Super

Chipmunk

Instructions

Another loop, roll and then a plunge earthward into a dive trailing billowing white clouds of smoke. Perilously close to the ground it pulls out and zooms a few hundred feet into a hammerhead stall. No, it isn’t Art Scholl performing at a summer airshow, its the C.G. version of his Super

Chipmunk at a R/C fun-fly. We’ve dedicated our model of the Super Chipmunk to the memory of its designer and creator, Art Scholl. His breathtaking precision aerobatics demonstrated to millions the safety and grace of disciplined flying.

Our Super Chipmunk’s super-stable, low speed manners let you fly at a crawl and it simply won’t quit. Bring it in a little nose high, and you’ll still have solid control to a perfect touch-down. Turn it loose and this performer will put on a airshow with all the flash and flair of the original.

Additional Items Needed:

† 4-5 channel radio

† CA glue and epoxy

† .45 to .61 (.90 4-cycle) R/C engine

† 2-1/4” CGP snap-on spinner

† Propellers, fuel tank and tubing to suit engine.

† 14 running feet of covering material

† Paint

† One 1-1/4” and two 3-1/4” Wheels

† Foam rubber

Optional Wing Flaps:

† CG 3/32” Strip Aileron Set

† CG True 1/16” pushrods

† 1/8” x 3” x 6” Aircraft Plywood

Tools & Supplies Needed

Miscellaneous rubber bands

Wax paper

Modeling knife or single edge razor blade

Sandpaper

Pins

Drill sizes:

1/16”, 5/64”, 3/32”, 1/8”, 5/32”, 3/16”, & 1/4”

Flat building board

Pliers

Small Screwdrivers

Iron for applying covering

Masking tape

CARL GOLDBERG PRODUCTS, LTD.

©Copyright 1988 Carl Goldberg Products Ltd.

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ASSEMBLING TOOLS

Die- cut beveling tools (from 1/8” ply)

TAIL ASSEMBLY

The stabilizer and fin are sheeted with 1\16” balsa, and their interior frames are 3/16” thick balsa. The elevator and rudder are not sheeted, and their frames are 5/16” balsa. for clarity, the stabilizer and fin are built first and then the elevator and rudder.

1

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First, glue narrow strip to handle, keeping them square, as shown above left. Then glue wide strip to handle and narrow strip, again keeping things square.

1

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Make stabilizer (stab) leading edge (LE.) from 3/16” x

1/2” balsa sticks. Cut balsa carefully to match with plan at center joint and exact length at tips.

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Pin in position, and glue at center joint.

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Using die-cut L.E. joiner, center platform, and

3/16”x1/2” balsa, glue outline together.

2.

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Cut two strips of 100-200 sandpaper to size shown above. Tack-cement sandpaper to tools as shown.

DIE-CUT SANDING TOOL

1.

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Glue one strip into handles notches keeping them square. Then glue remaining strip to other half of handles.

2.

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Cut one piece of 100-200 grit sandpaper to size of

2-1/4”x3”.

2.

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From 1/8” x3/16” strip balsa, cut all trusses to size over plan. Trim well-don’t force into place. Glue in place.

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Let dry thoroughly.

3.

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Assemble fin in same manner as stab, using die-cut and stick parts.

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Center 1/4” dowel over grit side of sandpaper. Roll sandpaper around it as shown above left.

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Slide dowel and sandpaper into tool and hold with rubber band as shown at right. Glue sandpaper to tool.

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4

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The die-cut balsa parts for elevator and rudder must be

on table.

Begin by gluing a 3/16” core between 1/16” top and bottom pieces. In this manner make two elevator tips and two inner ends as show

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Center second sheet under stab L.E. and glue in place.

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Cut out center slot in stab platform for fin post.

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Laminate rudder pieces in same manner,.

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Laminate center section.

5

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Assemble elevator halves and rudder in same manner as stab and fin, except use 5/16”x1/2” balsa for L.E. and 1/8” x 5/16” for trusses.

Carefully trim balsa sheet to match stab outline.

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Turn stab upside down and cover other side in same manner.

6a

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Flush edge of 1/16”x3”x24” balsa sheet even with stab

T.E. and allow a little extra at tip for trim off. Mark sheet

6b.

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Flush balsa sheet with fin L.E. and glue.

width on stab to show gluing limits.

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Remove sheet and apply CA to T.E., tips and trusses.

Turn stab over, position on balsa sheet and press down flat

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Use stab scrap to complete fin sheeting as shown.

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Trim sheet to match fin outline.

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7.

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Place fin and rudder over plan and mark hinge locations.

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Mark hinge locations for stab and elevator.

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Position elevator halves and joiner over plan, and carefully mark elevator L.E.’s for wire joiner location.

8.

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Using CG Center-line marker provided, mark centerlines along edges of parts as shown above. Tilt marker so guide pegs touch the wood, then lightly pass the marker back and forth. Point will scribe center line.

9.

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At locations marked in Step 7, make a slit wide enough for the JET Hinge to fit into.

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IMPORTANT! Although you are installing the hinge now, the hinges are not permanently installed until after the model is covered.

8

12

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Using no glue, TEMPORARILY attach elevator to stab and fin to rudder with hinges in place. Hold parts together with tape.

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First break corners with the sanding block. Then, follow low with stab sanding tool, rounding off all outside edges except bottom of fin and rudder. Blend stab and elevator at tip.

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Using a sanding block, flat sand stab, elevator, fin and rudder, smoothing out surfaces.

13.

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Remove tapes and separate elevator and rudder from stab and fin.

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Tape T.E. of elevator and rudder to work surface, using appropriate beveling tool, sand L.E. to center-line. Turn parts over and repeat beveling for other side.

15.

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For strength, the elevator joiner areas should be rein forced with nylon fabric as follows.

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Apply a dab of CA to the elevator and press one end of nylon fabric into it (cover finger with a plastic bag or similar).

14.

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Using no glue, trial fit elevator halves together with wire joiner. Carve a radius for better fit at wire bend. Elevator halves must lie flat on table and L.E.’s must be aligned. Punch a small pin hole through elevator at rear of joiner hole for glue squeeze-out. Glue joiner in place.

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Apply a squiggle of glue to elevator and pull nylon fabric down into it. Rub nylon into the glue with your finger.

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Continue gluing and apply nylon around elevator front and around to other side. Trim nylon Cut.

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Repeat this procedure and apply nylon on other joiner area.

T

his completes the tail assembly construction.

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Wing Assembly

PROCEDURE: The wing panels are assembled bottom side up and then turned over for joining and finishing.

IMPORTANT! Although the wing is a symmetrical section, because of internal structure (landing gear and aileron bellcrank mounts), some ribs are not symmetrical(such as Ribs No.

2,4,7,&8). As an aid for proper rib orientation, the tip spar notches for some ribs have only been partially laser cut.

IMPORTANT, wing assembly will begin with building a panel overt the “RIGHT WING” on the full-size plan, later on when it is turned over, this wing will of course become the left wing.

“Right” or “Left” wing refers to the panel being assembled during that particular step OVER THE PLANS.

Since the wing is built in two halves, and steps 1 to 17 are repeated in the process, two check boxes are provided with each of these steps. One for the right wing and one for the left.

Face ply doubler towards rib 4 location

Notched end

No notch here

2c.

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Using no glue, place platform ribs 3,9, & 14 on spar at their respective places over plan (position rib 3 so ply doubler faces towards rib 4)

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Rest notched Trailing Edge (T.E.) on rib platforms

(Important: the T.E. has no notch at one end-this unnotched end must be at wing center as shown).

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Press T.E. on rib 3 then slip ribs 9 & 14 into their respective notches,. Pin T.E. to ribs and rib platforms to building board. Glue ribs to T.E. and spar (avoid gluing T.E. to rib platforms).

Face ply doubler 5 towards rib 4

1.

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Position one main spar in place over RIGHT WING (or

LEFT WING) on plan. Align spar at center of wing on plan.

Hold spar in exact position by crosspinning at circled location on plan. CAUTION: Do not build two RIGHT WINGS!

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With landing gear slots facing up, set ribs 4 & 5 in position

(NOTE: rib 5 ply doubler must be facing rib 4).

2a.

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Lay parts out as shown. Glue plywood rib doubler 3 to rib 3 (IMPORTANT! Position slot in ply doubler at top edge of rib 3).

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Working one at a time, glue remaining ribs 2 to 8 & 10 to 15 to spar and T.E. (NOTE: slots in rib 2 must be towards upper rib edge, slots in ribs 7&8 must face up towards rear of wing as shown). Hold each rib straight up as it dries. IMPORTANT: for a warp free straight wing, make sure T.E. is kept straight and not bowed up or down, shim with balsa if required.

DOUBLERS MUST FACE EACH OTHER IN WING.

2B.

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Lay parts out as shown. Glue plywood rib doubler 5 to rib 5.

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3.

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Position the Set-Back Gauge (SGB) touching the bottom spar. Touch end of top spar to gauge, and set spar in rib slots.

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True top spar to all ribs.

6b.

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Align T.E. sheeting with center end of T.E. and adjust sheet so it is flush along T.E. Glue in place. If sheeting edge is not straight, let excess hang out over T.E. for trim off later.

6c.

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Gl ue 3/16”: Sq. x 36” balsa into forward rib notches. Cut to fit around L.G. mount. Balsa should project out from rib 2 about the same distance as main spar.

4.

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With slot facing out from wing, glue landing gear block to ribs 3,4,&5.

5a.

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Drill four 5/64” dia. holes(1/16” will do) at punchmark locations through aileron bellcrank mounting plates.

7.

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An opening for the L.G. mount must be made in the L.E.

sheeting. Begin by aligning 5/65”x3”x36” L.E. sheeting with front edge of spar and flush with spar end.

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Project and mark two lines straight back from the ends of the

L.G. mount and on to the L.E. sheet.

5b.

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Position aileron mounting plate in rib 7&8 slots, this part is designed to fit only one way. Glue plate in place.

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Slide sheeting over to side of L.G. mount. Align sheet with back of spar and measure and mark the front and rear L.g. block locations. Measure L.G. block locations from the back of the spar.

6a.

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Pin wing at outside of ribs 2 & 15 and T.E. and remove pins from interior area of wing.

11

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Cut the opening a little undersize at first and try in place.

Enlarge opening as required for proper fit.

8.

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Tape L.E. sheet in place along back edge of main spar. With taped edge acting as a hinge, lift sheeting up and apply glue to tops of all ribs and both spars. A shot of Kicker on the L.E. sheeting will help set things quickly. Carefully close sheeting and gently press it down

12.

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Glue laser-cut center sheeting in place, trimming to fit as required.

on glued structure beneath. (Moistening the sheeting’s outside surface can assist in bending it to air foil shape.)

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Allow wing structure to dry thoroughly

9.

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Glue laser-cut wing tip sheeting in place.

13.

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Remove all pins from wing structure and turn wing upside down.

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Trim excess T.E. sheeting flush with T.E

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Position a straight edge along front edge of outer ribs and mark a cutting guide line on the overhanging sheeting.

10.

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Glue laser-cut tapered L.E. sheet in place.

11.

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Install Mini-Snaps at both ends of 13-5/8” double threaded wire rod. About 1/16” of threads should protrude through Mini-Snap.

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Rough trim sheeting overhang to line, leaving about 1/8” of sheet for final sanding.

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Insert Mini-Snaps and rod into wing through rib holes just behind the spar. Temporarily tape Mini-Snap to aileron mount.

12

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Remove platforms from ribs 3,9,& 14.

14.

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Lay out wing supports as shown. glue together.

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Glue second torque block to first, making sure to align slots and angles.

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From 1/2”x1/2” triangular balsa, cut reinforcing gussets to fit as shown. Glue together.

18.

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Repeat steps 1 to 17 over “LEFT WING”on plan.

15.

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Using wing cradles, support wing and pin in position over plan.

16.

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Lay out laser-cut spar webs as shown. Glue spar webs to front of top and bottom spars.

19.

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With left wing on wing supports, pin in place on plan.

Position RIGHT WING in place next to it. Raise RIGHT WING tip and support it at rib No. 11 using laser-cut gauge. Note; gauge is shaped to fit under curved L.E. and angled T.E. sheeting. Hold gauge firmly to the rib by tack-cementing or stationery clamps, clothspins, etc.

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19.

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Study the entire center joint; all end parts of right wing should just touch those of the left ( tiny gaps are all right). If the fit between most parts is a little loose because one part protrudes too much, slightly sand only the protruding part for better fit. When sanding it is better to take off too little than too much.

20a.

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Pull wing panels slightly apart and slide aileron servo mount into forward slot in rib No. 2.

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FOR FLAPS ONLY. From 1/8” ply (not furnished) cut a flap servo mount using template on wing plan. Position flap mount in rear rib No. 2 slot.

20b.

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Using no glue, temporarily install ply dihedral joiners in left wing carefully insert them into rib notches. Hold joiners with laser-cut clamps.

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Reposition right wing next to left, engaging joiners and aileron (and flap) mounts in respective slots in Rib 2. Install joiner clamps on right wing and make a final check of center joint for good fit of all parts.

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Remove clamps and separate right wing.

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Glue joiners to left wing spars, and immediately reinstall clamps.

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Reposition right wing and pin to hold in position at center joint. Glue joiners in place and hold with clamps.

tapered fit with rib front.

22c.

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Glue block to mounting plate, and lower ribs.

22d.

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Position remaining small front rib over block and glue in place.

23a.

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Position T.E. sheeting on left wing. Trim sheeting to match center joint. Glue in place.

23b.

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Following same procedure as step 8, install L.E. sheeting on left wing.

23c.

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Install laser-cut tapered L.E. and center sheeting.

24.

Repeat step 23 and install top sheeting on right wing.

21.

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Remove narrow strip at bottom of rib No. 1. Position one half of one front rib No.1 so one side aligns with center line of wing.

Adjust rib to align with spar center joints. Glue in place. Glue remaining No.1 rib to first rib, making double thickness rib at center joint.

25.

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Trim and sand balsa L.E. sheeting flush with rib fronts.

22a.

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Glue dowel mounting plate to front dihedral joiner.

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Glue small filler rib at center joint.

22b.

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Mark and sand end of 3/4” Sq.x3-5/8” balsa block for

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26.

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Position Balsa L.E. and hold in place with tape as a hinge.

Open and apply CA (Slow dry Thick is good here) to all ribs and sheeting edges. Fold L.E. back into position.

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Fit 1/8” balsa rib 16 inside plastic tip. Slide rib towards tip front and flush it along all edges. Hold rib in position with a few drops of

CA, then apply more along all seams for permanent bond. Repeat for other tip.

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Check fit of tips on wing. Using CA, glue tips in place.

29.

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Position aileron exit sheeting pieces as shown on plan and glue in place (run aileron pushrods through slots.)

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From 5/64”x3/16” strips of balsa, cut cap strips to cover the exposed edges of all ribs top and bottom. Glue cap strips so they are centered over each rib.

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From the three 24” ailerons provided, choose the better two for the ailerons, the remaining one to be cut up for inboard T.E.s (and optional flaps.)

30.

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Position pre-cut opening of wing tips face down on flat sandpaper and wipe lightly a few times. Then, run your finger nail along edges to remove burrs.

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31.

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For “aileron only” wing cut parts over plan as shown above; two 24” long ailerons , and two 7-9/16” T.E. inboard sections.

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For “aileron/flap” wing cut parts as shown: two 19” ailerons, two 9-1/8” flaps, and two 3-1/4” T.E. inboard center sections. Cut over plan for exact size.

32.

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Using the center-line marker, make a center line along entire length of ailerons, (flaps), and wing T.E.

33.

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FOR AILERON-ONLY WING, continue with this step, for

FLAP wing proceed directly to Step 34.

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Glue inboard T.E. in position as shown above. Proceed to

Step 35.

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Using a sharp tool, make 1/16” deep grooves in T.E. and in inboard sections. Using threaded end of flap wire, file grooves to a rounded shape so half the nylon tubing will lie recessed in both the inboard section and the T.E.

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Cut two clearance slots about 5/8” from center joint in wing

T.E. and from inner ends of T.E. inboard sections.

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Using no glue at first, temporarily place horns in wing grooves, position both inboard sections and check for horn movement-top to move about 1” total fore and aft.

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Remove T.E. inboard sections, and carefully glue horn wire tubing and T.E. inboard sections in place (CAUTION: keep glue off wires).

34.

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FOR FLAP WING ONLY, cut nylon tubes to 3” length. slide nylon tube onto aileron horn wire. Repeat for other tube and wire.

35.

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Working over Wing Plan, transfer hinge locations shown on the plan to aileron (and flap) and wing T.E. When fitting aileron, keep it centered to allow clearance at ends.

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Press flap onto end of flap wire to make a mark, with a small nail, make a hole for the wire. Work carefully, keeping the hole centered inside the flap. Repeat for the other flap. Work carefully so that when finished, the threaded ends of horn wires tilt forward evenly with the flaps in position on pointed wires.

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Bend one flap horn as shown above. Hold threaded portion of wire at about a 45 degree angle. Firmly grasp UNTHREADED end of wire about 1/2” from end of nylon tube and bend wire horizontally 90 degrees. Check on table, adjust as necessary.

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Make second flap horn opposite to first by bending

UNTHREADED end as shown above.

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File bent ends to a slightly pointed shape for easier mounting of flaps later.

36.

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Using beveling tool “EA,” bevel front edge of aileron to centerline. Turn aileron over and repeat sanding. Repeat for other aileron.

16

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For flaps, follow this instruction carefully. Lay flaps side by side and upside down as shown. Using sanding tool “RF”, bevel only the front bottom edge of flaps up to center line (flaps only have to move one direction-down.

39.

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Apply a dab of CA to wing and stick one end of 3/4” nylon fabric to it. Let dry until the nylon is glued solidly to the balsa.

Flaps “up”

Flaps “down”

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Apply a squiggle of CA to wing and pull nylon fabric down into it. Rub nylon into glue with your finger (cover finger with plastic bag or similar).

37.

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Fill gaps, joints, etc. with a filler appropriate for balsa. Smooth out with applicator.

38.

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Using 240 grit sandpaper, flat sand entire wing to blend surfaces and remove high spots.

17

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Temporarily hook-up the aileron servo to the receiver and battery, turn R/C system on and with the transmitter aileron stick and trim tab at neutral, make sure the aileron servo arm is in vertical position(pointing straight up & down relative to wing).

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Position servo inside wing on ply mount, carefully align bellcrank pushrods with servo arm. Drill holes as required through plastic mount and screw it to ply mount with #2x3/8” sheet metal screws.

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Mount optional flap servo in same manner behind aileron servo as shown on plan.

4.

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Enlarge rough wheel opening by lightly tracing the raised outline with a sharp knife. Work slowly, making several passed, making the cut deeper each time.

3.

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Connect Mini-Snaps to opposite ends of servo arm. For balanced aileron movement, check that both aileron bellcranks are parallel to the wing T.E., make adjustments as required to Mini-Snap connections at bellcranks.

WHEEL PANTS & LANDING GEAR

5.

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Glue a pair of half round ply pieces inside pant, on both sides of slot.

6.

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Using a 3/16” dia. drill, open hole on side of pant (do not drill slotted side).

1.

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Rub cut edge of wheel pants over sandpaper and clean burr off edges.

7.

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Using L.G. axle (longer end) into pant. Axle should protrude out pant. Position nylon hold-down over wire at pant side as shown.

2.

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In the bottom of the four pant halves there is a slightly raised area, this will be removed for the wheel opening. Cut a rough opening in this area of all four pant halves as shown-but stay about 1/8” in from raised line.

3.

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The pants are designed so one half fits inside the other. Position one pant half (with side slot) inside pant half without slot. Adjust parts for good fit, with about 1/16” to 1/8” overlap. Glue halves together with a few drops of CA around seam.

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Assemble other pant in same manner.

Mark, drill, and mount with a #2x3/8” sheet metal screw. At side slotted end, use #2 shoulder screw. If L.G. wire fits loose under holddown, remove L.G. and glue scrap plastic shim in slot. To remove pant, simply snap hold-down off shoulder screw and rotate it away from L.G. wire.

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Reglue all pant joints using CA. glue.

This completes the wheel pants. They can be used as is and simply apply decals to them later. Or, if desired, the seams can be filled, sanded smooth and the pants painted.

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FUSELAGE ASSEMBLY

1.

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Carefully remove all fuselage (fuse) parts from laser-cut sheets.

Lightly sand any rough edges.

4.

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Be sure sides are laid down left and right as shown.

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Temporarily position fuse doublers on fuse side, checking fit and placement before gluing.

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Glue fuse doublers in place.

2.

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With side stamped “A” facing out, position two 1/8” ply formers

“A” (firewall) together, matching all edges. To hold them in alignment, tape them securely together along one edge as shown at right. Have four ply clamps ready for next operation.

5.

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Position former doubler “AA” on firewall so that mark at top of firewall is centered in notch in “AA” and match curved edges of parts.

3.

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Open firewalls and apply a liberal amount of glue to one part as shown on left.

6.

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Glue ply former doubler “BB” to bottom of former “B”. Hold until dry with firewall clamps.

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From 1/8”x1/2” balsa, cut and glue strips to match formers as shown. Apply strips as shown below.

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At center-punch mark drill a 1/4” hole through former.

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Keep edges aligned as you close firewalls and tape opposite edges together, squeeze firewalls together using laser-cut clamps.

When dry, remove clamps and tapes; set clamps aside for use later.

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7.

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Tack-cement the engine between plastic engine bearers, holding it vertical and parallel to mounts.

9.

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Mount propeller and spinner on your engine. Position engine over fuse top view on plan and compare it to the installation shown.

Back of spinner, should protrude about 1/8” beyond the cowl front as shown on the plan. Hold engine in this location. For long 4-cycle engines, check for at least 1/8” clearance between engine rear and firewall; to obtain this clearance the engine may have to be shifted forward as required. Measure the distance from the engine rear to the firewall. Write this measurement down it will be used later for engine mounting.

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Position engine/mounts on firewall for side mounted or inverted installation. Center-alignment marks are molded into engine mount bases; align these marks directly below the engine mounting flanges with the corresponding laser-marked line on firewall. Then measure and position mounts so they are equally spaced from second lasermarked line

10.

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Position one engine mount, butting its rear flange against the firewall location shown on the plan. Observe how the front engine mounting holes relate to the engine mount. If there is at least 1/4” of mount forward of this hole location, the spacer plate shown on the plan is not needed and you should proceed directly to step 11. If there is doubt that the mounts do not project far enough for adequate drilling and engine mounting, the spacer must be installed by completing the steps below. (Note for 4-cycle engines, make sure the spacer does not obstruct the carburetor, cut out spacer center if required for clearance).

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Mark straight down through holes in mounts.

8.

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Drill four 5/32” holes at marked locations.

21

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Position 1/4”x2-1/8” ply spacer on firewall so that it lies equally spaced over holes (trace spacer shape on firewall, to check position).

Glue spacer in place.

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Turn firewall over, at hole locations, drill 5/32” holes through

1/4” spacer plate.

12b.

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Hold fuse tail ends up, carefully spread fuse rear open, and plug former “E” in place, hold with a rubber band. Working towards front, install formers “C” and “D” (balsa doublers facing in towards each other) in same manner, using rubber bands to hold parts.

11.

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Permanently install four blindnuts in back of firewall using socket head screws and washers to pull blindnuts up into the screw holes as shown (firewall with spacer plate shown for clarity). Remove screws after seating blindnuts. Glue blindnut flanges to firewall.

12c.

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With laser-cut separation at tail end facing down, insert top sheet under rubber bands at former “B”, and work it towards tail, slipping it under bands as you go.

12a.

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Place fuse sides one on the other, tape rear together around the back end. Spread fuse fronts apart, and plug former “B”

12e.

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Lock tabs at sides and ends of top sheet into corresponding notches in fuse sides. Hold parts with tape.

into holes in body sides (doubler “BB” must face forward). Hold parts together with a rubber band.

12f.

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Position bottom sheet in same manner, sliding it towards rear.

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13.

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Install firewall and pull fuse fronts together with tape as shown.

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From 1/2”x1/2” triangular balsa, cut reinforcing gussets to fit behind firewall. Glue in place.

14.

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Place fuse over TOP VIEW on plan sheet. Viewing from above, carefully align the fuse to match plan outline. If an area of the fuse is off, adjust that position in the direction required. Tape parts to hold in position.

17.

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Set wing in place on fuse, then check and adjust until wing tips are equidistance from rear end.

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Project two lines straight forward from fuse sides on wing bottom.

15.

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When satisfied with alignment, permanently glue sides, formers and sheet parts in place. Apply a bead of CA along all joints inside and outside, or from both sides.

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Position a 1/8” ply bolt plate about 1/8” away from line and so that laser-marked line is aligned with T.E. joint as shown. Glue in place. Repeat for second bolt plate.

In the case of formers-it will penetrate the joint and leave a slight reinforcing fillet.

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At tail end, glue bottom sheet to conform to slight bend in fuse sides.

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Measuring carefully 1-7/16” from wing T.E. and 9/16” in from fuse sides, drill two holes 5/32” dia. down through wing and bolt mounting blocks.

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Glue two large washers at hole locations.

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Remove wing from fuse. Install blindnuts in bottom of mounting blocks, pulling them up in place using screws and washers.

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Install wing using bolts. Check alignment of wing and fuse at front. At hole in former “B”, drill a 1/4” dia. hole about 3” deep into wing (try to hold drill square and level into wing).

16.

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Plug 1/8” laser-cut braces into slotted locations in fuse doublers and glue securely in place.

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Position and glue wing mounting blocks. reglue these joints thoroughly, the wing attaches here-it must be strong.

23

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Cut 1/4”x4-1/2” dowel to 3” length. Remove wing and glue this dowel securely into wing, leaving about 1/4” protruding.

22.

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A 1/8” square balsa strip must be glued to the fuselage top to serve as a gluing brace for the top sheeting. Since the front sheeting is thicker than the rear, the front strips are spaced differently than the rear as described below.

18.

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With laser-cut separation facing out, bend and position front bottom sheeting. Glue in place.

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From 1/8” square balsa strip cut two pieces to fit from bottom notch in former “TC” to “TE”. Keeping strips about 1/16” in from and parallel to fuse edge, glue to top.

19.

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Trial fit the tail wheel bracket at laser-cut separation in bottom sheet. Using a knife or small saw, make a slot for bracket flange as required for correct fit. DO NOT GLUE bracket in place at this time!

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Install remaining 1/8” balsa strip in bottom notches in former

“TC” forward to firewall-position this strip 1/8” in from fuse side.

20a.

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Cut wing fairings from vac-formed sheets and try fitting them at L.E. and T.E. Cut out bottom of fairing holes and trim hole walls to match washers. Position fairings for best fit with fuse and glue to wing.

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From 1/4” square balsa cut and glue three top sheeting supports to fit notches in formers “TC”, “TD”, and “TE”.

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Cut three more supports and glue to notches in forward formers

“TB”, “TA” and firewall.

20b.

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From scrap 1/8” balsa, glue and trim lower tail end sheeting.

21.

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Install top formers “TA”, “TB”, “TC”, “TD” and “TE” in their respective slots in top fuse top (IMPORTANT: tilt formers TB and TC using gauge “TBTC” as shown below).

24.

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The three rear sheeting pieces are oversize wedge shapes and are designed to be shifted back and forth for best fit.

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Begin sheeting installation with one side. Slide sheet in position so lower edge butts against fuse side and upper edge fits about centered on 1/4” balsa support. When satisfied with fit, glue sheet in place

(slight dampening of outer balsa surface will help curve it to fit fuse shape).

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Install opposite side sheet in same manner. Trim sheets flush with front of former “TC” and rear of “TE”.

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Slide top center sheet in position and glue in place. Trim to fit with side sheets.

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Flat sand fuse and round off corners, except the following areas: top of tail mounting area, and wing saddle-repeat: do not sand these areas, except very lightly to remove burrs.

25.

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Install 1/8” laser-cut front sheeting in dame manner, applying side pieces first. Where 1/8” balsa butts against former “TC” glue a scrap of 1/8” sq. inside to reinforce the joint.

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Carefully remove scrap areas from formed cockpit as shown above.

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Gently bend cockpit front, rear, and sides along formed seamsdo not bend sharp or plastic will crack.

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Temporarily place cockpit inside fuse, trimming as required for good fit.

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Remove cockpit and set aside for painting.

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Bolt wing in place.

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Center stab on fuse, measuring to obtain equal distance from side to side, and from nose of fuse to rear corner of each stab tip. View from rear to make sure that stab is level in respect to wing.

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Trial fit fin in place, making sure that it points dead straight ahead.

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When tail parts are aligned and square with fuse, make several reference marks. Remove fin and stab.

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Using slow CA or epoxy, glue stab and fin in place. While drying, check parts for square and alignment.

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Glue balsa filler pieces to fuse at front of stab.

COWL ASSEMBLY

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Cut 7/8” sq.x16” balsa block into two 8’ pieces. Then, taper sand to pointed fairing shape as shown in photos above and fuse views on plan.

1.

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Using the measurement from step 9, position and tack-cement engine on mounts (engine must parallel mounts and point straight out from firewall).

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Carefully mark through engine mounting holes to mounts.

Remove engine. Drill four 1/8” holes straight into and through mounts.

#6 x 3/4” screws

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Install engine, muffler, and propeller and spinner.

2a.

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Cut cowl halves apart at center. Trim to match formed curved lines as shown in photo above.

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Glue fairings in place.

b.

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Cut out opening for prop shaft and front air intakes.

30.

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Refer to fuse views on plan for installation of rudder pushrod guide tube through balsa fairing. Using a sharpened 1/8” wire, drill a hole for the rudder pushrod guide tube through balsa fairing and former “TE”.

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Position nylon rudder and elevator guide tubes in fuse as shown on plan (insert long threaded rods to hold tubes straight). Glue nylon tubes in place where they exit fuse rear. From scrap ply, cut braces to support tubes at formers “C” to “D”. Glue tubes to former

“C”.

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Remove wire rids and trim nylon tubes flush where they exit fuselage at rear.

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Later, when installing your radio equipment , we recommend running the receiver antenna into the rear of the fuse. To make this easier to do, glue a length of plastic tubing, drinking straws, etc. from former “C” to “E”.

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To protect the engine area from becoming oil soaked, it needs to be “fuel-proofed”. Either polyurethane, CA, or epoxy is good for this. Apply your fuel proofer to entire engine area, firewall, sides and fuse front. Open up screw holes with toothpick while paint is wet. Let dry thoroughly.

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c.

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Try fitting cowl half in position over engine (allow about 1/8” space between cowl and spinner). Observe and mark where openings must be made in cowl for engine/muffler clearance. Begin making these openings, cut a little at a time, trying and fitting and enlarging openings as needed. Do not try to rush this or you may ruin the cowl or worse yet cut yourself.

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Try fitting other cowl half in place, cutting openings for engine/muffler as required.

d.

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When both cowl halves fit around engine, tape them together at center joint. Check for overall fit of cowl, match-up with spinner, etc.

If cowls must be overlapped to fit, mark and trim the overlap until both halves butt fit at center joint.

Lower strip must be cut into small segments in order to fit around curves.

e.

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Glue cowl halves together.

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Attach cowl to fuse using #2 x 3/8” screws and washers. At lower side screw locations, make spacers from scrap ply to fill gap between cowl and fuse. Glue spacers to fuse sides.

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From long plastic strip furnished, cut and glue a joining tab along the inside edge of one cowl half as shown.

IV COVERING

General. A good covering job should be preceded by careful sanding, filling nicks and dents, then more sanding. Use filler appropriate for balsa such as CG Model Mate. Any irregularities in the wood surface will show on the covering so a smooth sanding job is a must for good appearance. For final sanding, use fine sandpaper (grade 240 to 320) and a sandpaper block.

IMPORTANT! Raw fuel and engine oil residue, if allowed to puddle or stand, can eventually deteriorate the finish, resulting in loose edges of the covering and striping, peeling paint, etc. Wiping the model down after each flight will help maintain your plane’s finish for years.

Engine exhaust often affects details such as striping, etc. Careful applications of CA along the edges will hold them down securely in place.

As mentioned earlier, the easiest way to finish your Chipmunk is to cover it in one color and then either paint it or apply the color scheme cut from covering material. Follow the manufacturer’s instructions regarding applying multiple color paint schemes. If painting the color scheme, polyurethane spray paint is recommended.

Now is a good time to paint the cowl and canopy frame detail so they can be set aside to dry while you are covering the airframe. Cowl should be sanded smooth and joints filled with material suitable for plastic. ‘Wipe down completely with a tack rag to remove all dust.

Mask areas to be painted.

Read instructions on paint can, and follow them. The first coat should be applied very lightly. Do not try to cover in just one coat or the paint will run! Repeat applications, gradually building up color density while allowing time between coats as specified by the paint manufacturer. Let final coat set a bit, then remove the masking tape carefully. Set aside away from your work area so it can dry free from dust or other damage.

PAINTING PLASTIC FILMS. Modeling grade polyurethane or epoxy paints are recommended. To assure good paint adhesion to the plastic covering, the area to be painted should be washed with soap and water to remove surface grease and oil. Then dry thoroughly. You can also clean the surface with acetone. The design is then carefully masked; vinyl tape is best for this. Optional: gently wipe masked area with 000 steel wool to dull plastic surface for increased paint adhesion, being careful not to disturb the masking tape.

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