Tamiya 1/48 G4M1 'Betty'
KIT #:  
REVIEWER: Chris Cowx


The Mitsubishi G4M series of bomber was designed to meet a specification issued in 1937 and entered service in the spring of 1941. It was planned to be a replacement for the successful Mitsubishi G3M “Nell”, used widely in China. The Navy was delighted with the new aircraft, which was both fast and had an excellent range. At the time it was a very advanced aircraft and arguably the best in it’s class worldwide. Unfortunately, like it’s contemporary the A6M “Zeke” the high performance came at a price. The aircraft had virtually no protection of any sort. The outer kin of the wing in places formed the wall of the fuel tank. Needless to say, it was very vulnerable to puncture and fire. Being unwilling to sacrifice the weight of bombs and fuel, there was no armor installed. One small sheet, often removed in the field, protected the tail turret. Later models in 1944 and later had some protection installed, but the type was always vulnerable. In the system of code names used by the US the aircraft was referred to as a “Betty”. In the Japanese military, it was a “Rikko”, a generic term for “Land Attack Bomber”.

In the early battles the Betty did well. The attacks on Clark field were very effective. They sank the Royal Navy’s “Repulse” and “Prince of Wales” in the famous action off of Singapore on December 10th, 1941. Raids on Australia itself and other actions in Papua New Guinea added to the reputation of the type. Bear in mind that our perception of the Betty is coloured by later battles. Against an F4U Corsair and lacking fighter cover, a Betty was easy meat. However, when facing one in an F4F Wildcat at Rabaul it was a different story. You only had a sixty knot speed advantage instead of 150+ for one thing. You got one good pass and then more than likely you were in a stern chase situation. A stern chase gave a 20mm cannon a no deflection shot straight down your throat with a modest closing speed and him with a longer range. All this assumes that the Zeke escort left you alone to do it. Bettys had modest losses for the most part and were quite successful.

The invasion of Guadalcanal started on August 7th, 1942. This was the battle that spelled the first round of decimation for the Rikkos. In the six months between august of ’42 and January ’43 they were massacred in a series of day and night attacks in support of the ground fighting. Opposing them was the so called “Cactus Air Force”, a conglomeration of USN, USMC and Army units. There were several carrier battles centered around the Solomons at this time as well. Air activity was daily and fierce with such names as Joe Bauer, Marion Carl and Joe Foss becoming legendary. On the Japanese side it was Saburo Sakai, Junichi Sasai and Hiroyoshi Nishizawa of the Tainan Air Wing among many others. It became a war of attrition and the Japanese ultimately could not sustain it.

After the disastrous winter, activity picked up in the Solomons again in the spring. The Rikko units had reformed and were being based in Rabaul and it’s satellite fields. Some large scale raids in the spring were flown against Guadalcanal by both the IJN and IJA air forces. Overall though, it was quiet. On June 30th, this all changed with the invasion of the New Georgia Islands. Since December 1942 the Japanese had operated an airfield at Munda Point. It and Vila were too vulnerable to base aircraft there permanently, but they were used to stage aircraft through. For the next month, heavy fighting raged in the area at Rendova, Munda and other locations in the area. Nightly naval battles were fought, largely between destroyers and PT boats. This is where the famous incident of the ramming of future president John F. Kennedy’s PT109 occurred. Air action was quite heavy and included many raids by the Rikkos on the invasion beachheads as well as night torpedo attacks on shipping. The F4U Corsair did stellar service in these actions as well as the now aging Wildcats, P40’s and P39’s. The intensity of fighting rose and fell for several months and then flared in November with the landings at Empress Augusta Bay on Bouganville. By the time the February 1944 raids on Truk caused the final withdrawal of all remaining air units in the area, the Rikkos were decimated, again.

This was a cycle that was to repeat itself throughout the war for the Japanese air forces. Bettys soldiered on as bombers, torpedo bombers, night intruders, anti-submarine patrol and transports. Spectacularly, if not successfully, they were the mother ships for the Ohka suicide rocket plane attacks. The final famous flight of the Bettys was fittingly, flying the surrender delegations to Ie Shima to arrange the cease fire. 


This one is a bit of a mixed bag. On the plus side it is a typical Tamiya kit. Fit and accuracy is good, engineering is excellent, overall detail is pretty good. It includes some nice options such as night exhaust, dropped flaps, various payloads, props with and without spinners and the ability to open some of the transparencies. For a large aircraft kit especially, it is quite nicely done. It is sadly not common to see such large aircraft done this well. Typically we have a limited selection of older kits that neither fit as well nor have such a nice basic airframe and surface detail. Done as an OOB build that will look great in a display case or as a basis for super detailing, this is a beautiful kit.

There are a few things to keep in mind though. The main issues are that this kit is getting a bit long in the tooth, compared to the current crop of Tamiya kits and there is a surprising lack of references available. The age of the kit means that I would say it is more contemporary with the Brewster F2A, Fw190’s, etc than it is with the current crop such as the Storch and the J1N Irving. Detail is softer, engineering is simpler, etc. The lack of available reference material manifests itself in the interior mainly. There is very little to no sidewall detail. No ammo drums for the guns. Aside from basic items in the cockpit and a partial floor, the fuselage is basically empty. Ditto for the wheel wells. In some cases the detail that is there is inaccurate. More on this later.


In order to correct some of the issues mentioned above and to get the full potential  out of this kit, it is necessary to do some enhancing. I am surprised at how little aftermarket specifically designed for this kit has been done and much of it is now OOP. For the interior I went with the Eduard photoetch set 48-191 and the OOP Tekics  multimedia set. There was a set, also now OOP, from True Details but I am not sure it has much to offer. The guns desperately need replacing, being grossly out of scale. The 7.7mm guns were replaced with Vector versions, mainly because of the large number of ammo drums. There are tons of these all over the interior! CMK has a very nice 20mm cannon for this plane. The exhaust were replaced with Moskit items, which look great on this plane particularly. True details supplied the wheels, one of the cases where the flattening is not over done. This was a heavy plane on balloon tires! To finish it off, the decals were replaced with Montex Masks and Hobbydecal dry transfers.


As per usual, work began with the interior. I decided to open the round crew access hatch in the rear fuselage, so some additional work was needed. I cut it out and made a frame with a loop of plastic strip. Now that the interior was a bit more visible I needed to continue the interior structure farther down the fuselage. I used plastic strip for the ribs and formers on the walls and also to extend the floor to the rear of the plane. Probably in hindsight it would have been better to copy the corrugated floor in resin than to tediously lay down hundreds of strips of plastic, but it looks pretty good! I added a crew ladder, additional ammo for the waist gunners and a bulkhead for the “in flight sanitary facility, crew for the use of”. This bulkhead had the happy benefit of effectively blocking the view into the tail area from inside. The open door hinges that way too, so nothing can be seen aft of the crew hatch. Speaking of the hatch, I also took this time to make it’s mounts. I did not want to fish the hatch out and then try to figure out how to reattach it from the outside, so I over-engineered it. Two pieces of .040 sheet made angled brackets for the now removed round hatch.

The tail gunner’s position does have some opportunity for detailing. I added the armor for the cannon ammo from the Eduard set. That’s right, the only armor of any sort in the entire aircraft protected the ammunition rather than the gunner. I also used the two photo etch bits for the ammo stowage. The instructions refer to an early and late rack, but this is incorrect. In actual fact both should be used. Portside was a crank operated stowage rack for ready ammo and the starboard one was to keep the empty drums. Again with sparse references and not much visible, I simply went with the p/e bits and put some of the CMK ammo drums on them. I used the seat and frame from the TD interior set but probably would use the kit parts next time. Since there does not seem to be any belts for the tail gunner, I guess I am done. You could get a complex being a Betty tail gunner, between the armor placement and the seat belt situation!

The area forward of the waist gun blisters is effectively blocked off. Tamiya has this represented as a bulkhead but again, I think available references and age of the kit show here. This was a canvas curtain which I replicated with a card bulkhead faced on each side with tissue painted khaki. From the little you can see of it, any fabric texture will do. From this curtain to the cockpit, very little can be seen. I added ammo for the dorsal gunner, shelves just behind the cockpit and that was about it. Even that much is virtually invisible. I do wish I had added a couple of oxygen bottles, but even that may have been wasted effort.

The cockpit was where I concentrated. For the sidewalls, instrument panel and main floor, I used the Taknics set. In retrospect, next time I will likely use the main floor only from the set and a combination of kit parts and scratchbuilding for the rest. Assuming I am ever brave enough for a next time!  Anyway, the radio provided by Teknics is fantastic and worth it alone. It does lack the bracing that the original had up to the canopy top, but is otherwise very good. The sidewalls are fair but not up to current resin standards. They would be much better if they had p/e for the few instruments and the tubing molded in could be sharper. They do add a fair bit of detail and are much better than the virtually bare Tamiya effort. The navigator’s table is wood and needs to be painted accordingly. The molded in detail from Teknics includes parachutes, piping, control boxes, rudder pedals, seats, throttle quadrant etc. When it is enhanced with the Eduard p/e it is a very detailed and busy cockpit. I used a mix of the Teknics p/e and the Eduard parts. The Teknics seats are enhanced with the Eduard armrests and belts, for example. I added the map holder on the back of the pilot’s seat, made from solder and ca’d in place. I also added some grab handles (8 in fact) to the inside of the canopy along with some tissue sunshades. 

The bombardier’s position was  enhanced, though I did not go too far since most will not be visible. I added a couple of instrument boxes and some piping. Ammo drums, an oxygen bottle and more piping were added. I scratch built a cylinder inside the front glazing to represent the motor for the rotating nose turret.  And that is where I stopped, it is not worth getting too carried away here.  

The wings came up next. Fair bit to do here! I decided not to separate any of the flight surfaces, despite having the Cutting Edge set to do so. The reason for that is simple.  Real Bettys seem to have some sort of neutral lock, because in virtually every shot I have ever seen the surfaces are neutral. Besides, the kit allows for dropped flaps, which will give the final result some animation and is more representative of real Bettys. I did add the under wing fuel protection of a later production model 11 since the kit does not have them. This consisted of flat sheets of 3 cm rubber with light metal ribbing on the underside of the fuel tanks. It was then painted silver. I used thin plastic card with strips glued over top to replicate this. Tamiya gives a key type retention for the wings where a plastic piece fits into the wing and locks into the spar. I simply cut off the pin, put the piece in the lower wing and glued it in. I don’t think it could be removed without damaging the finish anyway. One thing to be aware of is that Tamiya depicts the ailerons as being fabric covered where in fact they were metal skinned. Only the tail control surfaces were fabric. I chose to ignore it and treat it as depicted on the model, but it is not strictly accurate. 

I wired the engines using solder. Not much is visible and they look great through the cowlings. The wheel wells are a bit of a dilemma. Tamiya has molded the doors integrally with the flat bulkhead that boxes in the wheel well. It allows for a very solid connection for the doors and looks good. The only problem is that they are complete fiction! The inside of the real nacelles are simply hollow round shells with a bit of wiring. I put some wiring in and a bulkhead and hatch on the front of the wheel well to hide the seam and left it at that.  On the plus side, the nacelles have a nice lip to sit upon and a very positive fit to the wing.

A word on interior colours for Bettys. Ignore the Tamiya instructions!! It is debatable what it was, but RLM 02 it was not! What is correct for a mid production G4M1 is to do the tail gunners position and cockpit/nose area in Mitsubishi interior green and the center section in Aotake. That is the blue green iridescent lacquer that you see as a protective coating. I did it using Gregg Cooper’s method from his excellent Gekko article. I painted the interior medium grey and then heavily dry brushed it with silver. This gives a silver finish with shadows. Over that I sprayed a 50/50 mix of Tamiya clear blue and clear green acrylics. The exact colour is not important as it was a pigment put into a clear protective lacquer so that workers did not miss any spots. It was not a colour that was mixed to any specific standard. The wheel wells are also in this Aotake along with the bomb bay. Boxes and panels are black, piping tends to be aluminum.

When all this was done, I buttoned up the fuselage. Fit was good as expected, but a bit of care does not hurt to minimize gaps at the bomb bay. I did not choose to detail this area or add the bomb bay cover. The bomb racks as supplied by Tamiya are again fictional, but I chose to leave it alone as they will not be seen anyway. My research shows bomb bay cover as either there, or gone, generally gone. I have no photos at all showing a partial covering as per the kit instructions. I did a bomb carrying aircraft so I left it off and just painted the area Aotake. The fit is pretty good but the seams are long so some care is required. After the fuselage was together I put on the wings and tail surfaces. As expected, they fit well.  Moving along nicely now!

 When it came to the transparencies, I chose to model it closed up. I like the sleek lines of the plane and did not want an open dorsal turret. I also chose not to cut open the side blisters. This limits what can be seen inside even more. I did modify the tail cone by cutting off the last row of windows. This was a common modification in the PNG area and was done to the plane I was modeling. I had to take care not to crack the glass, but no major issues. Also, I decided to paint the inside of the cockpit main canopy and the tail cone. In both cases you can see much of it directly and it in the case of the cockpit, there is actually some minor structure molded into it. In light of this, I was doubly happy to see the Montex masks show up at my place, since they provide both interior and exterior masks. Life is too short for all that masking! Speaking of masking, make sure to securely glue in the nose windows so you won’t be fishing them out later! I used epoxy. On to the paint booth.


Japanese aircraft are interesting subjects to paint. Information is often a bit sparse and the Japanese did not succumb to their axis partner’s mania for standardization. There are significant differences in colour from manufacturer to manufacturer and at different times.

When it comes to the Tamiya instructions, again, they are not 100% accurate. Contrary to long standing myth, it does not appear that any Betty was done with a grey underside. Either natural aluminum or in the case of night bombers, overall green is correct. I used Gunze H59 “IJN Green”, which is correct for a Mitsubishi built aircraft. The undersides were done in Alclad II. Primer was Model Master “Gray Primer”, which gave a sufficient barrier for the Alclad.

As mentioned above, I used Montex Masks for this build. Besides basic bone idleness on the canopy masking, it also made it easier to do custom markings. One of the big influences of my youth was Charles Darby’s book “Pacific Aircraft Wrecks and Where to Find Them”. I saw it in a museum gift shop at age 12 and was fascinated. I was particularly taken with the various Betty wrecks so I chose to model one of them. After some additional research I came up with some accurate markings for a 702nd Ku bird that was likely involved in the New Georgia campaign. Since my grandfather in law served in that one, it seemed a fitting choice.

I started by painting the areas where the numbers and stripes were in white. I did the same as an undercoating for the yellow wing leading edge stripes and in the places where the national insignia were. For the leading edge id stripes I used Gunze H329. I wanted them somewhat bright so I used it straight out of the bottle. Then I went back after and faded them on the top using about 25% white. After suitable drying time I masked them off. I also masked off the white panels behind the fuselage markings, the white tail stripes and the numbers. I put down the masks for the white outlines on the wing insignia and painted in the red centers using Gunze H327. I used a red with a bit of brown on the center to make it look faded and then masked them off too.

 Next was to paint the undersides in natural metal. I did the overall finish in basic “aluminum” then I masked off various panels and did them in other shades. I used my usual “White aluminum” and “Dark Aluminum” for some contrast. I also did some large areas of the upper surfaces in Alclad for the later salt chipping. After the Alclad was done I took regular Tamiya silver and painted the underwing fuel protection pads and fabric covered control surfaces. This was to differentiate them from the surrounding metal. Originally they were painted silver rather than nmf.  When all was done the overall effect was that of multiple subtle shades of silver.

For my basic weathering I decided to try salt chipping. I have never done this before so I was a bit nervous. As this build progressed I had been duplicating everything I was doing on a scrap wing. Now I did the salt method. I found that by putting a drop or two of water in a spot and then sprinkling salt on it I got a nice round patch. I then took a paint brush and moved them around to what I wanted. Many small to medium sized irregular blotches seemed to work best to my eye. My suggestion is that whatever you think will look good, half it! I did very little and only on some areas and I think I did ok. Bear a couple of things in mind. You will be adding more silver with other methods as part of the weathering. Also it is hard to make it look right if you overdo it. Even if you have a photo of a plane that weathered, it still is hard to carry off on the model. Keep it minimalist.

Once the salt was dry I got ready to do the painting. I mixed three shades of H59. One with about 15% white, one at 25-30% and one with no white at all. I used the medium shade for the overall upper colour. Then I did blotches of the lightest colour, concentrating on the higher areas. After that I finished off with some streaks of H59 out of the bottle, generally following the panel lines. For the fabric covered surfaces I painted them with the lightest shade as a base coat and put a bit of the medium green over top. I wanted them to generally look a bit more faded.  On it’s tail the real plane had a unit code painted out on each side, so I put a patch of the darkest green there. This offset the remaining numbers, depending on which side you look at. When the green was dry enough to mask over I did the antiglare panels using a home mix for Mitsubishi cowling colour. Painting in the hino maru on the fuselage and wing undersides completed the major painting.

For my weathering I first of all knocked off the salt, exposing the metal underneath. Then I added some additional wear and tear. I wanted to show paint worn from the abrasive dust on coral runways. I used a sponge and Testors aluminum non-buffing metalizer to touch  the backs of the props, the leading edges of the wings and tail and the cowlings. I also did some light application over some areas of the transparency frames. That was followed by some work with a silver pencil around panels, hatches and fuel points. I did a bit of light exhaust with pastels(actually women’s eye makeup!) and some general dirt. A few oil streaks painted on the cowling undersides with a fine brush completed the build. 

The only decal on the plane is the data stencil on the rear fuselage. The one in the kit provides the number for Yamamoto’s Betty only. I scraped off the constructor number with an exacto knife and then replaced them using a Hobby Decals dry transfer set of A6M stencils. After the build number was in place I went over the whole decal with Microscale’s liquid decal film. Once applied it looks perfect.

As a final finish over the green camo, I used Future flat. I make this using Future floor wax and Tamiya flat base in about an 80/20 mix. It is a nice tough finish and cheap as heck. It is also easier to tailor the gloss level to what you want. On the natural metal I did not do anything. That gave the best finish and showed the contrast between the national marking and the underlying metal. Off came the masks and looking she was looking pretty good!


The little bits that make it look complete came next. The prop and spinner assemblies were done and painted with Alclad II. Warning stripes were painted on. The Moskit exhaust were added next. The bombs got painted with the yellow and blue first and then the stripes were masked off and the overall bomb was painted in light grey. For the green nose I dipped them into a capful of IJN green. Extra detail in the way of braces between the fins was added but otherwise the bomb bay area was done OOB. In fact the detail for the bomb racks appears to be entirely spurious but it was have been a lot of work to redo it and it will not likely be seen anyway. Again, lack of references was obvious again here. I replaced the kit loop antenna with a piece of wire. Painted silver and either clear green or red for position lights. Some antenna wire from invisible mending thread and she was basically done.  I did not like the tail wheel with the solid fork and wheel molded together. I hollowed it out and replaced the wheel with a 32nd scale Bf109 tail wheel, if memory serves. For strength I put a steel pin from the top of the wheel into the fork and main tail wheel strut. Looks much better in my opinion! Don’t ask how often I broke it during building.


 enjoyed this build immensely. The good solid engineering of this kit gives an excellent basis for  a super detailed build. It allows you to concentrate on the detail stuff without having to stress over fit or surface details. It has good options such as positionable surfaces and transparencies. The occasional detail missed or accuracy issues are not the end of the world and to most the imposing size of the model and a good paint job will carry the day.

The lack of aftermarket for this kit does limit it to some extent. Of particular need is some decent exhaust since they are so prominent on this plane. Guns are taken care of but the interior is very poorly served. The only currently available item for it that I am aware of is the Eduard set, which while useful, is not overly comprehensive. Mind you, it is a great excuse to practice those scratch building techniques!

The biggest issue you will likely have if you try to get serious with this kit is the lack of available English language resources. FAOW, Maru Mechanic, etc are useful, but still interior shots of it are sparse. Some of the Japanese language references can be very helpful in filling some of the gaps. The good news is that much of it can not be seen anyway.

If you like Japanese twins or are a Pacific War fan in general, you owe it to yourself to do this one.

Chris Cowx

August 2012

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