Tamiya 1/48 G4M1 'Betty'
KIT #: 61110
PRICE: 2600 yen SRP
DECALS: Two options
REVIEWER: Charlie Isaacs
NOTES: Yamamoto Transport boxing


The Mitsubishi G4M1 (Allied codename ‘Betty’) was designed by a team headed by Kiro Honjo to replace the G3M Type 36 medium bomber. The 12-shi specifications called for maximum range of 2990 miles with a minimum bomb load and a maximum 1-ton bomb load or standard torpedo in anticipation of a war over long stretches of the Pacific Ocean. The design team originally preferred a four-engine layout, but the Navy board was adamant that it must be a twin-engine platform. The resulting G4M1 first flew in October 1939, and exhibited a capacious, cylindrical fuselage powered by two Mitsubishi Kasei engines. Although first used over China in May 1941, Allied forces were surprised by the appearance of the bomber over the Philippines on December 8, 1941. The Americans at Clark Field were amazed to be attacked by medium bombers and at first believed that the Japanese had launched them from aircraft carriers. The G4M1 also participated in the sinking of the British warships Repulse and Prince of Wales, thus rendering Singapore helpless to a Japanese onslaught. Allied fighter pilots, however, soon learned of the G4M1’s fatal weakness -virtually all protection had been sacrificed for maximum range. The G4M1, although relatively fast and maneuverable for a large medium bomber, was extremely flammable soon resulting in the allied nickname ‘one-shot lighter’ and the Japanese crews’ unfortunate nickname ‘Hamaki’ or flying cigar. The Betty was eventually improved as the G4M2 with a dorsal turret eliminating the side blisters, and went on to become a launch aircraft for the Yokosuka Ohka special attack aircraft. The Betty’s final mission was bearing the Japanese surrender committee. These final Bettys were painted all white with large green surrender crosses.

The Mission:

Allied forces intercepted a Japanese coded message that Admiral Yamamoto would be flying from Rabaul to Bouganville to inspect Japanese installations there. P38s from the 347th and 18th Fighter groups on Guadalcanal were dispatched at maximum range (at the time) to intercept the admiral’s plane. Bomber T1-323 picked up Yamamoto’s party at Lanukai airfield on Rabual at 6:10 AM on April 18, 1943. The admiral’s plane was accompanied by another G4M1 (T1-326) and was escorted by six Mitsubishi A6M2 Zeros from the 204th Kokutai. American P38s intercepted the bombers over Empress Augusta Bay on Bouganville a little before 8:00 AM. Yamamoto’s plane dived for the deck to escape the fighters. The P38s split up to separate the escorts from the bombers. The admiral’s plane was shot down around 8:00 AM into the jungle near Aku on southern Bouganville. The other bomber ditched into the sea off Moila Point. American pilot Tony Lanphier originally claimed the bomber, as did Rex Barber, starting a lifelong controversy over who actually shot down Yamamoto. Later research awarded the claim to Barber, who attacked from the rear. The crash site was so remote that it took Japanese personnel until late the next day to locate the crash site in the jungle. Subsequent autopsy of the admiral’s body showed no physical wounds other that a small cut above his eye. It was believed that he died from internal injury or shock. The crash site now displays  a  memorial plaque placed by the Japanese and is now accessible by a footpath.


 This is a reboxing of the earlier Tamiya G4M1 kit. The new offering also includes figures of Yamamoto’s crew as well as figures of waving groundcrew. This would allow a diorama of the plane as it departed Lanukai airfield on Rabaul. The kit also includes decals to build either of the planes on this mission (T1-323or T1-326). A real plus to this kit was the inclusion of pre-painted canopy frames (a lot of glass on this plane), but which would cause a problem later on! It is molded in Tamiya’s usual light gray plastic. Instructions also included a separate description of the Admiral’s final mission with a map, a photo of the G4M1 and a line drawing of a P38.


 As with most kits, construction began with the interior. I am used to building fighters, so I was surprised at the sheer size of the fuselage of this plane. There is fairly good detail of the interior, but a minimum of extraneous items one would find in an operational bomber. I generally no longer paint figures, but I felt that they were necessary for this build, so I painted the flight crew and Yamamoto while waiting for the interior light green to dry. Rather than use the supplied decal, I painted the instrument panel back and drybrushed the instruments. I then painted the tail gunner. While waiting for all the paint to dry, I assembled the wings, vertical, and horizontal stabilizers, glued in the nose windows,  and left them to dry over night. 

The next day, I assembled the fuselage. Betty bombers did not have opening bomb bay doors. The bomb bay had a panel to cover it when not in use. I glued in the panel but noticed that fit was not perfect (for a Tamiya!) I then attached the wings and tail surfaces. All of these fit very well. I then left all of this to dry over night.

Day 3 was reserved for my least favorite part of the build – sanding. Fortunately, this is a Tamiya kit and fit so well that there was a minimum of sanding involved. This was a real treat after my last build – a Smer SVA that just consisted of vaguely shaped blobs of plastic. The Tamiya kit was crisply molded and fit almost perfectly – except for the bomb bay cover. It could have been due to my ham-handed building skills, but the bomb bay required more than minimum sanding. However, no putty was sued in this build.


Day 4 was used to start the paint process. I first masked the nose windows with blue tape. I then painted the leading edges of the wings and the center fuselage sides with flat white Tamiya acrylic paint. I let them dry for a few hours. I then cut square masks out of blue tape for the fuselage sides. I generally try to paint markings that I can rather than use decals. I then painted the leading edges with Tamiya flat yellow mixed with a little Tamiya flat red (which will cause problems later.) I masked over the leading edges and painted that anti glare panels with Testors flat black spray. My airbrush is getting finicky, so I use spray cans for some things. After letting that dry, I masked off the anti-glare panels. Here is where I went wrong. I used the supplied clear parts that were not prepainted to mask off the interior areas of the fuselage. I then sprayed the underside of the plane with Testors 1246 metallic silver. The top was painted with Tamiya’s recommended color XF-11 JN Green. I figured that it would match the prepainted canopies – WRONG! The next day while trial-fitting the canopies, I found to my dismay that the prepainted color did not match – it was too light. I then mixed XF-11 with a little Tamiya XF-26 deep green and lightly sprayed along panel lines and a little more thickly along the top to show fading. T1-323 was only a month old when it crashed, so it should not have faded too much even in a harsh environment like Rabaul. Upon removing the masks from the fuselage, I found the inevitable bleeding through of the top color. This was no real problem for the white squares, but the leading edge color was hard to match on touch up, and my attempts at repair do not fully match. I then sprayed Glosscote all over the plane to facilitate adherence for the decals. I chose to use the markings for Yamamoto’s plane. Decals were also coating lightly with Microsol. After the decals had dried, I sprayed the whole top of the plane with Testors Dullcote.


I attached the canopies, blisters, nose cone, etc. The colors now matched fairly well. Landing gear went on easily, making me appreciate the engineering involved in designing Tamiya kits. Once built, it makes an attractive, if large, addition to my growing fleet of Japanese aircraft.


 I would definitely recommend this kit to collectors of WWII Japanese aircraft. I would like to thank Tom Cleaver who supplied the kit that had been provided by Hobby Link Japan.


Famous Bombers by William Green

Information supplied with the model

Pacific Wrecks.com http://www.pacificwrecks.com/aircraft/g4m/2656.html

Charlie Isaacs

February 2013

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