AH1”W” COBRA - Approach Engineering
Transcription
AH1”W” COBRA - Approach Engineering
AH1”W” COBRA DESIGNED FOR THE SWIFT 16 APPROACH ENGINEERING WWW.APPROACHENGINEERING.COM APPROACH ENGINEERING 1.0 Purpose To establish a process that ensures control and standardization in the manufacturing of AH-1W Cobra for use with Swift 16 electric mechanics. 2.0 Tools Required Note: (A) denotes tools required for assembly and (T) denotes tools required for testing. Basic Hand Tools (A, T) Sanding block and paper (A) Dremel Tool (A) Epoxy 30 Minute (A) Cyanoacratulate (CA) (A) 3.0 Reference Documents Exploded View Plans for AH-1W Cobra (A, T) 4.0 Attachments 5.0 Introduction 1. WARNING This aircraft is not a toy. It is capable of serious bodily harm and property damage. Every precaution must be taken to properly build this kit and install all radio components. It is your responsibility alone to ensure all safety steps are taken outlined in the Academy of Model Aeronautics safety codes. If this is your first time building a aircraft kit it is highly recommended that you find experienced help for the first flights. Consult your local hobby shop or write to the AMA for further guidance. Academy of Model Aeronautics 5151E. Memorial Drive Muncie, IN 47302 (800) 435-9262 2. Please inspect all parts before building. If any parts are broken or missing please feel free to call or write for replacement. All instruction manual photos are included with the CD along with other scale documentation pictures to ease in finishing. If a step or photo appears unclear to you inspect the CD for additional photos with different views to aid in assembly If you have any questions, comments, or improvements please call or write to: Approach Engineering Ridgecrest, Ca. 93555 www.approachengineering.com 3. We as the kit manufacturer can provide you with assistance and a top quality kit and instruction manual. When built light, straight, and true you will have a model that flies as well as it looks on the ground. However the finished product depends on the quality built into it. We can not guarantee the flight performance. Take your time and read all instructions carefully before and during construction. 4. During the assembly procedure the use of the term CA refers to thin CA glue and CA+ refers to medium viscosity glue. AH-1W COBRA—ELECTRIC Page 2 6.0 FUSELAGE ASSEMBLY 6.1 Locate fuselage side pieces S1, S2 and S3. Glue these together to make a left and right fuselage side. Add triangle stock as shown. 6.2 NOTE: before beginning, read through to step 6.4 and determine which assembly procedure you will use. Punch out the two FB1 side doublers and glue in place, taking care to align the bulkhead slots. On both sides, add the forward ply doublers FPD as shown, notch forward. triangle stock NOTE: alternate procedure listed below in 6.4 6.3 Install and glue bulkheads F3, F4 and F5 onto FB2 and FB3, then glue and insert into a fuselage side, ensuring that all the pieces are aligned and straight. Install the hardwood chassis mount blocks to the inside of bulkheads F4 and F5. Install the second fuselage side. 6.4 An alternate method is to assemble the fuselage center as a box. Fit the F3, F4 and F5 bulkheads to the deck pieces FB2 and FB3. Attach sides FB1, then glue each side to it’s proper fuselage side. Add chassis support blocks before final glue. NOTE: alternate procedure Hardwood blocks Below plywood 6.5 Temporarily position your mechanics in the enclosed Fuselage and mark mounting points on the mechanics mounts. 6.6 Drill holes in the mechanics mounts on the marked positions with a 9/64” drill bit. Press in the four 4-40 blind nuts on the bottom side of the mechanics mounts. This picture is for reference only— some parts are removed for clarity This picture is for reference only—some parts are removed for clarity AH-1W COBRA—ELECTRIC Page 3 6.0 FUSELAGE ASSEMBLY 6.7 Turn the fuselage over and add the 1/4” square corner stock as shown. Epoxy in the forward landing gear support block, and the rear gear doublers making sure that the holes align with the holes in the fuselage sides. Then glue the 1/4” Ply Doublers over that 1/8th inch Ply to strengthen the landing gear supports. Make sure to align the holes. 6.8 Now install 3/32” cross-grain sheeting from bulkhead F3 to bulkhead F4. The sheeting should only cover half of F4, leaving a ledge for the next bottom skin sheet, BS1. gear side doublers 1/8th Inch Ply then Epoxy the 1/4th ply doublers over this. Hatch area- leave open 6.9 Find the belly skin BS1 and hatch. Glue the hatch frame (1/8” Ply , Use 1/8th ply scrap for filler pieces) to the bottom of the hatch, then install the magnet bases on both the frame and the hatch. Fabricate a small catch on the front of the hatch using scrap 3/32” material. Glue BS1 to the bottom of the fuselage. A small UHF antenna will later be added to the hatch to pull it open. 6.10 Begin forming the nose by adding the nose floor sheet, NS1. Wet the nose pieces to make them contour to the shape, while adding bulkheads F1 and F2. The two bulkheads are tied together by the forward brace FBR. Continue with 3/32” sheeting until the nose is complete. NS1 6.11 Glue together the 3 upper nose blocks UNB and 3 lower nose blocks LNB as shown. Glue them to the front of the fuselage as shown. Then glue the TSU shim TUS to the bottom of the upper nose blocks as shown. 6.12 Assemble the four nose chin blocks NCB. Glue together three TSU lower mounts TMT. Glue them to the front side of bulkhead F1. NCB TSU shim AH-1W COBRA—ELECTRIC Page 4 6.0 FUSELAGE ASSEMBLY 6.13 Punch out the two 1/8” light ply vertical fin supports VFS and two tail rotor tube supports (TSR). The rounded edge of the tail rotor tube support faces foreword. Glue the two TSR supports in the mid and lower slots on one side only. 6.14 Assemble the two belt idlers pulleys as shown. The chamfered edge of the pulleys should face inward to help guide the belt. Bearings 2 each TSR Bearings Guide Washers 2 each 6.15 Assemble each pulley idler assembly by first pushing the 1/8” shaft through the bearings. Place one bushing on each side so that the end of the shaft is flush with both sides. Complete for both idlers. NOTE: plastic housing ends must be drilled open to make clearance for the shaft width, otherwise the shafts will be too long to fit into the tail. 6.16 Place the toothed idler assembly in the lower hole and the smooth idler in the upper hole. Take the supplied belt, not the one with your mechanics, and place it between your idlers so that the teeth are facing toward the toothed idler. Glue the other vertical fin support to the tube supports. You may place a small amount of glue on the outside of the bushings to help hold them in place. Note direction of teeth Smooth Idler Tooth Idler 6.17 Punch out the 1/8” ply tail rotor frame base (TFB). Note: the base has a break out tab that will be removed later at the front of the part. Do not cut at this time. Slide the vertical fin supports into the base and glue with CA+. AH-1W COBRA—ELECTRIC Page 5 6.18 Glue on the 1/8” ply side pulley doublers (SPD) to the outside of each pulley assembly by aligning the edges. 6.0 FUSELAGE ASSEMBLY 6.19 Cut out the 1/8” ply trailing edge former (TE-2) and glue 6.20 Pull out the larger diameter, longer, tail rotor tube. Using it into the notches provided on the top of the vertical fin assembly. 30 minute epoxy glue to the vertical frame so that the bottom edge is flush with the bottom surface of the bottom tail rotor tube support and the vertical cuts are at the top of the fin assembly.. Bottom edges line up. 6.21 Cut out three tail rotor tube leading edge supports (TSF) from the 1/8” ply. Using 30 minute epoxy glue to the vertical fin supports and the tail rotor tube. 6.22 TSF 6.23 6.24 Glue the completed assembly into the notches provided in the fuselage side. The telescoping tube fits inside this epoxied tube, with the clamp located at the top. Telescoping tube clamp goes here AH-1W COBRA—ELECTRIC Page 6 6.0 FUSELAGE ASSEMBLY 6.25 Once the nose blocks are sanded to the proper contour, dremel out the bottom of the nose blocks where they meet bulkhead F3. Using the existing oval hole in F3, form an air intake for the battery compartment. 6.27 Find the cheek corner blocks CCB and glue them together into two stacks as shown. Locate and install the cheek cowl blocks CCW, and chin cowl block CWB after taper sanding to the proper Cheek and chin blocks shape. 6.26 Install the balsa canopy retainer side rails CRR. Balsa side rails CRR 6.28 Glue together the TSU blocks and gun turret blocks TUR. Use these assemblies to aid in placing the chin and cowl blocks. Do not glue them into place at this time, wait until after finish and paint, then final assembly of the gun. TSU blocks Corner blocks CCB 6.29 Glue together the tail blocks TBL and fit them into the end of the tail, as shown. tail blocks here AH-1W COBRA—ELECTRIC Page 7 TUR blocks 6.0 FUSELAGE ASSEMBLY 6.31 Before adding the fuselage top and bottom sheeting, install the rudder control nyrod in the fuselage. It must be routed so it is free of binding, and does not contact the belt drive or pulleys. Telescoping tube and clamp 6.32 Using scrap plywood secure the nyrod away from contacting the pulleys. scrap plywood guard for NYROD 6.33 Install the lower fuselage sheeting LFS to enclose the bottom of the fuselage. 6.34 Working from the open top of the fuselage, install nyrod supports as required to position the nyrod so it will terminate in line with your servo arm. 6.35 Before sheeting the top of the fuselage, clip out this forward cross brace on the tail base. This is necessary to provide belt clearance. 6.36 Add the upper fuselage skin UFS. At this point it is advisable to install the tail drive gearbox as well. Add gearbox upper skin AH-1W COBRA—ELECTRIC Page 8 7.0 FUSELAGE ASSEMBLY 7.1 Install a piece of 5/8” triangle stock for the vertical tail leading edge. Make a paper template for the correct shape of the left and right skins. Using the template cut out the sheet stock and glue in place. Wetting the wood makes it bend easier. 7.2 Before proceeding further, adjust the tail housing height to 1 5/8” . This will provide the proper position for setting the belt tension. Telescoping section clamp 1 5/8” 7.3 Canopy frame construction begins by placing the canopy frame lower frames CLF in place on the canopy side skins CSS. Note that the CSS has a small additional piece that goes in front. Also test fit into your fuselage to ensure the proper curvature in the front. Glue the mid and read bulkheads in place as shown. 7.4 Locate the canopy side frames CSF, canopy center rails CTR, canopy top skin CTS, canopy middle bulkhead CMB and canopy rear bulkhead CRB. First glue the two bulkheads to the canopy side skins CSS. . Place the canopy front bulkhead CFB in place and glue the side frames, making sure the bulkhead is lower than the nose so the canopy fits flush. CSS 7.5 Do not glue the rear of the upper frames just yet. They will fit into the doghouse lower frame when it is installed, in a later step. AH-1W COBRA—ELECTRIC Page 9 7.6 Continue the upper fuselage by gluing the transmission lower rails to the trans side skins TSS. 7.0 FUSELAGE ASSEMBLY 7.7 Add transmission housing bulkheads TB1, TB2, TB3 and TB4 to the trans housing skins. 7.8 Assemble the exhaust frame by punching out EXH1, EXH2, EXH3, EXH4, EXH5, EXH6. First place EXH2 and EXH5 between EXH 3 and 4. Then place this assembly on top of EXH1. EXH 6 then goes on top. 6 2 4 3 1 5 angled 7.9 Glue spacer EXH9 to the back of EXH3, then install the two EXH7 and 8 pieces to the back of EXH3. Add block EXH10 to the rear of this assembly, then add 1/4” stock cap to the top edge as shown. 7.10 The lower portion of the housing can be filled with some scrap 1/4” balsa stock and sanded to the contour. Also note that now is a good time to apply wood sealer and primer to the aft portion of the housing, since the exhausts will cover this part making it impossible to seal later. 9 Seal and prime 10 Filler blocks 7.11 Prepare to sheet the engine cowl sides by adding the square basswood stock as shown. 7.12 Assemble the doghouse structure by first placing the trans top skin TTS in place at the aft and. Then place the doghouse base DHB across the trans housing bulkheads. Glue the canopy rails in place to the front of the doghouse base. Add DH1, 2, 3, 4 and 5. Then add the doghouse top DHT. DHT 1 AH-1W COBRA—ELECTRIC Page 10 2 3 4 8.0 FUSELAGE ASSEMBLY 8.1 Make small paper templates and apply the transmission housing sheeting using the supplied balsa sheet stock. Keep in mind that the trans housing will be split in the middle when complete. 8.2 Continue sheeting small sections, wetting the wood to aid in contouring around curves. Split line 8.3 Attach the sheeting on the intakes in sections. Keep the wood wet and it will contour around the corners. 8.4 Sheet the doghouse with the supplied 3/32” sheeting. Once the sheeting is applied, add the doghouse front DHF and rear DHR blocks. Lastly add the doghouse upper caps, DHC. Sand to the appropriate contours. The forward and rear sections of the trans bay may now be separated from each other. Cut here DHC DHF 8.5 Assemble the horizontal tails from the HTL pieces. The light ply tail support blocks TSB are added in their notches, also add a piece of basswood stock to the center to act as a spar. Glue the upper and lower pieces in place, sandwiching the center piece with the spar. Sand to an inverted airfoil shape and install on the left and right sides. AH-1W COBRA—ELECTRIC Page 11 DHR 8.6 Sand to an inverted airfoil shape and install on the left and right sides. 9.0 ENGINE AND TRANSMISSION BAY ASSEMBLY– INTAKE AND EXHAUST 9.1 Punch out the 10 INT intake pieces, and 18 EXH pieces. Assemble the intakes 5 per side, and exhaust 9 per side. Glue in place and sand to shape. 9.2 The intakes, exhausts and the exhaust center frame are glued to the rear transmission housing, and stay attached to it when the rear trans housing is removed. Glue the rare earth magnets into the forward and rear transmission housings and fuselage base. 9.3 The exhaust diffuser assemblies are made from supplied card stock. Using the interior of the exhausts, roll the card stock to conform to the inside of the exhaust, trim to fit so the overlap is only 1/2 inch. Glue with white glue. The diffuser rings DFR are glued to the card stock afterwards. 9.4 The diffusers will extend past the exhaust exactly 1 inch. Allow 1/4” inch extra length so the diffuser can be glued into the exhaust, and still protrude 1 inch. Add the stiffener pieces EXS to the outside edge for proper appearance. 9.5 The tail rotor drive fairing is made of 1/2” square balsa, rounded at the top. A relief hole must be made in the rear of the exhaust frame so that it will sit down over the fairing when installed. 9.6 Assemble the gun by placing the two gun barrel supports AH-1W COBRA—ELECTRIC Page 12 onto the 3 dowel gun barrels. This assembly fits in to the forward slot of the turret. On the bottom of the turret, dremel out a cooling duct that will align with the battery compartment cooling duct made earlier. Finish and detail the gun as desired. 9.0 Wing assemblies 9.7 Locate the 1/4” x 11.5” wing spar dowel. Cut it into two 4” long pieces. This will allow 1/4” spar insertion into the fuselage. Place a sharpie mark at 1/4” from the inside end, this is where WR1 will go. Then punch out wing ribs WR1—WR5. 9.8 WR1—5 have a flat spot to aid in alignment. Using the skin as a guide, space the ribs 7/8” inches apart and glue them to the spar only, with WR1 placed at the previous line. Keep the trailing edges aligned, not the leading edges. Be sure to make one left, and one right side. 9.9 On each wing rib, carefully cut off the alignment tabs at the dotted line, and apply the upper and lower wing skins WSS. Wet the wood to aid in bending. 9.10 Add the triangle stock leading edges, and WNG outer wing armament rack pieces. There are 2 balsa WNGs with a plywood WNG in the middle. Add alignment tabs. tabs 9.11 Sand the wing assemblies to final shape and glue in place after the fuselage is finished. Add armament as desired for a scale appearance. AH-1W COBRA—ELECTRIC Page 13 9.12 Now glue together the four CMM countermeasure pod blocks, glue in place on the tail after the tail is final sanded. 9.0 FUSELAGE ASSEMBLY— VERTICAL TAIL CAP & LANDING GEAR 9.13 Locate vertical tail cap ribs TR1 and TR2. Cut a piece of 9.14 Make a paper template for the two side skins, and using 5/8” triangle stock 1 5/8” in length. Glue the two ribs to the leading edge, and add a piece of scrap 1/4” balsa as a corner gusset for each rib. You can use the tail tube as a guide to keep the ribs aligned. that template cut out two skins out of the supplied sheet stock. Remember to keep the grain vertical so it will contour. 9.15 Wet the two skins with warm water, and shape them to 9.16 The two halves should slide together onto the tail tube. conform to the two ribs. Glue in place, bringing the skins together in the rear. Once the water in the sheets has dried, draw a line on the left and the right and split the pieces in to a front and rear section. Make 2 small screw tabs for installation. Adjust the telescoping tail clamp and trim the lower rib slightly so that the lower rib fits UNDER the clamp. The clamp will then help retain the tail cap. Install 2 small screws to secure it. Sand the trailing edge to match the trailing edge of the vertical tail. 9.17 Lay out the 4 landing gear struts and mark each one 9.18 With the struts in the fuselage, attach the lower gear 1 3/4” from the inside end. This will mark how far to push the struts into the fuselage. Now make another mark 3/8” further inboard from the first mark. This is the cutoff line. Cut the struts off at this line. When inserted into the fuselage, there will be 3/8” epoxy contact inside the fuselage. clamps to the lower strut ends, and insert the skids. Once satisfied with the alignment, epoxy everything in place. Note, you may want to wait to glue the gear into the fuselage until after the fuselage is painted. 3/8” 1 3/4” AH-1W COBRA—ELECTRIC Page 14 clamps 9.0 ENGINE AND TRANSMISSION BAY ASSEMBLY 9.19 Prior to installing the chassis, the top frame inside the rear transmission housing must be removed for clearance. Remove the section marked below. 9.20 Remove the forward plastic tray from your swift. It is not necessary in the chassis. 9.21 There is no need to use a section of tail boom for the belt exit. Allow the belt to simply exit the plastic belt drive housing as shown. 9.22 Cut out a section from the rear portion of the vertical tail 9.23 Trim the canopy for fit on the canopy sill. remove the skin and bulkhead sections in the 3 x 1.5 inch area I indicated in the picture for servo linkage clearance." AH-1W COBRA—ELECTRIC Page 15 cap to allow for the tail rotor bell crank clearance. 18.0 APPENDIX 9.24 The model is ready for final contour sanding and the finish method of your choice. You may apply an elaborate detailed paint scheme, or simply cover it with any of the available colored plastic films. Add armament details as desired. VERTICAL FIN EXPLODED VIEW AH-1W COBRA—ELECTRIC Page 16 18.0 APPENDIX AH-1W COBRA—ELECTRIC Page 17