KAVALIER RC39 FUSELAGE CONSTRUCTION

54.

Smooth and even F-IA and F-IB with the sandpaper block. Glue them together with epoxy glue, as shown in the accompanying drawing.

55.

The angled motor mount installation was chosen for the Kavalier to get the fuel tank in the optimum location in the fuselage and at the same time provide for installation of a standard type of muffler at a practical point in relation to the fuselage. Different motors may require different spacing than that shown on the plan.
  1. Layout the center lines and motor mount positions on the front of the F-l firewall assembly, using the F-l drawing on the plan as a guide.
  2. Position the nose gear bearing and drill holes for the 4-40 bolts.
56.
  1. Tack glue the motor mounts to the firewall. Bring the glue up over the mount ends to help hold it. (Double coated masking tape can be used for this purpose.)
  2. Drill through the mounting holes with a long drill bit. (If you do not have a long drill bit, a length of music wire with a notch filed in the end will do the same thing.)

57.

  1. Enlarge the holes just drilled in the back side to take the shank of the 6-32 blind nuts on the mounts and the 4-40 blind nuts for the nose gear bearing.
  2. Tighten the mounting bolts to pull the blind nuts into the wood. Coat them with epoxy glue to hold in place.
  3. Drill a 7/8" hole through the firewall for the tank.




58.

  1. Bolt the spinner backplate to the motor. (This must be done to allow for differences in spinners. For example, the Goldberg spinner used on the prototype Kavalier has a recessed backplate which requires the motor to be farther forward than a spinner without a recess. This is a good thing, giving more clearance behind the motor for fuel lines, and is one reason,,other than the pleasing shape, that we recommend the Goldberg for the Kavalier.)
  2. With 5 minute epoxy, tack glue the engine to the mounts so the back of the spinner is 3-7/8" from the front face of the firewall. (This allows for approximately a 3/32" space between the cowl and spinner.)
  3. Make a transfer punch by sharpening the end of a piece of 1/8" music wire.
  4. Center punch the mounting holes.
The recommended method of engine mounting is to tap the motor mount holes and use socket head bolts to retain the motor. If you do not have a tap, drill holes through the mounts and use bolts, lock washers and nuts.
STOP!
It is best to fit the cowling to the engine-firewall unit at this time, when they are easier to handle. Refer to the Cowling section further on in the instructions.

59.

Sand off the rear ends of the fuselage printed sheets.

60.

Glue FT and FB to the ends of the fuselage printed sheets. Use a ruler to line them up exactly with the stabilizer slot.

61.

Extend the fuselage datum line of the sides onto the FT pieces and over the end, where it can be located later for lining up decoration stripes or checking the incidence and alignment. (Also, do this at the nose.)

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62.

Glue the 1/4" sq. bottom stringer in place on the fuselage side sheets. Soak the front section forward of F-2 of the 1/4" square pieces in water until they are pliable and can be curved to follow the bottom outline.
NOTE: If dowels are used, cut out the holes for them in the sides now, before the ply doubler is glued over the hole markings.



63.

Add the top 1/4" sq. stringers. Note that they start just behind the location of F-3.



64.

  1. 1/4" sq. pieces are also glued above and below the stabilizer slot.
  2. The bottom stringer will not quite reach the end, so splice on a short piece of 1/4" sq. to complete it.
65.
  1. Put in the vertical 1/4" sq. pieces.
  2. Glue FA in place.
66. Mark the locations of Formers F-2 and F-3 on the 1/4" sq. stringer because the doubler will cover up the location lines.

67.

Fit the die-cut plywood doublers FD into place. Sand wherever necessary to make them sit in the proper location. Leave the top black line of the fuselage side visible, don't cover it with the doubler.
CAUTION: Do not glue the plywood doublers on with Sig Bond, Tite Bond, Elmer's, white glue or any other adhesive that has a water base. Water base glue will cause the doublers and sides to curl because of the large area being glued.

68.

Because of the built-in right thrust offset to the firewall, the printed right side of the fuselage nose from F-2 forward to the firewall location is slightly shorter than the printed left side. THIS IS INTENTIONAL. However, the ply doubler FD used on the right side must be shortened accordingly to match the printed right side. Lay the doubler in place and draw a trim line on it, using the guide marks that have been printed on the fuselage sheet.




69.

Trim off the end of the right side doubler. Spread a thin film of epoxy on the doubler with a paddle. You must work very quickly or the glue will start to set up before you are finished. Don't use a large amount of glue, it will add weight to the model. Rub down the plywood doubler thoroughly with a rag and continue doing it until the glue has completely set up. Full cure of 5 minute glue takes several hours or more so it is advisable to weight the doublers down for awhile for best results without any curling or warping.

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Some builders prefer contact cement to install doublers. The main consideration here is to prepare guides beforehand with pins placed so they will steer the doubler onto the exact required spot, for once the glue on each surface makes contact, the doubler cannot be moved. Another aid is to cut a piece of wax paper to cover the glue on the side and slip it out when the doubler is in place.




70.

  1. Use the marks previously transfered to the 1/4" sq. bottom stringer and the other guide marks on the printed sheet to draw guide lines on the doubler to show the positions of F-2 and F-3.
  2. Also mark the fuselage datum line for any future reference required.

71.

Cut the sides out of the sheets and sand the edges smooth. Leave the black line showing completely on the wing saddle and at the front of the fuselage.

72.

Cut slots through the 1/4" bottom stringers for F-2 and F-3.
NOTE: If you have selected Wing Mounting Method 2, do not use parts WP and FP and omit steps 73, 74 and 75.

73.

Cut WP from the 3/16" plywood piece provided and drill 1/4" holes.




74.

  1. Glue FP to Former F-2.
  2. Drill the holes previously put in FP on through Former F-2.






75. Cut short pieces of 1/4" dia. dowel to fit in the holes in F-2 and glue in place.

76.

Glue F-2 on one of the fuselage sides, using 5 minute epoxy and holding in place with a triangle for a guide, until the glue has set up.

77.

Repeat the process with F-3 on the same fuselage side.

78.

Over the top view, join the other fuselage side to F-2 and F-3. Pin and tape the sides in place to hold the parts together until the glue has set.

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79. Epoxy the previously assembled F-1 unit in place on the front of the sides.

80.

  1. Turn the fuselage assembly upside down on the top view plan and pin it in place.
  2. Pull the rear of the sides together and join with a vertical piece of 1/4" sq. balsa.
81.
  1. Add a piece of scrap 3/32" sheet to hold the bottom portion of the sides the same distance apart as the upper portion just joined with the 1/4" sq. vertical piece.
  2. While the sides are pinned down and centered, glue the bottom 1/4" sq. crosspieces between the sides and allow to dry so as to hold the fuselage true when it is unpinned.




82.

Remove the fuselage and install the top cross pieces.

83.

Glue pieces of scrap 3/16"x5/8" strip wood on each side of F-3.

84.

At the end of the fuselage, fill the top in between the sides with a piece cut from the 3/16"x1-1/2"x9" balsa for fin support.




85.

Plank the fuselage top behind F-3, with 3/32" sheet balsa. (NOTE: Photo shows grain of the wood crosswise, held to be stronger in the opinion of some builders, but others like to put the planking on with the grain lengthwise for speed of application and easier comer sanding. Either method is approved for the Kavalier.)

86.

The picture details the fill-in pieces of wood (not shown on the full size plan to avoid the confusion of too many lines) that are inset between the fuselage sides on the bottom. They form the floor in the radio and fuel tank compartments.


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87. The inset pieces in the nose protrude a bit because of the curvature of the bottom. Sand the inset pieces flush with the sides.

88.

Glue the 3/32" plywood piece LGB to the fuselage bottom.

89.

Plank the fuselage bottom on either side of LGB with 3/32" sheet balsa. (The comment above about grain applies here also.)

90.

  1. Glue LGP plywood to the inside of the fuselage, directly opposite LGB on the bottom.
  2. Glue scrap plywood in the corners to brace LGP to the doublers.

91.

Epoxy the wing bolt anchor blocks in place. (If Method 2 wing mounting is chosen, omit the anchor blocks.)

92.

  1. Glue the die cut pieces FW on the interior of the fuselage sides on top of the plywood doubler. Position them slightly below the edge, so that the black line on the fuselage side sheet showing the wing saddle is not covered.
  2. Fit and glue pieces of 3/8" triangular stock balsa in the corners of F-2. They will need to be trimmed slightly to clear WP and not obstruct the tank opening in F-2.


93.
  1. Brace the firewall with pieces of 1/2" triangular stock balsa, epoxied in place. (Seal the holes in covered blind nuts with a piece of tape to keep the glue out.)
  2. Fit F-IC into place, cutting away where necessary to clear the blind nuts, the tank hole, etc. The top edge of F-IC should be flush with the top edge of F-IB.
94. Practice installing the tank to make sure that it can easily be passed from the radio compartment on through the tank cap hole in the firewall. Modify anything that interferes with easy placement and removal of the tank.

95.

Glue scrap blocks on each side of the tank and at the rear end to hold it in position. Don't get the blocks too tight, just enough to keep the tank from rattling around. The tank will need to be removable after the fuselage top is on by pulling on it from the bottom side. Hold the tank in place with temporary scrap crosspieces across the bottom and the back. They can be broken out when necessary to take out the tank. Or, you can stuff paper or foam rubber and the battery under it for support.

STOP! Don't build any farther until steps 102 through 106 are completed.

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96. Install a temporary floor of scrap sheet between the fuselage sides and flush with them, just ahead of F-2 and wide enough to hold gauge G. (Don't glue G to the floor.)

97.

  1. Put a piece of plastic wrap over the front of the wing and mount it on the fuselage.
  2. Bevel the bottom of F-2A to sit on top of F-2
  3. Using the gauge piece G to set the angle, glue F-2A to F-2 with epoxy and allow to set up.
  4. Remove G and the temporary scrap floor.

98.

  1. Install 1/4" sq. stringers in the slots in F-1C and F-2A. The slots in F-2A must be beveled to fit the angle of the stringers.
  2. Bevel.the edges of F-2A to conform to the surface angle of the stnngers.




99.

Soak a piece of 3/32" x 3" sheet balsa in water until it is pliable. Bend it over the nose section and glue in place with Sig-Bond glue.

100.

  1. Trim off the balsa, after it has dried enough to stay in place, along the center of 1/4" top stringer.
  2. Repeat the process on remaining half of the nose.

101.

Sand the fuselage corners round with a sanding block.




Mounting The Wing

This requires the wing to be completed through instruction 53 and the fuselage completed through instruction 93.
Skip 102, 103, and 104 if rubber band wing mounting is used.

102.

Cut a notch in the leading edge of the wing center to accommodate the plywood piece WP, which had previously been made during fuselage construction.
NOTE: WP should fit on the F-2 dowel pins snugly but not so tightly as to bind on and be difficult to remove.

103.

  1. Put a piece of plastic wrap over the dowel pins in F-2. Cut holes in the plastic for the dowels.
  2. Push WP on over the dowel pins. Put a piece of masking tape over the dowel pins to keep glue from running down over them during the next step.
  3. Set the wing in place on the fuselage and epoxy it to WP.

104.

Remove the wing and brace WP to the bottom of the wing with scrap triangular stock.

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105.

Measure carefully the exact spots on the wing to match with the wing bolt anchor blocks in the fuselage. (Remember that the bolts angle forward because of the slope of the top of the wing surface.) Drill through the wing into and through the anchor blocks with a No.7 size drill. Remove the wing and enlarge the holes in the wing only to 1/4" to pass the 1/4-20 nylon wing bolts.



106.

Tap the holes in the anchor blocks with a 1/4-20 tap.



107.

A good seal around the wing seat is necessary to keep oil and fuel seepage out of the radio compartment. Some fliers use foam tape. Our preference is for a permanent seal, formed from Sig Epoxolite.

  1. First, cover the bottom of the wing with plastic wrap, stretched smooth, taped in place, with the end brought up over the trailing edge and taped on top of the wing.
  2. Put a bead of Epoxolite around the fuselage edges with enough on the fuselage opening.
  3. Mount the wing, press in place to squeeze out the bead and tighten down the wing screws or put on rubber bands.
  4. Allow the Epoxolite to set up, but not to fully harden. Remove the wing and trim off the excess before it gets too hard.


Fitting The Canopy

This requires the wing and the fuselage completed through Step 100.

108.

  1. Lay a piece of plastic wrap over the front of the fuselage and mount the wing on top of it.
  2. Bevel the bottom of F-2B to fit against the wing.
  3. Put the canopy in place and check the fit to the wing and to F-2B. Through a combination of trimming down the canopy where appropriate and sanding F-2B, work for a good fit of the canopy to the wing contour and over F-2B. Don't trim the canopy around F-2B too closely at this time, leave the final trim for after it is mounted permanently.
  4. Epoxy F-2B to the front of the wing.
  5. Sand a piece of 3/8" triangular stock to fit snugly against F-2B. Epoxy it in place to brace F-2B.

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109.
  1. Place the canopy on the wing and draw around it with a pencil.
  2. Soak a piece of 1/8" sq. in water until pliable. Glue it in place, slightly inside of the pencil line to allow for the canopy thickness.
  3. When dry, the 1/8" sq. balsa must be carved at appropriate angles around the outside so that the canopy curvature will fit over it.
  4. Glue the canopy to the 1/8" sq. rails with Sig-Ment, used sparingly. It is recommended that the canopy be left off the model until the very last, after covering and painting the wing.

Providing For A Pilot

Materials are not supplied for the optional installation of a pilot figure but picture 109 also shows the modifications to the wing required to have a place to mount him.

The planking should be removed from the center section back to the spar. Leave a little planking on each side near rib W-2 to support the 1/8" sq. canopy rail or put a doubler on the rib. Remove the top part of ribs W-l.
  1. To replace the loss of strength from making the opening, glue a piece of plywood similar to PW to the front faces of the main spars.
  2. Add a floor from balsa or 1/32" plywood.


110.

  1. Make an instrument panel hood from block balsa and epoxy in place over the leading edge. This also adds strength to the opening.
  2. A Williams Bros. 2" scale pilot figure was used in the prototype Kavalier. A block of balsa can be glued to the pilot bottom if he is not sitting high enough.

Fin Assembly

111.

Sand the parts of the fin with a sanding block so that the seams fit together properly.

Three Ways To Glue On A Fin!
Since the invention of epoxy, we've always glued the fin directly to the top of the model without insetting it into a slot or bracing it with triangular fillets. Done properly, this method holds well enough in flight yet will knock off cleanly in a flip during a bad landing (and thus can be easily replaced.) But the joint must have wood-to-wood contact, with holes punched into each surface and using plenty of glue, filling the holes and the joint. We've never had a fin become detached or loose in flight.

However, some modelers don't feel secure with surface gluing, so provision is made on the Kavalier fin printed parts for a large tab that can be left on and inserted into a full depth slot cut into the planking and the fill in wood beneath it for a very solid attachment. This method is shown in the following photos.

Or, for a third alternative, you can cut the tab shorter on the dotted line and only have a slot cut into the planking, with the fill-in wood beneath left solid. This is a compromise between the first two choices. It has more gluing contact than surface mounting yet can still break off cleaner than full depth mounting.

If you are in any doubt about what your choice should be, then we recommend you follow the photo sequence.


112.

Glue the parts together on a sheet of wax paper.

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113. Smooth and level both sides of the fin. In the process, the ink lines will be removed.

114.

  1. Mark a center line on the fin as a guide.
  2. Round the leading edge of the fin.
NOTE: To do the next steps, the fuselage must be completed through at least step 85.

115.

  1. Using the center line mark at F-2 and the center mark on the back of the fuselage, draw a center line for the fin on the fuselage top.
  2. Draw side lines on either side of the center line to mark the fin position.
  3. Cut a slot to accommodate the tab on the bottom of the fin (if you are using the tab.)
NOTE: You may want to cover the fuselage, the fin or both before expoxying the fin on permanently.




Stabilizer

116.

Cut pieces of 1/8"x3/8" strip to size. Pin and glue in place on the stabilizer plan.


117.

Continue by cutting the inner cross-pieces to approximate length.

118.

Finish the pieces to exact fit with the sanding block.
NOTE: The procedure described in the following steps in which both sides of the stabilizer are planked nearly simultaneously, before the glue has dried on the first side, was found to produce a truer and flatter stabilizer.

119.

Pin a strip of 1/16"x3" balsa planking to the stabilizer. Do not wait for it to dry, proceed to the next step.




120.

Cut a piece of planking to fit the remaining area and glue it in place. Do not wait for the glue to dry completely. Let it dry a few minutes to get a grip on the parts, remove the pins and turn it over on the building board.


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121. Repeat on the other side with another strip of 1/16" x 3" wood.

122.

Use a waste piece left over from the top to complete the planking.

123.

After the second waste piece is added, leave the stab pinned down until it is completely dry.




124.

Sand the stabilizer smooth with a sanding block. Round the leading edge in the same manner as the fin was shaped previously. The elevator is hinged to the stabilizer in the same manner as the ailerons.
NOTE: You may want to cover the stabilizer, the fuselage or both before gluing the stab permanently on the fuselage



125.

Fit the stab into the mounting slot in the fuselage. If the slot is too tight, open it up a bit as required, with the sandpaper file. Be sure that the stabilizer is lined up square with the fuselage. Coordinate the fitting of the stab with the fitting of the wing. Remove any stabilizer covering that touches the fuselage in the glue joint so there will be wood-to-wood contact.

Cowling Installation

CAUTION: Don't try to cover the cowl with plastic film. The iron heat will damage the cowl.

126.

To make openings in the cowl for the engine, first drill a series of holes about 1/8" in diameter around the area to be removed. Cut through the bits of plastic between.

127.

  1. Remove the carburetor from the engine during the initial stages and work with the cylinder head hole.
  2. Cut a slit out the back of the cowl from the cylinder head hole to assist removal.
  3. Start the hole undersize and open it up slowly, fitting as you go so it doesn't end up larger than necessary.



128.

The best way to open up the hole is to go around the edges with an "apple-peeling" motion, paring off a small amount of plastic with each stroke.

129.

  1. Cut the hole for the carburetor last.
  2. Round all of the comers.
  3. Put the spinner backplate on during final cutting to check exact cowl position.

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130. After the fuselage construction is completed, the cowl may be mounted.
  1. Epoxy the hardwood cowl blocks to the firewall.
  2. Place the cowling in position and put on the spinner backplate.
  3. Tape the cowl in place and drill small pilot holes into the blocks for the screw locations.
  4. Enlarge the holes in the cowling only to pass the No.2 screws.




Main Landing Gear

A heavy duty 8-32 x 1-1/2" axle bolt is included in the Kavalier, so the axle hole in the aluminum gear must be drilled out. Use a No. 18 or a 11/64" drill.

131.

Hold the aluminum gear in position on the bottom of the fuselage and drill through the plywood landing gear parts LCB and LCP.

132.

  1. Drill out the holes on the inside of the fuselage to accept the shanks of 4-40 blind nuts. This will require a 9/64" drill.
  2. Replace the gear and install the 4-40 x 3/4" bolts and 4-40 blind nuts. Tighten the bolts to pull the points of blind nuts into the wood. Coat the edges of the blind nuts with epoxy glue to hold them securely in place.



Nose Gear

133.

  1. The nose gear is held in the nylon bearing by the steering arm. Angle the arm forward so that when the servo pulls it back for a left turn, the arm will clear the face of the firewall. NOTE: Use the middle hole in the steering arm.
  2. A flexible steel cable pushrod with nylon outer tubing (not furnished) is recommended for the hookup of the nose gear, such as the SIC SH-559 Flexible Cable Pushrod, Run the nylon outer tubing through the firewall at the right spot to connect the inner cable to the nylon steering arm. Epoxy around the tubing at the firewall so that no oil will leak back into the fuselage.
  3. Sweat solder the last 1/2" of cable and file the end to a point so it can easily be inserted in the adapter fitting on the steering arm.
  4. Hold the wheels on the axle with a 5/32" diameter wheel collar (not furnished.) Or you can solder a washer on the end of the axle. Protect the wheel with a shim of light cardboard that can be tom and removed after the soldering operation. "Low Bounce" type wheels are recommended.