FOUR-STAR 60 RC73 FUSELAGE CONSTRUCTION

Fuselage Subassemblies




Before starting the main part of the fuselage construction, there are four subassemblies that should be built. This will avoid interruptions during the flow of the fuselage construction.
NOTE: You need to have the engine that you will be using before proceeding.

20.

  1. Mark the vertical center line and thrust line on the firewall (F1) using the cross section on the plan as a guide.
  2. Mark and sand the bevel on the bottom of the firewall to match the angle shown on the plan.
  3. Check the width of your engine and determine the spacing needed between the motor mounts. Using the lines on the firewall, locate the mounts, mark the location of the four holes on the firewall and drill an 11/64" hole at each mark.
  4. Bolt the engine mounts loosely to the firewall with four 6-32 x 1" bolts and 6-32 blind nuts. Double check the location and spacing of the mounts. Tighten the bolts until the prongs of the blind nuts are started into the wood and holding. Remove the motor mounts from the firewall and seat the blind nuts with a hammer. Spread SIG KWIK-SET epoxy glue over the blind nuts to hold them in place. Be careful not to get any glue in the threads of the blind nuts.

21.

  1. Using the side view of the plans as a guide, position the engine on the mounts so the propeller will clear the fuselage "cheeks" by 1/8" to a 1/4" and mark the engine mounting holes. Keep the engine as far back on the motor mounts as possible.
  2. Remove the motor mounts from the firewall and drill the holes for the engine mounting bolts.
  3. Bolt the engine to the motor mounts, the motor mounts to the firewall and mark the location for the throttle push rod to pass through the firewall. Allow clearance for the throttle pushrod connector included in the hardware package. Drill a 9/64" hole at this mark for the outer housing of the flexible cable.
  4. Remove the engine and motor mounts from the firewall.

22.

Using three 6-32 x1/2" mounting bolts and 6-32 blind nuts, bolt the aluminum gear to the landing gear plate until the prongs of the blind nuts are in the plywood and holding. Remove the gear and seat the blind nuts with a hammer. Spread SIG KWIK-SET epoxy glue over the blind nuts to hold them in place. Be careful not to get any glue in the threads of the blind nuts.




23.

With the 1/4" holes in formers F-2 and F-2D aligned, glue the two formers together.



24.

Glue the laser cut lite-ply tailwheel mount to the aft end of the fuselage bottom rear (FBR).

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Fuselage Construction

25.

  1. Tape the fuselage plans to the work bench and cover with waxed paper.
  2. The fuselage sides are assembled from two laser cut pieces. Align the fuselage front and rear pieces directly over the plan, check the fit of the parts, adjust if necessary and apply MEDIUM CA to the splice joint. Join another set of pieces for the other fuselage side.
  3. Glue the laser cut fuselage doublers to the fuselage sides with THICK CA or KWIK-SET-SET-Set epoxy.
    NOTE: Be sure to make one LEFT side and one RIGHT side.

26.

  1. Assemble all the fuselage formers (F-1 through F-6) into place between the fuselage sides. Put a rubber band around the fuselage at each former location to hold everything together.
  2. Slide the laser-cut lite-ply Fuselage Bottom Rear (FBR) under the rubber bands until it snaps into proper location between the fuselage sides. Do the same thing for the laser cut lite-ply Fuselage Top (FT) and the laser-cut lite-ply Stab Support.
    NOTE: The "Tee-Lock"tabs on the formers, FBR, and FT are made over-sized to protrude past the fuselage sides. These will be sanded off after the fuselage has been completely assembled.




27.

  1. Place the fuselage over the top view on the plans to check the alignment. Even if some of the plywood is badly warped, the interlocking parts are designed to be self-aligning - warps in individual pieces should cancel out. If there are any persistent warps or twists, now is the time to fix it! Once the fuselage is glued, it can't be realigned. Double check that the opening at the back end of the fuselage is square with the fuselage top. If necessary, gently twist or push the parts in the desired direction and use masking tape to hold them there.
    BUILDER'S TIP: To assist in keeping the nose section of the fuselage straight, you can install the laser cut lite-ply tank floor at this time but DO NOT GLUE IT IN PLACE.
  2. Glue all of the parts in place, working .trom the inside of the fuselage first, using MEDIUM CA. Start with small patches of glue in the corners, checking the fuselage alignment as you go. Keep applying glue until the complete inside of the fuselage has been gone over once. Now go back and glue all of the joints on both sides. Leave the rubber bands and tape in place until all of the glue has cured completely.

28.

Locate the laser cut lite-ply headrest (HR) on top of FT and glue HR in place. Use the 29 side of the Dual Tool to get the correct angle between HR and FT.



29.

  1. Position top formers F-4T and F-5T in the correct slots in FT and glue.
  2. Glue the five 1/8"x5/16"x24" balsa fuselage stringers into the fuselage top formers and the headrest. Note that the top stringer and the two bottom stringers sit in notches in F-6, while the two middle stringers butt against the front face of F-6.
  3. When the glue has cured, trim off the front of the stringers flush with the front of HR and the back of F-6. Savaothe scrap stringer material for later use.

30.

  1. Install the landing gear plate to the fuselage by gluing it to the sides, the doublers, and the bottom of F-2. Don't be stingy with the glue - you may find yourself picking up the landing gear as a separate piece after a hard landing.
  2. Glue the fuselage bottom front (FBF) in place using MEDIUM or THICK CA. Be sure to glue the joint between FBF and the landing gear plate from inside the fuselage.

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NOTE: The hole in FBF is provided to serve as an oil drain hole as well as a convenient place to route the vent line from the fuel tank and/or the breather line from the crankcase of a four-stroke engine.

31.

  1. Cut two 1-15/16" pieces from the 3/4" balsa triangle stock to reinforce the landing gear plate fuselage joint. For each piece; bevel the rear edge to match former F-2, notch to clear the blind nuts on the backside of the landing gear plate and glue in place with MEDIUM CA.
  2. Cut two 4-1/2" pieces from the 3/4" balsa triangle stock to reinforce the firewall (F-1). For each piece; bevel the bottom edge to match the fuselage bottom, notch to clear the blind nuts on the back of F-1 and glue in place with MEDIUM CA.
  3. After the glue has cured on all four pieces of triangular stock reglue each piece with THIN CA to insure complete penetration of glue into the joint - loss of the landing gear plate or the firewall is generally a disaster.










32.

  1. Install the tank floor. Make sure it is seated down on the fuselage doublers and is against the firewall before gluing it in place.
  2. Now is a good time to assemble and install the tank. Block the tank in position with pieces of balsa, foam rubber or styrofoam. If the recommended tank size is used (Dubro 12 ounce) the final installation can be completed after the airplane is covered or painted. If you use a tank other than the one recommended, it may not be possible to install the tank later on, so do a complete installation now.
  3. Remove the tank and glue in the nylon tubing for the throttle pushrod. Slide the tank back in position, insert the steel cable throttle pushrod and check for any binding. Correct any problems now as it will be hard to get to this area later on.

33.

  1. Glue the balsa top deck formers T-1, T-2, and T-3 into the correct slots in FT. Note that T-1 is placed in front of and slightly lower than the top of FT.
  2. Bevel the top edge of the fuselage sides with a sanding block to match the formers to provide a firm seat for the fuselage top deck. Notice that the angle between the top deck and the fuselage sides varies along the entire length. Use the top deck formers as a guide to the sanding angle. Don't worry about perfection - a few swipes with a sanding block on each side should do the trick.
  3. Tape the laser cut balsa top deck in place. You should apply some warm water to the upper surface of the top deck to make it easier to bend into shape and to prevent it from cracking. Apply MEDIUM CA to the top deck from the inside as much as possible. When the CA has cured, remove the tape.

34.

  1. The two 3/4"x3/4"x1-1/2" basswood wing hold-down blocks key into the pre-cut notches in the fuselage doublers. Temporarily tape the wing in place on the fuselage and check the fit of the blocks by working though the lightening holes in the rear of the fuselage. The blocks should seat firmly against both the fuselage side and the top surface of the wing.
  2. When satisfied with the fit of the wing hold-down blocks glue the blocks in the fuselage with medium CA.
  3. Cut two 1-3/8" lengths of 3/4" balsa triangle stock for reinforcements for the wing-hold down blocks. Bevel the back edge to match former F-3 and glue the triangle reinforcements to the top of the hold-down blocks, the fuselage doublers and fuselage former.
  4. Reglue all of the wing hold-down blocks and reinforcements with THIN CA. It's really embarrassing to have the wing fly off in an outside loop.

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35.
  1. Locate the two .270 o. d. x 36" nylon outer push rod tubes (black). Roughen the last 4" on both ends of each outer tube with sandpaper to aid glue adhesion.
  2. Slide the outer push rod tubes forward through the pushrod exit slots in the fuselage sides and the holes in the formers. Continue sliding the tubes forward as far as you can, they will be cut to length later.
  3. Apply CA to the outer tubes at the pushrod exit slots - from both the inside and the outside of the fuselage. With either glue or glue and filler fill the area around the tube where it exits the fuselage. Now glue the tube to each former front and rear.
  4. Use a single-edge razor blade to rough trim the outer push rod tubing flush with the outside surface of the fuselage. Sand the pushrods flush with the sides of the fuselage.

36.

Check the fuselage for joints that could use another application of glue. Fill any gaps at the Tee-Lock tabs and slots with MEDIUM CA. The fuselage should now be ready for final sanding. With 80 grit sandpaper and a block, sand the tee-lock tabs flush with the fuselage sides and round the bottom edges of the fuselage and the corners of the balsa top deck. Switch to 220 or 360 grit for the final sanding.


Mounting The Wing To The Fuselage

NOTE: You must have a completed wing before proceeding.

37.

  1. Careful alignment is particularly important, so take your time and be very accurate when making alignment marks and taking measurements. Measure the span of the wing and mark the center of the leading and trailing edge of the bottom of the wing. I know, you built both wings identical, but you'd be surprised how often one wing turns out to be just a 'little bit' longer than the other. Measure and mark the center of the fuselage at the front and rear of the wing saddle.
  2. Place the wing on the fuselage and check the fit. If everything was properly built the wing should fit into the opening without any gaps. If the wing does not fit properly, now is the time to sand off any bumps or fill any hollows to match the contour of the wing. DO NOT CHANGE THE INCIDENCE OF THE WING.
  3. Tape the wing to the fuselage and take measurements from the wing tip to the tail of the fuselage. Both measurements should be the same. If not, rotate the wing, keeping the leading edge in place, until both measurements are identical. Remark the trailing edge to reflect the correct position. Remove the wing from the fuselage.


38.

  1. Locate the two 1/4" diameter x 1-3/4" wing dowels and sharpen one end of each to a point, keep the point symmetrical and centered. Push the dowels into the holes in F-2 so that only the points remain sticking out into the wing opening. Slide the wing into position, making sure it is centered on and square to the fuselage. When you remove the wing, there should be two small indentations in the leading edge.
  2. Drill 1/8" holes through the leading edge at the indentations. Enlarge the holes to 1/4". Extend the 1/4" hole completely through the dowel support block. It is important to keep the drill aligned with the wing center line.
  3. Remove the wing dowels from F-2. Put a piece of wax paper over the face of F-2 and reinsert the dowels, forcing them though the wax paper. Push the dowels in only 3/8", leaving most of their length exposed.
  4. Trial fit the wing in position, sliding it onto the dowels. Check to see that the wing seats properly on the fuselage. If not, slowly enlarge the holes in the leading edge of the wing until it does seat properly.

39.

When satisfied with the fit of the wing and wind dowels, coat the inside of the holes in the leading edge with epoxy. Slide the wing back into position on the dowels. Hold the wing in place until dry, then remove the wing and fill any gaps around the dowels with another application of glue.

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40.
  1. Fit the wing in place on the fuselage and check its alignment one last time. When you are satisfied that the wing is aligned correctly, tape it so that it can't move.
  2. Drill #7 (or 13/64") holes through the wing using the laser cut holes in the wing hold-down plate as a guide. Keep the drill perpendicular to the bottom surface of the wing so the heads of the nylon bolts will seat flush against the plywood plates.
  3. Remove the wing and apply a few drops of THIN CA to the holes. When the CA has cured, tap the wing hold-down blocks with a 1/4-20 tap. Apply a few drops of THIN CA to the holes to strengthen the threads. After the CA has cured, clean up the threads by re-tapping the holes.
  4. Enlarge the holes in the wing to 1/4"to pass the nylon wing bolts.

Stabilizer And Elevator

41.

  1. Tape the stabilizer plan to the building board, and cover it with waxed paper.
  2. Glue and pin down the 1/4" laser cut balsa pieces (S-1, S-2, S3, and S-4) over the plans.
  3. Cut the six 1/4" x 3/8" balsa ribs and glue in place with THIN CA.
  4. When the glue has cured remove the frame from the building board and fill any gaps in the stabilizer frame with MEDIUM CA.

42.

  1. The stabilizer is sheeted on both sides with 1/16" x 3" x 36" balsa. Assemble the balsa sheets per the diagram on a piece of waxed paper with THIN CA to make two stabilizer skins. If the waxed paper is sprayed with accelerator before gluing the skins the CA will not wick between the waxed paper and the balsa skins. The remaining balsa sheets will be used for the fin skins.
  2. Separate the skins from the waxed paper and sand the joints smooth BEFORE attaching them to the stabilizer. Sanding the skins after attaching them to the framework will result in a "ripple effect".

43.

  1. Sand the top and bottom of the stabilizer frame to smooth out the glue joints. Also sand the ends of the leading and trailing edges.
  2. Apply THICK CA or SIG-BOND to one side of the stabilizer frame, place it over the stabilizer skin, press in place and immediately pin the assembly down to the building board to keep it flat while the glue cures.
  3. Repeat for the opposite skin and allow the glue to cure.
  4. Sand the sheets flush with the stabilizer frame all around. Round the leading edges with a sanding block and sand a small flat spot at the center "point" of the stabilizer so that it will seat correctly against former F-6.

44.

  1. Locate the two pre-cut 3/8" balsa elevators and sand the trailing edges round. Sand two 30 bevels on the leading edge of the elevators with a sanding block. A pencil line drawn down the center of the elevators will help keep the bevel symmetrical.
  2. Use the plans to mark the elevators for the position of the 1/8" diameter music wire elevator jointer. Drill and groove the leading edges to accept the elevator jointer. Sand the jointer wire and wipe it clean before gluing it to the elevators with KWIK-SET Epoxy. Keep the leading edges of both elevators aligned as the glue cures.
  3. Wrap two short pieces of 2" glass tape over the 1/8" jointer wire and glue in place with THIN CA.
  4. Temporarily tape the elevators to the back of the stabilizer. Use a sanding block to match the ends of the elevators to the stabilizer.



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Fin And Rudder

45.

  1. Tape the fin plan to the building board, and cover it with waxed paper.
  2. Glue and pin down the 1/4" laser cut balsa pieces (FN-1, FN2, FN-3, and FN-4) over the plans.
  3. Cut the two 1/4" X 3/8" balsa ribs and glue in place with THIN CA.
  4. Glue the 1/4" x 5/8" fin trailing edge to the fin frame.
  5. When the glue has cured remove the frame from the building board and fill any gaps in the fin frame with MEDIUM CA.

46.

  1. The fin is sheeted on both sides with 1/16" x 3" x 10-1/2" balsa left over from sheeting the stabilizer. Assemble the balsa sheets per the diagram on a piece of waxed paper with THIN CA to make two fin skins. If the waxed paper is sprayed with accelerator before gluing the skins, the CA will not wick between the waxed paper and the balsa skins.
  2. Separate the skins from the waxed paper and sand the joints smooth BEFORE attaching them to the fin frame. Sanding the skins after attaching them to the framework will result in a "ripple effect".

47.

  1. Sand both sides the fin frame to smooth out the glue joints. Also sand the ends of the leading and trailing edges.
  2. Apply THICK CA or SIG-BOND to one side of the fin frame, place it over the fin skin, press in place and immediately pin the assembly down to the building board to keep it flat while the glue cures.
  3. Repeat for the opposite skin and allow the glue to cure.
  4. Sand the sheets flush with the fin frame all around. Round the leading edge with a sanding block.




48.

  1. Temporarily pin or tape the stabilizer to the fuselage. Trial fit the fin in the fuselage and on top of the stabilizer. It may be necessary to trim the length of the fin trailing edge to allow the base of the fin to set on top of the stabilizer. Leave the fin in place until after the tailwheel has been fitted.
  2. Round off the trailing edge and the bottom of the laser-cut 3/8" balsa rudder. Sand two 300 bevels on the leading edge of the rudder with a sanding block. A pencil line drawn down the center of the rudder will help keep the bevel symmetrical.
  3. Cut a slot in the bottom of the rudder to accept the tailwheel wire.

49.

  1. Align the bottom edge of rudder with the fuselage bottom and tape in place.
  2. Trial fit the tailwheel assembly. Adjust the bends in the wire and the slot in the bottom of the rudder as necessary until the nylon tailwheel bracket seats properly on the fuselage bottom and the tailwheel wire is aligned with the rudder; i.e., flat in the slot and in line with the rudder.
  3. When satisfied with the fit of the tailwheel assembly remove it from the fuselage and rudder. Prepare the washers and wire for soldering.

BUILDER'S TIP:
#2 flat washers are included in the kit to act as retainers for the tailwheel and as a support to transfer the loads from the tailwheel wire to the tailwheel bracket. You can use 3/32 "wheel collars (not included), but the soldered washers give a more "finished" look and are more reliable.

The secret to successful soldering is cleanliness. Sand the washers and the wire where the washers are to be soldered and then wipe everything clean with alcohol before attempting to solder the washers to the wire.

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50.
  1. Solder the tailwheel wire support washer in place first. This washer transfers the load on the tailwheel wire to the bracket without splitting the bracket. If the wire is clamped upside down in a vise the washer will lay in the correct position. Before soldering the washer check the spacing between the bracket and the wire. The wire should protrude 1/8" below the bracket to lay flush in the groove in the rudder. Place a thin cardstock spacer between the wire and the bracket to minimize the heat transfer during soldering. Solder the washer with a minimum of heat to avoid damaging the tailwheel bracket.
  2. To hold the inner tailwheel washer in place for soldering slide a small, short piece of silicon fuel tube over the wire. Solder the #2 washer close to the bend in the wire to keep the wheel centered and free turning.
  3. When the wire has cooled, place the tailwheel on the wire, place a thin cardstock spacer on the wire, place the outer washer on the wire and solder the washer in place. Wash all the flux off the wire and washers with alcohol and/or hot water to keep everything from rusting together.
  4. Sand and wipe clean the top of the tailwheel wire and glue it in the bottom of the rudder with SIG KWIK-SET epoxy. Tape the nylon tailwheel bracket to the fuselage to maintain alignment until the glue cures.
  5. Allow the epoxy to cure, then reinforce the tailwheel area with a 2-1/2" long piece of 2" wide fiberglass tape applied with SIG KWIKSET epoxy. When the glue has cured, remove the rudder along with the entire tailwheel assembly from the fin and fuselage.
NOTE: The tailwheel bracket will be attached to the fuselage during final assembly.

51.

  1. The balsa tail fairing blocks can now be glued to the fuselage using the stabilizer and the fin to position them accurately. Cut two 3" lengths of 1/2" balsa triangle stock to serve as tail fairing blocks. Make sure your fin is centered on the fuselage (as viewed from above), then carefully glue the fairing blocks to the back of F-6 (not the tail surfaces). Gently slide the fin and stabilizer off the fuselage and apply a second coat of glue to the front of the fairing blocks.
  2. Temporary scrap spacers are used to support the fairing blocks during shaping. Spot glue a 3/8"x3/4"x2" balsa spacer (not included) to the stab support centered under the fairing blocks. Glue a scrap piece of 3/16"x3/8" balsa (not included) to the top of the spacer between the fairing blocks. Finally, spot glue the fairing blocks to the spacers.
  3. Carve and sand the fairing blocks to blend in smoothly with F6 and the fuselage stringers. Use a sanding block with one end wrapped with paper to protect the stringers from the sandpaper. Leave the spacers in place until the fuselage is covered. This will help prevent damage to the fairing blocks.




FINISHING AND FLYING

General Covering Instructions

We recommend that you cover the wing, fuselage, tail surfaces, and control surfaces individually before hinging and final assembly. The individual parts are much easier to handle and will suffer far less hanger rash.

The Four-Star 60 prototypes were covered with SIG SUPERCOAT iron-on plastic film. SIG SUPERCOAT is ideal for sport models because it's lightweight and easy to apply.

The following instructions provide advice and procedures specific to covering the Four-Star 60 with either SIG SUPERCOAT or SIG KOVERALL. If another brand of covering material is selected, be sure to read the manufacturer's directions and follow them carefully.

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Surface Preparation

A good covering job starts with good surface preparation. Regardless of what type of covering you choose, it won't hide poor workmanship. Fill any small surface gaps or dents with a lightweight filler or spackling paste. Sand every piece of the model; first with 220-grit sandpaper, then again with 360 or 400-grit sandpaper.

The engine compartment and the cockpit require preparation before general covering is started. Since it's too difficult to apply covering material to the engine compartment, it must be fuel-proofed with several coats of clear dope or two coats of polyester resin, sanding between coats. Finish off the engine area with a few coats of colored SIG SUPERCOAT Dope. Most of the SUPERCOAT plastic iron-on films have a matching SIG SUPERCOAT Dope color.

Covering With Sig Supercoat Iron-On Plastic Film

You will need at least three rolls of SUPERCOAT to cover the Four-Star 60. If a multi-colored finish is wanted, more than three rolls of SUPERCOAT may be needed.

Covering The Wing

Begin the wing by covering the wingtips and plywood hold-down plates. On the wingtips, run the covering material "around the corner" 3/16" to 1/4". Later, when the main top and bottom covering pieces are applied, there will be an overlap that is easily trimmed and will leave a nearly invisible seam. Extend the covering material 3/16" to 1/4" past the outside edges of the hold-down plates to provide an area for overlap and sealing.

Cover the main portion of the wing in four pieces, starting with the bottom. Trim the covering off at the top of the leading and trailing edges. Cover the top of the wing last so all of the seams will be on the bottom or back edges. The top covering should overlap the full width of the leading edge and the vertical section of the trailing edge.
BUILDER'S TIP:

When trimming material at overlaps be especially careful not to cut through the layer of covering underneath. Laying a small strip of plastic or cardstock under the trim line makes it much easier to trim and eliminates the worry of cutting the covering underneath.
Wait until both the top and bottom pieces of covering material have been sealed completely around their edges before shrinking the large open areas between the ribs. Alternate between the top and the bottom surface to avoid uneven shrinking which could cause a warp. Keep the heat gun moving at all times as it's possible to burn a hole in the covering. If the covering material starts to "balloon up", put a small pin hole in the bottom of each rib bay to allow the expanding air to escape.

After all of the covering is tight, bond the covering material to all of the spars and ribs by going over them with the sealing iron. This will maximize the torsional stiffness of the wing.

Cut an "X" pattern at the hatch opening on the bottom of each wing panel and iron the overhanging material to the spars and hatch rails. Trim off the excess after all edges are sealed. Don't forget to cover the plywood hatches - for a neat looking job, wrap the covering around the edges of the hatches 3/16" to 1/4".

Covering The Fuselage

The fuselage should be covered with six pieces in the order described below:
  • Fuselage Bottom - 2 pieces, front and rear
  • Fuselage Top - 2 pieces, top deck and stringers
  • Fuselage Sides - 2 pieces, left and right
All seams should overlap 3/16" to 1/4". When covering solid wood surfaces like the front of the fuselage sides, better results can be obtained by starting at the center and working toward the outer edges. This avoids trapping air under the covering.

The trickiest part of covering the fuselage is the stringer area behind the cockpit. Cut a piece of covering wide enough to go completely over the top of the fuselage and long enough to overlap the headrest and the tail fairing blocks. Start by applying one edge of the covering to one of the fuselage sides, overlapping 3/16" to 1/4" onto the sides. Drape the material to the other fuselage side, pull tight, seal the covering to the side and trim off the excess leaving 3/16" to 1/4" overlap.

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Go back over the side seams with the iron and then seal the covering to HR at the front as well as F-6 and the tail fairing blocks at the rear. Trim away the excess covering at the rear flush with the edges of the fairing blocks and F-6. At the front, leave a 1/8" overhang to the front of HR. Fold the overhang to the front of HR and seal down. Use a heat gun or iron to shrink the material tight over the stringers.Think about covering or painting the headrest (HR) and the cockpit floor with another color like grey or black, to set off the cockpit area.

Covering The Tail Surfaces And Ailerons

The stabilizer, elevator, fin, rudder, and ailerons should each be covered with two pieces of material - bottom first, then top. Iron the material from the center out to avoid trapping air bubbles. Be sure to cover the back edge of the fin trailing edge all the way to the bottom.

Covering With Sig Koverall And Dope

KOVERALL is a polyester-based heat-shrinkable, synthetic fabric much like the covering used on full-scale aircraft, only lighter. Its toughness and relatively low cost make it ideally suited for sport models or giant scale aircraft. One large package of KOVERALL (48" x 5 yards) is plenty of material to cover most models. It can be applied to the structure using dope or SIG Stix-it, a heat-activated adhesive.

Surface Preparation

Whichever application method is used, you should first brush two coats of clear dope onto the framework wherever the covering material makes contact - even the edges of the wing ribs. If dope is going to be used for the entire finish, apply SIG LITE-COAT (low-shrink butyrate dope) for the first two coats. If enamels or epoxy colors are going to be used, apply SIG NITRATE dope for the first two coats. Lightly sand after each coat to remove any raised grain or fuzz.

Applying Koverall With Dope

The bottom of the wing panel is a good place to start covering. Cut a piece of material about an inch larger all around the panel, with the grain running spanwise. The grain of KOVERALL runs parallel to the finished edge. Lay the KOVERALL on the wing, pulling out any major wrinkles. KOVERALL has considerable shrink when heated, so there's no need to worry about packaging fold creases because they will disappear when the KOVERALL is shrunk. Pull the KOVERALL snug across the root of the wing and brush clear dope along the tight edge. The dope will soak through the fabric, adhere to the dope already on the framework and lock the fabric in place. When the dope has 'set' move to the wingtip and snug up the fabric spanwise and chordwise and brush clear dope through the fabric. Repeat the tensioning, doping sequence all around the rest of the wing. Allow the dope to dry before trimming off the excess material with a sharp razor blade. Check for any rough edges or places that are not stuck down properly and apply more dope. Let the dope dry thoroughly before applying the next piece of fabric. This process continues until all the parts are covered.
Any parts that are going to be glued in place at a later time should have the glue areas masked off to preserve the bare wood and enhance the adhesive properties of the glue.

Applying Koverall With Stix-It

Directions for using STIX-IT are on the can. The basic procedure is to apply STIX-IT around the edges of the framework where you want the covering to attach. When dry, the fabric can be ironed-on around the edges where the STIX-IT was applied.

Shrinking And Sealing Koverall

After both sides of a surface are covered, shrink the KOVERALL evenly with an iron or heat gun. It is possible to 'burn' KOVERALL with too much heat, yet not show any damage. Heat the KOVERALL only enough to get the tautness needed. It is possible to badly warp lighter structures because of the high level of shrink obtainable.

The fabric is now ready to be sealed with clear dope. The dope that you apply to the top of the fabric will soak through and bond with the dope underneath, firmly cementing the KOVERALL in place.

Thin the dope until it brushes on easily and flows out smooth (25% to 30% thinner.) The first coat should be applied sparingly to avoid puddles underneath the fabric. The second coat will seal most of the pores of the KOVERALL, from then on running through will not be a problem. Sand the edges of the KOVERALL very lightly with fine sandpaper after the second coat is dry. It may take three to five coats of clear dope on the KOVERALL before going to color, depending on how heavy the coats are. The type or quality of finish desired will determine when enough clear dope has been applied. Keep in mind that weight can build up fast when painting! Generally, don't bother trying to completely fill the weave and avoid using heavy sanding sealer or primers. The goal is to hide the seams and provide an even base for the color paint.

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Finishing With Supercoat Dope

Complete assembly of the model before applying the color coats to the model. The best results can usually be obtained by applying the color coats of dope with spray equipment. Thin the dope for spraying by mixing in an equal amount of SIG SUPERCOAT DOPE THINNER or SIG RETARDER. Apply two, or three coats, starting with the lighter color, followed by the darker trim colors. Mask off the trim scheme with low-tack drafting tape or 3M automotive striping tape. Seal the edges of the tape with clear dope (applied with a small brush) before applying the trim colors. A final coat or two of clear dope over the color coats will add a nice gloss to a finish that is rugged and easy to repair.

Applying The Decals

The supplied decals can be used over any type of finish as long as the surface is clean. If needed, replacement decals are available from SIG (order SIGDKM273A, SIGDKM273B, and SIGDKM273C).

Cut out the decals with sharp scissors, leaving about 1/32" to 1/16" of clear at all edges, rounding the corners as you cut. Wet the surface on which the decal will be placed with soapy water. Place the decal on the model and squeegee the water from underneath the decal with a balsa paddle. This procedure allows time for repositioning and prevents air from being trapped under the decal. Allow several hours to dry.

Installing Easy Hinges

52.

  1. With a No. 11 X-Acto blade, cuts slots approximately 1/2" in depth and slightly wider than the hinges. Cut six slots in the stabilizer and six matching slots in the elevators at the locations shown on the plan.
  2. Place a small straight pin in the middle of each hinge.

53.

Insert EASY HINGES halfway into the stabilizer slots, the pins will provide automatic location. DO NOT GLUE THE HINGES! Starting at one end slide the elevators onto the hinges at an angle, one at a time. It's next to impossible to start all of the hinges at once. Don't be concerned if the hinges aren't perfectly straight or centered in the slots, they'll work regardless of their final position. Remove the straight pins.

54.

  1. To set the hinge gap, deflect the elevators to the maximum amount needed. For best control response, the gap should be as small as possible but big enough to allow full movement of the control surface without binding.
  2. EASY HINGES were designed to use THIN CA for maximum glue penetration. Place three or four large drops of THIN CA directly onto the hinges in the gap. The glue will wick into the slot as it penetrates both the wood and the hinge. Continue this process, gluing the same side of all of the hinges. Turn the stabilizer over and repeat the gluing process on the other side of each hinge. Set the stabilizer/elevator assembly aside while the glue cures - about an hour.

55.

  1. Repeat steps 53 and 54 to attach the ailerons to the wing. Use six hinges in each aileron.
  2. The rudder is hinged in the same manner as the other control surfaces, but it's easier to permanently install the rudder hinges AFTER the fin has been glued to the fuselage. Cut matching slots for four hinges while the fin and rudder are easy to handle.

56.

  1. Mark a centerline on top of the stabilizer, making sure that the centerline is perpendicular to the trailing edge of the stabilizer. Pin the stabilizer to the fuselage, mount the wing to the fuselage and measure from the trailing edge of the wing to the trailing edge of stabilizer. Both measurements should be the same. If there is any difference rotate the stabilizer until the measurements are identical.
  2. When satisfied with the alignment, draw cut lines on the bottom of the stabilizer at the fuselage sides, and on the top of the stabilizer at the tail fairing blocks. Remove the stabilizer and cut away the covering between the lines, exposing the bare wood underneath. Use a sharp knife to cut the covering material - try not to cut into the balsa sheet. Use the same method to expose the area under the tail fairing blocks.
  3. Permanently glue the stabilizer to the fuselage using KWIK-SET epoxy. Recheck the stabilizer alignment and adjust as necessary before the glue cures.

57.

  1. Cut away a 3/8" wide strip of covering from the center of the stabilizer where the fin is to be glued. Also, remove the covering material from the front of the fin where the tail fairing blocks make contact.
  2. With KWIK-SET epoxy glue the fin to the top of the stabilizer, using a triangle to check its alignment before the glue cures. Make certain that the fin trailing edge is firmly glued between the fuselage sides.

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58.
  1. Repeat steps 53 and 54 to attach the rudder to the fin. Use four hinges in the rudder.
  2. After the glue has cured (about an hour) flex all the hinge lines in each direction a couple dozen times to reduce any stiffness.

59.

Swivel the nylon tailwheel bracket into position on the bottom of the fuselage, and mark the two mounting holes. Drill at the marks with a 5/64" drill and screw the bracket to the fuselage with two #4 x 1/2" sheet metal screws.

60.

Install the two 3-1/4" main wheels on the aluminum landing gear using the hardware as shown on plan sheet #1. Once the wheels have been attached, the landing gear assembly can be bolted to the fuselage using the three 6-32 x 1/2" mounting bolts.

61.

  1. If you wish to install a pilot, now is the time to do it. A William's Brothers 2-5/8" Sportsman pilot was used in our prototype models. Be sure to glue it firmly so it won't come loose in flight.
  2. Cut the excess plastic from the canopy using scissors. Cut to the molded line on the sides, and around the front. Cut across on the sharp corner across the back. Sand the rough edges smooth, being careful not scratch the clear plastic.
  3. Trial fit the canopy to the fuselage and trim it as necessary for a good fit. Position the canopy fore and aft so that the raised frame ends at the rear tips of the front top deck and tape it down.
  4. With a soft pencil, draw a line forward on the fuselage along the bottom edge of the canopy, over the front top deck and back along the side. Remove the canopy and carefully cut away a 1/16" wide strip of covering using the line as your guide. The idea is to expose a strip of bare wood where the canopy makes contact so that it can be securely glued to the fuselage.
  5. Check the fit and location of the canopy one more time. If everything is correct wash the canopy with soap and water and dry thoroughly. Now is the time to apply trim tape to the inside of the canopy on the raised area to simulate a frame. Tape the canopy to the fuselage and apply glue along the bottom edge of the canopy.
  6. Dress up the bottom edge of the canopy by applying 1/4" striping tape, half on the canopy and half on the fuselage. Start at the rear corner of one side and work forward up and over the front deck and back along the other side. Another piece of striping tape will finish off the rear edge of the canopy.

BUILDER'S TIP:
CA can be used without fear of fogging the canopy if a light spray of accelerator is applied before taping the canopy down. Use MEDIUM CA as it will not wick as far nor as quickly as THIN CA.

Engine And Fuel Tank Installation

62.

  1. Engine installation in the FOUR-STAR 60 is simply a matter of bolting the engine and engine mount in place on F-1.
  2. Install the throttle cable on the carburetor arm and assemble the pushrod connector on the throttle servo arm. The exact position of the cable in the pushrod connector will have to be adjusted after the rest of the radio has been installed.
  3. If the construction of the fuselage followed these instructions, installation of the tank is just a matter of sliding the tank through the wing opening and blocking in place. Like most SIG kits, the fuel tank in this model is installed from the rear of the fuel tank compartment rather than through a removable hatch. This choice was made for several reasons: hatch openings make the nose weaker, it's very difficult to keep oil from leaking in around a hatch, a method of fastening the hatch must be built into the fuselage, adding to the complexity and construction time of the model. Further, fuel tanks that are installed properly seldom need to be removed for maintenance.

Radio Installation

63.

  1. Mount the elevator, rudder and throttle servos in the laser cut plywood tray provided with the kit.
  2. Place the tray in the slot in the doubler. The fore and aft location of the servos will vary depending on engine weight, so it will be necessary to do a preliminary balance with the model to establish the tray position. Reinforce the servo traylfuselage joint with leftover 1/8"x5/16" balsa stringer scraps.
  3. Cut off the front ends of the outer pushrod tubes about an inch behind the rear of the servo tray.

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64.
  1. Cut two 2-56 x10" threaded rods to an overall length that is equal to the distance from the rudder and elevator servo arms to the end of the black tube. Solder a 2-56 solder clevis to the smooth end of each rod.
  2. Screw the threaded end of the rods completely into the two inner nylon pushrods tubes. Insert the rudder and elevator pushrods into the black outer tube. Connect each clevis to it's respective servo arm.

65.

  1. Screw the nylon control horns onto the rudder and elevator as shown on the plans.
  2. Snap a 2-56 R/C link onto the rudder horn and cut off the rudder pushrod, leaving a 1/8" gap between the end of the tubing and the R/C link. Cut a 2-56 x10" threaded rod to an overall length of 4-5/8", measuring from the threaded end. Install the threaded rod in the nylon tubing, smooth end first, so that approximately 1/2" of the threaded portion remains exposed. The metal rod inside the inner nylon tube will prevent the nylon tubing outside the fuselage from buckling under flight loads. Thread a 2-56 hex nut onto the end of the pushrod, remove the 2-56 R/C link from this rudder horn and thread onto the end of the push rod. Adjust the link until the rudder is in neutral position. Tighten the hex nut against the clevis to reduce the "slop" in the linkage.

66.

Snap a 2-56 R/C link onto the elevator horn and cut off the nylon tubing, leaving a 1/8" gap between the end of the tubing and the R/C link. Cut a 2-56 x10" threaded rod to an overall length of 3-5/8", measuring from the threaded end. Install the threaded rod in the nylon tubing, smooth end first, so that approximately 1/2" of the threaded portion remains exposed. The metal rod inside the inner nylon tube will prevent the nylon tubing outside the fuselage from buckling under flight loads. Thread a 2-56 hex nut onto the end of the pushrod, remove the 2-56 R/C link from the elevator horn and thread onto the end of the pushrod. Adjust the link until the elevator is in neutral position. Tighten the hex nut against the clevis to reduce the "slop" in the linkage.

SAFETY TIP: Use a small length of fuel tubing over top of the RIC link. This will keep the link from popping open during flight, causing a loss of control. A drop of THIN CA on both ends of each push rod where the wire enters the tubing will insure that the wires will not pull out of the plastic tubes.

67.

  1. Hook up the ailerons by installing control horns and aileron pushrods. The servo leads will need short extensions to reach the center "Y" harness required to connect the servos to the receiver. Radio manufacturers generally have these items available as stock equipment. It's best to keep the extensions as short possible because excessively long wires can cause radio "glitches" under certain conditions.
  2. Use the laser cut lite-ply Aileron Positioning Guide (APG) to set the ailerons at neutral (as shown on plan 2 of 2). Adjust the R/C link on each aileron pushrod until the APG seats perfectly against the bottom of the wing and aileron.

68.

Always wrap your receiver and battery in foam rubber and position them forward of the servos. If a lighter than average engine is used, it may be necessary to install the battery under the fuel tank to achieve proper balance. Use a scrap balsa stick or rubber bands to keep the receiver and battery pack from moving around during flight.

Pre-Flight Checkout

IMPORTANT! For the first flights make certain that the model balances with an empty fuel tank somewhere between the two points that are shown on fuselage side view. Add weight if needed as trying to fly with the balance point too far aft is much more dangerous than the slight increase in wing loading caused by adding weight to the nose. It is easiest to balance the FOUR-STAR 60 while upside down. By-the-way, a balanced aircraft hangs perfectly level, not nose down, nor nose up. Be certain to range check the radio equipment according to the manufacturer's instructions before attempting the first flight. If there are any questions about range, resolve them now - it doesn't get better when the plane is in the air rapidly disappearing in the distance!!

Another set of problems can be avoided if the engine has been well run in and properly adjusted on a test stand before installation in the airplane.

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Before flying, check and adjust all the pushrod linkages so that the control surfaces are in neutral position when the transmitter sticks and trim levers are centered. When you get to the field, don't be surprised if the elevator and rudder are slightly misaligned. Temperature and humidity changes can cause the nylon pushrod tubes to expand or contract slightly. Use the trim levers on the transmitter to return the control surfaces to neutral, and do the final trimming in the air.

The control surface movements listed here are recommended for the first flights of your FOUR-STAR 60. These movements will provide the model with a fair degree of aerobatic capability if it's balanced correctly. Test flights may indicate a need for slightly more or less movement depending on individual model performance and personal preference.

RECOMMENDED CONTROL SURFACE MOVEMENTS ELEVATOR 3/4" UP and 3/4" DOWN
RUDDER 1" RIGHT and 1" LEFT
AILERON 5/8" UP and 5/8" DOWN

The Golden Rule of Success in R/C:

"A model, engine or radio that is not prepared and working properly on the ground before takeoff will not improve in the air - it will get worse! There is no point in attempting to fly until everything is 100% correct."

Flying

The Four-Star 60 is a fun aircraft to fly, but it is not a basic trainer. If you have little or no R/C flying experience, SIG strongly suggests that you get an experienced pilot to help you fly your model until you're comfortable with the controls. Contact a local R/C club or ask your hobby dealer for the names of good fliers in your area and a suitable location for flying.

Make any changes, especially to the balance point, gradually. We recommend that the balance point be shifted no more than 1/8" at a time. In general, moving the balance point forward will make the model more stable, slowing down snap rolls and spins. Moving the balance point back increases sensitivity to rudder and elevator inputs. An aft balance point, carried too far, can produce a model that is completely unstable and uncontrollable. The balance range shown on the plans is a safe area to use for test flights. Don't exceed the rearward CG limit unless you are a very experienced pilot and are totally familiar with the airplane.


LIMIT OF LIABILITY:
The craftsmanship, attention to detail, and actions of the builder/flyer of this model airplane kit will ultimately determine the flight performance and safety of the finished model. SIG MFG. CO.'s only obligation shall be to replace those parts of the kit proven to be defective or missing. The user shall determine the suitability of the product for his or her intended use and shall assume all risk and liability in connection therewith.

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© Copyright SIG Mfg. Co., Inc.
SIG MFG. CO., INC............Montezuma, Iowa 50171-0520