KADET SENIOR RC58 FUSELAGE CONSTRUCTION

34.

  1. Soak the front end of the bottom 1/4" sq. fuselage stringer in water so that it may be more easily pinned into place on the plan in the curved part at the front.
  2. Add the other lengthwise stringers of spruce and balsa.
  3. Glue in FN.
  4. Install the vertical 1/4" square balsa uprights.
  5. Put in the 1/4" sq. diag. braces.



35.

Glue G-1 and G-3 into the side (Leave G-2 until later).



36.

Continue on down the fuselage with vertical and diagonal 1/4" squares.

37.

  1. Trim a piece of 1/4" sq. to fit here.
  2. In the rear of the fuselage the diagonal braces are 1/8"x1/4" balsa strip.
Build the second fuselage side directly on top of the first side, using pieces of wax paper at each point to keep from gluing the sides together. Remove the sides from the board and mark a left and right side so as to insure the next step is done correctly.

38.

  1. Glue a strip of 1/4" sq. spruce to the INSIDE of each fuselage side at section "D", just behind G-1 as shown.

39.

  1. Glue a strip of 1/4" sq. spruce to the INSIDE of each fuselage side at section "C".

40.

Using a straightedge to insure accurate alignment, join the two parts of the Fuselage Top View plan. Turn the fuselage sides upside down on the cabin top and pin them to the plan in the cabin area. Make certain that they are supported exactly perpendicular. Here we show temporary braces tack glued to the fuselage sides and to the board.

41.

Keeping check on the alignment, add FC


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42. A 1/4"x1/2" crosspiece on edge is used at section-D on the bottom.

43.

Glue in the bottom 1/4" sq. crosspieces.



44.

  1. Use two flat sided weights to pull in the fuselage sides at the tail end.
  2. Check with a 90deg triangle to insure they are directly over the plan.
45. Add the other rear cross pieces

46.

Complete the 1/4" sq. fuselage cross pieces between the cabin and rear end. (Look ahead to see the extra top crosspieces in the area of the fin. They can be put in later, after the sides are removed from the board).




47.

This picture shows the front crosspieces in the nose section after the fuselage has been removed from the plan, but it is best to actually install them before the assembly has been unpinned and removed.

48.

Closeup of the fuselage top Section "D" - "a" is a 1/4"x1/2" piece on edge and "b" is a 1/4"x1/2" piece installed flat, behind the first piece.

49.

Shows the top section "D" as seen from the bottom. The 1/4" diameter rear dowl is fitted in now, but do not glue it in until later so it will not be in the way of the fuselage covering.




50.

  1. Mark and glue the grooved landing gear block in place on the fuselage bottom.
  2. 1/4"x1/2" crosspieces on each side of the block installed flat.



51.

Begin sheeting the fuselage bottom with 3/32"x3" balsa with the grain running across the fuselage. Save the 5" sheets for the fuselage sides.

52.

  1. Complete the sheeting, leaving a gap for the landing gear groove.
  2. Glue strips of scrap 3/32" sheet balsa to the bottom of the stringers as shown.

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53.
  1. Feather the scrap strips into the lines of the bottom, leaving them full depth where they touch the front sheeting, tapering to nothing at the back. (See fuselage side view.)
  2. Glue in the 1/4" sq. stringer doublers.

54.

  1. Glue the hardwood anchor blocks on top of the grooved landing gear blocks and to the insides of the G-3s

55.

  1. Add the extra 1/4" sqs. on top.
  2. Fill in the rear section with 1/8" sheet.
  3. Draw a centerline on the top of the fuselage.
  4. Cut Holes to take the fin stubs.

56.

Shows the fin in place. Do not glue it on permanently until after the fuselage and fin are covered. At that time remove a strip of covering under the fin so that there will be a wood-to-wood gluing surface. The same rule applies to the portions of the stabilizer that are glued to the fuselage in the final assembly. Use a generous amount of epoxy to glue stab the leading edge and the trailing edge to the fuselage frame.

57.

  1. Cover the firewall blind nuts with tape to keep glue or fuel proofing out of them and epoxy the firewall to the front of the fuselage.
  2. Epoxy 3/4" triangular stock in the corners.
  3. Glue one of the FT ply formers to the back of the firewall.


58.

Glue a 3/32"x4-3/4"x24" fuselage side sheet in place on the fuselage.

59.

Trim the side sheet to fit.




60.

  1. Add the second and third FT formers.
  2. Glue 1/8"x1/4" spruce stringers into the former holes.

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61. We occasionaly receive suggestions from builders that a removable hatch be designed into a 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 from 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 the 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.

We show a Sullivan RST tank on the plans. Other types of tanks, such as the DuBro, will require slightly different mounting and application but the principles discussed here are the same for all tanks.

The newer Sullivan type of tank requires a 15/16" diameter hole in the firewall through which the tank cap protudes, as we show in the first part of the firewall section. So as to also cover the DuBro type of tank, the pictures of construction following this tank section will show one of these tanks installed in the fuselage. The main difference in the tanks is that the cap of the DuBro tank is meant to remain inside the fuselage, with only the fuel lines going through the firewall. The following comments apply to both types.

With most engines, the best installation will be with the tank as high in the fuselage as the cutouts in the FT formers will allow. Put scrap wood crosspieces under and at the back of the tank. Seal the firewall hole with G.E. Silicone Bathhtub Seal (available at hardware stores). Put an oil proof finish on the firewall and in the hole before sealing the tank cap or fuel lines with silicone. Gel some of the silicone sealer in the hole and over the edge at the front. Don't install the tank permanently until after the model is covered and painted. Should you need to remove the tank, break out the scrap wood cross piece in the rear and push out the silicone rubber seal around the front. Reach into the fuselage and guide the tank inside.

Some builders, after putting their receiver battery in a plastic sack, taping it shut, wrapping it in 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 everythig 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 valve 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 needle valve also.

PRESSURE FEED

If the engine you are using is equipped with a muffler pressure tap, make use of it for more even fuel feed and reliable operation. The hookup for pressure is shown in the picture. To fill the tank, remove fuel line from the needle valve on 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.



62.

Shows a DuBro 8oz. tank installed in the fuselage. Also see the next picture. Two lines are enough unless you have a fuel fitting on the carburetor that is not accessable. In this case, use a 3rd line as a fill tube. You can also use individual holes for each line.

63.

Cover the top of the fuselage nose with pieces of 3/32"x3-1/4" sheet. If the grain does not allow bending it into position dry, and it likely will not in many cases, dampen the top of the sheet with water and allow it to soak in before curving it into place on the formers. It helps to have one edge glued on first, as shown here, rather than trying to put it on in one step. (We left the tank and lines in to show you more of them. Have them out when you are sheeting the top.)

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64. On the plans we show the servos mounted high in the fuselage for easy access. Some think this spoils the appearance, since they stick up and show through the windows. So in this picture we have a 3-servos-abreast installation mounted a bit lower, below the cabin window line. Because Futaba doesn't make a 3-servo tray of this type, we used three single FST-28V trays. You can also see the flexible cable pushrods running from the throttle and nose wheel and glued to scrap standoffs. Silicone seal makes a good adhesive for fastening the outer tubing to the fuselage because it is slightly flexibile and doesn't make a hard spot in the tubing.




Life is not simple in the model game when it comes to pushrod installation. Most servos are standardized as to which direction they move in response to a particular transmitter stick movement but there are exceptions. Regardless of the direction of movement of the servo, you can adapt to it by moving the pushrod to whichever side of the servo output arm or wheel will give the pushrod movement direction desired. Sometimes this requires that a pushrod brought down the side of the fuselage has to crossover to the inside of the servo output arm to get the desired direction of pushrod movement.

Some radio manufacturers make available reverse direction servos and often include one or more in an outfit for situations were the opposite direction of pushrod movement without changing servo sides is desired. For example, it is desirable to have the hookup for the pushrods to the nose on the outside of the servo so that the pushrod tubing need not be flexed as far as crossing over to the inside would require. At the same time the pushrods to the tail would be on the inside where there is plenty of room to maneuver it around. The current trend is for equipment to have a servo reversing switch built into the transmitter. If the servo doesn't run the direction you prefer, just flip the switch. Several companies make reversing converters that can be plugged into a servo cord to reverse the direction of movement of a standard servo. But if you do not have a reverse servo it is quite possible to get along without it.

WHICH SIDE FOR THE RUDDER PUSHROD?

The choice of which side of the fuselage the rudder pushrod will exit from is determined by the position of the throttle control arm on the engine to be used. If it is on the right (most common), use the servo nearest the right side of the fuselage for motor control. Use the servo nearest the left side of the fuselage for the rudder, with the rudder pushrod coming out to the left side of the rudder and the nose wheel steering arm hooked up on the left side of the nose gear bearing. This setup would be the case with most glow-plug engines, as with the Fox shown on the plan.

The opposite is true of the O.S. .40 Four-stroke we are using in the picture sequence so as to cover this circumstance. On this engine the throttle arm is located on the left side, so the servo on the left side would be used for engine speed and the one on the right for rudder and nose wheel. This calls for the rudder horn to be located on the right side of the tail instead of on the left as the plan shows.


As you can see, it is best to know in advance the radio and motor brand you will be using before you install permanent cable pushrods. Decide on which type of fittings you will use in the case of the cable pushrods and have them on hand during construction because the type chosen will affect the location of the pushrod exit holes through the firewall, etc. The balsa pushrods to the rudder and elevator are not limited as to location and can be adapted to any of the types of connectors shown without preliminary planning.

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SERVO HOOKER-UPPERS

Having the proper connector makes servo installation much easier. We show here a variety of ways to attach pushrods to servos.

DuBro Ball Links, which come in several different types - threaded, bolt-on, rivet etc. - gets the pushrod action up above the control arm so the pushrod can approach from a variety of angles without any chance of interfering with the servo center post. It is good for cable pushrods. A line adjustment can be made by screwing the end in and out.

The Sig Pushrod Connector included in this kit can be used for attaching the nosewheel pushrod cable to the steering arm as shown. Additional pushrod connectors can be purchased (Sig No. SH-736) for use on the throttle and nosewheel servo arms. Adjust by loosening the set screw and sliding the cable.

A typical Futuba plastic servo mount. Similar mounts in a variety of styles are available from most radio makers.
Angle the nose gear steering arm forward in neutral to allow more range of movement.

PREPARING CABLE PUSHRODS
To keep ends of cable from unraveling during handling, tin the end with solder. Use a non-corrosive paste flux (shown here is Kester, available at hardware stores) and rosin core solder. Have a hot iron and flow the solder completely through the cable.
Grind or file the end smooth. Bring it to a point so that it will easily insert into the pushrod fittings.
After the proper length is arrived at, sweat solder the area to be cut so that it will not fray and unravel while being cut. It can be cut with a good pair of side-cutting pliers, filed in two, ground through on the edge of a grinding tool, or cut with a silicon cutting wheel on a motor tool.


FOUR CYCLE THROTTLES

It is common for 4-cycle engines to have their throttle control arm on the back of the engines, unlike 2-cycle types which have front carburetors and plenty of room in front of the firewall for adjustable linkages and couplers. In the installation of the O.S. 4-stroke, we got around this problem by use of a DuBro 180 Bolt-On Link. The ball was bolted to the carburetor arm. Since there was no room for the threaded coupler, it was discarded and the nylon ball link socket was bound to the end of the throttle control cable with epoxy glue and fine copper wire. The photo shows this installation.

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65.
  1. Pre-bevel the front edge of FF, using the pattern on the plan and glue it onto the front of the cabin.
  2. Glue tapered scrap shims on each cabin window upright. The idea is for the cabin window frame to be flush with the fuselage sides at the bottom and glue directly to the top edge of the top spruce cabin stringer at the top. (See cross-section drawing here.) Shims are also a nice idea on the sides just behind the cabin window frame. It makes covering a neater job.
66. The clear cabin windows are glued to the inside of the die cut ply window frame. Make sure you do it left and right. The main necessity here is to avoid warping this thin assembly. Therefore do not use water base glues such as Sig Bond or Tite Bond. Do not use cements like Sig-Ment or Ambroid. The ideal adhesive appears to be slow-setting cyanoacrylate but precautions should be taken for this to come out right. First, make sure the ply frame will stay in place on the table by fastening it down with double-stick tape or a tack-glued corner or two. Then stick several pins along the bottom as guides. Have one at the corner to position the window material lengthwise as well (The pin seen on the far right). The critical step is next, getting the right amount of glue. About a 3/32" diameter bead, located 3/32" to 1/8" from the window frame edge is approximately correct. The idea is for the bead to spread almost to the edge, but not over it, when the clear plastic is pressed down. Too big a bead and it will squeeze out onto the window. Since glues are of different viscocity, I'd suggest a trial run on a bead size with scrap plastic from the windshield. Also, of course, put glue beads on the frame farther away from the window outline, such as in the back portion that is a long way from a window. So having practiced, apply the glue to the frame, sit the clear plastic on the pins as shown in this picture and hinge it down onto the glue.




67.

So that the clear window will not be damaged during handling and covering, protect them with masking tape. Use a sharp, new modeling knife to trim the tape against the edge of the ply frames. We covered right over the masked-off windows with silk, then doped the silk, finally trimming it off flush with the ply frame and removing the tape last. It is also a good idea to tape the inside of the windows. This doesn't need to follow the frame lines, just cover the whole clear window. Caution: Don't leave the tape on a long time, it dries out and sticks down tightly. Low tack drafting tape is best for the job but regular tape will work if you do not leave it on too long.

68.

We have previously established the final windshield pattern shape. Now use the pattern to locate the position of the dowel holes in the windshield. Use plenty of epoxy glue to glue the dowel to the fuselage and to former FF. Make a fillet of epoxy over the dowel on the face of the verical 1/4" sq. balsa and 1/4" sq. spruce. Do the same for the areas where the fuselage crosspieces attach to the fuselage sides. Cover and/or paint the model before gluing on the windshield. Use Wilhold RC-56 or cyanoacrylate glue to attach the windshield. It helps to glue down one side of the windshield to the fuselage first so you can pull against it to stretch the rest of it into position for gluing. Make certain, however, that the first side is properly lined up. Taping the rest in place helps.

69.

Drill 5/32" holes into the anchor blocks for the torsion arms. Recess nylon straps into the 3/32" bottom sheeting.




70.

Cut out the cowl parts C-1 and C-2 and glue together as shown. Note that the bottoms are lined up flush and the backs are even. We have laid the C-3 parts in place here to show their general location but do not glue them in until later, after the cowl main shaping and sanding is completed. If you make use of a longer cowl for a specialized engine you will have to plot a new C-3 to match the modified shape. The cowl used on the plan will fit most engines. C-3 simply makes a notch so it is easier to glue the 1/8" bottom sheeting.

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71. Glue the cowl halves to the fuselage, flush with the bottom and sides.

72.

Carve the cowl sides to a pleasing shape. Add C-3 exactly 1/8" deep from the sanded bottom cowl shape.




73.

Cut away the inside of the cowl to clear space for pushrods or engine parts. It is a good idea to carve a taper into C-2 on the inside to make it easier to paint or fuel proof the cowl interior, but do not do this until later, after the front and any top fill-in blocks desired are added.

74.

Put the spinner backplate on the engine and glue on pieces of 3/4" triangular stock as shown, using the spinner backplate as a guide for correct placement. Don't carve to final shape until top and bottom wood is in place.

75.

Cover the bottom with 1/8" sheet balsa.




76.

  1. Cut a hole for access to the nose wheel steering arm adjustment screw.
  2. Add scrap wood as desired to complete the cowl shape


77. We added some more scrap wood to the top to improve the appearance. This addition is determined by the engine used and/or your preference.

TAIL SURFACES

78.

  1. Pin down the pieces of 3/8" square for the outside frame of the stabilizer.
  2. Make a corner gusset from scrap wood.



79.

Cut center brace to fit.

80.

Glue in place

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81.
  1. A 1/8"x3/8" hardwood brace is glued across the back.
  2. Next add the 3/8"x3/4" strip center rib.



82.

Cut and fit 1/4"x3/8" strips of balsa.

83.

  1. Pin down the 1/4"x3/8" elevator leading edge.
  2. Pin down the notched trailing edge,
  3. Glue E-1 elevator ribs between them.
  4. Pre-taper 3/8" sq. ends.
84.
  1. Add the diagonal elevator ribs.
  2. Fill in the center with scrap.

85.

  1. Saw the front off and leave it square and unshaped.
  2. Shape the leading edge to a rounded contour.
  3. Do not shape the stabilizer trailing edge. Leave it square.

86.

  1. Pin and glue pieces of 5/16" sq. balsa to make the main frame of the fin.
  2. Note the stubs, left on below the bottom fin line.



87.

  1. Add 3/16"x5/16" ribs.
  2. Glue in 1/8"x5/16" diagonal braces.



88.

  1. Pin down the 5/16" sq. rudder leading edge.
  2. Pre-notch the shaped rudder trailing edge. (It is not practical to suppy it notched accurately at an angle as required.) Pin down to the plan.
  3. Glue R-2, R-4 and R-6 ribs between them.


89.

  1. Add the diagonal ribs R-1, R-3 and R-5.
  2. The top and bottom of the rudder are pre-tapered pieces of 5/16" square.

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90.
  1. Fill in some scrap as a control horn mounting place.

91.

Glue RD in place on the fin leading edge and shape.

92.

Carve the fin leading edge and tip to a rounded shape. (The elevator tip is similarly shaped.)

93.

  1. Although it isn't shown on the plans, you should add a scrap piece of 3/16"x3/8" balsa as shown in the photo to provide additional gluing area for the stabilizer.
  2. Cut a slot in the 1/8" balsa sheet for the rudder pushrod (see "Which Side For Rudder Pushrod" detailed earlier.)



We recommend that you cover the wing, fuselage, tail surfaces, and control surfaces all separately before hinging and final assembly. This way, the parts are much easier to handle.

A CAUTION ABOUT THE KADET SENIOR WING

A recent experience leads us to add further caution to the one here.

It is simply: USE ENOUGH GLUE! Even in properly fitted structures, a failure can occur because of an inadequate amount of glue holding the parts together. A ply dihedral brace, for example, can't do its job if it tacked on with a few drops of glue. Strain will cause these spots to pop, transferring stress to other joints, in turn resulting in catastrophic wing failure. All surfaces joined together by glue should be fully coated, a wet joint, before assembling. Clamps should be used to hold dihedral braces firmly to the spars until dry.

If cyanoacrylate glues are used, the thin variety works well in small joints that are tightly fitted. Large are joints, such as those under doubler braces, are best glued with slow cyano or epoxy applied before joining, because the thin variety may not penetrate completely between the two surfaces when applied to the outside seams. For best safety in structures that are assembled with thin cyano, we recommend going over the joints and "filleting" them with a second application of medium or thick cyano glue.

Check the structure carefully after a cartwheeled landing or a flipover. The dihedral joint or other seam could be cracked or damaged internally, setting up a condition for later failure.