Modeling the Ki-51 ‘Sonia’ in 1/72nd Scale
Jack Gartner IPMS 30538 (
IPMS/Pelikan Model Club of the Pinellas Suncoast
St. Petersburg, FL 33704

Historical Info

The Mitsubishi Ki-51 was designed as a ground attack aircraft, being developed as a successor to the Ki-30. Prototype aircraft were completed in 1939, and the Ki-51 first saw service in China. It was powered by the 14 cylinder Mitsubishi Ha-26-II radial engine and carried a crew of two in tandem, the rear crew member being variously employed as a rear gunner, bombardier, and photographer, depending on the situation and the mission.

Originally, Mitsubishi planned two separate aircraft designs for the Ki-51, which would be used in the ground attack role, with limited instrumentation and flight controls in the rear compartment, and the Ki-51a, in which the rear equipment would be replaced with cameras recording through a large window mounted in the fuselage underside between the wings. It was decided to merge the designs into one aircraft type, and it was constructed in such a fashion that the one aircraft type could be quickly field modified for either mission type.

The Ki-51 was better armored than many other Japanese Army Air Force planes, possessing armor plating under the engine and cockpit, and was rather maneuverable, but was relatively slow (max. speed of 263mph at 10,000ft). Armament in most aircraft consisted of two 7.7mm Type 89 machine guns in the wings (later upgraded to two 12.7mm Type 1 machine guns) and a single 7.7mm Type 89 machine gun on a flexible mount in the rear cockpit.

The Ki-51 was given the Allied code name ‘Sonia’. Production of this aircraft continued from 1939 through the wars end, totalling some 2,385 planes (including protoypes and trial aircraft). A few survived the war to be used by the Indonesian Air Force during their insurrection campaign against the Dutch.

The Kits

About a year ago, I visited a modeler who was selling off much of his kit collection, and picked up the original Mania release of the Ki-51. This particular kit included two complete airplane kits so the modeler could build both the ground attack and recon versions instead of having to choose, which is exactly what I did.

The kits possess the very finely incised panel lines we have come to associate with Hasegawa (in fact, many of the Mania kits, including the Ki-51, are currently released by Hasegawa), crisp flash-free moldings, and finely detailed instrument panels. The canopies were perfectly clear. One of the kits was produced in a light gray styrene, the other a silver grey styrene. Almost all of the parts and sprues for the two planes were identical except for the underwing piece and the fuselages. For the recon version, the underwing section came with the clear underwing viewing panel opened, and the fuselage halves were molded with the side windows hatch covers in the closed position on one and open on the other. The current Hasegawa release is for the ground attack version (solid underwing panel), with markings for three aircraft.

The instructions, while in Japanese, were easily followed, and include four color plates for different aircraft (3 assault, one recon). The decal sheet provided markings for a total of 7 different aircraft, the other three of which were illustrated in color on the box art and side panels. In my opinion, Mania was obviously a company far ahead of its time.

The only shortcomings that I found to the kit contents were that Mania neglected to include a second control stick necessary for the ground attack version, and the telescopic aiming sights that passed through the pilots windscreen (both versions) were not included. Worse, Mania didn’t have the front windscreen panels drilled out, so I did it myself, which was a bit nerve wracking!


Interior, Engine, Cowling and Canopy - Interior construction in both kits was straightforward. I only made one alteration here, scratchbuilding a new Type 89 machine gun for each plane out of styrene rod, stainless tubing and brass wire, as the kit gun is on the crude side. Both were painted with ModelMaster Flat Black to which I added just a touch of Testor’s Metallizer Steel. Additional machine gun ammo drums which came with kit were painted the same color and installed along the rear fuselage wall.

The seats and seat backs were slightly deepened with a Dremel tool. Interior surfaces were painted with Xtracolor Japanese Metallic Blue, the seats and control panels in a Model Master British Interior Green that looks quite similar to the green seen on interior fittings in the Air & Space Museum’s Zero. Seat belts were painted on using PollyS Antique White, ModelMaster Leather and Chrome Silver. Dial faces were Flat Black dry brushed with Flat White for indicators (ModelMaster for both), and Testor’s Sky Blue for the turn and bank indicators and the dial faces were sealed with a drop of Krystal Kleer to simulate glass.

For the recon version, the supplied camera was installed in the open floor panel after being painted flat black. The camera lens was simulated with Krystal Kleer. In the ground attack version, the missing second control stick was scratchbuilt and installed.

The engines were sprayed Model Master Flat Black, as were the cowling interiors, and the crankcase housings were painted Model Master Dark Gull Gray, while the push rods were highlighted in Gloss Black. The ignition wire distributor ring comes as a separate piece, and this was also painted in gray. After drying the cowling was attached to the fuselage. The exhaust stacks are molded into the fuselage halves and there are small cutouts in the cowling where it fits over the stacks. The fit left a slight but noticeable gap between these cutouts and the stacks, so I filled them with putty and sanded smooth. In order to get the proper depth effect in the exhausts, I drilled them out and filed smooth, then glued a thin sheet of styrene inside the fuselage. The inside of the stacks were painted flat black.

The prop blades needed only a small amount of cleanup to remove seam lines. The three bladed props were painted Floquil Railroad Roof Brown with thin yellow visibility stripes near the tips. The spinners on both planes I was doing were white, so these were painted with ModelMaster Insignia Flat White and the spinner hubs were painted with Testors’ Metallizer Steel. The fit of the spinners to the back plates were the only bad fits in both kits. The prop blades and spinner come molded as a single piece. When glued to the back plate, there is a noticeable gap between the edges of the back plate and the prop blades that must be filled.

After painting the engines, they were fitted inside the cowlings. While the engines fit just fine, there are NO locating pins for positioning or attaching them inside the cowling, so a bit of careful placement and holding until the glue sets is necessary here.

After the interiors were assembled and the fuselages sealed with Tenax (after creating the hinge lines for the rudder with an X-Acto blade) and puttied smooth, I attached the canopies. Before attachment, I masked all windows using 3M Magic Tape, cutting away the frame portions with a brand new #11 X-Acto blade. The interiors of the canopies were given a brushed application of Future Floor Wax. I then attached the canopies with white glue. The fit of the canopy was nearly perfect, needing just a light application of white glue to merge the seams. After drying, the white glue was rewet with a stiff brush and smoothed down until a perfect seam was produced. After that, a coat of Xtracolor metallic blue was sprayed on as the interior frame color. After the canopy assembly was dry, I marked the position for the telescopic sight and drilled through the front windscreen. I scratchbuilt the sight and mounting posts from styrene rod and painted them flat black. However, these were not installed until after all painting, gloss and flat coating were complete.

The antennas were attached by drilling a #80 hole, inserting a small piece of brass wire, and attaching to the canopy. The antenna "wire" was smoke colored nylon sewing thread. Antenna wire insulators were small drops of superglue painted with Model Master Flat White.

Wings, Elevators - The fit of these parts to the fuselage and tail were excellent in both kits. The wings come with the typical two upper panels with the entire lower wing as a single part. The hinge lines for ailerons, flaps and elevators were deepened using the back of a #11 X-Acto blade. Remember when joining the elevators and wings to the fuselage that the Sonia, like many Japanese a/c, had distinct join lines at the wing and elevator roots which look just like the other panel lines and these should be apparent on the finished model!

The pitot tube is accurate in shape, but the tube itself is a bit thick, so I sanded it down to reduce the diameter and then installed it.

After joining the wings with Tenax and letting them dry, I used a jeweler’s saw with a very fine toothed blade to cut out the landing light compartments for each plane (one under each wing in the Sonia). I then boxed in each compartment with .005" sheet styrene, again using Tenax to weld it to the wing. After sanding smooth, I drilled a depression in the center of the light "box" and superglued a small HO railroad silver headlight into the depression. After all painting is completely finished, I use 3M transparent tape cut fractionally larger than the opening as landing light covers. If you burnish the edges of the tape with a toothpick or other blunt tool, the tape is sufficiently tacky to hold fast (I’ve had a couple of covers remain stuck on for over 3 years now!), however, you can ensure a seal with a minute amount of superglue on the very edges of the tape. This produces a very realistic looking landing light!

After all painting, decaling and flat coating, I painted in the navigation lights. The rear clear light is a touch of ModelMaster Chrome Silver with a drop of superglue on top. For the wing tip lights, I first masked and painted the lights ModelMaster Flat White. I then used Testor’s Flat Red and the new ModelMaster RLM 24 Dunkelblau. What I do is give the bottles one quick shake to get some pigment up into the clear fluid carrier, which is of much thicker consistency than paint thinner. Brushing this very thin color on over the white gives a glossy brightened color that looks like a clear red or clear blue light cover (remember that Japanese aircraft used red and blue wing tip lights rather than red and green!).

The wing guns were installed after drilling out the barrels and painting them flat black with a touch of steel.

Undercarriage - The Sonia possessed a fixed, spatted undercarriage. In both kits the undercarriage comes in right and left halves for each wing, so some sanding of seam lines is inevitable. Also the wheel halves are molded into the undercarriage legs, so I scribed around them to make it appear as if they were separate. The sockets in the wing undersides for the wheel assemblies are very shallow, so I drilled holes in the tops of the wheel assemblies and inserted brass wire, and then fitted the assemblies into holes drilled in the sockets. These were were superglued in place and puttied in to produce smooth joins. The tires for both were painted with AeroMaster Tire Black, and ModelMaster Silver for the hubs.

Decaling and Painting - For my recon version, I selected an unusual late war scheme which featured a dark blue upper surface over Army gray-green lower surface. The dark blue that I found which almost perfectly matches color chips is ModelMaster Blue Angel Blue. For the lower surface, I used Model Master’s new Japanese Army Gray Green, which is a nice semi-gloss. Wing leading edge markings were applied using ModelMaster Japanese Deep Yellow After gloss coating, I applied the kit national markings and rudder decals for aircraft ‘07’ of the 49th Reconnaisance Squadron, stationed on Formosa in 1944-45. The white fuselage band was painted on using ModelMaster Flat White.

The direct attack plane was finished in a solid gray-green with a Japanese Army dark green (ModelMaster) mottle on the upper surface. Except for the hinomarus, all markings were applied by hand. The finished product looks very much like the instruction sheet, which is supposedly an aircraft of No. 73 direct command (assault) squadron. I have not seen any photos of this rather striking plane, so I’ll have to assume that somebody at Mania knew what they were doing!

Both planes took about 20 hours apiece to complete the basic construction. The mottling on the attack aircraft took up about an additional 4 hours, but was well worth the effort, making a distinctive addition to my Japanese collection!