Page 1: Table Of Contents
Mitsubishi Ki-15 “Babs” In Quarter Scale Construction Manual Table of Contents: Fuselage Assembly Completion Views Cowl Assembly In-Flight Photos Canopy Construction Flying Fiberglass Wheel Pants Donald Thorpe Photos Wooden Wheel Pants Full-size Photos Fin & Rudder Assembly Markings Stab & Elevator Assembly...
Page 2: Fuselage Assembly
Fuselage Assembly Overview of the fuselage assembly: A horizontal crutch framework of ¼” sq. balsa is assembled over the plans on a flat surface. First, the upper half of the fuselage is attached to this crutch. Then the cockpit interior is painted and installed before sheeting.
Page 3 Cut out all the formers before beginning assembly. Note how some formers have temporary cross-braces to hold their shape until installation. These can be cut away with a razor saw or Dremel wheel cutter after installation and sheeting. Formers visible in the cockpit area should be assembled and painted before installation.
Page 4 Stringers and sheeting butt up against F12. Paint the cockpit interior before sheeting. Install rudder and elevator servo cables at this time, before sheeting. Sheet and glass the cockpit interior surfaces. Then sheet the rest of the fuselage. V3 is installed, rudder servo and p/r attached. Install fin platform and partial sheeting.
Page 5 Fin platform ready to accept fin. Round the rear turtle deck with a razor plane. Leave a temporary opening for access to the rudder servo. Fit the completed fin and rudder to the fin platform. After the fin and rudder are completed and primed, install them on the fin platform.
Page 6 Shape and hollow the tail cone fairings. Install the tail cone fairings on the tail cone. Fit the stabilizer and install the elevator fairings at this time. See Stab and Elevator Assembly instructions. Turn the fuselage over, fin hanging over the edge of the workbench. Support the fuselage with foam blocks.
Page 7 Route sheet balsa for observer’s window. Reinforce the tank box at F1-F5 with triangular gussets. Depth equal to window thickness. Install plastic windows, mask, paint inside, Paint and install the observer’s floors. and attach over the observer’s area. Wing saddle support before shaping. After shaping to match formers.
Page 8 Install two wing bolt blocks. Drill holes for wing bolts under the flap. The receiver switch can be hidden under the flap here too. This step should be performed in conjunction with fitting the wing to the fuselage. See Wing Assembly instructions. Tap wing bolt blocks for two Assemble the antenna mast and its socket.
Page 9 Epoxy the antenna mast socket in place. Rear scale antenna attachment is a nylon control horn and clevis. Drill a hole at the top of the antenna mast. Install filet formers with the wing in place. Insert a cotter pin, bend the ends around Verify that formers align.
Page 10 Glue the upper rear filet in place. Glue the upper middle filet in place. Moisten the inside surface if necessary. Glue the upper forward filet in place. Trim the wing filet to the wing saddle like so, leaving a squared-off, not tapered, edge. Sand the underside of the filet edges.
Page 11 Fuselage sides and filets ready for glass. The entire fuselage is now ready for ¾ oz fiberglass cloth and resin. Weight before glass as shown is less than 6 lbs. Glass right over the masked observer’s windows. After glassing, remove the masking tape After primer, apply masking tape to the filet from the observer’s windows and apply edge and apply auto body filler.
Page 12 Stab attachment bolt access holes.
Page 13: Cowl Assembly
Cowl Construction This section describes construction of a wooden cowl. Alternatively, a fiberglass cowl can be purchased from Micko Aircraft and Accessories at www.mnbigbirds.com. Some of the steps apply to the fiberglass cowl too. These are marked with an *. *Fit C2 to F1.
Page 14 Nosebowl quadrants glued together. Nosebowl ready for shaping. Temporarily attach the nosebowl to C1 with screws. Sand the outside flush with the cowl frame. Use the template from the plans to rough-carve the nosebowl with a razor plane. Then sand the outside to final shape, continuing to use the template as a guide.
Page 15 *Rear view of assembled cowl. Ready for glass and paint. *For the glass cowl, C1 can be fitted but not installed at this time. *Cut the exhaust holes by drilling small holes approximately in the center of the exhaust pipes while the engine and cowl are attached.
Page 16 *Temporarily attach the spinner backplate to the engine fairing with double-faced foam tape and bolt it to the engine. Fit and glue the fairing to C1. Then remove the backplate by cutting away the foam tape. There must be at least 1/16-inch clearance between the fairing and the backplate. Block-sand the front of the fairing if necessary.
Page 17: Canopy Construction
Canopy Construction The canopy has 31 windows! (Plus 5 windows elsewhere.) All but one are flat sheet. Assembly proceeds from rear to front, installing the windscreen last. The only window that must be molded is the upper part of the windscreen. A fully formed complete windscreen can also be purchased from Micko Aircraft and Accessories at www.mnbigbirds.com.
Page 18 Verify that the frames line up. Block-sand if they don’t. Frame wideners in place. Paint and install horizontal canopy rails. Mark each piece prior to trimming. Roughen the canopy edge for gluing. Epoxy the rearmost canopy section in place. Epoxy the observer’s section in place. Install the section in front of the observer.
Page 19 Epoxy the next canopy section in place. Clean up spilled epoxy with alcohol before it sets. Glue the Micko windscreen in place. Mark the outline of the windscreen Hold it in place with tape until the frames using a paper pattern cut from the epoxy sets.
Page 20 Mask the edge of each window using the Cover each window with masking tape. 3/8” tape as a guide. Then, remove the 3/8” tape. Fill the seams and pin holes between Form the lower windscreen filet with auto sections with auto body putty. body putty.
Page 21: Fiberglass Wheel Pants
Fiberglass Wheel Pant Assembly The plans and instruction manual show wooden wheel pants too. But fiberglass pants are 2-3 times lighter than wood, more durable, typically cheaper, and a lot less work. So I recommend fiberglass pants. You can make your own fiberglass pants by first assembling one wooden pant and using it, as a plug, to make two molds.
Page 22 Trim the scrap and install a fiberglass lip inside one side of the pant at the curved edges. This will strengthen and align the halves when they are glued together.
Page 23 The notch in the top of the pant is necessary clearance for the mounting bracket when the oleo is compressed. While the axle is in the hole in the lower pant, epoxy hard ½” sheet balsa blocks beside the upper strut. Refer to the plans for positioning. Smaller hard balsa sticks at the straight edges are trimmed flush at the edge of the pant.
Page 24 Pant half ready to be glued to its other half, axle in hole in pant. The strut is in contact with the inside of the pant but it is not attached to it yet. The unpainted aluminum sheet wheel cover is glued to wheel with methacrylate glue. Pant halves being epoxied together.
Page 25 File two flat spots on the landing gear strut and install it in the wing. Use medium thread-locker on the set-screw threads. Set-screw access is thru a hole in the leading edge and another hole in the rib. Note how the upper pant moves into the wing with oleo compression.
Page 26: Wooden Wheel Pants
Wooden Wheel Pants Assembly Sequence The wooden wheel pants are composed of several layers. Each pant is composed of a left half and right half held together by four recessed bolts. This allows disassembly for maintenance and repair, with the option of permanent gluing together if you do not want a visible seam. Blind nuts and washers are imbedded in the innermost layers, layer A, with access to the bolts via a small ball driver.
Page 27 Glue layers B, C and D together with yellow glue. Bevel level D for tire clearance. Glue BCD to A. Weight while glue sets. ABCD left bolted to ABCD right. Lay right E on plans, align axle hole. Glue right E to ABCD right and ABCD left. Standard wheelchair wheel.
Page 28 Glue left E in place, axle in the hole. Weight down with old batteries while the glue sets. Wax paper protects the plans. Glue F in place. Both sides. Note bolt access holes. Clamp while glue sets. Disassemble. Glue G in place, one side at a time. Clamp with clothespins.
Page 29 Fill the gap in C with 3/32” sheet. Fill the gap in D with a triangular block. Interior view of assembled wheel pant. Plane to teardrop shape before rounding edges. Bolt halves together and sand to final shape. Ready for glassing.
Page 30 For extra security, insert a sheet metal screw or self-tapping machine screw thru the pant and into the strut three inches above the axle, inside surface only. This will reduce wear on the axle holes. File two flat spots on the landing gear strut and install it in the wing. Use medium thread-locker on the screw threads.
Page 31: Fin & Rudder Assembly
Fin and Rudder Assembly The vertical stabilizer (fin) is constructed in left and right halves and glued together like clamshells. The fin is sheeted but the rudder is an open structure of ribs on a sheet balsa base, covered with fabric per scale. The steerable tailwheel strut is attached to the rudder but supported by a plywood former in the fuselage.
Page 32 Bend the tailwheel strut with a wire bending tool. Complete the final bend after partial assembly. Drill the tailwheel axle holes after bending the bracket. Assemble the entire tailwheel strut before its installation. Assemble the rudder over a flat surface. Tape rudder hinges in place and glue from other side.
Page 33 Cut a slot for the t/w strut close to the lower hinge. Support the hinges in the rudder with balsa blocks. Round the rudder’s leading edge after its hinges are installed. Enlarge the slot around the hinges with an X-acto blade so that the rudder hinges swing 45 degrees each way. Cover the rudder with SIG Koverall and two coats of clear dope.
Page 34 Primed fin, rudder & t/w ready for installation. Install fin, rudder & t/w in fuselage. Reinforce the fin with balsa gussets. Install sheet balsa fin fairings. Fill edge of fin fairing with spackling. Smooth spackling on the fin filet with foamy sander.
Page 35: Stab & Elevator Assembly
Stab and Elevator Assembly The horizontal stabilizer and elevator are constructed in upper and lower halves and glued together like clam shells. The stab is sheeted but the elevator is open structure, covered with fabric as was the full-size airplane. To resist warping, the elevator has crossbracing between the ribs that doesn’t quite contact the fabric covering.
Page 36 Fit large Robart Hinge Points to the stab. Harden hinge notches with thin CA glue. Don’t glue yet. Don’t glue yet. Route a groove in both elevator halves for the elevator horn music wire. Glue elevator halves together with horn Mark positions of hinges using the elevator in place.
Page 37 With elevator hinges in place, glue Round the elevator L.E. with a razor the stab halves together. Clamp with plane and a sanding block. Slide it onto the clothes pins, T-pins or whatever. Trial-fit stab hinges. Epoxy them in place. Cover the the elevator to the stab and sand with a elevator with SIG Koverall or other fabric.
Page 38 Remove the stab. Cut a slot between the stab/elev for a ply stab support plate. Install the stab support plate in the fuselage, resting against the T.E. of the stab. Reinforce well. The purpose of this little support plate is to resist the rearward force when running up the engine while the pilot is standing in front of the tail—a practice that I don’t recommend for any giant scale airplane.
Page 39 Assemble and glass the elevator fairings. Install the elevator fairings on the tailcone. Install and test the elevator servo. Then Sheet the stab fairing. glue F17A, lower F18 and F19 to the stab. Add stringers. Waxed paper protects fuselage. Stab, primed, ready for color paint. Two holes for access to nylon bolts.
Page 40: Wing Assembly
Wing Assembly The wing is three-piece for ease of assembly and transportation. With the center section in place and the stab removed, the airplane fits into a compact hatchback car. Removing the outer panels also allows access to set screws that hold the landing gear in place. Wing bolts are hidden under the single flap which, when lowered, allows access to the wing bolts.
Page 41 Temporarily screw Ribs F and 1 together. Drill holes in Ribs F and 1 for the Sand Ribs F and 1 to exactly the same shape. wing panel alignment dowels. Screw, don’t glue, the LG mounting plate Fit strut base to the mounting plate To the mounting plate bearers.
Page 42 Screw and glue Rib E to the LG bearer. Assemble aileron skins on a flat surface. Clamp a stick to Rib F to keep it straight during wing center section assembly. Assemble the center section over the plans on a flat surface. There is no washout in the center section (all washout is in the outer panels) so the main spar cab be placed on the building table as the rear of the ribs are supported by a ½-inch balsa stick near the rear spar.
Page 43 Add gussets & epoxy around ribs E and F. Route and install flap hinges in a balsa This is a high-stress area. sheet. Glue thin balsa sheet over the hinges and Install the aileron servos and Spangenberg sand them flush with the surface. linkage (or other linkage) in Ribs 8 before Do not attach the flap to the wing yet.
Page 44 Add the aileron upper leading edge. Leave enough room between it and the rear spar for a backless saw blade that will be needed later to cut the aileron free. Washout is built-in during assembly. Tabs on Rib 15 provide its washout and alignment with the other ribs.
Page 45 Turn over. Elevate the rear spar with the Upper (surface) Alignment Jig to provide the proper washout angle. Install the alignment dowels. Rib 15 is aligned to the other ribs with its own tab. Add the lower aileron leading edge. The lower surface is now ready for the lower aileron skin. Taper the leading edge to match the ribs before sheeting the lower surface.
Page 46 Turn the inner and outer panels upright. Elevate the outer panel by the dihedral angle and weight the inner panel with an old starter battery (shown here) or other weight. Slide the inner section and outer panel together on an empty wing tube socket, leaving a gap just big enough for a backless razor saw to fit between them.
Page 47 Glue the sheer webs in place in both the inner and outer panels, including the wing tube area where they connect the spars to the sockets. Glue the previously prepared flap to the Glue flap servos in place before sheeting. wing center section.
Page 48 Install ROBART hinges in the ailerons. A hole in the surface provides access for applying epoxy. Recessed hinge line is marked on the aileron’s surface. The amount of recess is shown on plans. The hole will be covered when fabric is attached to the aileron. Sheet center panel upper surface from ribs D to D.
Page 49 Remove sheeting to the wing saddle line. Drill holes in wing for wing dowels using The wing saddle should fit into this holes in F1-F5 as a guide. Then plug the holes in F1 so that oil won’t leak in later. recess.
Page 50 Opening in wing for landing gear leg. Ball driver access to the set screw in the Attach strut base with six #8 1-1/2” front of the landing gear mounting bracket round head wood screws (only 4 shown is via a hole in the leading edge. in these views).
Page 51: Surface Details
Surface Details Observer’s camera base and seat made Observer’s radio on F12 before installation. from balsa blocks. Cut two loop antennas from wing tube scrap. Add bolts to attach them inside the canopy. Install them before attaching the canopy. Scale antenna attachment is an aileron horn. Install the pilot before attaching the canopy.
Page 52 Pitot tube parts. Pitot tube is friction-fit and removable. Cut a slot in the wing and stall the lower portion with support blocks inside the wing. Draw the panel lines with a fiber-tip pen and a straight edge after the first coat of primer has been applied and wet-sanded.
Page 53 Remove tape residue with a rubber Cut a paper pattern of the wingtip sunburst squeegee. Spray silver base color. and trace it onto the wing. Apply masking tape. Spray bright gloss red. Remove the upper half of the backing of a ProMark paint mask, position it per a pencil-drawn reference line, press and remove the lower half of the backing.
Page 54 Rub on the ProMark dry transfer markings. Our eager pilot watches the author remove the window masking tape. English markings on the left side. Equivalent Kanji on the right side. Observer’s camera window and red signal light on bottom. Receiver switch and wing bolts under the flap.
Page 55 Carve the large, right side exhaust pipe from a 2” x 1” x 2 ½” balsa block. Round the corners. Cover with 3 layers of 6-ounce glass cloth. Remove the balsa with a large drill. Smooth the inside. Cut small exhaust pipes from ½-inch diameter cardboard Estes model rocket body tubes.
Page 56 Completed canopy views. Note the red signal light, loop antennas and removable pitot tube. Aileron rib stitching—3M Hair Set Tape Landing light is a cut-down GE over glue drops. Magicube flashbulb. Remove and stow the antenna mast here for transport.
Page 57: Parts List
Babs Parts List Plywood: 1--3/8 x 6 x 12 ply: firewall 1--1/4 x 12 x 24 ply: ribs E & F, C2 1--3/16 x 6 x 12 ply: L.G. plates 1--1/8 x 12 x 36 ply: tank box, F1, F20, center section ribs(2), Rib 1(2), center section L.E., ail servo mount.
Page 58 1 pkg—Radio Shack Red 12 VDC Lamp Assembly, ½”, P/N 272-0332: signal lamps Vacuum-formed windscreen & signal light fairings, fiberglass wheel pants & cowl available from Jeff Micko. See www.mnbigbirds .com or email jmikhl@aol.com. Graphics: “Andersen Mitsubishi” graphics, shown on plans and Markings Callie Graphics. callie@callie-graphics.com...
Page 59: Modelers' Comments
Modeler’s Comments “It flew as if on rails, not feeling at all overweight but rock steady. My friend’s came out at 36 lbs and flies superbly in the same manner…superb unusual aircraft - has real presence in the air.” --Pete in England “Congratulations on the beautiful model you've designed and built.”...
Page 60: Completion Views
Completion Views...
Page 61 L to R: Throttle servo, receiver battery pack, In the car. Eager to go flying. vent/overflow drain, exhaust pipes, fuel-dot fill plug, yellow inner Nyrod choke pushrod.
Page 64 Recommended tail hold-down—denim jeans and a large screwdriver minimizes stress on the tail.
Page 65 TV interview at a Minnesota air show. Designer relaxes with an Asahi beer after completion of 12 and final test flight. Best of Show award at 2010 Northern Alliance Military Fly-In, Owatonna, Minnesota Dick Galley’s Babs From a modeler in Padova Italy...
Page 66 Miroslav Hirsl in the Czech Republic Brian Rawcliffe in England Lennart Henriksson in Sweden...
Page 67 Smaller Babs in trainer squadron colors. (RCM plans).
Page 68: In-Flight Photos
In Flight Photos...
Page 70: Flying
Flying Babs is a delight to fly. The large, ball-bearing wheels track straight even in rough grass fields. Flight is stable and responsive. She is possibly the smoothest-flying airplane I have ever owned. The wide fuselage, big wing and huge wheel pants make the orientation of the plane visible at a distance and in poor light.
Page 71 The wheel-chair wheels are rather heavy, about 1 lb each. On touchdown, the inertia of the wheels pulls back on the landing gear which tends to resist the nose rising, thus counteracting the tendency to bounce. Notice the lack of bounce in the landing video. This is known as “The Heavy Wheel Effect.”...
Page 72: Donald Thorpe Photos
Donald Thorpe Photos...
Page 74: Full-Size Photos
Full-Sized Photos First prototype. Smithsonian photos.
Page 76 Arrival in London...
Page 77: Markings
Markings ASAHI MITSUBISHI NIPPON...
Page 79 Graphics in model size. Callie Graphics. callie@callie-graphics.com. Ask for Andersen Mitsubishi graphics.
Page 81: Alternate Color Schemes
Alternate Color Schemes...
Page 84: Four-View Drawing
Four-View Drawing...
Page 85: Paint Masks
Paint Masks...

Mitsubishi Ki-15 Babs Construction Manual

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