J-3 CUB RC48 FUSELAGE CONSTRUCTION

1.

Building The Fuselage Formers

Due to their large size, some of the fuselage formers could not be furnished in one-piece, but need to be built up from several pieces. Take great care in the next few steps to insure that these formers are built accurately. How well you make them match the plan will determine how well other fuselage parts will fit together later

a.

Refer to Cross-Section F5 of the full size plans. Former F5 consists of one 1/4" ply Top, two 1/4"x1/2" ply Sides, and one 1/4"x1/2" balsa Bottom. Cut the 1/4"x1/2" ply pieces from the 24" long stock provided. Cut the 1/4"x1/2" balsa Bottom from 36" long stock. A piece of 1/4"x2-1/4"x6-1/4" plywood is provided for the former Top. Cut two 1/2"x15/16" notches in the bottom corners of the top as shown here.

b.

Cover the Cross-Section F5 drawing with waxed paper and epoxy the pieces of F5 together directly over the drawing.

c.

Build former F6 directly over plan Cross-Section F6. This former consists simply of four pieces of 1/4"x1/2" balsa, cut from 36" stock.




d.

Former F7 consists of two 1/4"x1/2" balsa Sides, one 1/4"x1/2" balsa Bottom, one printed balsa part F7A, and one die-cut lite-ply Cabin Bulkhead. Cut out these parts and glue together over the F7 CrossSection drawing.

e.

The die-cut balsa rear fuselage formers F8, F9, F10, and F11 each come in two pieces. Glue the halves together at the center. F8, F9, and F10 should each be reinforced with a piece of 1/8"x1/4" balsa, as shown.



2.

Fuselage Frame Assembly


a.

Cut the MF-1, MF-2, MF-3, MF-4 and MF-5 pieces from the 5/16" printed balsa sheets. Cover the Fuselage Main Frame drawing with wax paper or plastic wrap for protection. Using the printed parts and 5/16" square balsa stick, construct two identical main frame sides directly over the drawing. When dry, pin both main frame sides together and lightly even up the edges with a sanding block.

b.

Epoxy the die-cut lite-ply Fuse Side Sheeting onto the main frame sides. Be sure to make a right and leftl And try not to get excess epoxy in the cutouts in the main frame for the landing gear blocks.

c.

With a sanding block, bevel the inside rear ends of the fuselage sides where they will join together later.

d.

The top structure of the cabin/window area, where the wing will sit, is a lamination of 1/4"x3/8" spruce to 3/16"x3/8" balsa. From 36" long stock, cut two spruce and two balsa pieces to proper length. Glue the balsa pieces to the spruce pieces in a manner which will give you a Right and Left Cabin Top piece.

e.

Pin the Right Cabin Top piece in place on the Side View plan (balsa side up). Pin the Right Fuselage Side in place on the plan (plywood side down). Carefully draw lines on these parts to mark the exact locations of formers F5, F6 and F7.

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f.

Epoxy formers F5, F6 and F7 to the Right Fuselage Side and Cabin Top piece. Glue them on one at a time with 5-minute epoxy. Use a triangle to get them on square.

g.

Epoxy the Left Cabin Top piece in place along the top of the formers. When dry, measure at each former from the bottom of the Right Cabin Top to the top edge of the Right Fuse Side. Then transfer this measurement onto the left side of the formers, this time measuring down from the bottom of the just-installed Left Cabin Top. These marks will come in handy as a guide when aligning the Left Fuse Side in the next step.

h.

Epoxy the Left Fuselage Side onto the formers. Accurate positioning during this assembly is very critical in building a straight fuselage! It's best to mark the former locations on the inside of the Fuse Side before gluing them on. We prefer to use slow drying epoxy and lots of pins for this assembly so that there is plenty of time for getting an accurate alignment of the fuse sides to each other before the glue dries. And don't forget to check that the sides will properly line up with each other at the tail end. Let dry before proceeding.




i.

Epoxy 1/8"x1"x6" plywood Landing Gear Block Doublers to the top side of the Grooved Landing Gear Blocks. When dry, epoxy the blocks in place in the fuselage. Make sure that the grooves in the blocks are 5-7/8" apart as shown in the side view fuselage plan.

j.

Epoxy the 1/8"x1"x6" plywood Strut Mount Insert in front of the rear Landing Gear Block

k.

Set the fuselage on the Top View plan, pinning down the area between formers F6 and F7. Pull in the rear ends of the fuse sides and glue together parts MF-5 where they meet on the center line of the plan. Let dry.


NOTE: With the rear half of the fuselage down against the plan, the length and curve of the sides won't match that drawn on the plan. This isn't a mistake but is simply because the Top View plan shows the fuselage as it would look from above when the fuselage is sitting level not like it is now with the upswept rear half sitting flat on the plan.


l.

Consequently, to join the remainder of the rear fuselage, first unpin the fuselage from the plan after the MF-5 joint is dry. Then cut the 5/16" square balsa cross-pieces to length according to the patterns for each that are drawn alongside the Top View. Glue and pin these in place starting with the F13 cross-pieces, and then working forward.

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3.

Nose Assembly

a.

Epoxy the die-cut plywood firewall parts F1A, F1B and F1C together. Make certain that F1C is centered on the back. Carefully mark the vertical centerline and the thrust line on the front of the firewall assembly. Position your engine mount on the front of the firewall, drill holes for mounting, and install blind nuts.

b.

Join the nose main frame sides at the top with the die-cut lite-ply Nose Joiner. Note that the Joiner should not be flush with the front of the sides, but leaves clearance room for F1C.




c.

Epoxy the nose assembly to the fuselage main frame. Make sure that the nose main frame sides are lined up with the fuse main frame not flush with the lite-ply fuse side sheeting. The nose will have its own lite-ply side sheeting added later.

d.

Epoxy the firewall assembly in place. Double check with the Side View plan that you get it correctly located vertically. The easiest way is to draw the thrust line on the main frame sides and match up the line on the firewall with it.

e.

Refer to the F5 cross-section drawing. Make a 5/32"x5/16" hole in the top of plywood former F5 where the 5/32" Cabin Wires will pass through.

f.

Cut a groove through the top 5/16" square main frame pieces so the Cabin Wires can enter the slot that is between MF-1 and MF-2.

g.

Trial fit the Cabin Wires in place and rebend them slightly if necessary to get a good fit in your model. Take coarse grit sandpaper and sand the wires in the areas where they will be glued into the model structure. This will improve glue adhesion. When satisfied with the fit, epoxy the Cabin Wires into the side slots in the nose main frame. Use the glue liberally, to completely cover the wire where it imbeds into the structure. Be careful that the wire doesn't stick out past the surface of the main frame since lite-ply sheeting must still be applied later.

h.

Wrap with copper wire and solder the Cabin Wires together where they meet at the front of former F5. When cool, clean any excess solder flux off the wires and surrounding plywood with dope thinner and a stiff nylon brush. Let the thinner evaporate out. Smear a fillet of epoxy around the wire binding and onto the front of F5 where they meet.

SPECIAL NOTE: It is best to make provisions now for the fuel tank mounting, while you still have easy access through the bottom of the nose. Refer ahead to "Tips On Tanks" (section 20), for some recommendation on the type of setup to use. At this time you should drill any necessary fuel line holes in the firewall, and make any provisions you prefer for securing the tank in position.

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i.

Glue in place balsa formers F2, F3 and F4, and the 1/4" square balsa stringer that goes between them. Check the exact locations of the formers carefully. When dry, lightly touch up the edges of the formers by running a sanding block over all three and the ply firewall at the same time.

j.

Sand the sides of the firewall flush with the main frame. Glue on the die-cut lite-ply Nose Side Sheeting.

k.

A 1/8"x4"x18" balsa sheet is provided for planking over the top of the nose formers. It may be necessary to wet the outside of the sheeting slightly with water to get it to bend easily around the formers.

4.

Cabin Area

a.

Add 3/16"x3/8" balsa fill-in pieces to each side of former F7.

b.

Cut out and glue in place the 1/4" printed balsa Window Outlines. They should be glued in flush with the outer surface of the lite-ply Fuse Sides and the spruce Cabin Tops.

c.

Fill in along both sides of formers F5 and F6 with 1/4"x1/2" balsa. These will stick out past the surface of the lite-ply and spruce slightly, but will be sanded flush later.

d.

Add 1/4"x1/2" balsa Window Braces to both sides of the cabin, where shown on the plan just ahead of former F6. Glue these in flush with the Fuse Sides and Cabin Tops.

e.

Install F5G gussets on the back of former F5, to brace it to the Cabin Top pieces.


f.

Cut and glue in place the 5/16" sq. balsa front Windshield Braces. They should also be glued in flush with the lite-ply Sides and spruce Cabin Tops. You'll have to hollow out the bottom inside corner of the Windshield Braces slightly so that they will clear the Cabin Wires.

g.

Block sand all the window area flush with the surface of the fuse sides and cabin tops.

h.

Wood for cabin floor pieces CF-1 and CF-2, that go around the landing gear blocks, is available on printed sheet #10. The lines drawn there are not exact size - cut the wood oversize and sand the edges down until the pieces slip into place between the main frame sides. Then glue in flush with the bottom of the fuselage.

i.

Cut out and glue in the CF-3 Nose Fill-In piece

j.

Add the 5/8" balsa Nose Bottom Block. Note proper grain direction.

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5. Completing The Fuselage
Steerable Tailwheel Unit Assembly

1.

Temporarily bolt the two formed metal Leaf Springs together using the 6-32x1/2" Mounting Bolts and the 6-32 Square Anchor Nuts provided. Note in the drawing that the shorter leaf spring goes on top.

2.

Push the bottom end of the long Leaf Spring in place inside the Nylon Tailwheel Bearing. Bolt securely with the 4-40x3/8" Mounting Bolts & 4-40 Lock Nuts.

3.

Prepare the Formed Tailwheel Wire for installation by first grinding or filing any burrs from both ends of the wire. Next clamp the entire bottom fork of the tailwheel wire in a vice and bend the top shaft backward slightly, so that when installed the tailwheel will be swept back slightly as shown in the full-size side-view drawing on Plan Plate 1.

4.

Solder a Flat Metal Washer just above the top bend of the Formed Tailwheel Wire. The purpose of this washer is to keep the wire from riding up too high into the Nylon Tailwheel Bearing and causing a bind. A second Flat Metal Washer is provided to solder onto the axle portion of the tailwheel wire to keep the tailwheel itself from binding against the bend of the wire.



5.

Install a 1-1/2" diameter Tailwheel (not furnished) on the axle. Use the 3/32" Wheel Collar and Headless Set Screw provided to hold the tailwheel in place.




6.

Push the other 3/32" Wheel Collar provided into the round cavity in the molded nylon Steering Arm. Make sure that the set screw hole in the wheel collar is lined up with the hole molded into the steering arm. Thread the 4-40 x 3/16" Set Screw (round head) into the wheel collar.

7.




8.

Insert the top of the Formed Tailwheel Wire thru the Nylon Tailwheel Bearing and secure in place with the Steering Arm. Be sure to file or grind a small flat spot on the wire where the 4-40 x 3/16" Set Screw will make contact.

During final assembly of the model, after all covering and painting is done, link the Steering Arm to the Rudder Control Horn with the two Steering Springs provided. Use a needle nose pliers to bend a hook in each end of the springs to attach in the outermost holes of the steering arm and the back edge of the control horn (see photo in section 23)

a.

Glue rear formers F8 through F13 in place on the main frame. They must be centered side-to-side. Note in the side view plan how these formers should be sitting straight up and down when the fuselage is propped up level - not installed 90 to the main frame itself.

b.

Glue in place the 1/4" sq. balsa Top Corner Stringers and the 1/4" sq. T.E. Cross-piece that goes on top of former F7. It may be necessary to soak the Corner Stringers in water to bend into shape between formers F7 and F9.

c.

Add the 3/16"x3/8" balsa Top Stringer.

d.

Put scrap balsa gussets on each stringer where they connect to the back of former F7.


e.

Glue on the 1/8"x1/4" balsa Side Stringers. When dry, use a sanding block to taper them near the front and the back as shown in the Fuselage Top View.

f.

Glue on the 1/8"x1/4" balsa Bottom Corner Stringers. Notice in the cross-section drawings that these are glued on flat against the main frame - not on edge as were the Side Stringers. Taper these stringers also, aft of F13, to blend into the end of the fuselage.

g.

Add 1/8" sheet balsa fill-in on the sides of former F13.

h.

Cut the Stab Mount Blocks out of the printed balsa sheet. Make sure that these are cut out very accurately and that they match each other. Glue them in place on the fuselage, allowing them to stick out slightly past the already-tapered Side Stringers. When dry, shape the sides of the Blocks down to blend into the stringers. Remember to maintain a constant 3/8" width at the end of fuse where the rudder will be hinged.

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i. Next you must prepare the die-cut plywood Tailwheel Mount (TWM) for installationon the bottom of the fuselage. Refer to the instructions on assembly of the Steerable Tailwheel Unit. Once you have the tailwheel assembled, hold it in position on plywood TWM and mark the hole locations for the 6-32 Mounting Bolts. Then epoxy the 6-32 Square Anchor Nuts to the top side of TWM. When dry, carefully inlet the bottom of the fuselage to accept TWM, and then glue it in place. Be careful not to get any glue in the threads of the anchor nuts.

j.

Shape the entire fuselage with a knife and sanding block to match the cross-sections. You will need to have the cowl at hand in order to get the shape of the nose area just right for a good cowl fit. Thus, refer below to the "Cowling" instructions and complete the cowl through step (6h.) at this time. Then come back and finish shaping the fuselage.

6.

Cowling

a.

Lay the left cowl half on the Fuselage Side View plan and scribe a small mark on the outside of it with a knife to indicate the exact location of the thrust line. This mark won't be needed until after the cowl halves are joined, but it is much easier to mark it now while the cowl will sit flat on the plan.

b.

Butyrate dope thinner, MEK, or cyanoacrylate adhesive can be used to assemble the cowl. Hold the plastic joiner in place on the inside of one cowl half. Leave half of the joiner strip extending over the edge so as to lap onto the other cowl half when it is attached. Flow a few drops of adhesive under the edge of the strip. It will spread along the seam by capillary action. Squeeze and hold together any area of the strip that is not down tight against the cowl. Be careful not to let the adhesive get under you finger, it will leave a finger print that may be hard to remove.

c.

After the joiner strip has dried in the first cowl half, hold the second half in place and carefully flow adhesive into the seam. Squeeze and hold together any areas of the seam that are open. Allow to dry thoroughly.

d.

Even up the back edge of the cowl with a sanding block.

e.

Due to its large size, the cowl needs to be strengthened by lining the inside with fiberglass cloth, stuck down with slow-drying epoxy glue or polyester glass resin. The first step is to sand the inside of the cowl with 80 grit garnet or similar grained sandpaper. Remove as much of the gloss from the plastic as possible. Don't worry about scratches in the plastic, a rough surface on the inside will help the cloth and glue stick better.

CAUTION: Never use.sandpaper coarser than 220 grit on the outside of the cowl! It will cut deep scratches in the plastic that may open up wider when paint is applied. Refer to section "Sanding and Painting Plastic Parts", in section 22.


f.

Cut a piece of Sig Regular Weight Glass Cloth (SIGGF001, not supplied) that will cover approximately half of the inside of the cowl. The cloth is stretchy and will flow most of the contours of the cowl easily. Trial fit the piece of cloth inside the cowl without any glue to see if you can get it to lay down without any bad wrinkles. If you have had no experience in applying cloth before, you might consider doing the cowl in 3, or even 4, separate pieces of cloth and batches of glue. It will take a little longer that way, but you'll probably do a better job.

g.

Mix up a batch of glue large enough for the area you've decided to cover in one step. Brush the glue onto the inside of the cowl, putting on as smooth a coat as you can. Lay the cloth in place and pat down until it's well saturated with the glue. Smooth out the cloth, pulling out any wrinkles. When satisfied with the job, mix up another small batch of glue and apply the next piece of cloth. (Note: An alcohol soaked rag is handy for wiping excess epoxy off your hands or off the outside of the cowL) After the entire inside of the cowl is covered, let dry thoroughly.

h.

When dry, trim off any excess cloth along the back edge of the cowl with a single edge razor blade or sharp X-Acto knife. If there are any big uneven spots or ridges inside the cowl, sand them down smooth so that they will not interfere with the fit of the cowl to the fuselage.

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i. Scrape the seam on the outside of the cowl to take out any rough spots or flaws. Low spots in the seam can be filled with Sig Epoxolite putty. Don't put on too much Epoxolite and expect to sand away the excess later. Epoxolite dries very hard and must be worked into its final desired shape before it hardens. Use your finger or a single-edge razor blade, dipped in water, to smooth the Epoxolite into the low spots along the seam. Let dry overnight, then sand the entire cowl smooth and scratch free with fine sandpaper.

j.

With a Dremel tool or X-Acto knife, cut an opening in the front of the cowl large enough for the engine's prop shaft and drive washer to fit through. Locate this hole according to the thrust line mark that you made on the cowl at the start of this section.

k.

Cut out the two small air intake openings in the front of the cowl. Refer to the Fuselage Front View plan for the exact size and location.

l.

A piece of 1/2"x1/2"x6" basswood is provided for making six equal 1" long Cowl Mount Blocks. After cutting them to length, epoxy the blocks in place on the front of the firewall, letting them stick out past the edge of the nose planking slightly. Mount the engine on the firewall. Slip the cowl over the engine and up to the Cowl Mount Blocks. Now you should be able to see where the blocks need to be taken down in order to fit properly inside the cowl. Use a sanding block to bevel and reshape the blocks as necessary until the cowl will slide back over the blocks and onto the fuselage.

m.

Tape the cowl in correct alignment on the fuselage. Drill pilot holes for the Cowl Mount Screws (#4 sheet metal type, furnished) through the cowl and into the Cowl Mount Blocks at the same time. Take the cowl off and open up the holes in it large enough to pass the mounting screws. Then put the cowl back on and thread the mounting screws into the blocks.

n.

Trim out the molded plastic Air Cleaner Cover to fit on the chin of the cowl. Leave a small flange around the edges for gluing. Hold the Cover in position on the cowl and draw around the outside of it with a pencil. Cut out the cowl plastic about 1/8" inside of the lines, so that cooling air will be able to flow through the Air Cleaner Cover and into the engine compartment. After this is done, glue the Cover in place and then cut open the front of it (within the framed area) with an X-Acto knife. This opening can be left wide open, or if you want a more scale appearance you can glue in a piece of plastic window screen (wait until after all painting is done).

o.

Trim out the Right and Left Dummy Engine Cylinder moldings along the lines shown in the photo. Leave a small flange, about 1/16" to 1/8" wide, along the back of the part where it will match the curvature of the cowl. The best procedure for trimming is to rough out the part with a heavy-duty scissors or shears, and' then finish the edges with a sanding block or Dremel tool. Next, carefully position the Right and Left Cylinders on the cowl using the plans and photos as a guide. Mark their location on the cowl with a pencil. Then carefully bond the cylinder moldings in place with dope thinner, MEK, or cyanoacrylate adhesive. Again, avoid getting adhesive on your fingers and making finger prints on the plastic.


p.

Trim out the Right and Left Top Shrouds according to the trim lines molded into them. The trim lines are not very prominent. Holding the parts up to a light will make the lines more visible. You can trial fit the Top Shrouds onto the Cylinders at this time in order to fine-tune the fit of the trimmed edges, but it is best if they are not glued on permanently until after the Cylinders and Cowl are completely painted. The Top Shrouds can be painted after they are in place.

q.

Make any small openings or other provisions where necessary to allow access to the needle valve and for hooking up the glow plug.

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Engine Cooling Notes
The most important factor in cooling a fully cowled model engine is to keep a constant stream of fresh, cool air moving through the cowling. Large volumes of air aren't necessary, just a steady flow of new air.

This is accomplished by having more exit area for the air than incoming area. Inadequate exit space can cause heated air to be trapped in the cowl, and this is what causes overheating and engine failure.
Consequently, on our prototype models, we provided for additional exit space by:
  1. opening up the bottom of the cowl at the rear, and
  2. cutting away the cowl plastic that is inside the dummy engine cylinders and then opening up the back of the cylinders themselves.
As an extra precaution, we also installed a baffle (made of sheet balsa) in the bottom of the cowl. It directs all of the air that comes in through the Air Cleaner Cover upward towards the engine cylinder before it can exit out the bottom opening in the cowl.

With the setup described here, we have never experienced any overheating problems with glow engines from .60 to .90 cu. in. You may need to use a little ingenuity with some similar tricks to insure that your engine installation runs cool.

Soldering Hint
When soldering a flat metal washer onto a wire part, it is very helpful to first slip a short piece of Sig Heat-Proof Silicone Fuel Line Tubing onto the wire and push it up tight against the washer to hold it in correct position for soldering (the following photo is not actually of the Cub's tailwheel assembly but does show a typical example of the method we're describing). The heat-proof tubing will not melt from the heat of soldering, and it will also keep excess solder from getting on the wrong side of the washer. After the solder cools, cut the fuel tubing off of the wire.

7.

Main Landing Gear

Assembly of the main gear requires the completed fuselage.

a.

Place the 3/16" Main Gear wire and the 3/16" Rear Brace wire into the grooved L.G. Blocks in the bottom of the fuselage. Note on the plan that the Main Gear wire should be perpendicular to the bottom of the fuselage while the Rear Brace wire should be angled forward to meet it near the axle. You will have to trim the groove in the rear L.G. Block slightly to allow the Rear Brace wire to swing forward.

b.

Using the soft copper wire supplied, bind the ends of the two 3/16" wires together near the axle, along with the 1/8" dia. Bottom Shock Strut wire that goes between them. Use tape, clamps, or whatever you can come up with to help hold the three wires in alignment while you wrap them. If the wires don't line up exactly right with each other, rebend as necessary to get them to fit properly. Make the copper wire wrappings as tight as you can, with each strand of copper wire right next to the previous one. There should be no gaps between the strands of copper wire. Don't worry about running out of copper wire, as we have included extra to help insure that you can make these bindings very strong.

c.

When you have the wires bound together in proper alignment, solder them securely with normal rosin core solder. It is not necessary to have them brased or welded - just be sure to use a soldering iron or torch with enough heat output to get the wires and bindings hot enough for the solder to flow smoothly. Also, use plenty of soldering paste to help the solder flow completely around and thru the bindings. Protect the fuselage during the soldering operation with a cloth so that dripping solder or paste will not fall on the wood. After both axles are soldered and cooled off, carefully remove the wires from the grooved blocks.

d.

Next bind and solder the 1/8" dia. Top Shock Strut wire in place at the top of the 3/16" Main Gear wire. Position this wire carefully before soldering - note in the front view on plan plate 4 that the middle bend of this Top Shock Strut wire should contact the middle bend of the Bottom Shock Strut wire so that they can later be bound together by rubber bands for flying. The rubber bands will serve as an effective shock absorber.

e.

After all the solder joints are cool, file and sand them to smooth out any prominent bulges in the bindings. Clean all joints with dope thinner or other suitable solvent.

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f. Cut a 1" long piece of wire, about 1/16" dia. or so, from left-over scrap pieces you undoubtedly have in your workshop. Form it into a shallow "V". Bind and solder it into the bottom of the Top Shock Strut. This serves as a hook for wrapping the rubber bands around both shock strut wires to as a shock absorber. (You can see this scrap wire hook in the pictures under "Bungee Cover Simulations".
Bungee Cover Simulations
Factory fresh J-3 Cubs had "leather boots" covering the bungee shock chords of the landing gear. Some recently restored J-3's have gone to airfoil shaped fiberglass or metal covers. You can easily simulate either type on your model.
Leather Boots: Cut two pieces of scrap balsa to approximately 3/4"x1"x21/2". Cut a groove halfway into each and epoxy them in place on the Bottom Shock Strut wire. Fill the groove with putty or epoxy glue. Carve and sand the balsa blocks to resemble the leather boots. Smear a thin coat of epoxy glue on the blocks. Sand smooth when dry. Finish as you do the rest of the landing gear.
Airfoil Covers: (See drawing on plan plate 4) Four molded plastic Bungee Cover halves are provided. Trim each out leaving a small flange around the outside. Notch the ends to fit over the L.G. wire. Groove 1/4"x 1/2"x21/2" balsa sticks and epoxy onto the wire. Shape the balsa pieces as needed to slip the Cover halves over them. When right. epoxy the Covers together and to the balsa and wire at the same time.

g.

A single sheet of 3/16" x 6" x 7" balsa is provided for fairing in the sides of the Main Gear. Cut out a right and a left fairing to fit between the 3/16" wires. Note proper grain direction on the plan. Epoxy the fairings in place and allow to dry.

h.

For maximum strength, we recommend that you completely cover the balsa fairings with regular weight fiberglass cloth and slow-drying epoxy glue (applying it like you did on the inside of the cowl). Lap the cloth past the edges of the wood, completely around the 3/16" wires, and onto the back side of the fairings. Sand smooth when dry.


i.

Set the completed landing gear in place on the fuselage. The wires are to be held in the grooved blocks with the four Nylon Landing Gear Straps provided. Notice in the next photo that the straps should be installed all the way to the ends of the grooved blocks, right up against the wire where it exits the block. This is done to insure that the landing gear cannot shift sideways in a rough landing.

To install the straps, first mark the hole locations.on the grooved blocks. Then use a 1/16" drill bit to drill a pilot hole in the blocks. Next screw the straps in place using the #4 x 1/2" Sheet Metal Screws provided.

8.

Stabilizer And Elevators

Carefully cut all of the stabilizer "S" parts and the elevator "E" parts from the 3/8" printed balsa sheet #9. A jig saw works best for cutting these out. Cut just outside the lines, leaving all of the line on the parts. When fitting into place in the structure, use a sanding block to bring the edges of the parts to an exact fit.
Cover the plan with waxed paper or plastic wrap. Pin all of the parts to the plan, gluing them to each other in the following order:

a.

Pin down the 3/8" x 1/2" balsa stabilizer trailing edge.

b.

Add the 3/8" x 1/2" balsa elevator leading edges and the 3/8" sq. spruce elevator joiner. Be careful not to glue these parts to the stab trailing edge while gluing them to each other.

c.

Fit in Sl-A and Sl-B.

d.

Add printed parts S2, S3, S4, S5, S6, S7 and S8.

e.

Fit in E1, E6, and the 3/8" basswood elevator horn insert.

f.

Add printed parts E2, E3, E4, E5, E7, E8, E9 and E10.

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g. Cut to length and glue in all 1/4" x 3/8" balsa ribs.

h.

Add 1/8" x 1/4" balsa braces where called for on the plan.

i.

When dry, unpin from the plan. Carve and sand all the outside edges round - remember the tail surfaces on the full-size Cub are constructed out of steel tubing, thus the leading and trailing edges are all perfectly round.

j.

Install the hinges where shown on the plan.
NOTE: Many modelers feel that the tail surfaces are easiest to cover before they are hinged. If you elect to do this, first test assemble the tail surfaces on their hinges without glue, to insure that a good edge and end match has been obtained in the sanding operation. Then refer to "Covering and Painting the Framework", section 19, and prepare all the tail surfaces (except the fin) through the point of covering and applying at least 2 coats of clear dope. After that, epoxy in the hinges permanently.

9.

Fin And Rudder

The fin and rudder are assembled over the plan in the same manner as the stab and elevators were.

a.

Pin the 3/8"x 1/2" balsa Fin Trailing Edge and Rudder Leading Edge to the plan. Do not glue to each other.

b.

Add R1 and R2 printed pieces.

c.

Shape and install the 3/8"x5/8" balsa Fin Leading Edge and Rudder Trailing Edge.

d.

Add R3 and R4 printed pieces.


e.

Shape and install the 3/8"x5/8" balsa Rudder Bottom.

f.

Cut to length and glue in all 1/4"x3/8" balsa ribs.

g.

Add RG-1, RG-2, and the 1/8"x1/4" balsa brace.

h.

When dry, unpin from the plan and sand the outside edges round.

i.

Inlet the bottom of the Rudder to accept the rudder horn. Epoxy the horn in place. Reinforce the installation with glass cloth and epoxy glue.

j.

Install the hinges where shown on the plan.


Dana Anderson warms up the Continential in his beautifully restored Piper J-3 Cub before departing Sig Airfield after a tour of our plant. Dana is a crop duster from Nebraska who likes to fly the J-3 just for fun. He's also an avid model builder.