HET-RC F-20 Tigershark Retract Conversion

1 - The F-20 as it comes in the box. 2 - Parts loosely assembled. This model will be retrofitted with Air Retracts. 3 - Larger picture of the F-20 Tigershark. 4 - We begin by measuring CG at 67mm from the leading edge. The leading edge root of the wing is placed perpendicular to the table along with a ruler used to find CG. 5 - A mark is made at 67mm for CG. 6 - With the ruler anchored to the CG mark at the bottom, a smaller ruler is used to keep the large ruler even with the Aileron root on the right. The Aileron root is perpendicular to the fuselage, so it makes a good measurement reference point. 7 - The top and bottom of the ruler is made even using the Aileron edge. 8 - The Ruler is taped in place and a line for CG is drawn. 9 - Southeast Model Products small Air Retracts that will be used. 10 - Top view dimension. 11 - Height dimension. 12 - The covering is trimmed from the bottom of the fuselage. It will be replaced with White covering once assembly is completed. 13 - Covering being removed. 14 - Covering removed from fuselage bottom. 15 - Spar location is marked. 16 - Second spar location marked. 17 - A ruler is used to connect spar location marks on both sides. 18 - Center strip, which was cut 1/8" forward of the spar to spar line. A second line was drawn 2 1/4" forward of the spar line (shown lifted on the left) and the 2 1/4" wide strip of balsa sheet is removed. 19 - Inside of fuselage is exposed. 20 - Paper towel is wadded up to prevent wheel from falling in while measuring. 21 - Paper towel is wadded up to prevent wheel from falling in while measuring. 22 - Wing is placed on fuselage and marked following normal instructions. 23 - Wing area shown marked. 24 - Covering is ironed, removing any wrinkles. 25 - A razor is used to remove the covering where the wing will attach. Cut just inside the line. 26 - Covering shown being removed from fuselage side. 27 - Fresh cut edges are ironed down. 28 - Marker was cleaned off with denatured alcohol and a paper towel. 29 - Area for the retract is cut from the side of the fuselage. 30 - Excess balsa removed from Aileron Servo wire hole in fuselage. It is a good time to enlarge this slot and make sure it aligns with the wing slot so the wires will feed through without binding. 31 - Foam removed from Aileron Servo wire hole in wing. 32 - Wing Initial measurements for Retract. Bare Balsa show the shape how the door will be cut. 33 - Removing the area in the wing. 34 - Initial cut shown and final forward cut must be made at the CG line. 35 - Area cut and ready to remove. 36 - Wing area removed. Note that more foam was removed later, all the way to the CG line shown on the left. 37 - Forward balsa support for the wing spar was removed. This may take a little cutting to remove. 38 - Note that some of the wing sheeting remains to the right of the ruler. This is so the wing spar has top and bottom sheeting to use when being glued in place. 39 - Area cleaned and sanded. Note that the spar side area is 4" deep. 40 - Note the lip / sheeting that still remains at the top...this is used to keep the main spar aligned when gluing the wing to the fuselage. 41 - Aileron Servo Wire run cleaned out with a ruler. 42 - The wheels we used are Hangar-9 Pro-Lite 1 3/4" for the mains and 1 1/2" for the nose wheel. They come with 1/8" shafts, so the next several steps show how to make a bushing to adapt the 3/32 rod to the 1/8" wheel. 43 - Piece of 4-40 rod inserted into brass 1/8" OD tubing to keep it rigid. 44 - Length of brass tubing cut at mark. 45 - End ground flush. 46 - Tubing was placed back on the rod and the rod was cut to the length of tube. 47 - Edge of small piece is beveled for easier insertion. 48 - End is placed into the wheel. 49 - Hammer is used to drive the wheel over the brass tube. 50 - Tube/Rod removed and short piece is now installed in wheel. 51 - Retract and wheel is place in the wing to check for clearances 52 - Forward ply wing spar being marked. Spar Templates will be available and many of these steps show the development process. 53 - Wing being marked at 1mm above bottom per standard instructions. 54 - Spar is epoxied in place and fuselage root area has epoxied applied. Tape shown at bottom is used to align wing during installation. 55 - Epoxy is applied to the Spar area. 56 - Wing installed against the rear tape, then pinned and tape is removed leaving the rear of the wing 1mm from the bottom. There is a slight dihedral in the wing. 57 - Wing shown with clamp holding spar in place while epoxy sets. Clean up excess epoxy with denatured alcohol and paper towels. 58 - Wing glued and you can see the Spar on the left side where it's identified. 59 - The lip that was left in place to assist with Spar alignment is now removed. 60 - Initial cut is shown for the Forward Spar. 61 - Forward Spar fit checked to the fuselage. 62 - Piece cut to extend the Main Spar. 63 - Ply Main Spar extension shown in place. 64 - Ply end cap is cut and initially fit. 65 - Additional rear spar support added. 66 - Pic showing retract area boxed in. 67 - Area to the right will be lowered/shortened so a retract mounting tray can be fit in the location. 68 - Final cuts on spars, shortening them on the right where the retract tray will be installed. 69 - 3/16" x 1/2" piece of balsa was glued underneath the forward sheeting flush to the edge of the forward fuselage sheeting. The Forward Spar will attach to this area. 70 - Ply Retract Tray initially cut. 71 - Final fit of all spars shows recessed area that was lowered for the tray. 72 - 1/4" wide by 3/8" tall spruce supports added to bottom of tray for retract screws to bite into when installed. 3/8" Balsa pieces were fitted forward for support. 73 - Tray is ready to install. 74 - 1/8" balsa plug was installed just under the lip of the forward wing sheeting so the Forward Spar has something of substance to adhere other than foam. Scrap pieces of balsa were used to wedge the piece in place until the epoxy set. 75 - Plug shown installed. 76 - Forward Spar shown with epoxy applied. 77 - Spar is held in place with scrap balsa used to "wedge" it in place. Note the 1/4" balsa square added top right to support the corner and give the retract plate more surface to adhere. 78 - Spars glued in place and ready for the retract tray. Two 1/4" balsa supports added flush to the top of the spars for support. 79 - Dry fit the tray before gluing. 80 - Epoxy is applied to tray and wing area. 81 - Tray installed into wing. 82 - Full view of tray area. 83 - Retract installed and holes marked for screws. 84 - Holes drilled with 1/16" bit. Tape was used on the bit to mark depth so you don't go through the top of the wing. 85 - Screws were run in holes to make threads, then the holes were reinforced with thin CA. 86 - Retract installed with Great Planes #2 x 1/2" Button Head Screws. 87 - Retract is shown installed. 88 - Photo showing gear installed in "Gear Down" position. 89 - Photo showing gear installed in "Gear Up" position, with about 1/8" clearance in the front and back for the tire. 90 - A Retract Cover is made from a 1/32" ply base on the right and covered by a piece of 3/16" balsa shown in the middle. The ply piece is cut to fit around the retract, while the balsa is cut to only expose the moving part. 91 - Ply base for the retract cover put in place this base will allow reset screws to be used for mounting. 92 - Balsa Retract Cover top piece set in place over the ply lower cover. 93 - Balsa and ply plate trial fitted and drilled through retract plate. 94 - 3/16" holes for the entire screw head to sit recessed are drilled in balsa plate only! The ply and balsa are glued together with medium CA, then screws are inserted through the holes into the lower ply plate and the assembly is tightened. 95 - Covering was removed and 100 grit sandpaper was used to properly shape the Retract Cover so it sits flush with the wing. 96 - Retract Cover completed. 97 - Retract Door was made from initial template from 1/32" plywood. Note the grain orientation in this photo and all that follow. 98 - The Retract Door was temporarily set in place, evenly spacing it between the two plywood spars and its location was marked. 99 - Pencil Marks show Door location. 100 - Pieces of 3/16" balsa were cut and fitted to each side of the bay, then glued in place. The top of the balsa is flush with the spar and there is a 3/16" overhang for the door to rest on when closed. 101 - 3/32" balsa was glued along the door line on both sides, then sanded flush to the wing. 102 - Balsa shown fitting flush to the door with a small gap on each side to allow for the covering. 103 - Door shown in place with sanding completed. 104 - A piece of 1/16" Ply with grain shown running top to bottom was cut 3/4" wide and half of it was glued to the door, then shaped to contour. 105 - Back side showing 3/8" overhang on ply plate. CA was added for drilling to prevent splintering. 106 - The piece was laid over its position and the hole was marked , then drilled. The bolt for the landing gear wire is used to hold the door in place. 107 - Hole drilled and CA added. 108 - Retract Door shown installed using the bolt for the wire gear. Note the area to the left on the Retract Cover that was cut out for the door so the retract could lock in place. 109 - Retract extended and locked in place, showing why the area under the door needed to be removed. 110 - A piece of 1/8" ply 1/4" wide was cut, the ends were beveled, then it was set in place as shown. Make sure it is 1/8" above the wheel so it doesn't rub. A pencil marks the gear location. 111 - a second piece of 1/8" ply 1/2" long was beveled and glued to the center. 112 - The ply brace was cut out to clear the landing gear wire. 113 - Brace was then pushed over the wire. 114 - Brace test fit. The ends are beveled to help with alignment, making sure the door closes straight. 115 - A rule is used across the back spar in the fuselage to make sure the wheel is parallel to the fuselage centerline. 116 - CA is added to the brace, then the door is swung in place. IMPORTANT! Note the 1/8" clearance between the brace and the top of the wheel; make sure you space it like this so there is no rubbing. 117 - Retract Door with Brace installed. 118 - Fuselage door cut from 1/32" ply and 3/32" balsa, then laminated. Note that the ply grain is cross while the balsa grain is vertical. Crossing grains like this is important for strength. 119 - A piece of balsa 1/8" thick by 3/8" wide by 1" long is installed with the top recessed and even with the rear ply spar plate. 120 - The Fuselage Door is tack glued in place, then sanded until it is flush with the fuselage. 121 - Door is "popped" out from its tack spot. 122 - Edges of the door are sealed and strengthened with thin CA. 123 - Door is set in place and checked for clearance. Marks are made where the top of the wheel is located. 124 - A piece of 1/16" ply 1/2" wide is glued to the inside ply of the door. The center of the ply is 1/8" to the right of the wheel edge previously measured. 125 - A piece of micro pushrod wire is installed in the fuselage at the second mark (left) which is 1/8" beyond the first marker (top of wheel). Wire holes were drilled 1/16" below the top of the ply spars. 126 - 1/16" thick by 1/4" wide strips of ply were cut and glued in place with the wire running down the center. Note the door has been notched on the right to clear the ply spar when opening. 127 - A 1/32" ply cap was glued to retain the wire on the left. 128 - A hole was drilled and a piece of 2-56 rod was glued in place, protruding about 3/8". Pliers are used to fine tune the wire by bending it until the door closes without binding. 129 - Retract Door Assembly shown fully opened. 130 - Retract Door Assembly closing. 131 - Retract Door Assembly wheel contacts 2-56 rod. 132 - Retract Door Assembly wheel pushes rod downward closing the door. 133 - Retract Door Assembly Fuselage Door and Retract Door closed. 134 - Top view showing clearances and fit with doors closed. 135 - Fuselage Door Stop cut from 1/8" ply. 136 - Wing Door semi closed and Fuselage door is checked for clearance. The inner door (left) was adjusted for around 1/4" clearance to the wheel. 137 - While the inner Fuselage Door is held at the angle, the door stop is installed. 138 - The Wing was covered, as were the doors and retract cover, then the insides were painted with aluminum paint. 139 - Retract Assembly area covered, painted and installed. 140 - Finished Retract area with doors closed. 141 - Upright View of the retract Assembly. 142 - Retract Outside View. 143 - Starting the second wing. Covering is ironed down to remove wrinkles. 144 - Masking tape is stacked to make a block, then positioned so the wing rear top butts against it and the wing rear bottom is positioned 1mm from the bottom of the fuselage. 145 - Fuselage is marked once the wing is in place. 146 - Wing pattern marked on fuselage. 147 - A razor is used to cut inside the drawn line. 148 - Covering is removed so there is a good glue surface. 149 - Once cut, the covering is ironed to seal the edges. 150 - Area shown ready for epoxy. Marker can be cleaned with alcohol . 151 - Front and rear of fuselage are used for alignment to draw on wing. 152 - Dimension lines shown drawn. 153 - Forward line is cut, then the outside line and finally cut on the "Spar Front" line. 154 - A razor or saw can be used to cut through the root spar. 155 - A razor was used to cut the spar at the covering, then a long razor was used to saw through. 156 - Using a razor, carefully remove the balsa block. Be careful not to crack the wing sheeting below; the block is thick and mounted well. 157 - Balsa block removed. 158 - Wing area is cleaned out. 159 - The rest of the balsa block is shaved out. 160 - Wing area is sanded with 100 grit to remove glue, foam and balsa from the block. 161 - Wing prepared and ready to install. Note the wing sheeting on the left that remains to help with spar alignment when glued. 162 - Wing is installed in place and fit is checked before gluing. 163 - Photo shows wing bottom. 164 - Hole in wing for Aileron servo wire was cleaned out. 165 - Hole for Aileron servo wire cleaned out in fuselage and enlarged. 166 - Make sure the hole for the Aileron wire is aligned on both parts. 167 - Epoxy is applied to the Spar Slot and the Wing Spar is installed. 168 - 15 Minute epoxy has been added to the Fuselage area, Spar and Wing. Do not add epoxy to the front of the Spar, but rather only the rear where it contacts the wing. 169 - Wing is installed on Fuselage and a clamp is used to hold the spar in place. Check rear alignment at 1mm and follow the normal installation instructions. Note that there is a slight Dihedral in the wing. Clean up the excess epoxy with denatured alcohol. 170 - Wing shown clamped in place while epoxy sets. 171 - Second Wing installation completed. 172 - Use a razor to cut the sheeting at the "Spar Rear" line. It is best to do this while epoxy is still soft. 173 - A razor saw is used to remove the fuselage area. The cut is flush with the rear former. 174 - Fuselage side removed for wheel clearance. 175 - The second gear wire is bent and cut the same as the first. 176 - Gear wires match and are ready to install. 177 - Patterns previously drawn on 1/8" ply for retract framework from templates. They are cut out and fitted to the retract bay. 178 - Main Spar is notched to clear retract tray. 179 - Piece from Main Spar is removed. 180 - All pieces for the Retract framework are cut and fit. 181 - Main Spar is notched to clear retract tray. 182 - Piece from Main Spar is removed. 183 - All pieces for the Retract framework are cut and fit. 184 - Main Spar is notched to clear retract tray. 185 - Piece from Main Spar is removed. 186 - All pieces for the Retract framework are cut and fit. 187 - Main Spar is notched to clear retract tray. 188 - Piece from Main Spar is removed. 189 - All pieces for the Retract framework are cut and fit. 190 - Main Spar is notched to clear retract tray. 191 - Piece from Main Spar is removed. 192 - All pieces for the Retract framework are cut and fit. 193 - Main Spar is notched to clear retract tray. 194 - Piece from Main Spar is removed. 195 - All pieces for the Retract framework are cut and fit. 196 - Cover is installed in place. 197 - Cover is sanded flush to the wing. 198 - Balsa Cover shaped and completed. 199 - Retract installed to work on gear door next. 200 - Door is cut from pattern from 1/32" ply and top cap is shown and cut from 1/16" ply. 201 - Retract Door set in place and marks made on balsa cover. 202 - Base made for lower door frame from 3/16" balsa. 203 - Piece is set in place. 204 - The door is positioned and drawn on the balsa frame piece. 205 - A mark is made parallel to the side of the piece and then cut to shape along both lines. 206 - Door frame piece is cut and installed. 207 - Frame glued in place. 208 - A piece of 3/32" scrap was placed under the door. 209 - The door was drawn on the balsa. 210 - The balsa upper frame was cut. 211 - Upper frame piece is glued in place. 212 - Rear lower frame made from 3/16" balsa. 213 - Once again, the door is used as a guide to mark the frame. 214 - Lower frame cut and glued in place. Photo shows cap piece of 3/32" balsa to even the door area with the wing sheeting. 215 - Front and Rear Door Frames installed, then sanded flush with the wing sheeting. The edges of the frame pieces are touched with thin CyA to add strength. 216 - A Lower Gear Door Bracket is cut from 1/8" ply. 217 - It is evenly spaced on both sides from the base of the retract. 218 - Gear Wire location marked on the ply bracket. 219 - A 5/8" long piece of 1/8" ply is glued to the top, centered over the marks. Then a slot is cut between the two marks to fit it around the gear. 220 - Ply bracket glued in place one position is checked. 221 - Lower bracket shown installed on gear. 222 - Wheel Door installation completed. 223 - Fuselage door is cut from 1/32" ply and fitted in place. 224 - Top piece of 1/16" balsa is cross-grain laminated to the ply door. 225 - Fuselage Door ledge glued at rear former, even with the top of the Ply Bulkhead, leaving it recessed for door clearance. 226 - Fuselage Door tacked in place to sand. 227 - Door is sanded flush with Fuselage bottom. 228 - Door is flipped over and a 1/16" ply strip is added, then a 1/16" wire is cut, set on top of the first ply strip and sandwiched between two narrower strips of 1/16" thick ply. 229 - A 1/32" piece of ply is made to cap the top of the wire channel. 230 - Marks are made for the 2-56 pushrod that closes the door. 231 - Punch is used and a hole is drilled for the rod. Make sure the 1/16" wire is installed and drill at a slight angle. 232 - Rod is epoxied in place. 233 - A flex drill with a 1/16" bit is used to drill the holes for the door hinge wire. They are drilled 3/32" down from the top of the balsa door ledge on the right. 234 - Wire holes drilled. Take your time and adjust the door height by filing the hole upward or downward as needed for the door to close flush without binding. The excess space can be filled with a toothpick and glue. 235 - Door installed and aligned. 236 - Fuselage Door Stop installed at bottom as shown in photo. 237 - Make sure the Fuselage Gear Door has at least 1/8 - 1/4" clearance for the wheel to clear. 238 - Retract shown closed in up position. check for binding. 239 - A piece of 1/4" x 3/8" maple is used both as a center fuselage brace and door tension wire holder. A 1/16" hole is drilled through the wood. 240 - Hole has a tapered opening carved to ease wire installation. 241 - Hole drilled through top of Maple centered over horizontal hole area. 242 - Door Tension Wire is installed and a 2-56 bolt is cut to length and used to cut threads into the Maple. The threads are then stiffened with thin CA. The music wire is .015 diameter and 7 3/4" long to start, then trimmed at final installation to adjust tension. 243 - The center of the Fuselage is marked. 244 - Epoxy is used to install the Maple support. 245 - 1/4" balsa triangle is added on the rear side to support the balsa sheeting. Make sure you have at least 1/4" clearance between the end of the triangle and the door so the door can open without binding. 246 - Triangle installed and area is ready for sheeting. 247 - Balsa sheeting is rough cut. 248 - The edges are beveled to clear the doors when they open, then they are stiffened with thin CA. 249 - Sheeting is set in place and sanded for a good fit. The doors should not bind when opening. 250 - Sheeting is held in place, then pushed down on the 2-56 bolt area to mark for drilling. 251 - Hole is drilled to clear the bolt. 252 - Balsa sheeting glued in place with CA. Make sure clearance is even on both doors. 253 - Sheeting is sanded flush to the bottom of the fuselage. 254 - Bungee hook block is removed by grabbing with pliers and twisting. 255 - Wing, Retract Cover and Doors were covered with white covering and the wheel bay was painted with silver paint. 256 - Wing Retracts are installed to assist with measuring nose gear height. 257 - Landing gear installed...it has a nice wide stance. 258 - A filler piece of balsa is installed in the door area, then sanded flush and checked for clearance and binding. 259 - Piece of plastic tube from an antenna wire guide cut to 5/8" long and epoxied in place on the door. This will hold the door spring wire. 260 - Side view showing position. The tube was also covered in place. 261 - Fuselage Door installed. 262 - Tension wire being installed in the tube. The wire is made extra long so the tip butts excessively against the firewall. Tension adjustment is made by inserting the wire through the center retainer, then through the tube as shown and continuing until the wire end butts against the former wall. Push the wire from the other side until tension is set, then lock the center screw. Insert the wire through the tube on the second door and butt it's end against the former wall, then it back until tension is set correctly. 263 - Nose Gear Retract Installation: A line is drawn on the Fuselage for reference. 264 - The center from the sides of the Fuselage is marked. 265 - A ruler is used to mark 7 1/2" forward from the previous line. 266 - A line is then drawn across the fuselage. 267 - A center line is drawn down the middle of the fuselage. 268 - The "rear" of the Retract is positioned at the line and its outline drawn. 269 - Initial lines drawn. 270 - Area cut from bottom of fuselage. 271 - Saw used to cut and remove former bottom. 272 - Area ready for retract plate. 274 - I put a bend at the top to re-align the gear shafts.. 275 - Front Wire Gear shown bent to shape. 276 - A plastic button was drilled for the 3/32" wire and installed. 277 - Button is installed and used to space the wheel. 278 - 1 1/2" wheel and Wheel Collar installed. 279 - Top of the wire is marked at 7/8" in length from the spring. 280 - Wire is cut to length. 281 - Wire shown with gear installed. 282 - Plywood Plate cut from 1/8" ply for retract mount. 283 - Centerline was drawn and retract evenly spaced, then holes were drilled and retract was mounted. 284 - Plate shown recessed in fuselage. 285 - Plate had to be slightly tapered to fit the fuselage. Sand until it fits well. Two pieces of 1/2" square balsa are cut as supports for the plate. 286 - Balsa Supports are epoxied to the plate, flush to the outsides. 287 - Holes are re-drilled to clean out excess epoxy. 288 - Plate is temporarily installed with the rear balsa square against the ply cockpit former while the front is butted against the forward former as shown, then lines are drawn for gluing. 289 - Epoxy is applied to the plate, then , with the back part of the plate pressed down flush to the former, you should measure 1 7/16" to the top edge of the fuselage. Make sure the plate is not tilted forward; adjust it evenly at both the front and rear. 290 - Plate is shown glued in place. 291 - A mark is made back 1/4" from the wheel opening. 292 - The strip is cut only 1/16" deep. 293 - Area is chiseled out then replaced with a 1/16" thick piece of ply for extra support. The ply is epoxied in place. 294 - The inside of the cockpit floor is very thin, so it was reinforced with 1/8" balsa strips shown above and below the center spar. 295 - A 1/32" piece of ply is cut 1 1/2" x 1 1/4" as a servo support plate. One side is glazed with thin CA and sanded so the servo tape has a smooth mounting surface. 296 - Epoxy is applied and the 1/16" thick ply brace is installed on the floor of the cockpit area. 297 - The servo plate is installed on the cockpit floor area in the fuselage. 298 - Steering Servo plate shown installed. 299 - Steering servo shown...a HS-81 was used. Be sure to center the servo arm before proceeding. I used a servo tester to center the servo. A ball mount is connected to the outer arm hole. 300 - The top of the gear wire is notched for better retention. 301 - Gear wire is installed with steering arm, then the servo is held in place and a pushrod wire is shown below having been marked for bend. 302 - Wire needed to be ground down a bit in diameter to fit the steering arm hole, then it was bent at the mark. 303 - The Steering Pushrod Assembly shown as completed. 304 - The servo is held in place and adjusted/lowered for alignment as shown. 305 - View of the pushrod connected to the steering arm. 306 - The mounting side of the servo is cleaned with Acetone. 307 - Servo tape is applied to the servo. 308 - Steering Servo is mounted in place. 309 - Forward Retract Landing Gear shown installed. 310 - A 1/8" thick plywood frame is made for the air valve. It is 3/4" square and assembled with epoxy. 311 - A mark is made for the valve mounting hole and the front and rear of the plate are coated with thin CA so the ply will not chip when drilling. 312 - A 1/4" drill is used to make the hole. 313 - The mount is epoxied to a piece of 1/16" thick ply plate that measures 2 1/4" x 1 1/2". 314 - The air valve switch is installed. This is the switch used by Bob Violett as a door switch. You can use other air switches, but will need to make the mount fit your selection. 315 - Air switch temporarily installed. 316 - A HS-56 Karbonite servo is used with the air switch. The servo arm was cut into an "egg" shape, similar to a lobe on a camshaft. It is long enough to completely depress the switch in one position, while allowing the switch to completely open in the other position. With the servo arm this short, the maximum amount of pressure it can produce is applied to the switch button. Also, using a "lobe" like this prevents overstressing of the servo as the arm can not bind. 317 - The mounting side of the servo is cleaned with Acetone. A double thick layer of servo tape was installed in order to bring the center of the servo in line with the center of the switch, from a top view. 318 - Small servo mounting blocks are cut from maple. 319 - The maple blocks are saturated in CA, then drilled and installed on the servo. Note the blocks are high enough to come flush to the bottom of two layers of servo tape. 320 - The top of the ply plate is coated with thin CA, then sanded smooth. 321 - Servo tape is shown being prepared to install. Note that the bottom of the tape is flush with the bottom of the maple mounts. 322 - A dab of epoxy is applied to each maple block, then the servo is carefully positioned so it is just touching the switch, then clamped in place until the epoxy sets. 323 - Photo showing correct position of the servo. The arm is in line with the switch center. 324 - Servo arm lobe and switch shown in the opened position. 325 - Servo arm lobe and switch shown in the closed position. 326 - A 1/32" x 3/8" piece of ply was epoxied in place as shown to add support for the rear door hinges. 327 - Balsa supports were added to this fuselage front. If you cut your door hole to the new length, this will not be needed. 328 - Side supports made from 1/8" Balsa. 329 - Supports cut to proper spacing. 330 - Side support panels glued in place. 331 - Filler pieces cut from 3/16" balsa. 332 - Filler pieces set in place. 333 - Pieces are each glued using epoxy, then their height is adjusted using a 1/32" piece of ply that will be used for the door. They should be made so the door piece is flush to the rear and side. 334 - Inner rear door made from 1/8" balsa and a 1/32" x 3/8" wide piece of ply, which is installed flush to the balsa. 335 - A view of the 1/8" lip that will assist with keeping the door in place during flight. 336 - The inner door is epoxied to the outer door made from 1/32" ply. 337 - Door is beveled on three sides at the balsa. 338 - Door checked for fit. 339 - A 1/32" x 3/8" wide piece of ply is epoxied to the rear for hinge support, then a drill and needle file is used to open up the holes for the hinges. 340 - Rear of the fuselage door support are is removed with a knife and drilled with a 1/8" bit. 341 - Robart hinges are used and shortened to fit the door. 341 - Robart hinges are used and shortened to fit the door. 342 - Hinges installed in place and door closed to check for fit. 343 - Door opened to check for binding. 344 - Retract screws are still accessible for maintenance. 345 - Photo of Rear Door installed with retract down. 346 - Small 1/32" ply strips used as door frame sides and glued in place. 347 - Balsa filler sheeting added to the sides of the door. 348 - 3/32" balsa added to each side so the bottom of the fuselage could be shaped. 349 - Bottom of the fuselage is then sanded and shaped flush. 350 - Rear door area finished and sanding / shaping is completed. 351 - Both doors cut and set in place. 352 - Hinge added to side of wheel door using 1/16" ply and wire. 353 - Channel epoxied in place and ready to trim. 354 - Forward area removed for ply plate. 355 - 1/2" square ply plate is epoxied in place to support the hinge area. 356 - Plate shown installed. 357 - Inner frame being epoxied to door to help stiffen the assembly. 358 - Wheel Door installed showing inner frame and wire hinge. 359 - The bottom of the Fuselage is recovered in white. 360 - The area around the door opening is finished. 361 - Doors are covering and checked for fit. 362 - Tail cone is roughed up with 60 grit sandpaper, then 5 minute epoxy is used to attach it to the tail of the model. 363 - I used the canopy from my other F-20 to mark the cutout lines. 364 - Canopy trimmed so it could be installed and CG checked to see if components could be mounted fore or aft. We wound up mounting the Receiver and U-BEC in the rear of the model as the standard instructions show. CG is very manageable with the this setup. 365 - Heat Shrink is used on the Steering Servo and Retract Servo extensions to insure they will not pull apart. 366 - A 3/16" hole was drilled on the right side for the servo wires. 367 - Servo tape installed on the Retract Servo Assembly. 368 - The Retract Servo Assembly is mounted on the forward left side of the cockpit area. 369 - Retract Servo Assembly in place. Enough room was left (approx 3/4") to the right side so the air switch could be removed for maintenance. 370 - Wires were routed and wires ties were used to keep it clean. 371 - Stainless wire was used to secure the air lines at each cylinder. 372 - The wire was pre-wrapped and placed over each air line prior to installation.. 373 - The Air Line was heated with a Heat Gun to make it slightly soft and easier to install over the cylinder fitting. 374 - Air Line is secured with the stainless wire. 375 - Wires is trimmed to about 1/4" in length. 376 - Air line installed on wing retract cylinder. 377 - Horn Brackets were used to dress up the air line routing. 3/32" -6/32" brackets can be used...I used what I had laying around. 378 - A small screw that came with the servo was used to install the bracket. 379 - A drill bit was then inserted into the hose end to help weight it down and make running it inside the fuselage much easier. 380 - Hose and drill is pulled to the front of the cockpit area from the wing. 381 - A second Bracket was installed to help keep the air line out of the way of the wheel. 382 - Both air lines from the wing have been pulled forward and a 1/4" drill is used to make a hole to pass the lines through. 383 - Air lines for the wing retracts shown routed through the hole. 384 - A small Pressure Tank was used. It is just under 4" in length and out worked well. Photo shows air line installed and ready for installation. 385 - Velcro is attached to the tank so it can be removed later if necessary. 386 - The tank is installed with its rear passing through the rear top former hole and the velcro is fastened to the top inside of the turtle deck area. 387 - The tank line is run forward and pieces of heat shrink are cut to make a harness for the air lines. 388 - The two wing cylinders are connected with the "T" fitting on the left and then to a second "T" that goes to the switch and forward retract cylinder. The tank is connected to a "T" that runs down to the air switch and out to a hose for a fill valve. 389 - Horn brackets are once again used as air line retainers. 390 - The horn bracket is installed.. 391 - Heat shrink is placed over the retract cylinder to hold the line in place. 392 - Air line installed on the front retract cylinder. 393 - Air line run completed. 394 - Fill Valve is installed on the tank line. 395 - The plastic steering rod shown below was not long enough, so the steering bracket would pull off the top of the rod when retracted. A new steering assembly needed to be made. 396 - A spare steering arm was used. 397 - One end of the steering arm was cut off. Make sure you cut it so the lock screw is facing rearward when installed. 398 - Locking bolt is installed in the steering arm. 399 - The arm is trimmed short, right up to the closest hole. 400 - A mark is made to drill a new hole. 401 - A hole is drilled for a 4-40 threaded rod. 402 - A nut is installed on the rod and secured with Loktite. 403 - The nut is tightened until it bottoms on the rod. 404 - The hole that was drilled is tapped with a 4-40 tap set. 405 - The rod is threaded in the steering arm, then a nut is used for spacing and the rod is marked for cutting. 406 - The threaded rod is cut to correct length. 407 - Rod cut and threads cleaned up. 408 - Rod is re-installed in the steering arm. 409 - A nylon lock nut is installed. 410 - The steering rod is installed and ready for trimming to length. 411 - The old steering arm is used to mark it's length on the rod. 412 - A mark is made 1/4" above the first mark. 413 - The wire is cut, then fit and ground until is clears the retract frame. 414 - Retract is shown in the up position. The old rod's mark is still seen and you can see about 3/16" was extended, longer than the old rod. 415 - The old slide bracket could be re-used as it fit the 4-40 rod perfectly. Gear shown in "UP" Position. 416 - Gear shown in "DOWN" position. 417 - View shows servo, control rod and new steering arm. 418 - To mount the front door, the wire should be installed in the front first. 419 - The rear of the door is placed in position. 420 - Pliers are used to work the hinge wire into its hole. 421 - The forward door is shown installed. 422 - A 4-40 button head screw and 3/32" Horn Bracket are used for the door mechanism. 423 - The Screw is installed in order to cut threads in the bracket. 424 - The screw is marked and then cut flush. 425 - Elastic cord is used for a door puller. 426 - The mount is positioned and installed as shown. 427 - A piece of 1/4" x 3/8" maple is drilled on the 1/4" side for the cord. 428 - A knot is tied in the cord and sealed with epoxy, then installed. 429 - The block is epoxied to the inside of the fuselage. 430 - The set screw is used for adjustment so the door completely closes. 431 - A wire retainer is made from 1/4" x 3/8" maple and a piece of plastic antenna tube. 432 - The block is epoxied in place. 433 - A piece of .015 music wire is used for the door spring. 434 - The wire is installed in the tube and holds the door open. 435 - The wire door spring shown from a top view. When open, pressure is applied to the left of center and holds the door open. When closed, pressure is applied to the right of center and springs the door closed. 436 - Photo shows wire end bends for installation and retention in the plastic tube. 437 - Hinges are mounted in the small door so the door can be used to install them in the fuselage. 438 - Hinges are glued in place with epoxy. Be very careful not to get epoxy in the hinge points. 439 - Door is mounted to the hinges to check for fit. 440 - A Horn Bracket will be used to close the small door. The bottom is trimmed off. 441 - Bracket shown cut and ready to install. 442 - Hinge Bracket is installed in door after area cut out. 443 - Door cover panel cut from thin ply and epoxy over the door plate. 444 - A piece of fuel tubing is used to hold the elastic cord for the small door. 445 - The cord is tied to the tubing several times. 446 - A hinge point is mounted to the door bracket. 447 - Hinge point installed. 448 - Heat shrink placed over the elastic knot for the fuel tube. 449 - Door is epoxied to the the hinges and left to set. 450 - Elastic is installed and tension is adjusted, then set screw is tightened. 451 - Retract Installation - Lower Front View. 452 - Retract Installation - Full View of Retracts Down. 453 - Retract Installation - Bottom View Retracts Down. 454 - Retract Installation - Bottom View Retracts up, All Doors Closed. 455 - Retract Installation - Full Bottom View of Retracts Up. 456 - Retract Installation - Right Side Retracts Up. 457 - Retract Installation - Left Side Retracts Up. 458 -Retract Installation - Angled View Retracts Down. 459 - Retract Installation - Head On View Retracts Down.

460 - The HET-RC F-20 Tigershark EDF Jet Retract Conversion

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