Baixe rebites porcas parafusos cabos aeronauticos e outras Notas de estudo em PDF para Administração Empresarial, somente na Docsity! 1.0 Standard Methods and Practises 26/06/98 Page 1 Please read the following information carefully and refer to it often throughout the building process. It contains information on corrosion protection, drilling, deburring, gusset building etc. Also included is a section on bolt and rivet selection to assist you in areas of the manual where bolt or rivet sizes have not been indicated. 1.1 Metal Surface Preparation Some of our kits include the following chemicals to be used for surface preparation and treatment: C-2200 MET-L-SOL Surface Cleaner EP-420 Epoxy Chromate Metal Primer EP-430 Epoxy Primer Catalyst As a protective measure against corrosion, mating metal surfaces should be fully deburred, cleaned with C-2200, then coated liberally with epoxy chromate primer. This provides a seal between the surfaces to prevent corrosion and moisture buildup. It is a good practice to coat the end of the rivet on the inside surface after installation. As an optional measure, the rivets can be dipped in chromate prior to installation. This provides protection inside the hole and seals out moisture. If the airframe is not to be painted be careful to avoid excess chromate on the exterior. The epoxy primer is to be pre-mixed in accordance with the manufacturers directions as displayed on the containers. It is advisable to mix only the amount you need in a small container each time you work, however, larger amounts can be mixed and reused in a sealable container. 1.2 Drilling Holes It is good practice to use a #40 drill when doing any assembly- if possible never drill to final hole size until assembly is complete. This allows for any movement between parts or adjustment you may want to make that may cause misalignment of the holes during assembly. Always use a sharp drill bit as: -A sharp bit will not wander as easily as a dull one. -You can drill faster with a sharp bit. -You don’t have to push as hard, risking bending flanges etc. -Always be careful to drill squarely to the work surface. -Always make sure when drilling through multiple parts or layers that they are clamped together tightly so as not to move around whole drilling. -Always debur holes on both sides of each part before final assembly. 1.0 Standard Methods and Practises 26/06/98 Page 2 1.3 Bolts Throughout the building process there will be instances where bolts are used to fasten parts or materials together. In some instances It may be for the builder to determine the correct length of the bolt to be used. The “Rule of Thumb” for determining bolt length is that the bolt must be long enough to pass through the parts or material being fastened together so that: 1. The threaded part of the bolt is never in shear (no threads are allowed inside hole). 2. No more than three and no less than one thread must be showing when the nut is attached and tightened to the correct torque value. 3. At least on flat washer must be used under the nut and no more than three are allowed. More precise determinations of Grip Length are found in a number of books including the Standard Aircraft Worker’s Manual. The following information is provided for reference when using AN grade hardware. Most of the time torque values are done to feel. But this table does provide a good outline. Occasionally bolts, other than a standard bolt will be called out for use in the manual. Please ensure that these bolts are used where called out. The Engineering Department selected these as they provide the strength for the connection where a standard bolt can not provide. 1.4 Standard Torque Table (Inch Pounds) * Fine Thread Series Bolt Size Standard Nuts Shear Nuts (MS20365, AN310, AN315) (MS20364, AN320, AN316, AN23-31) 10-32 20-25 12-15 1/4-28 50-70 30-40 5/16-24 100-140 60-85 3/8-24 160-190 95-110 7/16-20 450-500 270-300 1/2-20 480-690 290-410 9/16-18 800-1000 480-600 5/8-18 1100-1300 660-740 1.0 Standard Methods and Practises 26/06/98 Page 5 Table 2 Screws Recommended Hole Sizes for Self-tapping Sheet Metal Screws Metal Clearance Drill for Sheet Metal Screws Thickness Material. #2 #4 #6 #7 #8 #10 #12 #14 0.015 Steel 52 44 37 Alum. 0.018 Steel 52 44 37 33 Alum. 0.024 Steel 51 43 36 32 27 19 Alum. 52 0.03 Steel 50 42 36 32 31 27 19 13 Alum. 52 44 37 33 32 0.036 Steel 49 42 35 32 31 26 19 13 Alum. 52 44 37 33 31 27 0.048 Steel 49 41 34 31 30 24 18 11 Alum. 51 44 37 32 30 27 20 0.06 Steel 48 39 32 30 29 24 16 8 Alum. 50 43 36 31 29 27 19 8 0.075 Steel 38 31 29 28 22 14 6 Alum. 43 35 30 28 26 17 7 0.105 Steel 30 28 25 20 13 4 Alum. 42 34 29 26 26 15 6 0.125 Steel 25 18 9 1 Alum. 31 29 26 23 14 4 0.135 Steel 24 18 9 1 Alum. 31 29 25 23 14 4 0.164 Steel 17 7 15/64 Alum. 31 29 24 21 12 3 0.187 Steel 17 7 15/64 Alum. 31 29 24 21 12 3 1.0 Standard Methods and Practises 26/06/98 Page 6 Table 3 Clearance Drill Sizes for AN Bolts, Screws and Cotter Pins AN BOLTS AN SCREWS COTTER PINS Bolt Drill Size Drill Size Drill Size #10 #11 #4 #32 1/16 #48 1/4 1/4 #6 #28 3/32 #36 5/16 5/16 #8 #19 1/8 #28 3/8 3/8 #10 #11 5/32 #16 7/16 7/16 1/4 1/4 3/16 #4 1/2 1/2 5/16 5/16 1/4 #1 9/16 9/16 5/8 5/8 11/16 11/16 3/4 3/4 7/8 7/8 1 1 1.6 Nuts AN310 CASTELLATED NUT Figure 1.6.1 The AN310 Castle Nut is designed to be used in conjunction with a cotter pin for safetying. The nut may be used in tension and on assemblies that turn on the bolt or vice versa. This nut is used primarily with the AN3 to AN20 series bolt. Example Callout: 1.0 Standard Methods and Practises 26/06/98 Page 7 AN310D4 An AN310 aluminum nut (D) for use on a 1/4 in (4) bolt. Thread from table - 1/4-28NF-3. AN315 PLAIN NUT Figure 1.6.2 The AN315 Plain Nut may be safetied through the use of a shakeproof or lock washer - may be used in conjunction with the AN3 to AN16 series bolt. The nut may be had in right (R) or left (L) hand thread (see example callout). AN316 CHECK NUT Figure 1.6.3 This nut is used as a check nut to eliminate travel of other nuts or parts on the threads of a bolt or rod. This nut must not be used in tension or shear. The AN316 nut may be had in either right (R) or left (L) hand thread (see callout). UNF-3 THREAD SIZE 6- 40 8- 36 10- 32 1/4- 28 5/16- 24 3/8- 24 7/16- 20 1/2- 20 9/16- 18 5/8- 18 3/4- 16 7/8- 14 1- 14 1-1/8- 12 1-1/4- 12 -3 -4 -5 -6 -7 -8 -9 -10 -12 -14 -16 -18 -20 -3 -4 -5 -6 -7 -8 -9 -10 -12 -14 -16 -18 -20 -4 -5 -7 -8 -9 -10 -12 -14 -18 -20 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10 -12 -14 -16 -18 -20 1.0 Standard Methods and Practises 26/06/98 Page 10 All edges should be filed to remove shear or tin snip marks then have the corners ‘Chamfered’, as shown in Figure 1.11.1, with a file. Figure 1.11.1 All flange ends should have corners rounded or at least be cut at 45 degrees, then filed. See Figure 1.11.2. Figure 1.11.2 1.12 Inside Corners Should always have the largest possible radius in the corner. Shown in Figure 1.12.1. 1.0 Standard Methods and Practises 26/06/98 Page 11 Figure 1.12.1 1.13 Riveting The standard rivet used in the aircraft is the avex rivet. Many people mistakenly refer to them as pop rivets. “Pop” is a brand name and the correct terminology is blind rivet which simply means it can be used from one side only. There are considerable differences between the avex rivet and the more common pop rivet. Never substitute a pop type rivet for the avex rivets. In the kit there are two diameters of rivets and various lengths. Both countersunk and domed head avex rivets are used. Stainless steel rivets are used in a few location, normally in high shear application. Check carefully with the instructions on where to use the different types, lengths and heads. In your kit you will also find a number of large head all aluminum rivets. These rivets are non-structural and are used in installing the windows. - Always check that you are using the proper grip length rivet for the job you are doing. I.E.: 1/8: X 1/8” rivet refers to ‘Diameter’ and ‘Grip’ length will secure only up to 1/8” of material thickness, just as a 1/4” grip length rivet will secure only up to 1/4” of material. - Make sue the rivet is all the way into the hole and that the parts being riveted have not pulled away from each other or separated. - Keep rivet gun square to the work when pulling rivets. - See next section on edge distance 1.14 Edge Distance Edge distance is simply the distance from the center of the rivet or bolt to the edge of the skin or fitting. The proper edge distance is required to ensure that the rivets or bolts are not ripped from the skin/fitting because of inadequate shear strength. 1.0 Standard Methods and Practises 26/06/98 Page 12 The rule of thumb is that edge distance from center line hole to edge of material should always equal twice the rivet/bolt diameter. At Murphy Aircraft we normally add 1/16” in case we have to drill to the next size or too much material is trimmed off. To go any greater dimension than this does not increase the strength, it just adds extra weight and is unsightly. A circle template will assist you and is very cheap and easily purchased. Most office or school supply stores carry them. - Always make sure that you have adequate edge distance on your parts. Rule of thumb for edge distance is: * Rivet/bolt diameter X2 or.... * 1/8” rivet X2 = 1/4” edge distance * 3/16” bolt X2 = 3/8” edge distance Never have less than 1 1/2 ties edge distance. Avoid more than 2 1/2 times edge distance. Rivet Chart Rivet Number Rivet Diameter & Length RV-1410 Rivet, 1/8" x 3/16" Avex RV-1414 Rivet, 1/8" x 5/16" Avex RV-1512 Rivet, 5/32" x 1/4" Avex RV-1521 Rivet, 5/32" x 1/2" Avex RV-1613 Rivet, 3/16" x 1/4" Avex RV-1619 Rivet, 3/16" x 3/8" Avex RV-1621 Rivet, 3/16" x 1/2" Avex RV-1631 Rivet, 3/16" x .781 Avex RV-2621 Rivet, 3/16" x 1/2" Avex LH RV-2631 Rivet, 3/16" x .781 Avex LH RV-4412 Rivet, 1/8" x 3/16" CSK Avex RV-4621 Rivet, 3/16" x .500 CSK Avex RV-4514 Rivet, 5/32" x 3/8" CSK Avex RR-5402 Rivet, 1/8" x 1/8" S.S. RR-5404 Rivet, 1/8" x 1/4" S.S. RR-5406 Rivet, 1/8" x 3/8" S.S. RR-5408 Rivet, 1/8" x 1/2" S.S. RR-5602 Rivet, 3/16" x 1/8" S.S. RR-5604 Rivet, 3/16" x 1/4" S.S. RR-5606 Rivet, 3/16" x 3/8" S.S. RR-6602 Rivet, 3/16 x 1/8 Closed End RR-6406 Rivet, 1/8" x 3/8" Closed End RR-6604 Rivet, 3/16 x 1/4 Closed End RR-6606 Rivet, 3/16 x 3/8 Closed End RV-6614 3/16" x 1/2 SS Varigrip RR-7402L Rivet, 1/8" x 1/8" Fabric RR-7402L Rivet, 1/8 x 1/4" Lg Hd Al. RR-7408 Rivet, 1/8 x 1/2 " Aluminum RR-8402 Rivet, 1/8 x 1/8 Al/SS 1.0 Standard Methods and Practises 26/06/98 Page 15 4D, the edges may curl upwards and not lie flat and binding. When aircraft rivets are installed using less that 2D edge distance, the bearing edge strength of the metal will weaken. To select the correct drill, and to drill the holes to the proper size. All rivet holes must be center punched in order to prevent the drill from walking over the surface of the metal and defacing it. The indentation made by a center punch must be hard enough to catch the point of the drill, yet light enough to prevent denting the surrounding mental. Proper drill selection depends upon the size of the rivet being used. The hole for a solid-shank rivet is drilled approximately .002 to .004 of an inch larger than the nominal rivet diameter. A rivet that is driven into a properly prepared hole needs to be sized according to diameter and length so that a correct size bucktail can be formed. Figure 1.16.2 shows the width and height of a normally driven bucktail. 1.0 Standard Methods and Practises 26/06/98 Page 16 Figure 1.16.2 The use of thin skins on many light aircraft requires that the upset rivet head be .66 times the diameter of the rivet high, and 1.33 inches times the diameter of the rivet wide. To determine the rivet length for a particular job, the thickness of all the metal parts must be known. All the individual thickness of the metal are referred to as the grip length. The grip length plus 1.5D is the proper length of the rivet. Figure 1.16.3. 1.0 Standard Methods and Practises 26/06/98 Page 17 Figure 1.16.3 The hand tool used to drive a rivet is called a pneumatic rivet gun or rivet hammer. Rivet guns are normally powered by compressed air and are classified as light-, medium-, or heavy-hitting. A light- hitting gun is used to install 3/32 and 1/8 inch diameter rivets. Medium-hitting guns are used to install 5/32 and 3/16 inch diameter rivets. Heavy-hitting guns are used to install larger diameter rivets and some special fasteners, There are two types of gun sets, one for universal head rivets and one for countersunk. The universal gun set is sized to fit the various shapes of manufactured heads on the rivet’s driven end. The opposite end of the universal gun set fits into the rivet gun barrel and is held in place by a beehive retainer spring. The countersunk gun set fits all sizes of flush head rivets. The countersunk rivet cannot use the beehive retainer ring. The countersunk rivet set uses a specially designed retainer spring. 1.17 Bucking Bars The tool used to form an upset head while using a pneumatic rivet gun is a bucking bar. Bucking bars are made in various shapes, sizes and weights. The weight of the bucking bar must be proportional to the size of the rivet. To obtain a proper upset head, a good technique to use is shown in Figure 1.17.1. As the gun is firing, press the bucking bar firmly against the forming rivet shank and roll the bar slightly. This rolling action will aid in the formation of a barrel-shaped bucktail. If the bucking bar is too light for the size of rivet and gun, the metal will bend toward the bucktail. If the bucking bar is not held firmly against the rivet shank, the metal will bend away from the gun. 1.0 Standard Methods and Practises 26/06/98 Page 20 Universal head rivets, also called protruding head rivets, are used internally in structural areas and on the skin surfaces of low to medium speed aircraft. A universal head rivet can with stand a much stronger bearing load than a countersunk rivet because the head is installed flat and binding on the surface of the riveted metal while the countersunk rivet is installed into a machine-tapered will. The universal head rivet is a combination of several older head styles. When rivets were first used, various rivet head styles were available. Round head (AN430) rivets were used internally on high strength structural areas. The flat head (AN442) rivet was used in tight areas where the round head could not be installed. Some modern jet aircraft still use round and flat head rivets in structural areas. Aircraft built prior to World War II were low speed aircraft, so a smooth aerodynamic air flow over the wing was not a major concern. As the speed of the aircraft increased, the need for smaller protruding head rivets accounted for the development of a modified brazier head (456), which causes less drag than larger protruding head rivets. Today, brazier head rivet styles are likely to be found only on aircraft built before 1955. Because the rivet sets used to drive rivets other than universals are difficult to obtain today, the older styles can be replaced by universal head rivets. Advisory Circular 43.14-1 explains the procedure. 1.21 Countersunk Rivets As aircraft speeds increased, the need for smooth airfoils led to the development of the countersunk rivet. After experimenting with head angles of 78o, 90o and on high-speed jet fighters, 110o, the aircraft industry adopted a 100o standard. All of these experiments were attempts to increase the bearing strength of the rivet head around the skin. The countersunk rivet has to be installed in a depression in such a way as to be flush with the surface of the skins it is holding together. The depression in the skin is called a nest or a well. The well can be made using a freehand or microstop countersink cutter. Whenever the metal is cut to form a well or nest, the area around the rivet head is weakened. To compensate for this loss of strength, aircraft manufactures must install a greater number of rivets in order to increase bearing and shearing strengths. Figure 1.21.1 shows how countersunk rivets re installed, by either machine or dimple methods 1.0 Standard Methods and Practises 26/06/98 Page 21 Figure 1.21.1 To remedy the loss in bearing strength caused by machine countersinking, the NACA (National Advisory Commission for Aeronautics) developed a method of countersinking that has been adopted by aircraft manufacturing companies. Two different angles may be cut into the top skin, 60o or 82o . Military aircraft were the first to use the 60o well, on some of the older jet fighters. The 82o well is used when installing sing slugs on the Boeing 747. On some aircraft, a universal is installed from the inside of the wing and driven into an 82o well. Installing rivets using either the 60o or 82o NACA countersink method makes them as strong as universal head rivets. When coldworked, the bucktail formed in the 60o or 82o angle well is stronger than the conventional countersink riveting method because the driven head is packed into its well, creating a much stronger head than the regular countersunk rivet can produce. 1.22 Dimpling Thin skins are never machine countersunk, because the cutter will go completely through the thin skin into the second skin and reduce the bearing strength around the countersunk rivet head. There is an alternative process call dimpling, which solves this problem. Dimpling can be done in two ways, cold dimpling or hot dimpling. Cold dimpling of sheet metal skins is done on material less than .040 of an inch thick if countersunk rivets are required. The benefit of cold dimpling is that it produces stronger shearing and bearing strengths in the joint than would a driven universal head rivet of the same size. 1.0 Standard Methods and Practises 26/06/98 Page 22 Dimpling bars or sets can be made in the shop by cutting steel stock to the same size as the rivet to be used, and then setting a microstop countersink to cut about .015 of an inch deeper than the rivet head. To use the dimpling bar, drill a hole into the sheet metal just as you would for a universal head rivet, place the dimpling bar under the rivet hole and insert a countersink rivet. Using a rivet gun with a mushroom head set or a ball peen hammer, tap the rivet head into the dimpled well. Because dimpling does not produce the flushness of a machine countersunk rivet, be careful not to hit the area around the head too hard, or the metal surrounding the rivet will stretch, creating a problem which could be difficult to remedy. Metal that becomes stretched must be removed and replaced either by a patch or by changing a complete skin panel. 1.23 Inspection of a Rivet Joint There are three places to check when inspecting a rivet joint: The MFG. head, the shop head, and the skin around the rivet heads. Any damage to either of the two rivet heads is not critical because rivets can e drilled out and replaced. Note: Never oversize the hole when drilling out a damaged rivet! If skin damage is extensive, a new skin panel must be installed. The procedures for removing rivets depends upon the situation. If, for example, an aircraft has extensive damage to a wing leading edge or a section of the spar, the mechanic will remove the damaged metal as well as some of the parts that are still useable. In removing rivets from reusable aircraft parts, it is essential that the rivet holes not be oversized. The correct way to remove the rivets is to file a flat spot on all protruding head rivets except the 2117 rivets, to center punch each MFG. head, to back up each rivet with a bucking bar, to select a drill ONE SIZE SMALLER THAN THE RIVET BEING REMOVED, to drill only the depth of the MFG. head, to use a pin punch which is the same size as the drill, to snap off the drilled MFG. heads and to back up each remaining stem by tapping out the shank without stretching the metal. A different procedure is followed in removing the occasional rivet badly driven during re-assembly. Such rivets should be removed by the same size drill as the rivets being installed. Drill the depth of the MFG. head only; then lightly tap off the MFG. head and gently knock out the remaining shank. Figure 1.23.1 illustrates an assortment of faulty rivets which must be removed and replaced. The most troublesome rivet fault is a clinched rivet, which results from improper bucking action. The rivet forms to one side, which can lead to a corrosive condition at a later date. Rivets that crack do so because they became too hard while the bucktail was forming. This is a result of hitting the rivet too lightly or allowing an icebox rivet to recover its age hardening by keeping it out of the freezer too long before driving. 1.0 Standard Methods and Practises 26/06/98 Page 25 2) If possible, backdrill through the holes to be covered. Cleco while drilling. 3) Remove the Gusset. 4) Draw circles around the end holes to mark out the shape of the Gusset. As shown in Figure 1.25.2. The radius of the circle should be two times the rivet diameter. Figure 1.25.2 5) Draw tangent lines to the cicles. See Figure 1.25.3. Figure 1.25.3 1.0 Standard Methods and Practises 26/06/98 Page 26 6) Cut out the Gusset following the lines you marked out. Debur all edges. Cleco the finished Gusset back in place. NOTE: This method will work for odd shaped Gussets. Just find the rivet holes that mark the outside shape of the Gusset and mark circles around them. 1.26 Using Sealant WARNING- Do not get sealant on your skin! Use rubber gloves! Good ventilation is also a good idea. Use a scotchbrite pad and soapy water to remove from your skin - not solvent, M.E.K. etc. Clean all mating surfaces before applying sealant. Use a Scotchbrite pad and scuff surfaces well, wipe or blow dust away (do this immediately before applying sealant). DO NOT USE ANY SOLVENT OR M.E.K. AFTER SCOTCHBRITING THE SURFACE The sealant supplied with this kit is a two part mixture. It is very important that the mix ration specified by the manufacturer is adhered to and that it be used at room temperature. Improper mix ration or too low a temperature may cause the sealant not to cure! Only mix enough sealant to do the job, don’t waste it. It is better to under estimate and run out before completing an assembly. You can always mix a little more to finish up. Working time is about 2 hrs. The best way to mix the sealant is on a flat sheet (aluminum is good). Use a putty knife or a piece of aluminum to mix. Scrape sealant up from mixing surface completely when mixing to make sure there is no uncatylized sealant underneath. How much do I use? - After riveting you should see a small amount of sealer being squeezed out all along the joint. 1.27 Do’s and Don’ts in Handling Aluminum Sheets Do- use a soft leaded pencil to mark aluminum sheet. Don’t - use scribe Don’t- scratch the surface of aluminum- protect sheet against abrasion Do- bend aluminum where possible so the flange be bend line runs perpendicular to the metal grain (direction or rolling). Do- use the recommended bend radius in bending aluminum sheet. Do- use a protective layer between adjacent alclad sheets 1.0 Standard Methods and Practises 26/06/98 Page 27 Don’t-use a brown sulphite paper -this paper, when wet, will cause corrosion Do- store aluminum sheet in a dry area - atmosphere must not be moist or humid 1.28 Castings Castings may be made from both the heat-treatable and the non heat-treatable alloys. No general rules can be cited in determining the alloy composition, as each type (aluminum-silicon, aluminum-magnesium, etc. ) has alloy compositions which are suited for most design considerations. It can be stated, however, that many die cast and permanent mold castings are made from the non-heat- treatable alloys. Heat-treatable castings are used where physical properties are required which are greater than those obtainable from the non-heat-treatable alloys. While the chemical compositions vary somewhat from those of corresponding wrought alloys, the method of heat-treatable castings is about the same as those used on wrought alloys. 1.29 Forgings and Extrusions Forgings are usually made from the heat treatable wrought alloys. The most common forging alloys are 2014, 4032, 7075, 3003. They are made by the common methods used with other metals and are subject to the same kinds of defects. Extrusions are made by “squirting” an aluminum slug through a shaped hole in a die. Complex shapes can be made accurately to dimensions. Extruding can produce shapes (for example, finned tubing) which could not be made by rolling. Both heat treatable and not heat treatable alloys are extruded. 1.30 Heat Treatment of Aluminum Alloys There are four types of heat treatment used in aluminum alloy fabrications, namely, Stress Relieving, Annealing, Solution Heat Treatment and Artificial Aging. Stress Relieving is used on the non heat treatable alloys. To relieve stress, the part is heated to a temperature of 650º to 750º Fahrenheit and allowed to air cool. This is done to remove the effects of cold work stresses so that further forming may be done without cracking. Annealing is used on the heat treatable aluminum alloys to remove the effects of solution heat treatment or artificial aging. It consists of heating the material to 750º to 800º Fahrenheit and followed by slow cooling to prevent the introduction of unnatural stresses. Both wrought and cast alloys are annealed to put them into the softest and most ductile condition for further work. 1.0 Standard Methods and Practises 26/06/98 Page 30 AISI AND SAE STEEL NUMBERING SYSTEM Type of Steel Aisi Number Carbon Steel 1XXX Plain Carbon 10XX Carbon and Sulphur 11XX Manganese Steel 13XX Nickel Steel 2XXX 3.5% Nickel 23XX 5.0% Nickel 25XX Nickel-Chromium Steel 3XXX 1.25% Nickel, 0.60% Chromium 31XX 1.75% Nickel, 1.00% Chromium 32XX 3.5% Nickel, 1.5% Chromium 33XX Molybdenum Steel 4XXX Chromium-Molybdenum 41XX Chromium-Nickel-Molybdenum 43XX Nickel (1.75%)-Molybdenum 46XX Nickel (3.50%)-Molybdenum 48XX Chromium Steel 5XXX Low Chromium 51XX Chromium 1.0% 52XX Chromium -Vanadium Steel 6XXX Chromium 1% 61XX Nickel-Chromium-Molybdenum Steel 8XXX Nickel 0.55%; Chromium 0.50%; Moly 0.20% 86XX Nickel 0.55%; Chromium 0.50%; Moly. 0.25% 87XX Silicon-Manganese Steel 9XXX Boron and Nickel Steel 80BXX 1.35 Cable Rigging The following are instructions for installing thimbles on the ends of the cables for rigging Elevator, etc. The instructions show a standard installation procedure for a 5/32” cable. The procedure is the same for the different size cables also for attaching cables to turnbuckles. NOTE: You may have to drill out the hole on the end of the WT-06 Tang to fit the thimble through. 1.0 Standard Methods and Practises 26/06/98 Page 31 Put a 5/32” nico on the end of a 5/32” cable. Pass the end of the 5/32” cable through the WT-06 Tang and over the 5/32” thimble. (Figure 1.35.2). Thread the cable back through the nico (slide nico tight against thimble) and ‘press’ the nico, equally spaced, twice. Figure 1.35.1. Figure 1.35.1 Cut a length of Heat Shrink Tubing and place it over the two cable ends close to the nico. Cut off excess cable and shrink the Heat Shrink Tubing. Figure 1.35.2. Figure 1.35.2 1.36 Push Pull Tube Fabrication The following is a standard practice for manufacturing the push pull tubes used throughout the aircraft. The example shown is for the 1/4” (HM-4M) Rod End Bearing on 3/4” x .035 tubing. Other combinations are: 1) 1/4” HM-4M Rod End Bearing, AN316-4 Jam Nut and CC-29 End Plug for 3/4” x .035 tubing 2) 1/4” HM-4M Rod End Bearing, AN316-4 Jam Nut and CC-28 End Plug for 1” x .058 tubing 3) 5/16” HM-5M Rod End Bearing, AN316-5 Jam Nut and CC-30 End Plug for 1” x .058 tubing. 1.0 Standard Methods and Practises 26/06/98 Page 32 The length of the tubing will be determined by the distance between the two Rod End Bearings. Figure the total length between centers and subtract the head of the end plugs from both ends and the length of the End Bearings from the center of the hole back to the jam nut with three to five threads showing at the top of the bearing. Cut the tube. Debur the ends of the tubing and insert the appropriate CC End Plug. On the tube draw a line 3/8” in from the ends and layout an equally spaced rivet pattern for four (4) rivets. Drill #30 holes. Remove the End Plugs. Debur, zinc chromate and re-install the parts and rivet together using RR-5404 1/8” x 1/4” SS rivet. Figure 1.36.1. Figure 1.36.1 1.37 Metal Working Terms DUCTILITY The ability of a metal to be permanently deformed under tension without fracturing. A good example is wire which is drawn and stretched to dimension through a series of dies. ELASTIC LIMIT The maximum stress that a metal will withstand without permanent deformation. ELONGATION Elongation is a percentage figure determined by measuring the amount of stretch a material test specimen can be pulled after the elastic limit or yield point has been passed until the metal is fractured. FATIGUE 1.0 Standard Methods and Practises 26/06/98 Page 35 Figure 1.40.1 1.41 Aircraft Control Pulley The dash number indicates the size of the pulley according to the table, used in conjunction with Figure 1.41.1. Dash Number Cable Size B +.010 Dia. G H +.0000 -.0005 Dia. J +.000 -.005 -1B 1/16, 5/64, 3/32 1.250 .250 .1900 .297 -2B 1/16, 5/64, 3/32 2.500 .250 .1900 .297 -3B 1/8, 5/32, 3/16 2.000 .422 .2500 .484 -4B 1/8, 5/32, 3/16 3.500 .422 .2500 .484 -5B 3/16, 7/32, 1/4 5.000 .500 .3750 .620 -6B 3/16, 7/32, 1/4 6.000 .500 .3750 .620 -10B 5/16, 3/8, 7/16 10.000 .875 .5000 1.125 -14B 7/16, 1/2 14.500 1.000 .625 1.245 Note: 1B and 3B pulleys shall not be installed on frequently used aircraft controls where a bend in the cable exceeds 15° from a straight line. 1.0 Standard Methods and Practises 26/06/98 Page 36 Figure 1.41.1 1.42 Continuous Hinge (Piano Hinge) This continuous hinge is used in lightly loaded applications such as hinges for control surface tabs and small doors. It is available in either aluminum alloy or corrosion resistant steel material. Corrosion resistant steel is indicated by the letter “C” following the part number. The part is available either as a complete hinge as shown or as a half hinge without the pin. The letter “H” following the part number indicates a requirement for a half hinge. The first dash number indicates the available widths as shown in the table. Length is indicated by the 2nd dash number in inches and hundredths. Figure 1.42.1. Figure 1.42.1 1.0 Standard Methods and Practises 26/06/98 Page 37 1.43 Nut Plates (Floating Anchor Nuts) Nut Plates are used in areas where you need to frequently remove a plate or part for inspection purposes. Installing Nut Plates: To install use the appropriate size bolt to hold the nut in place. If a hole is not already in place, locate the area where you wish the nut, layout and drill a larger hole to accommodate the bolt. With the nut held in place drill #40 holes through the flanges on the nut. Remove the nut and drill the two flange holes out to #30. On your work area drill the two #40 holes out to #30 and countersink (or dimple) to accept a RV-4412 CSK rivet. Debur all parts. Cleco the nut plate on the back side of the work and rivet. Figure 1.43.1. Figure 1.43.1 1.44 Some Final Thoughts... The last page of this section contains instructions for building a work table, if you do not have one. Any table will do as long as it is sufficient in size to build all the components on. The most important and critical thing is to ensure that the table is absolutely flat, containing no twists. Any twist in the table will translate into twisted aircraft sections, which usually results in an aircraft that doesn’t fly straight hands off. When you are reading the instructions, you will see solid and dashed lines in some of the figures. Solid lines refer to the top most layer of material while dashed lines indicate a part or material beneath another. A common request throughout the manual is for you to draw a center line down the flange of parts. This center line is used for lining up the part with a pre-punched hole in another part. This line, drawn with a felt pen, is for reference only and need not be 100% accurate. We have heard many stories of builders spending numerous hours measuring and drawing lines or creating apparatuses to do the same. Such extremes are not necessary. At Murphy Aircraft, we simply hold the felt pen between the thumb and forefinger and use the middle finger as a gauge. By eyeball estimating only, put the tip of the pen in the center of the flange and using the middle finger as a rule, slide the pen along the part, drawing your middle line. In other words, run the pen along with thumb and forefinger resting on the middle finger, which acts as the ruler while drawing the line.