KADET LT-40 RC67 FUSELAGE CONSTRUCTION

74.

Use a sanding block to very lightly sand the edges of all the die-cut plywood fuselage parts to remove any burrs or rough spots. Hold the sanding block at a 90 angle to the part while doing this. Remember, sand very lightly! You only want to smooth the edges of the parts, not change their size or shape.


75.

Fuselage formers F1, F2, F3, and F6 are laser-cut plywood, and they do not have their part name/number pre-printed on them. Use a pencil to mark each of these formers with their proper name/number. Also mark TOP and FRONT on formers F1, F2, and F3, after making sure that the holes in those three formers are oriented EXACTLY as shown.

76.

The group of four holes located at the bottom center of former F1 are for the mounting of the Nose Gear Bearing. Turn F1 over, and use a hammer to gently tap a 4-40 Blind Nut into each of those four holes from the backside. Tap the Blind Nuts in until the flange is flush against the back surface of F1. Apply a little Medium CA around the flanges of the Blind Nuts to keep them from coming loose. Be careful not to get any glue in the threads of the Blind Nuts.

77.

Trial mount the nylon Nose Gear Bearing to the front of F1 using the four 4-40 x1/2" Mounting Bolts provided. Then remove the Nose Gear Bearing and the four Mounting Bolts and store them away until needed later.




78.

Draw a vertical center line on the front of F1, exactly equal distance from each side. Then set your engine on the front of F1 as shown in the photo, with the crankshaft of the engine directly in line with the vertical center line. Finally, make two pencil marks on F1, one on each side of the engineís crankcase, to indicate where the inside of the two Engine Mounts should be.



79.

Draw a vertical line through both of the pencil marks you made in the previous step. Make sure that both lines are exactly parallel to the vertical center line.


80.

Bolt the Engine Mounts onto the front of F1 as shown, using the four 6-32 x3/4" Mounting Bolts and the four 6-32 Blind Nuts provided.

NOTES:
The holes in F1 for the bolts are oblong, to allow the Engine Mounts to be shifted sideways to accommodate engines with different width crankcases. Thus, we can't just hammer the Blind Nuts in as we did for the Nose Gear Bearing. Instead, first assemble the Mounts, Bolts, and Blind Nuts loosely in place on F1.
Then as you begin to tighten down the Bolts and Blind Nuts for the first time, line up the inner sides of the Mounts with the two lines that you drew in the last step. Continue tightening down the Mounting Bolts until the prongs of the Blind Nuts start to get a grip on the back of F1. Double check that the sides of the Mounts are still lined up with the lines, and then continue tightening the Bolts. Keep tightening the Bolts until the prongs of the Blind Nuts are drawn all the way into the wood, with the flange flush against the back of F1.

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81. Apply a little Medium CA around the flange of the Blind Nuts to keep them from coming loose. Be careful not to get any glue in the threads of the Blind Nuts.

82.

Position your engine on the Engine Mounts, with the front face of the engineís prop washer approximately 4-3/8" away from the front of F1.
Note: This measurement is not critical - 1/8" further forward or back is OK!

83.

View down on the engine from above to make sure that the engine is pointing straight ahead, without any left or right side thrust. Hold the engine in correct position on the Engine Mounts, while you use a pencil to mark the locations of the engineís mounting holes onto the Mounts.
Note: Zero degree side thrust is the ideal! However a slight amount of right thrust would also be OK, but under no circumstances should you have left thrust!




84.

Drill down vertically through the beams of the Engine Mounts, on the pencil marks, with a 1/8" dia. drill bit.




85.

Mount the engine to the Engine Mounts with the four 4-40 x1" Mounting Bolts and the four 4-40 Aircraft Lock Nuts provided. Unbolt the Engine Mounts from former F1, leaving the engine bolted to the Mounts. Set the engine/engine mount combination aside until needed later.

86.

Cover your building board with wax paper, and pin both of the die-cut plywood FS-R (fuselage side rear) pieces down on top of it. Make sure you have them situated as shown in the photo so that you will end up with both a left and a right fuselage side.
NOTE: Itís a good idea to permanently mark the inside surface of the fuselage sides with the words LEFT and RIGHT, as shown, to avoid any chance of confusion.

87.

Glue a die-cut plywood FS-F (fuselage side front) onto the front of each FS-R. Wipe off any excess glue before it dries so that there wonít be any lumps in the glue joint.

88.

Glue a die-cut plywood FD (fuselage doubler) in place on top of each Fuse Side (FS-F/FS-R assembly). Use a slow drying glue, such as Sig Epoxy Glue or Sig-Bond aliphatic resin glue, for this step to allow you plenty of time to accurately position FD before the glue dries.

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NOTES: Study the full-size plan to make sure you know exactly where FD should go before you apply the glue. Notice that there are some places where the edges of FD should be flush with the edges of the Fuselage Side (like the wing, hatch, and nose areas, etc.), and that there are other places where FD is inset 1/8" away from the edge of the Fuselage Side (like the windshield area, and along the entire bottom). Then spread a layer of glue on the bottom side of FD (a small wire, stick, or throw-away brush works best for spreading on the glue). Make sure the entire bottom surface of FD has glue on it! Then lay FD down against the Fuselage Side and slide it into correct position. Press FD down tight against the Fuselage Side and use lots of pins to insure that it stays down tight without any gaps. Wipe off any excess glue that oozes out of the joints before it dries!

89.

You may have already noticed that small "dimples" have been pressed into parts FD and FS-R to indicate where the 5/16" dia. Dowels will go. We arenít going to glue the Dowels in at this time, but it is easiest to drill the holes for the dowels right now, before we continue with the fuselage construction. Locate the dimples on your assembled Left and Right Fuselage Sides - they will be on the doubler side of the Left Fuselage Side and on the outside of the Right Fuselage Side. Drill straight down completely through the fuselage side and doubler, on the dimple marks, with a 5/16" dia. drill bit. Be sure to use a hardwood (2x4 or similar) backing block while drilling, to avoid splintering the edges of the holes.


In the following steps 90 through 97, the fuselage parts will be assembled with rubber bands and tape. Do not glue any parts until told to do so in step 98!


90.

Stack the Left and Right Fuselage Sides on top of each other with the doublers touching. Align all the edges, and then tape the tail ends of the sides together.

91.

Spread the fuselage sides apart at the front and plug former F2 into position, inserting the taps on the sides of F2 into the notches in the doublers. Loop a rubber band over both fuselage sides to hold them together against F2.
CAUTION: Make sure you install F2 with the words TOP and FRONT properly oriented towards the top and front of the airplane.

92.

Plug former F1 in place and loop a rubber band over both fuselage sides to hold them together against F1.





93.


Starting at the rear and working forward, carefully spread the fuselage sides apart just enough to plug formers F6, F5, F4, and F3 in place, one at a time. Use a rubber band at each former location to hold the fuselage sides together against the formers. When finished, remove the tape from the tail end.



NOTE: The tabs on the sides of formers F3, F4, and F5 are oversize and will protrude past the fuselage sides slightly. These will be sanded off after the fuselage has been completely assembled.

At this point your fuselage should look like this, with all the formers installed between the fuselage sides, and the entire assembly being held together with rubber bands only. DO NOT APPLY ANY GLUE TO THE FUSELAGE STRUCTURE YET!

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94. Slide die-cut plywood part FT-R (fuselage top rear) underneath the rubber bands at formers F3, F4, F5, and F6, and work it towards the tail, into final position between the fuselage sides. Lock the tabs on the sides of FT-R into the corresponding notches in the fuselage sides.
NOTE: Be sure to install FT-R with the slot for the rudder pushrod on the left side of the airplane, as shown in the Fuselage Top View on Plan.





95.

Turn the fuselage assembly upside down on the workbench and slip die-cut plywood parts FB-F (fuselage bottom front) and FB-R (fuselage bottom rear) into place. Lock the tabs on the sides of FB-F and FB-R into the corresponding notches in the fuselage sides.

96.

Slip die-cut plywood parts F7 and Tank Floor in their correct locations. Notice that both these parts should sit on shelves provided by the cutouts in doubler FD.


97.

Slip die-cut plywood part F8 in place between the fuselage sides at the tail end of the structure. Use rubber bands and/or tape to hold the fuselage sides together against F8. Make sure the top surface of part F8 is level with, or just slightly below, the edges of the fuselage sides - not above!

Now you will start gluing the fuselage parts together!

98.

Lay the fuselage on its side on the building board, and press down firmly on the fuselage side directly above former F2. This should cause the former and the fuselage sides to lock tightly together in square alignment. Be sure you are pushing straight down - not off to one side, which would cause a twist in the structure. If everything looks good, run a bead of Medium CA along the side of F2 to glue it permanently to the fuselage side. When dry, turn the fuselage over and repeat the process to glue the other side of former F2 to the other fuselage side.


99.

Repeat the process described in the last step to glue formers F1 and F3 to both fuselage sides.

100.

Glue the Tank Floor and part F7 to the fuselage sides. Also glue the front of the Tank Floor to the back of F1.


101.

Set the fuselage upside down on the building board, and double check that part FB-F (fuselage bottom front) is in correct position. Make sure the bottom of FB-F is flush with the fuselage sides, and that the fuselage sides are pulled in tight against the sides of FB-F. Use more rubber bands and/or masking tape if necessary to hold the parts in correct position. Then flow Thin CA into the side joints.

102.

Turn the fuselage over and use Medium CA to glue FB-F to the bottom of formers F1 and F2. When dry, remove all rubber bands and tape from the front of the fuselage, in the area of parts F1, F2, and FB-F.

103.

Glue the die-cut plywood Windshield in place.

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104. Double check to see that the rear of the fuselage structure, the area from former F3 all the way back to the tail end, is in correct alignment. Make sure that the structure is square and that all the parts are tightly held together without any significant gaps between parts. When satisfied with the alignment, permanently glue all of the parts together with Medium CA. Start with small applications of glue in the corners of the formers, constantly checking the fuselage alignment as you go. After youíve got everything tacked glued together in the corners, go back and finish gluing the rest of the joints. Glue FT-R and FB-R to the fuselage sides. Glue formers F3, F4, F5, and F6 to the fuselage sides and to FT-R and FB-R. Glue F8 to the fuselage sides and to the back of former F6. Remove the rubber bands and tape after you have glued all the joints and the glue has dried.

105.

Glue the 3/8"x1"x3-1/2" Grooved Landing Gear Block in place.

106.

Glue the two 1/2"x1"x1" L.G. Anchor Blocks in place inside the fuselage. Glue them securely to the top of the Grooved Landing Gear Block and to the fuselage sides.




107.

Two pieces of 3/8" Balsa Triangle stock are provided to reinforce the firewall-to-fuselage joint. Cut notches in the Balsa Triangles where necessary to clear the blind nuts and pushrod holes, and then glue the Balsa Triangles in place on the back of F1.

108.

Now go back and re-glue every joint in the fuselage with Medium CA! Use enough glue to fill up the joint, plus leave a visible, but small, reinforcing fillet in every joint. Take your time and donít miss any joints! Each and every one of them contributes to the finished strength of the fuselage. Work on small sections at a time to avoid having excess glue running all over the place. Let dry thoroughly.

109.

Carefully block sand the Hatch area to remove any bumps, glue spots, or mismatch between the fuselage sides, the doublers, and the top of F1. Be careful not to sand a curve in the fuselage sides which would cause an unsightly gap when the Hatch is installed.

110.

Locate the die-cut plywood Hatch. Inspect both sides and choose the best looking side for the top. Draw guidelines on the bottom of the Hatch for the location of the Hatch Tongue. The guidelines should be 1/4" in from each side, and 5/8" down from the square end of the Hatch (see Plan Sheet 1). Glue the die-cut plywood Hatch Tongue in place on the bottom of the Hatch.




111.

There is a small dimple near the curved end of the Hatch which indicates the location for the screw that will be used to hold the front of the Hatch on the airplane. Drill completely through the Hatch, on the dimple mark, with a 3/32" dia. drill bit.

112.

Put the Hatch on the fuselage (the Hatch Tongue should slide underneath the front lip of the Windshield). Drill a 1/16" dia. pilot hole into the top of F1, locating the pilot hole right in the middle of the 3/32" hole already in the Hatch. Screw the Hatch down with the #2 x1/2" Sheet Metal Screw and #2 Flat Metal Washer provided.

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113. The fuselage is now ready for final sanding. Use a sanding block with fresh 80 grit paper to sand smooth all the exterior glue joints on the sides, top, and bottom of the fuselage. Sand all protrusions (tabs, glue, etc.) until they are level with the surface. After leveling everything with the 80 grit sanding block, go over the entire fuselage with hand held 220 grit sandpaper.

OPTIONAL: Block sand the main exterior corners of the fuselage slightly round for a more pleasing shape, as shown in the fuselage cross-section drawings on Plan Sheet 1. Do not round the corners in the areas where the wing and stabilizer will be mounted, or in the Hatch area.

114.

Two pieces of Large Dia. Nylon Pushrod Tubing (3/16" O.D. x26-5/8" long) are provided for making the outer sleeves of the Elevator and Rudder Pushrods. Itís easiest to glue these two tubes into the fuselage structure at this time, before the fuselage is covered, even though the radio equipment wonít be installed until later. Study all the views on Plan Sheet 1 to familiarize yourself with the proper location for each pushrod. Then slide the tubes in place.
NOTE: The elevator pushrod tube should go through the right hole in F3 and through the hole in the middle of F6. The rudder pushrod tube should go through the left hole in F3 and through the slot in FT-R just in front of F6.

115.

Notice that the servo end of both pushrod tubes should stick forward about 4-3/4" in front of former F3. When youíve got the tubes properly positioned, glue them permanently to former F3 with Slow CA.

116.

Glue the tail end of the elevator pushrod tube to former F6.

117.

Apply glue liberally (either Slow CA or epoxy) to the rudder pushrod tube where it exits the slot in FT-R. Apply glue from both the outside and inside of the fuselage.

118.

Use a razor saw to cut off the excess rudder pushrod tube as close as you can to the top of the fuselage. Then block sand the tube, and any excess glue, flush with the top.




The basic fuselage construction is now complete! Set the fuselage aside until "COVERING THE KADET LT-40"


STABILIZER AND ELEVATOR

119.

Cut the drawing of the STABILIZER and ELEVATOR loose from the rest of Plan Sheet 2. Tape or pin it on top of your building board. Cover the plan with wax paper.


120.

Locate the 5/16" x 6" x 3" balsa Stab Center Section and pin it in exact position on the plan.

121.

Pin the laser-cut balsa Stab L.E. Joiner in place on the plan, gluing it to the front of the Stab Center Section at the same time.

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122. Three 5/16"x1/2"x36" balsa sticks are provided for making the Leading Edge, Trailing Edge, and End Ribs of the Stabilizer (plus some parts of the Fin). Inspect all three of the sticks to determine which one is the straightest, and use that one to make the Stabilizer Trailing Edge. Cut it to 27" long with a razor saw, and then pin it in place on the plan, gluing it to the back of the Stab Center Section at the same time. (Save the leftover 9" long piece of wood for step 124.)

123.

Use the next straightest 5/16"x1/2"x36" balsa stick to make both Stabilizer Leading Edges. Cut the ends of the Leading Edges at angles matching the exact shapes on the plan. Then pin the Leading Edges in place, gluing them to the front of the Stab L.E. Joiner at the same time. (You should end up with about 6" of wood leftover for step 124.)


124.

Use the 5/16" x 1/2" balsa pieces leftover from the last two steps to make the Stabilizer End Ribs. (Do not cut into the third 5/16"x1/2"x36" long balsa stick for this step - it is for building the Fin later in steps 134, 135, 136, and 138.) Cut the End Ribs carefully to fit snugly between the leading and trailing edges. Then glue and pin them in place.

125.

Two 5/16"x5/16"x36" balsa sticks are provided for making the rest of the parts for the Stabilizer (plus some parts of the Fin). From both sticks, cut the eight 5/16" Sq. Balsa diagonal ribs required for the Stabilizer. (Be sure to save all the leftover wood for building the Fin later in step 137.) Work on one rib at a time. Cut the rib to exact size over the plan, angling the ends to fit well against the leading and trailing edges. Glue and pin the first rib in place before going on to the next one.


126.

Once the glue is dry, unpin the Stabilizer from the plan and re-glue all the joints with additional Medium CA. Use just enough glue to completely fill the joint, plus leave a visible, but small, fillet of glue between the parts. Take your time and donít miss any joints! Each and every one of them contributes to the finished strength of the Stabilizer.

127.

Lay the Stabilizer flat on the building board and lightly block sand the entire structure just enough to smooth out all the glue joints. Do this to both sides of the Stabilizer.
CAUTION: Do not sand so much that you thin down the Stabilizer more than 1/32" under its original 5/16" thickness.







128.

Block sand the tip ends of the leading and trailing edges flush with each End Rib.

129.

Mark a center-line on the front of the Stabilizer Leading Edges. Using the center-line as a guide, carve and sand the front of the Leading Edges to a round shape.
NOTE: Leave the End Ribs and Trailing Edge of the Stabilizer flat and square.

130.

Lay the Stabilizer back on the plan and mark the locations for the Sig Easy Hinges (4 total) on the trailing edge.

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131. Locate the pre-shaped balsa Elevator and mark the hinge locations on its leading edge. Also compare the overall length of the Elevator to the overall length of the Stabilizer. They should already be very close to the same length, if not exactly the same. If they arenít, block sand the ends of the Elevator until it matches the Stabilizer.

132.

Cut slots for the hinges in the Stabilizer and Elevator following the instructions on "INSTALLING SIG EASY HINGES" (perform steps 1 through 5). Then set the Stabilizer and Elevator aside for covering.

FIN AND RUDDER

133.

Cut the rear portion of the Fuselage Side View (the part that includes the Fin and Rudder) loose from Plan Sheet 1. Tape or pin it on top of your building board. Cover the plan with wax paper.

134.

You should have one 5/16"x1/2"x36" balsa stick left for making parts for the Fin. The first part to cut from that stick is the Fin Leading Edge. Use a razor saw to cut the ends of the Leading Edge at the same angles shown on the plan. Notice on the plan that the bottom end of the Fin Leading Edge extends down into the top of the fuselage about 1/4" - be sure to cut to the correct line! Then pin the Leading Edge in place on the plan.

135.

Next cut the 5/16"x1/2" Fin Trailing Edge. Note that the ends of the Trailing Edge should be cut 90į square. Pin the Trailing Edge in place on the plan.

136.

Cut a piece of 5/16"x1/2" balsa for the top of the Fin. Pin it in place on the plan, gluing it to the leading and trailing edges at the same time.


137.

Locate the 5/16" x 5/16" balsa leftover from making the Stabilizer. There should be enough left to make the five pieces of 5/16" Sq. Balsa called for in the Fin. Work on one piece at a time, cutting it to exact shape over the plan, angling the ends to fit well against the adjoining pieces. Glue and pin the pieces in place.

138.

Cut two pieces of 5/16" x 1/2" balsa for the bottom of the Fin. Glue and pin them in place.

139.

Once the glue is dry, unpin the Fin from the plan and re-glue all the joints with additional Medium CA. Use just enough glue to completely fill the joint, plus leave a visible, but small, fillet of glue between the parts. Take your time and donít miss any joints! Each and every one of them contributes to the finished strength of the Fin.

140.

Lay the Fin flat on the building board and lightly block sand the entire structure just enough to smooth out all the glue joints. Do this to both sides of the Fin.
CAUTION: Do not sand so much that you thin down the Fin more than 1/32" under its original 5/16" thickness.

141.

Block sand the top end of the Fin to make the leading and trailing edges flush with the top 5/16" x 1/2" Balsa.


142.

Mark a center-line on the front of the Fin Leading Edge. Using the center-line as a guide, carve and sand the front of the Leading Edge to a round shape.
NOTE: Leave the trailing edge, top end, and bottom of the Fin flat and square.

143.

Lay the Fin back on the plan and mark the locations for the Sig Easy Hinges (2 total) on the trailing edge.

144.

Locate the pre-shaped balsa Rudder and mark the hinge locations on its leading edge. Also compare the overall height of the Rudder to the overall length of the Finís trailing edge. Notice on the plan that the Rudder should be 1/8" shorter in height than the Finís trailing edge. This is to provide a gap between the bottom of the Rudder and the top of the Stabilizer after the model is assembled. Sand the end of the Rudder slightly if necessary to achieve an adequate gap.

145.

Cut slots for the hinges in the Fin and Rudder following the instructions on page 23 "INSTALLING SIG EASY HINGES" (perform steps 1 through 5). Then set the Fin and Rudder aside for covering.