INSTRUCTION MANUAL E! Z I S .40 DE MA Wingspan (Standard): 76.5 in [1,945mm] Wingspan (Clipped): 61.5 in [1,560mm] Wing Area (Standard): 820 sq in [58.9dm2] Wing Area (Clipped): 653 sq in [42.1dm2] Weight: 6.5-7.5 lbs [2950-300g] Wing Loading: 18-21 oz/sq ft [55-64g/dm2] Length: 49 in [1,245mm] Radio: 4-channel transmitter with 4 standard servos Engine: .40-.61 cu. in. [6.5-10cc] two-stroke .48-.80 cu. in. [8-13cc] four-stroke IN A US WARRANTY Great Planes® Model Manufacturing Co.
Building the Seats (Optional) .....................................40 Build the Landing Gear Suspension (Optional) .........40 Build the Dummy Engines .........................................41 Other Scale Details....................................................42 Install the Windshield .................................................42 Install the Side Windows............................................43 Balance Your Model ...................................................
quality. If any parts are missing, broken or defective, or if you have any questions about building or flying this airplane, please contact Great Planes at the address or telephone number below. If you are contacting us for replacement parts, please be sure to provide the full kit name (Piper J-3 Cub .40) and the part numbers as listed in the Parts List. PROTECT YOUR MODEL, YOURSELF & OTHERS...FOLLOW THESE IMPORTANT SAFETY PRECAUTIONS 1.Your Piper J-3 Cub .
❏ ❏ ❏ For the best scale effect, an OS .48 Surpass 4-cycle is ideal. For maximum aerobatics, an OS .70 Surpass 4-cycle is all the power you will need. This kit includes a Great Planes EM4070 engine mount that fits most .40 - .60 2-cycle engines and most 40 - .70 4-cycle engines. (4) 3/16" Wheel Collars (GPMQ4308) (2) 3/32" Wheel Collars (GPMQ4302) (2) Rolls Top Flite® MonoKote® covering (TOPQ0220, Cub Yellow) Adhesives & Building Supplies In addition to common household tools (screwdrivers, drill, etc.
❏ ❏ ❏ ❏ ❏ ❏ ❏ ❏ ❏ ❏ ❏ ❏ ❏ ❏ ❏ ❏ ❏ Pliers with wire cutter (HCAR0630) Robart Super Stand II (ROBP1402) 18" x 24" [460 x 610mm] Builder’s cutting mat (HCAR0455) 16" x 48" [410 x 1220mm] Building board (GPMR6950) Masking tape (TOPR8018) Threadlocker™ thread locking cement (GPMR6060) Denatured alcohol (for epoxy clean up) Z-bend pliers (HCAR2000) Rotary tool such as Dremel® Moto-Tool® Rotary tool reinforced cut-off wheel (GPMR8200) Servo horn drill (HCAR0698) Dead Center™ Engine Mount Hole Locator (GPMR8130) A
TYPES OF WOOD GET READY TO BUILD 1. Unroll the plan sheet. Re-roll it inside out to make it lie flat. 2. Remove all parts from the box. As you do, figure out the name of each part by comparing it with the plans and the parts list included with this kit. Using a felt-tip or ballpoint pen, lightly write the part name or size on each piece to avoid confusion later. Use the die-cut drawings shown on page 7 to identify the die-cut parts and mark them before removing them from the sheet. Save all scraps.
DIE-CUT DRAWINGS 1/64" = 1/32" = 1/16" = 3/32" = 1/8" = 5/32" = 3/16" = 1/4" = .4 mm .8 mm 1.6 mm 2.4 mm 3.2 mm 4.0 mm 4.8 mm 6.4 mm METRIC CONVERSIONS 3/8" = 1/2" = 5/8" = 3/4" = 1" = 2" = 9.5 mm 12.7 mm 15.9 mm 19.0 mm 25.4 mm 50.8 mm 7 3" = 6" = 12" = 18" = 21" = 24" = 30" = 36" = 76.2 mm 152.4 mm 304.8 mm 457.2 mm 533.4 mm 609.6 mm 762.0 mm 914.
TAIL FEATHERS Build the Rudder ❏ 3. Cut the four Ribs from the 3/16” x 1/4” x 24” balsa stick (CUB4SO4). Fit the ribs into the rudder frame and securely glue them in place with thin CA. ❏ 4. Remove the Rudder from the building board and inspect all the glue joints on the bottom side. Add thin CA to all the tight fitting joints and thick CA to any open joints. NOTE: The process of re-gluing the joints on the bottom side is necessary on the thick balsa parts.
make sure all the joints are good and tight. Securely glue all the joints with thin CA. Note: The bottom end of the trailing edge stops at the top edge of the horizontal stabilizer. ❏ 8. Check the plans and mark the location of the tailgear on the rudder. Drill a 7/64” hole in the rudder 3/4” deep (the hole is drilled slightly oversize to allow room to create a hard epoxy “sleeve” around the wire). Then groove the rudder LE to accept the tailgear wire. ❏ 3.
❏ 2. Position the S1 and the two S4’s over their locations on the plans. Check the fits of the joints and sand them if necessary. Pin them in place. ❏ 2. Cut the Elevator LE from the 1/4" x 3/4" x 24" balsa strip (CUB4S03) and pin it in place. Glue all the joints with thin CA. ❏ 3. Cut the elevator Ribs from the 3/16" x 1/4" x 24" balsa ❏ 3. Cut the Stabilizer TE from the 1/4" X 3/4" X 24" balsa stick (CUB4SO4). Fit the ribs in the elevator frame and glue with thin CA. strip (CUB4S03).
❏ 11. Test fit the joiner wire into both elevators. Position the elevators against a straight edge to check for straightness of the LE with the joiner wire installed. Adjust the holes if needed to achieve a straight LE. ❏ 2. Cut the hinge slots on the centerlines which you previously drew, using a hobby knife following the recommended hinge slotting technique listed below. NOTE: For pinned hinges use a slotting fork and slotting hook. ❏ 12.
first two #3 ribs. Keep the plans aligned and tape the inner and outer halves together. The plans are now ready to use for the clipped wing version. Align the end of the spar with the outboard edge of rib #7. The spars are cut slightly too long, and the excess will be cut off later at the center of the wing. ❏ 1.Tape the plan to your flat work surface. Align a straightedge on the wing centerline and draw a continuous line extending out past the leading and trailing edges.
❏ ❏ 9. Carefully inspect the notches in the die-cut 1/8" balsa Outboard TE (CUB4F03). The 1/8" wide notches are to be aligned with the #6 rib locations. Insert the tab on the die-cut outboard TE into the slot at the aft end of the #4 rib, with the notches facing up. ❏ ❏ 14. Trim the bottom sheeting in the aileron area, along the #4 rib and the outboard TE to the end of the sheet. Maintain a straight cut past the #7 rib location.
❏ ❏ 23. Install rib #2 by sliding it in between the spars and the #7 rib. Align the top notch in the wing tip brace with the #8 rib on the plans and glue the brace in place. Make sure the “legs” of the brace are parallel with the spars. twisting it into place. Center it on the LE and glue it with thin CA. Do not glue it to the spars yet! Note: Maintain a 1/16" gap between the bottom edge of the rib and the work surface to allow for the center sheeting which will be installed later.
❏ ❏ 30. Remove the wing panel from the work surface and install the 1/8" x 1/4" x 33-1/2" Bottom Forward Spar (CUB4W12) following the same procedure used in step 25. ❏ ❏ 27. Place the die-cut 1/8" balsa triangular Gusset (CUB4W01) in the corner formed by the #4 rib and the tapered TE. Securely glue it in place. ❏ 31. Go back to step 4 and build the other wing panel. Joining the Wing Panels (Photo taken at a later stage of completion.) 28.
❏ 6. Securely glue the remaining four 1/16" balsa vertical grain shear webs to the front and back sides of the main spar joiners between the #2 and #3 ribs. ❏ 3. Trial fit the dihedral brace between the main spars of the wing. Sand the edges of the dihedral brace if necessary to get it to fit without forcing the spars apart. ❏ 7. Install the two #1B ribs as shown in the photo. The top surface of each rib should be flush with the top surface of the spars. ❏ 4.
❏ 10. Glue the die-cut 1/16" ply TE Joiner (CUB4W05) in place between the #1B ribs as shown in the photo. (Wing is upside down in photo.) 13. Hold your aileron servo in position against the servo rails and mark where to drill the mounting holes. Drill 1/16" holes at each mark and mount your servo using the screws provided with the servo. NOTE: The screws are installed from the bottom side of the servo lugs. ❏ Install Aileron Linkage ❏ 14.
❏ 20. Cut the 36" long Outer Pushrod Tube (PLTB011) into two 18" long pieces. Scuff up the outer surface of each pushrod tube with 150 grit sandpaper so the glue will adhere better. Slide the 18" long outer pushrod tubes over each aileron pushrod wire. ❏ 17. Cut eight pieces of the Inner Pushrod Tube (PLTB004) approximately 1/4" long to make the pushrod wire spacers. Slide four spacers on each of the 24" long pushrod wires. Space them out on the wire as shown on the wing plan.
❏ 5. Wet the LE sheeting with a wet paper towel from rib #7 to the end of the sheet. Form the sheeting down against the wing tip and glue along the LE and the edge of the wing tip. Hold the sheeting against the wing tip until the glue sets. Trim the sheeting even with the wing tip. ❏ 2. Prepare the 1/16" x 1-1/2" x 36" balsa Top Leading Edge Sheeting (CUB4W25) by sanding the front edge to a slight bevel so it will fit snugly against the LE (check by trial fitting). ❏ 6.
the edges smooth with a piece of fine (220 grit) sandpaper. Use extreme caution to avoid cutting into the spars! Install Center Sheeting ❏ 1. Use a sanding block to sand off any excess epoxy on the top and bottom of the spars in the center of the wing. Also lightly sand both the tops and bottoms of each rib to remove any glue bumps or other irregularities. ❏ 5. Trim a piece of the 1/16" x 3" x 14-7/8" center wing sheeting to fit between the spar and the bottom LE sheeting.
❏ 8. Sand the front and side TOP edges of the die-cut 1/16" plywood Wing Bolt Plate (CUB4W05) to a feathered edge. Leave the TE square. The top of the wing bolt plate has the embossed centerline and punch marks on it. Align the embossed centerline with the centerline of the wing and securely glue the wing bolt plate to the top of the wing TE so the punch marks are showing. ❏ ❏ 5. Use a razor plane and a T-bar or other good flat sanding block to shape the ribs to the cross section shown on the wing plan.
plans. This goes on the bottom of each aileron. Sand it to match the shape of the ribs. Install Ailerons NOTE: Do not glue the aileron hinges until after your model has been covered. ❏ 1. Lay the ailerons on the plan and mark the hinge locations on the ailerons. Center the ailerons in the wing panels and transfer the marks over to the wing TE. ❏ 2. Cut the hinge slots in the ailerons and wing TE using a hobby knife. (The suggested procedure was given on page 11). ❏ 3.
❏ ❏ 3. Remove the fuse side from the plans and inspect the glue joints for gaps, adding thick CA glue to any open joints. Sand the glue joints smooth on both sides using a T-bar and 150-grit sandpaper. against the aileron pushrod outer tube and glue them to several of the ribs as shown in the photo. Securely glue the outer pushrod tube wherever possible. ❏ 9.
❏ 9. Test fit the two die-cut 1/8" balsa Aft Fuse Tops (CUB4F05) together. Sand them if necessary to achieve a good fit and glue them together as shown in the photo. ❏ 13. Glue one of the 1/8" x 2-3/8" x 2-3/8" ply Firewall Doublers (CUB4F18) to former F1B so that it is centered over the engine mount holes as shown in the photo. After the glue cures, drill the engine mount holes through the firewall doubler as well.
Assemble Fuselage ❏ 4. Position the right fuse side in place so all four formers key into their slots. Tack glue the fuselage side to the formers. Do not apply glue to the joints near the TOP of former F3, because you will later (step 6) have to spread the fuse sides to install the wing mounting block. ❏ 1. Test fit Former F2 in place on the left fuse side so that F2B is in front of F2A. Press it down into its slots and use a 90 degree triangle to keep it perpendicular to the fuse side.
❏ 8. Insert the top tab of the die-cut 1/8" ply Cabin Brace (CUB4F12) into the notch at the bottom of former F2B. Insert the die-cut 1/8" ply Top Tank Floor (TTF) (CUB4F09) with the embossed “TTF” facing upward, rear tabs into the top notches of former F2. Allow the cabin brace legs to key into their notches in the top tank floor. Glue the top tank floor at the F2 notches only. LTF and TTF lay on the ledges formed by the fuselage doublers. ❏ 11. Go over all the joints, gluing them securely with medium CA.
❏ 14. Cut two 4-3/4" long sheets from the 3/32" x 3" x 12" balsa Nose Sheeting (CUB4F16). Glue one piece of sheeting to the right fuselage side and stringer so the corner of it is against the cabin side. Do not bend it around the firewall yet. Firmly apply two or three 15" long pieces of strapping tape to the sheeting. Wet the outside of the nose sheeting with a paper towel and allow it to soak for about 5 minutes. Carefully pull the strapping tape around and stick it to the other fuselage side.
❏ 2. Place the left side of the engine mount on the mount spacer and center it on the diagonal lines you just drew. Mark the mounting holes on the diagonal lines and then drill a 3/16" hole at each mark. NOTE: You will not glue this doubler to the firewall. It is used as a spacer only. Later, if you decide to change to a 4-cycle engine, you can easily remove the spacer. ❏ 20. Insert the die-cut 1/8" ply Top Deck Former #4 (CUB4F11) into its slot at the tail end of the balsa aft fuse top.
❏ 6. While the engine is still mounted, determine where the Final Fuselage Assembly fuel lines and the throttle pushrod should pass through the firewall and mark these locations. NOTE: With most tank and engine combinations, the fuel lines can pass through the center of the mount. ❏ 7. Remove the engine from the engine mount and drill 1/4” holes for the fuel line holes. Center the mount on the centerlines embossed on the firewall. ❏ 1.
❏ 4. Sand the bottom edges of the fuselage smooth with your sanding block. Use the 3/32" x 2-3/4" x 24" balsa Bottom Sheeting (CUB4F15) to sheet the bottom of the fuselage from the grooved landing gear block forward and from the landing gear block aft. NOTE: The sheeting is applied with the grain running across the fuselage. Trim and sand the bottom sheeting even with the fuselage sides and round off the bottom corners as shown on the fuselage cross-sections. ❏ 2.
tubes flush with the covering supports. Sand a slight taper into the covering supports so they will not bulge the covering when it is applied. ❏ 6. Refer to the fuselage plans to determine the placement of the 3/16" x 3/16" x 36" balsa Fuselage Side Stringer (CUB4F15). Cut a notch 6-1/4" from the front of each stringer to allow it to bend. Glue the stringer in place with thin CA.
Install Main Landing Gear ❏ 3. Position Nylon LG Straps (NYLON36) over the landing gear wire approximately 1" from the bends in the landing gear wires. Mark the locations of the mounting screws on the grooved block. Drill a 1/16" hole at each of these marks. ❏ 1. Using a flat file, chamfer the ends of the main landing gear wire to remove any sharp edges. Note: For best ground handling, the main landing gear should have one or two degrees of “toe-in.
shown in the photo. Cut the protruding part of each #2 x 3/8" screw off on the outside of the fairings and sand (or file) the screws flush with the fairing. Use a small rubber band near the wheel end of the fairing to allow the strut to move against the fairing. Remove all the screws and apply thin CA to each of the holes to harden the wood. You can leave the fairings off until after the plane is covered. ❏ 3.
Install Servos, Horns and Pushrods ❏ 1. Hold the Large Nylon Control Horns on the elevator and rudder in the positions shown on the fuselage plan and mark the mounting hole locations. REMEMBER: The elevator horn is located on the bottom of the elevator! Drill 3/32” diameter holes at these locations. Mount the control horns with 2-56 x 5/8" screws (SCRW002) and the nylon nutplates which were attached to the horns. ❏ 5.
trace around the strap. NOTE: Make two Right and two Left struts and keep in mind that these straps are on the top of the outboard end of the struts. These are the recommended control surface throws (NOTE: Throws are measured at the widest part of the elevator and rudder.
of the wings are level. Drill a 1/16" hole in the middle of each wing strut mounting block and screw a strut to each block using a #2 x 1/2" Button Head Screw (SCRW088). Mark where the struts cross the fuse side and cut them off at the marks. Replace the struts and check their fit. ❏ 11. Replace the forward struts using the #2 screws and test fit them against the aft struts. Trim and sand the joint if necessary to achieve a good fit between the two struts.
❏ 2. Without the engine on the fuselage, test fit the cowl in place. Round off the corners of the fuselage to obtain a good fit. When satisfied with the fit, install the engine and mount. ❏ 2. Wrap the Battery in a plastic bag, surround it with latex foam rubber and slide it under the die-cut lower fuel tank floor. NOTE: If your plane happens to be a little nose heavy, you can move the battery to a different location. ❏ 3.
combinations will determine where the screws should be installed. In any case, keep the screws approximately 3/8" forward of the aft edge of the cowl. Tape the cowl in place so it does not move and drill a 1/16" hole for each screw. Balance the Airplane Laterally NOTE: Do not confuse this procedure with “checking the C.G.” or “balancing the airplane fore and aft”. That very important step will be covered later in the manual. ❏ 5. Remove the cowl and enlarge the holes in the cowl only to 3/32".
wire elevator joiner. Reinstall the rudder and check the ❏ 3. Rudder right side notch. The notch should be large enough to allow the rudder ❏ 4. Bottom of elevators to freely move throughout its entire range of motion. ❏ 5. Top of elevators ❏ 6. Stab bottom ❏ 2. Using coarse sandpaper, roughen the horizontal part ❏ 7. Stab top of the tailgear wire, then clean off the sanded portion of the ❏ 8. Fuse bottom wire with alcohol or a degreasing solvent. Using a toothpick, ❏ 9.
Painting the Pilot (Optional) ❏ 5. Position the seat backs over the 1/16" holes you drilled ❏ 1. We used a 1/5 scale Williams Brothers #185 Sportsman earlier in the cockpit floor. Screw the seat backs to the cockpit floor using #2 or #4 sheet metal screws (not included). Pilot. Assemble your pilot and then glue it to a 1/2" thick balsa block so he will be about the right height. Shape the block to match the body contour of the pilot.
❏ 4. Make the “Shocks” by drilling a 3/32" hole through the ❏ middle of a 5/16" x 5/16" x 1-1/4" long piece of balsa. Use your hobby knife to carve a few irregular slices out of the square pieces. Slide them onto the lower wire and glue them in place about 1" below the bend in the wire. Cover them with a piece of 3/8" diameter. black heat shrink tubing and shrink it tightly around the shocks. 2. Cut the Engine Shroud out along the trim line and sand its edges smooth.
Other Scale Details ❏ 5. A scale prop can be made using a regular Top Flite 10 x 6 Power Point Prop. Round off the ends using sandpaper and use a little bit of dark stain to give the prop a darker color and to bring out the grain of the wood. Paint the tips black, the leading edges and tips gold and then apply spots of silver with a tooth pick to resemble the screws as shown in the photo. The prop decals are included on the decal sheet. NOTE: This prop should only be used for “show,” and not for flying.
Balance Your Model NOTE: This section is VERY important and must not be omitted! A model that is not properly balanced will be unstable and possibly unflyable. ❏ 1. Accurately mark the balance point on the bottom of the wing on both sides of the fuselage. The balance point is shown on the plan (CG), and is located approximately 4" back from the leading edge. This is the balance point at which your model should balance for your first flights.
❏ 2. Adjust your pushrod hookups as necessary to provide the proper control surface movements as listed on Page 38. *NOTE: These control surface “throws” are approximate and provide a good starting point for the first flights with your J-3 Cub. You may wish to change the throws slightly to provide the smoothness or quickness that you prefer. ❏ Find a Safe Place to Fly The best place to fly your R/C model is an AMA (Academy of Model Aeronautics) chartered club field.
near the engine or fuel; remember that the engine exhaust gives off a great deal of deadly carbon monoxide. Therefore do not run the engine in a closed room or garage. 3. Where established, I will abide by the safety rules for the flying site I use, and I will not willfully and deliberately fly my models in a careless, reckless and/or dangerous manner. • Get help from an experienced pilot when learning to operate engines.
Flying CAUTION (THIS APPLIES TO ALL R/C AIRPLANES) If, while flying, you notice any unusual sounds, such as a low-pitched “buzz”, this may be an indication of control surface “flutter”. Because flutter can quickly destroy components of your airplane, any time you detect flutter you must immediately cut the throttle and land the airplane! Check all servo grommets for deterioration (this will indicate which surface fluttered), and make sure all pushrod linkages are slop-free.
BUILDING NOTES Kit Purchased Date: _______________________ Date Construction Finished: _________________ Where Purchased:_________________________ Finished Weight: __________________________ Date Construction Started: __________________ Date of First Flight: ________________________ FLIGHT LOG 47
Two-View Diagram Use this drawing for planning your trim scheme.