MiG-3 - 2004/11

MiG-3

Mikoyan-Gurevich fighter design translates into delightful model

by Dick Sarpolus

Large-airplane modelers usually like World War II fighters as subjects, as can be seen at most International Miniature Aircraft Association fly-ins. It’s easy to spot P-51s, P-47s, F4Us, Fw 190s, Me 109s, Zeros, and so on, but where are the MiGs and the Yaks? During World War II the Russians produced many fine fighters that make excellent R/C projects, but they’re rarely seen. Information and three-view drawings for Mikoyan-Gureviches, Yakovlevs, Lavochkins, and Ilyushins are readily available, so I decided to model the Mikoyan-Gurevich MiG-3.

Although the full-scale MiG-3 had a streamlined, aggressive appearance, it was a weak performer because of a heavy engine. Even with lightweight, mostly wood construction, the airplane didn’t perform up to competitive standards. The MiG’s far-to-the-rear cockpit, placed to balance the heavy engine, resulted in a poor forward view. Some improvements were made, but the heavier armament required couldn't be added because of the heavy engine. More than 3,000 MiG-3s were built around 1941, but they were quickly replaced by better Lavochkin LaGG-1 and Yakovlev Yak-1 fighters.

The full-scale MiG-3 often wore an all-white finish with red stars and lightning bolts, which makes for an attention-getting model. They were also finished in the typical brown/green camouflage, but the white topside/light-blue bottom winter scheme is more unusual (the red stars and red wing panels stood out against snow camouflage).

This model is not exact scale; it’s a Fun Scale design emphasizing easy construction and good sport aerobatic performance. Size is determined by the power plant. For years I’ve built similar models around the Cheetah 42 (US Engines/Quadra 42) gas engine for its low cost and reliability. Today, in the 40cc/2.5 cu. in. displacement size, more choices exist.

Recommended engines:

• Glow: Moki 2.10
• Gas (examples): ZDZ 40, Zenoah G-45, Taurus 42, 3W-38, Brison 2.4, FPE 2.4
• Other larger engines may be used; keep weight in mind. The fuselage is about 6 inches wide at the cowl area.

Typical model dimensions and weights:

• Wingspan: 88 inches
• Wing area: approximately 1,240 square inches
• Length: 66 inches
• Typical flying weight: 16–17 pounds (depending on detailing)

If you want a true scale MiG-3, plans are available from Roamin' Research, 37137 Clubhouse Dr., Sterling Heights, MI 48312. If you prefer a quickly built Fun Scale MiG-3 with foam-core surfaces, a somewhat boxy fuselage, fixed gear, and sporty aerobatic flight, consider this design.

I prefer to use a semi-symmetrical airfoil for this model. Foam-core construction (cut foam wing cores, wingtip cores, fuselage top-block cores, and tail-section cores) is quick, simple, economical, and reasonably light for sport projects.

A plastic canopy is available (made for a larger scale MiG and can be trimmed for this design). A fiberglass cowl specifically for this sporty model and the plastic canopy are available from Fiberglass Specialties Inc., 15715 Ashmore Dr., Gilmore, AR 72732; Tel.: (479) 359-2429; Web: www.fiberglassspecialtiesinc.com.

Although retractable landing gear could be used, I recommend the low-cost approach of bent 1/4-inch music-wire fixed gear. Robart RoboStruts can be added for better ground handling and a scale appearance if desired. Retracts are possible but add weight; consider staying with fixed gear for a lighter, more aerobatic model.

A Fun Scale design involves scale compromises. The MiG wing has a flat center section and dihedral in the outer panels; this means a longer plywood spar/wing joiner and two dihedral joints. If desired, you can simplify by using a single dihedral joint at the wing center to save weight and construction time.

Prototyping notes:

• Lou McGuire and Pete Mularchuk each built prototypes using the Cheetah 42cc gas engine.
• Lou finished his model with MonoKote; weight was 16.5 pounds.
• Pete finished with silk and dope, carved a balsa cowl, added detailed air scoops, wing fillets, a larger 5-inch spinner and a three-blade Zinger prop; his model weighed 20 pounds.
• Both flown models balanced nearly as shown on the plans and flew well; keeping the model light improves aerobatic performance.

CONSTRUCTION

All materials are standard balsa and plywood. Cut out all pieces before beginning. I work from paper templates, trace with a ballpoint pen onto plywood or balsa, and cut with a band saw or scroll saw. Cut grooved hardwood landing-gear blocks on a small table saw; a club member may have a wire bender for the 1/4-inch wire fixed gear. You will need to cut foam cores for the wing, tail surfaces, and fuselage top blocks. A club member may be able to cut the foam for you.

If you’re a plans builder, you’ll probably prepare a wood order; I’ve been very happy with Lone Star Balsa (Texas). If you want to try scratch building, this is a reasonable starter project.

Wing

1. Cut each of the two foam-core panels at the dihedral-break locations. Also cut cores for the full-depth plywood spar, plywood dihedral-break joiners, plywood ribs, and landing-gear blocks.
2. Mark all foam cuts carefully before cutting. Use a band saw or a hot-wire cutter. As foam pieces are removed, trim the foam groove in the landing-gear blocks and reassemble them with plywood parts and epoxy before sheeting.
3. Glue the grooved landing-gear blocks in place, protruding from the foam core by 3/32 inch. Cut balsa sheeting as you contact-cement it in place to fit around the landing-gear blocks.
4. Sheet the three wing panels with 1/16-inch balsa. Bevel the leading edges and sand round after the sheeted panels are assembled on the joiner. If using a hot-wire cutter for leading edges and wingtips, make templates of the planform sections to check shapes before sanding.
5. Wingtip construction: use foam-core wingtips glued to a center balsa core (top and bottom), then sheet and add to the wing cores. Burn holes through wingtips for aileron extension cables before joining cores.
6. Make wing sheeting from 3/32-inch balsa, edge-glued to obtain needed width. Use 3- or 4-inch-wide balsa; sand edges for a good fit and use aliphatic resin glue for easy sanding and a smooth surface.

• Tape the balsa sheets together, flip them, open the taped joint like a hinge over the workbench edge, and apply glue. With wood flat on the bench, scrape excess glue and weight until dry. Remove masking tape and use the taped side as the outer sheeting surface. Sand sheeting before applying to cores.

1. For foam-to-balsa adhesion, I use Dave Brown Products’ Southern Sorghum contact cement, but thin epoxy or spray contact cements are alternatives—test adhesives on scrap foam first; some dissolve foam.
2. Sheet the center-section (tougher because of plywood spars protruding from each end). Sheet outer panels, trim sheeting edges, check fit at dihedral joints by sliding outer panels over the stub plywood spars, and epoxy the whole wing together. Epoxy the wingtips in place.
3. Cut a slot through the leading edge for the plywood wing-mounting tab and epoxy it after fitting the wing to the fuselage saddle.
4. Wrap the two wing dihedral joints with medium-weight fiberglass cloth and epoxy. Scrape off excess epoxy, leaving just enough to saturate the cloth. Also reinforce the wing center at the trailing edge where wing bolts attach to the fuselage.
5. Cut ailerons from the sheeted wing panels, trim for balsa edging, sand to shape. Hinges run along the centerline. Cut recesses in the wing’s lower surface for aileron servo mountings.

Fuselage

1. Use firm-to-hard balsa for the two sides; edge-glue and splice to the required size. Glue plywood doublers, balsa wing-saddle doublers, stabilizer-saddle doublers, and lower rear edge strips to both fuselage sides.
2. Firewall: epoxy 1/8-inch and 1/4-inch plywood pieces together for a thick firewall. With one fuselage side flat on the workbench, epoxy the firewall and the next three plywood bulkheads perpendicular to that side. Glue the second side to those bulkheads; sides should be parallel from the firewall to the wing trailing edge position.
3. Reinforce the firewall joint with triangle stock and fiberglass cloth behind the firewall, and add several small screws through the sides into the firewall.
4. Add the plywood wing-bolt plate, then pull the tail end together and install rear bulkheads. Fit top foam blocks to the fuselage structure, sanding them if necessary so they will be flush with the sides after sheeting. Do not add bottom sheeting until tail pushrods are installed.
5. Use a thick firewall and three-layer plywood pads behind engine mounts for secure engine installation. Cheetah and similar engines mounted easily with clearance for mufflers.

Final Assembly

1. Build tail surfaces flat. Cut foam cores, add balsa framing, and apply balsa sheeting with contact cement.
2. Align and mount the wing to the fuselage; drill and tap the plywood wing-mounting plate for two nylon bolts.
3. Add the horizontal stabilizer and align it with the wing. Add the vertical fin perpendicular to the horizontal stabilizer.
4. Recess control surfaces to accept 1/4-inch plywood mounting pads for nylon horns on ailerons, elevators, and rudder. Epoxy the plywood mounts into the surfaces and mount nylon horns with self-tapping screws.
5. Use 4-40 threaded rods and clevises for all linkages. Use fiberglass tube pushrods for elevator linkages. Use two separate servos for the elevators, each with its own pushrod to keep the pushrods straight. Since pushrods cross inside the fuselage, mount one elevator servo slightly higher than the other to avoid rubbing.
6. Make aileron extension cables into a Y harness for two aileron servos mounted in the wing. Another short Y harness is needed for the two elevator servos.
7. Power/battery: I use a 1200 or 1800 mAh battery pack wrapped in foam rubber and positioned behind the firewall. I used a 16-ounce tank with plenty of room inside the fuselage for gas installations.
8. Landing gear: bend main gear to shape with a K&S wire bender. Retain gear in the grooved blocks with nylon straps and screws. Plywood landing-gear doors are held to the gear with small metal straps soldered to the gear legs. Robart scale wheels are recommended—order internal foam tire “doughnuts” directly from the company for adequate support.
9. Ignition and muffler access: mount an ignition-cutoff switch with a sheet-metal bracket on the firewall near the bottom; it will be accessible through the cowl cutout.
10. Cowl mounting: the available fiberglass cowl is cut for engine, muffler, and carburetor clearance. You can mount the cowl by overlapping it slightly on the fuselage and using nylon bolts (easiest). For a flush fit, cut the cowl to length and mount it to hardwood blocks epoxied to the front of the firewall.

FINISH

• Pete and Lou finished their aircraft in the white-top/blue-bottom color scheme with Russian star insignia—an attractive alternative to brown/green camouflage.
• Finishing options include MonoKote or traditional silk-and-dope. Amount of detailing (canopy, interior, instrument panel, pilot figure, exhaust stacks, air scoops, machine guns, wing fillets) is up to the builder; even a Fun Scale project should include most of that detailing.

FLYING

• Both prototype MiGs flew well. Keep the model light for better aerobatic performance.
• During test flights both MiGs tended to tip forward while taxiing. This was corrected by removing the wire landing gears, bending them forward to get wheel axles closer to the leading-edge position, and reinstalling them.

We’re pleased with these MiG-3 warbirds; they build quickly and are fun to fly.

Dick Sarpolus 32 Alameda Ct. Shrewsbury, NJ 07702 rsarpolus2@comcast.net

ADDITIONAL SPECIFICATIONS

• Length: 67 inches
• Wingspan: 88 inches
• Wing area: 1,230–1,240 square inches
• Wing loading: 28–32 ounces per square foot
• Radio: Four-channel
• Controls: Ailerons, elevator, rudder, throttle (six servos)
• Propeller: 18 x 10 or three-blade 16 x 8

Transcribed from original scans by AI. Minor OCR errors may remain.