, and the stressed-panel fastener in the heavy-duty line. The latter is used in stressed panels which carry structural loads.
The Camloc fastener is used to secure aircraft cowlings and fairings. It consists of three parts;
a stud assembly, a grommet, and a receptacle. Stud receptacles Studs Two types of receptacles are available, the rigid type and the floating type. Figure 6-19 illustrates the Camloc fastener.
The stud and grommet are installed in the removable portion; the receptacle is riveted to the Cross pin structure of the aircraft. The stud and grommet are installed in either a plain, dimpled, counter- FIGURE 6-20. Airloc fastener.
1/8 - 3/8 Diameter 7 X 19 7 strands, 19 wires Diameter to each strand 1/16 - 3/32 Diameter 7 × 7 7 strands, 7 wires Diameter to each strand FIGURE 6-21. Cable cross sections.
The cross pin (figure 6-20) is manufactured from chrome-vanadium steel and heat treated to provide maximum strength, wear, and holding power. It should never be used the second time;
once removed from the stud, it should be replaced with a new pin.
Receptacles for Airloc fasteners are manufactured in two types, rigid and floating. Sizes are classified by number-No. 2, No. 5, and No. 7.
They are also classified by the center-to-center distance between the rivet holes of the receptacle:
No. 2, 4 inch; No. 5, 1 inch; and No. 7, 1g inch.
Receptacles are fabricated from high-carbon, heattreated steel. An upper wing assures ejection of the stud when unlocked and enables the cross pin to be held in a locked position between the upper wing, cam, stop, and wing detent, regardless of the tension to which the receptacle is subjected.
CONTROL CABLES Cables are the most widely used linkage in primary flight control systems. Gable-type linkage is also used in engine controls, emergency extension systems for the landing gear, and various other systems throughout the aircraft.
Cable-type linkage has several advantages over the other types. It is strong and light in weight, and its flexibility makes it easy to route through the aircraft. An aircraft cable has a high mechanical efficiency and can be set up without backlash, which is very important for precise control.
Cable linkage also has some disadvantages.
Tension must be adjusted frequently due to stretching and temperature changes.
Aircraft control cables are fabricated from carbon steel or stainless steel.
Cable Construction The basic component of a cable is a wire. The diameter of the wire determines the total diameter of the cable. A number of wires are preformed into a helical or spiral shape and then formed into a strand. These preformed strands are laid around a straight center strand to form a cable.
Cable designations are based on the number of strands and the number of wires in each strand.
The most common aircraft cables are the 7 X 7 and 7 X 19.
The 7 X 7 cable consists of seven strands of seven wires each. Six of these strands are laid around the center strand (see figure 6-21). This is a cable of medium flexibility and is used for trim tab controls, engine controls, and indicator controls.
The 7 X 19 cable is made up of seven strands of 19 wires each. Six of these strands are laid around the center strand (see figure 6-21). This cable is extra flexible and is used in primary control systems and in other places where operation over pulleys is frequent.
Aircraft control cables vary in diameter, ranging 143
from 76 to 8 inch. The diameter is measured as shown in figure 6-21.
Cable Fittings Cables may be equipped with several different types of fittings such as terminals, thimbles, bushings, and shackles.
Terminal fittings are generally of the swaged type. They are available in the threaded end, fork end, eye end, single-shank ball end, and double-shank ball end. The threaded end, fork end, and eye end terminals are used to connect the cable to a turnbuckle, bellcrank, or other linkage in the system. The ball-end terminals are used for attaching cables to quadrants and special connections where space is limited. Figure 6-22 illustrates the various types of terminal fittings.
The thimble, bushing, and shackle fittings may be used in place of some types of terminal fittings when facilities and supplies are limited and immediate replacement of the cable is necessary.
AN663 Double shank ball end terminal AN664 Single shank ball end terminal AN665 Rod end terminal AN666 Threaded cable terminal Turnbuckles A turnbuckle assembly is a mechanical screw device consisting of two threaded terminals and a threaded barrel. Figure 6-23 illustrates a typical turnbuckle assembly.
Turnbuckles are fitted in the cable assembly for the purpose of making minor adjustments in cable length and for adjusting cable tension. One of the terminals has right-hand threads and the other has left-hand threads. The barrel has matching right- and left-hand internal threads. The end of the barrel with the left-hand threads can usually be identified by a groove or knurl around that end of the barrel.
When installing a turnbuckle in a control system, it is necessary to screw both of the terminals an equal number of turns into the barrel. It is also essential that all turnbuckle terminals be screwed into the barrel until not more than three threads are exposed on either side of the turnbuckle barrel.
After a turnbuckle is properly adjusted, it must be safetied. The methods of safetying turnbuckles are discussed later in this chapter.
PUSH-PULL TUBE LINKAGE Push-pull tubes are used as linkage in various types of mechanically operated systems. This AN667 Fork end cable terminal AN688 Eye end cable terminal FIGURE 6-22. Types of terminal fittings.
type linkage eliminates the problem of varying tension and permits the transfer of either compression or tension stress through a single tube.
A push-pull tube assembly consists of a hollow aluminum alloy or steel tube with an adjustable end fitting and a checknut at either end. (See figure 6-24.) The checknuts secure the end fittings after the tube assembly has been adjusted to its correct length. Push-pull tubes are generally made in short lengths to prevent vibration and bending under compression loads.
PINS The three main types of pins used in aircraft structures are the taper pin, flathead pin, and cotter pin. Pins are used in shear applications and 144
Length (Threads flush with ends of barrel) Swaged terminal - Pin eye FIGURE 6-23. Typical turnbuckle assembly.
for safetying. Roll pins are finding increasing uses in aircraft construction.
Taper Pins Plain and threaded taper pins (AN385 and AN386) are used in joints which carry shear loads and where absence of play is essential. The plain taper pin is drilled and usually safetied with wire. The threaded taper pin is used with a taper-pin washer (AN975) and shear nut (safetied with cotter pin) or self-locking nut.
Flathead Pin Commonly called a clevis pin, the flathead pin (MS20392) is used with tie-rod terminals and in secondary controls which are not subject to continuous operation. The pin is customarily installed with the head up so that if the cotter pin fails or works out, the pin will remain in place.
Cotter Pins The AN380 cadmium-plated, low-carbon steel cotter pin is used for safetying bolts, screws, nuts, other pins, and in various applications where such safetying is necessary. The AN381 corrosionresistant steel cotter pin is used in locations where nonmagnetic material is required, or in locations where resistance to corrosion is desired.
Rollpins The rollpin is a pressed-fit pin with chamfered ends. It is tubular in shape and is slotted the full length of the tube. The pin is inserted with hand tools and is compressed as it is driven into place.
Pressure exerted by the roll pin against the hole walls keeps it in place, until deliberately removed with a drift punch or pin punch.
SAFETY METHODS Safetying is the process of securing all aircraft, bolts, nuts, screws, pins, and other fasteners o that they do not work loose due to vibration. A familiarity with the various methods and means of safetying equipment on an aircraft is necessary in order to perform maintenance and inspection.
There are various methods of safetying aircraft parts. The most widely used methods are safety wire, cotter pins, lockwashers, snap-rings, and special nuts, such as self-locking nuts, pal nuts, and jamnuts. Some of these nuts and washers have been previously described in this chapter.
Safety Wiring Safety wiring is the most positive and satisfactory method of safetying capscrews, studs, nuts, boltheads, and turnbuckle barrels which cannot be safetied by any other practical means. It is a method of wiring together two or more units in Self-aligning, anti-friction rod end assembly, adjustable Tube, steel or Clevis, Rod end, Check nut Rod end-threaded aluminum alloy adjustable OUD ОлЮт FIGURE 6-24. Push-pull tube assembly.
6 8 FIGURE 6-25. Safety wiring methods.
such a manner that any tendency of one to loosen is counteracted by the tightening of the wire.
Nuts, Bolts, and Screws Nuts, bolts, and screws are safety wired by the single-wire or double-twist method. The doubletwist method is the most common method of safety wiring. The single-wire method may be used on small screws in a closely spaced closed geometrical pattern, on parts in electrical systems, and in places that are extremely difficult to reach.
Figure 6-25 is an illustration of various methods which are commonly used in safety wiring nuts, bolts, and screws. Careful study of figure 6-25 shows that:
a. Examples 1, 2, and 5 illustrate the proper method of safety wiring bolts, screws, squarehead plugs, and similar parts when wired in pairs.
b. Example 3 illustrates several components wired in series.
c. Example 4 illustrates the proper method of wiring castellated nuts and studs. (Note that there is no loop around the nut.)
d. Examples 6 and 7 illustrate a singlethreaded component wired to a housing or lug.
e. Example 8 illustrates several components in a closely spaced closed geometrical pattern, using a single-wire method.
When drilled-head bolts, screws, or other parts are grouped together, they are more conveniently safety wired to each other in a series rather than individually. The number of nuts, bolts, or screws that may be safety wired together is dependent on the application. For instance, when safetywiring widely spaced bolts by the double-twist method, a group of three should be the maximum number in a series.
When safety-wiring closely spaced bolts, the number that can be safety-wired by a 24-inch length of wire is the maximum in a series. The wire is arranged so that if the bolt or screw begins to loosen, the force applied to the wire is in the tightening direction.
Parts being safety-wired should be torqued to recommend values and the holes aligned before attempting the safetying operation. Never over torque or loosen a torqued nut to align safety wire holes.
Oil Caps, Drain Cocks, and Valves These units are safety wired as shown in figure
6-26. In the case of the oil cap, the wire is anchored to an adjacent fillister head screw.
This system applies to any other unit which must be safety wired individually. Ordinarily, anchorage lips are conveniently located near these individual parts. When such provision is not made, the safety wire is fastened to some adjacent part of the assembly.
Oil caps Drain cocks Note: The safety wire is shown installed for right-hand threads. The safety wire is routed in the opposite direction for left-hand threads.
Valves FIcURE 6-26. Safety wiring oil caps, drain cocks, and valves.
Electrical Connectors Under conditions of severe vibration, the coupling nut of a connector may vibrate loose, and with sufficient vibration the connector may come apart. When this occurs, the circuit carried by the cable opens. The proper protective measure to prevent this occurrence is by safety wiring as shown in figure 6-27. The safety wire should be as short as practicable and must be installed in such a manner that the pull on the wire is in the direction which tightens the nut on the plug.
Turnbuckles After a turnbuckle has been properly adjusted, it must be safetied. There are several methods of safetying turnbuckles; however, only two methods will be discussed in this section. These methods are illustrated in figure 6-28 (A) and 6-28 (B).
The clip-locking method is used only on the most modern aircraft. The older type aircraft still use the type turnbuckles that require the wire-wrapping method.
AN3102 receptacle Bulkhead AN Standard fillister head screw (drilled head) AN3106 plug "AN3057 adapter FIGURE 6-27. Safety wiring attachment for plug connectors.
Straight end Hook shoulder
- Loop end Hook lip- - Hook loop Hook end Lock clip NAS 651 Direction of pull for inspection (A) AN161 or AN162 Turnbuckle fork Lock wire Turnbuckle barrel AN155 - 4 turns wrap Cable 4 turns wrap Tumbuckle eye AN170 - Thimble AN100 Lock wire 4 turns wrap Swaged terminal (B) AN666 or AN669 FIGURE 6-28. Safetying turnbuckles;
(A) Clip-locking method; (B) wire-wrapping method.
Double-wrap Method Of the methods using safety wire for safetying turnbuckles, the double-wrap method is preferred, although the single-wrap methods described are satisfactory. The method of double-wrap safetying is shown in figure 6-28 (B). Use two separate lengths of the proper wire as shown in figure 6-29.
Diameter of Material (annealed Cable size Type of wrap safety wire condition) (in.) (in.)
·16- Single - 020 Stainless steel 332- Single - 040 Copper, brass!
8-- Single - 040 Stainless steel 78- Double - 040 Copper, brass' 7/8- Single . 057 min Copper, brass' 32 and greater. Single - 057 Stainless steel
1. Galvanized or tinned steel, or soft iron wires are also acceptable.
FIGURE 6-29. Turnbuckle safetying guide.
Run one end of the wire through the hole in the barrel of the turnbuckle and bend the ends of the wire towards opposite ends of the turnbuckle.
Then pass the second length of the wire into the hole in the barrel and bend the ends along the barrel on the side opposite the first. Then pass the wires at the end of the turnbuckle in opposite directions through the holes in the turnbuckle eyes or between the jaws of the turnbuckle fork, as applicable. Bend the laid wires in place before cutting off the wrapped wire. Wrap the remaining length of safety wire at least four turns around the shank and cut it off. Repeat the procedure at the opposite end of the turnbuckle.
When a swaged terminal is being safetied, pass the ends of both wires, if possible, through the hole provided in the terminal for this purpose and wrap both ends around the shank as described If the hole is not large enough to allow passage of both wires, pass the wire through the hole and loop it over the free end of the other wire, and then wrap both ends around the shank as de- Single-wrap Method The single-wrap safetying methods described in the following paragraphs are acceptable but are not the equal of the double-wrap methods.
Pass a single length of wire through the cable eye or fork, or through the hole in the swaged terminal at either end of the turnbuckle assembly.
Spiral each of the wire ends in opposite directions around the first half of the turnbuckle barre: so that the wires cross each other twice. Thread both wire ends through the hole in the middle of the barrel so that the third crossing of the wire ends is in the hole. Again, spiral the two wire ends in opposite directions around the remaining half of the turnbuckle, crossing them twice. Then, pass one wire end through the cable eye or fork, or through the hole in the swaged terminal. In the manner described above, wrap both wire ends around the shank for at least four turns each, cutting off the excess wire.
An alternate to the above method is to pass one length of wire through the center hole of the turnbuckle and bend the wire ends toward opposite ends of the turnbuckle. Then pass each wire end through the cable eye or fork, or through the hole in the swaged terminal and wrap each wire end around the shank for at least four turns, cutting off the excess wire. After safetying, no more than three threads of the turnbuckle threaded terminal should be exposed.
General Safety Wiring Rules When using the safety wire method of safetying, the following general rules should be followed:
1. A pigtail of ¼ to ½ inch (three to six twists) should be made at the end of the wiring. This pigtail must be bent back or under to prevent it from becoming a snag.
2. The safety wire must be new upon each application.
3. When castellated nuts are to be secured with safety wire, tighten the nut to the low side of the selected torque range, unless otherwise specified, and if necessary, continue tightening until a slot aligns with the hole.
Optional Preferred FIGURE 6-30. Cotter pin installations.
4. All safety wires must be tight after installation, but not under such tension that normal handling or vibration will break the wire.
5. The wire must be applied so that all pull exerted by the wire tends to tighten the nut.
6. Twists should be tight and even, and the wire between the nuts as taut as possible without overtwisting.
7. The safety wire should always be installed and twisted so that the loop around the head stays down and does not tend to come up over the bolthead, causing a slack loop.
Cotter Pin Safetying Cotter pin installation is shown in figure 6-30.
Castellated nuts are used with bolts that have been drilled for cotter pins. The cotter pin should fit neatly into the hole, with very little sideplay.
The following general rules apply to cotter pin safetying:
1. The prong bent over the bolt end should not extend beyond the bolt diameter. (Cut it off if necessary.)
2. The prong bent down should not rest against the surface of the washer. (Again, cut it off if necessary.)
3. If the optional wraparound method is used, the prongs should not extend outward from the sides of the nut.
4. All prongs should be bent over a reasonable radius. Sharp-angled bends invite breakage. Tapping lightly with a mallet is the best method of bending the prongs.
Snaprings A snapring is a ring of metal, either round or flat in cross section, which is tempered to have springlike action. This springlike action will hold the snapring firmly seated in a groove. The external types are designed to fit in a groove around the outside of a shaft or cylinder. The internal types fit in a groove inside a cylinder. A special type of pliers is designed to install each type of snapring.
Snaprings can be reused as long as they retain their shape and springlike action.
External-type snaprings may be safety wired, but internal types are never safetied. Safety wiring of an external type snapring is shown in figure
6-31.
RIVETS An aircraft, even though made of the best materials and strongest parts, would be of doubtful value unless those parts were firmly held together.
Several methods are used to hold metal parts together; they include riveting, bolting, brazing, and welding. The process used must produce a union that will be as strong as the parts that are joined.
Aluminum and its alloys are difficult to solder.
To make a good union and a strong joint, aluminum parts can be welded, bolted, or riveted together. Riveting is satisfactory from the standpoint of strength and neatness, and is much easier to do than welding. It is the most common method used to fasten or join aluminum alloys in aircraft construction and repair.
A rivet is a metal pin used to hold two or more metal sheets, plates, or pieces of material together. A head is formed on one end when the rivet is manufactured. The shank of the rivet is placed through matched holes in two pieces of material, and the tip is then upset to form a second head to clamp the two pieces securely.
together. The second head, formed either by hand or by pneumatic equipment, is called a "shop head." The shop head functions in the Snapring Single-wire method Shaft FIGURE 6-31. External type snap ring with safety wire installed.