FUSELAGE CONSTRUCTION

NOTE:
Vertical or side mounting may be used, but the tank position should be changed accordingly to keep it in the same relationship to the motor's needle valve hole.

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

48.

The angled motor mount installation was chosen for the Kougar 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.
  1. Layout the center lines and motor mount positions on the front of the F-l firewall assembly, using the F-l drawing as a guide.
  2. Position the nose gear bearing and drill holes for the 4-40 bolts.

49.

  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 instead to attach the mounts.) Check and see if your motor fits properly on the mounts.
  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.) Or--start the holes using a tap holder for a drill bit as shown.

Motor Mounting Notes
When tapping holes in the aluminum motor mounts, use kerosene or a specialized aluminum tapping lubricant such as Tapmatic Fluid, rather than oil. This will reduce the chance of the tap sticking in the motor mount and breaking. SIGSHI09 6-32 xl" Socket Head Bolts are recommended for mounting the motor. They are not furnished because some builders may not have a tap. Use SIGSH159 bolts, nuts and washers in this case.
50.
  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. (If you don't have a 7/8" wood bit, the hole can be cut out on a jig saw. Or, drill a series of small holes around the edge of the large hole, punch out the center and finish the edge with a sanding drum in a motor tool or with sandpaper wrapped around a dowel.



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51. (NOTE: The photo shows the Kavalier firewall, but the process is the same for the Kougar.)
  1. Bolt the spinner backplate to the motor. (This must be done to allow for differences in spinners. For example, the Goldberg spinner 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 Kougar.)
  2. With 5 minute epoxy, tack glue the engine to the mounts so the back of the spinner is 4 l/2" from the front face of the firewall. (This allows for approximately a 3/32" space between the cowl and spinner.)
  3. Make a 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 The recommended method of engine mounting is to tap the motor mount holes and use 6-32 socket head bolts to retain the motor. Back the top out frequently and clean to avoid jamming in the aluminum. Use kerosene or a special aluminum tapping lubricant. If you do not have a tap, drill holes through the mounts and use bolts, lock washers and nuts.

52.

Sand off the rear ends of the fuselage printed sheets.

53.

Glue the fuselage end pieces FX-F2 and FY-F2 to the end of the fuselage sheet. Use a ruler to make sure the top line (where the stabilizer will be mounted) is straight. Mark the thrust line on the end of the fuselage side where it can be located later if needed for incidence check or for parallel decorations. (Also do the nose.)

54.

  1. Glue the top 1/2" triangular stock top pieces on to the fuselage sides.
  2. Glue on the back bottom piece of triangular stock.

55.

  1. Add the piece of triangular stock just under the stabilizer position.
56.
  1. Glue on the bottom front piece of triangular stock.
  2. FW is cut from scrap 1/16" sheet using the accompanying pattern.
57. Glue FW in place.




IMPORTANT NOTE:
Do not use Sig-Bond, White Glue or any other water-base adhesive to glue the plywood doubler to the fuselage sides. The water in these glues causes the parts to curl. Use Sig Epoxy or Sig Kwik-Set. Only a thin film of epoxy glue will be necessary. Sig Kwik-Set sets up in under 5 minutes so you must work rapidly when using it.

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58. Mark the locations of Formers F-2 and F-3 on the triangular stock because the doubler will cover up the location lines.
59. Fit the die-cut plywood doublers into place. Sand wherever necessary to make them sit in the proper location. Leave the black line of the wing saddle area --- 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.
The doublers on the prototype were glued in place with Sig Kwik-Set five minute epoxy. Work quickly, spread a thin film of glue over the entire doubler, put in place and press down with your hands while it is setting up. Do not take it from the building board immediately after setup. Five-minute epoxy sets up quickly but doesn't fully cure for some hours. During this time it can warp. Put some heavy weights on the doublers and leave them overnight if possible.

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 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. Press the parts firmly together.

60.

Cut the completed sides from the sheet.

61.

  1. Mark the positions of F-2 and F-3 on the plywood doublers.
  2. NOTE: It occurred to us after doing the photo sequence that the notching of the bottom triangular stock to pass F-1B could more easily be done at this point. Look ahead to picture No. 72 and you may agree and want to do the notches now.
  3. Cut pieces of triangular stock for the fuselage front. Allow 3/32" back from the front edge to accomodate F-1B. DO NOT glue these pieces in at this time. Put them aside for later use after the firewall has been glued on.

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62. Notch out the plywood doubler and side as required to pass the motor mount blind nut later when the sides are joined.

63.

  1. Using the pattern, drill 1/4" holes in F-2.
  2. Check the dowels in the holes. They should fit snugly but not so tight as to be difficult to remove. Sand the holes as required to make the dowels come out without a lot of force.
64. At this point check the top view plan of the rear of the fuselage and look ahead to picture No. 71. They show the bevel that should be cut into the triangular stock now so the rear ends will fit together when the sides are joined later.

65.

Glue F-2 and F-3 in place on a side with epoxy glue. Use a 900 triangle to get them exactly perpendicular.

66.

Pin the side on the top view plan - see the end of the instructions.




67.

Join the other side to F-2 and F-3. Pin securely to the building board.

68.

Glue F-4 in place, holding the fuselage pinched together while pinning the sides to the building board.

69.

Continue on back along the fuselage, gluing in F-5 and pinning the sides to the building board.




70.

Pinch the sides together at the back. Glue and pin.

71.

Add FB to the back of F-3. The edges of FB will have to be beveled to fit against the triangular stock.



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72. Saw a notch in the bottom triangle stock, flush with the plywood doubler to accomodate F-IB.

73.

  1. Sand the bottom of the fuselage smooth and level with the sanding block. (As is shown being done to the fuselage top in picture No. 79.)
  2. Cover the bottom of the fuselage with pieces of 1/8" sheet.
IMPORTANT! Leave the sides pinned down to the board until after the bottom sheeting is glued on and is dry. If the sides are removed from the board before the bottom sheeting is on, the fuselage may twist if one side happens to be a different grain of wood than the other. After the bottom is on, it will remain perfectly true and can be removed from the board.

74.

Use scrap triangular stock to brace the wing bolt anchor blocks, which have just been installed during the performance of Steps 32 and 33 of the wing construction.

STOP! Don't proceed any further with the fuselage until it has been used for Steps 32, 33 and 34 on the wing.
OIL PROOF YOUR MODEL!
One of the most destructive things that can happen to a model is allowing engine oil to soak into bare, untreated balsa or plywood. It will cause glue joints to loosen and results in a steady increase in weight. An oil soaked model cannot be properly repaired or re-painted after a crackup, since glue and finish will not hold. Cover all wood parts of the model and put on enough coats of finish so that oil cannot soak in. Don't leave any exposed wood on the outside. Around the nose and engine compartment, apply extra effort at oil proofing. Coating the firewall and front joints with epoxy glue is best, but several extra coats of dope or paint will also do the job. Take special care during building to use plenty of epoxy glue to attach the firewall and coat the back of the firewall and the firewall braces with the glue. Fill any cracks with epoxy.

75.

Fit the 3/4"x3" bottom front block in place, with firewall taped on.


76.

Hollow out the block to make more room in the nose for a battery.

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77.
  1. Cover the holes in the blind nuts on the back of the firewall with small pieces of tape to prevent glue from oozing into the threads. (Look ahead to Picture No. 80.)
  2. Epoxy the block and firewall to the fuselage.
  3. Shape and sand the block to the contour formed by the firewall and F-2.

Assemble the tank for use during Steps 78 and 79.

TIPS ON TANKS

IMPORTANT: To prevent fuel spray from staining the canopy, run the tank vent line out of the bottom of the cowling. Fill the tank through the muffler pressure line or needle valve line.
We occasionally receive suggestions from builders that a removable hatch be designed into the model for access to the gas tank. Our opinion is this is not the best method in most cases. The hatch opening makes the nose weaker and there is no good way to keep oil leaking in around the hatch. A method of fastening has to be built into the fuselage to hold a hatch in place.
Modern plastic tanks are virtually indestructable under normal use and bursting or cracking is almost unknown. If you use Sig Heat Proof Silicone tubing (which will not harden or deteriorate in fuel) in the plastic tank, the tank will seldom have to be removed. We have models in which tank has been installed for three or four years without ever needing removal. So it is quite practical to put the tank in semi-permanently. Check the models at a contest - you'll find that the majority have sealed noses, as does this kit.
Read this before you drill the 7/8" hole in the firewall.
Some fliers prefer not to bring the tank cap through the firewall as is shown in the construction sequence in these instructions. Instead they drill two holes for the vent tubes only and make the vent tubes long enough to extend through the firewall. This method requires little sealing but it is more difficult to install and remove the tank. The best way to manage this is to feed long pieces of fuel line through the holes and attach them to the tank in the cabin area. Steer the tank into the nose as the tubes are pulled back through the holes. If you are undecided as to which method you should use, our advice is that large hole installation shown in the construction pictures is the best for beginners.
Put scrap wood supports under and at the back of the tank. The front is supported by the 1/4" hole in the firewall. Seal the tank cap in the hole with G.E. Silicone Bathtub Seal (available at hardware stores) or Devcon Seal-It. Put an oil-proof finish on the firewall and in the hole before sealing the tank cap. Get some of the sealer on the sides of the hole and also put a bead over the edge of the cap at the front. Should you need to remove the tank, break out the scrap wood supports in the rear and push out the silicon rubber seal around the front cap. Reach into the fuselage and guide the tank outside.
Some builders, after putting their receiver battery in a plastic sack, taping it shut, wrapping it in a foam rubber package and stuffing it into the nose under the tank, then stuff paper toweling or foam rubber in to fill the nose compartment and keep everything firmly in place.
After installation, put fuel tubing on the vent tube and run it to the outside of the cowling on the bottom, so that fuel overflow is not blown over the wing-fuselage joint, where it may leak into the fuselage. The best way to fill the tank is to take off the fuel line to the needle vlave and pump the fuel in there until it runs out the vent. Be sure and use a filter on your fuel supply can, and it is a good idea to have a filter between the tank and the needle valve also.
Pressure Feed
If the engine you are using is equipped with a muffler pressure tap, make use of it for a more even fuel feed and reliable operation. The hookup for pressure feed is shown in the picture. To fill the tank, remove the fuel line from the engine and pump the fuel in. When the tank is full, it will overflow through the muffler pressure line. Use transparent or translucent fuel line so you can see the fuel starting to overflow when the tank is full. Should some fuel happen to get in the muffler, drain it out before starting the engine. Do not try to fill the tank in reverse from the pressure line, the tank will not fill properly and fuel may be forced into the engine.

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NOTE: Photos 78 and 79 show the Kavalier fuselage, but the procedure is exactly the same for the Kougar.

78.

Practice installing the tank to make sure that it can easily be passed from the radio compartment of through the tank cap hole in the firewall. Modify anything that interferes with easy placement and removal of the tank.

79.

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.
This is a good time, while access to the nose is open, to install the radio equipment and the pushrods for the steerable nose wheel and throttle. SIGSH559 cable and tubing pushrods are recommended. The nose compartment can be oilproofed at this time by painting it with warmed Sig Epoxy Glue (See Paragraph No. 43).

80.

  1. Reach through the top and epoxy in the triangular firewall braces that were cut to fit previously in Step 62c.
  2. Cut a top triangular brace to fit and epoxy in place.




81.

Sand the top of the fuselage level and smooth.



82.

Glue pieces of 1/8" sheet to the top of the fuselage.

STOP! At this point you will need the tail parts.

83.

  1. Fit the plastic turtle deck and canopy to the fuselage. The canopy must be trimmed down as required along the bottom to fit down snugly on the plastic turtle deck. Temporarily tape the tail, plastic turtle deck and canopy in place on the fuselage.
  2. Outline the position of the plastic turtle deck and canopy on the top of the fuselage with pencil.
  3. Round the comers of the fuselage with a modeling knife. Note that the fuselage cannot be rounded quite as much next to the canopy as it can elsewhere, because the canopy is close to the fuselage edge.
84. Pin 1/8" square balsa pieces to the top as mounting rails for both the canopy and turtle deck. Allow for the thickness of the parts.

85.

Taper the 1/8" sq. pieces so the canopy will fit snugly down on them.

86.

Paint the canopy before gluing it on (see "FINISHING THE PLASTIC") but do not leave it laying around painted. Put it on soon as the paint is dry. The rest of the model should be completely finished before the canopy is attached. Sigment glue, used sparingly, will fasten the canopy to the gluing rails. "Super" cyanoacrylate type glues may also be used. Careful! Too many fumes from the glue trapped inside may fog the canopy. Put a ventilation hole into the cockpit floor and preceed slowly.

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REAR DECK AND TAIL ASSEMBLY


Note: The stabilizer and rudder parts are easiest to cover before they are hinged and attached to the fuselage. Refer to the Finishing section and prepare the tail parts before hinging and attaching to the fuselage. Test assemble them on the hinges before covering to insure that a good edge and end match has been obtained in the sanding operation.


87.


Saw out the tail parts. Fit them together, using the sanding block. Glue and pin down the wax paper.

88.

  1. Sand off the lines and round the leading edge of the stabilizer and fin.
  2. Sand and shape the rudder and elevator.
NOTE: Install hinges in the controls first. After they are set up, attach the controls to the tail surfaces. Read "INSTALLING EASY HINGES" mentioned earlier.

89.

  1. Put the wing on the fuselage and check to see if the stabilizer lines up with it when pinned in place on the fuselage. If it does not, sand one side or the other of the fuselage so that the stabilizer is level.
  2. Glue the stabilizer to the fuselage. Use epoxy. To insure that the stabilizer is solidly glued to the fuselage, cut out the covering material in the area that contacts the fuselage to expose the bare wood. Puncture a series of 1/16" holes with a pointed wire in the stab and the fuselage top where they make contact. Have the holes at a slight angle to each other. When epoxy glue is worked into these holes and sets up it will act like small nails holding the parts together.

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90.

Shape the front of part FF so that the plastic turtle deck will fit over it.



91.

Pin FF in place and mark the contour on the front where it contacts the plastic turtle deck.

92.

Carve and sand FF to a streamline shape.

93.

  1. Cut a 1/8" x 1-1/8" slot in the fuselage to pass the rudder pushrod.
  2. The picture shows a Goldberg small pushrod exit guide being used to line the slot. However, the slot can be coated with epoxy glue to harden it and an exit guide will not be necessary.



94.

The control horns should be installed before covering, then removed until the covering is completed. Models with silk and dope covering have a hard enough "shell" on the wood so that plywood reinforcement of the control horn area has not been found necessary. Other types of covering call for reinforcement by insetting a scrap plywood "scab" into the surface on the opposite side from the horn. This will keep the horn from pulling out of the wood when subjected to unusual strain.


95.

The elevator pushrod exits through the opening in the fuselage rear end. Take note that the elevator horn mounting holes are not centered on the elevator, but must be offset to the side slightly to have the horn arm in the center.

Cut the wheel cover from .030 ABS Sheet Plastic and glue to the landing gear with Celastic dipped in Acetone or Dope Thinner.