Brief background

Luckily for the Allies, the Nakajima B6N Tenzan ("Jill") was a classic example of too lttle, too late. Stemming from a 1939 requirement for a successor to the same company's B5N "Kate" torpedo-bomber, the new aircraft was of similar size, but was a lot more powerful, with a speed approaching 300 mph. While the IJN demanded that a Mitsubishi Kasei radial engine, Nakajima insisted instead on their own Mamoru 11 - a decision that was to lead to serious delays, as the powerplant proved troublesome and unreliable. These combined with other unexpected flight testing problems, so it wasn't until 1943 that the Tenzan was finally ready for service - by which time, the cream of the Navy's crews had been lost and the balance of power in the Pacific had shifted irrevocably to the U.S.

Even then the Tenzan's troubles weren't over. After only 135 B6N1 production aircraft had been delivered, Nakajima was ordered to cease manufacturing the Mamoru engine, so they were finally forced to fit the rival Kasei - the very engine the Navy had wanted in the first place! The resulting B6N2 proved a potent machine and saw extensive service in the final two years of the war, many ending their days in Kamikaze attacks. But, with Japan's carrier fleet all but wiped out, the type could never achieve its early promise in the role for which it was designed, and one can only wonder if the story would have been different if the Tenzan had been ready in time for Midway...

The kit

Hasegawa released their quarterscale B6N2 "Jill" back around 1999. It's a very fine kit - well detailed and straightforward to build. I've always thought the company's 1:48 kits from this period, particularly their Japanese subjects, rate among the best produced, so I was very interested to see the announcement of a new limited edition of the kit, reworked as the earlier B6N1.

The new version arrives in a very attractive conventional box, with the main sprues bagged together, and the clear parts and accessories packed separately. I noticed a few items were a bit scuffed, one or two small parts had become detached from the sprues in transit - but my kit had a rather more convoluted journey than most, bouncing around between Japan, the US and finally the UK, so this is perhaps not entirely unexpected.

The kit comprises:

126 x grey styrene parts (plus 22 unused)
14 x clear styrene parts
14 x grey resin parts
3 x sets of poly washers
Decals for 2 x colour schemes

The moulding of the styrene parts is excellent. The kit maybe nearly 15 years old, but it certainly doesn't look it. The parts are crisp and virtually flash-free, although I noticed a couple of shallow sink marks where there's deep detail on the reverse. The designers managed to keep ejector pins mostly out of sight - the only really irritating ones are on the underside exterior of the separate Fowler flaps.

The surface finish comprises very neat engraved panel lines and a few raised details. Rivets and fasteners are quite restrained, and the fabric covered control surfaces are nice and subtle.

Basic test fit

The fuselage halves clip together perfectly with quite a nice thin trailing edge to the rudder. The wing is built up from from five parts, with separate outer panels that can be displayed folded. The centre section is a very solid assembly that ensures the correct dihedral, and the fit at the roots is such that you shouldn't require any filler if you're careful. The horizontal tailplanes have interlocking tabs that keep everything straight and true and, once again, no filler should be needed at their roots.

I don't know if the kit was originally planned to allow for a B6N1 option, but it looks that way with the forward fuselage, cowling and propeller being on a separate sprue. Presumably Hasegawa decided the market didn't justify tooling up for styrene parts of the earlier version, so the replacement parts are all produced in resin. The old (unused) styrene forward fuselage fits beautifully, it'll be interesting to see if the same is true for its resin counterpart...

The answer in the sample kit is a qualified "Yes". The parts are a near-perfect match for the fuselage contours, but are a tad slim in depth (perhaps down to mould shrinkage), so they need a spacer between them. I think the best approach will be to glue the each forward part in place prior to assembling the fuselage halves, dealing with the centre-line seam as necessary - otherwise you could be left with a nasty step.

A few details

Hesegawa kits in the '90s really set new standards for the cockpit detail they included, and it still impresses today. The detail on the sidewalls is quite superb for an injected kit. To be honest, with careful painting it'll give many resin sets a run for their money. The pilot's seat, inevitably, does look a bit heavy compared with the best resin parts available, so it seems a bit of a missed opportunity in this limited edition kit not to include a new seat among the other resin parts. But to be honest, the only things really lacking are harnesses, even as decals. There's a choice of ways offered to tackle the instrument panel - either a solid decal or dials on a clear carrier film to lay over the moulded bezels. Experienced modellers may go one better and use a punch and die to separate the dials to apply individually.

The upper rear gun is designed to be stashed in the starboard fuselage half, but the lower "tunnel" position can be extended with the gun in its mount.

The undercarriage features an impressively deep well with good rib and stringer detail. I've no doubt you could add additional wiring and pipework if you can find suitable references. The gear legs are well moulded and quite sturdy, but you'll find a couple of ejector pin marks that need filling. I'm usually a fan of weighted wheels, but in this case I do think Hasegawa went a bit overboard, and when I built the original kit I built up the base of each tyre with a piece of plastic card. Maybe the kit does have it correct for a fully loaded Tenzan(?), but seeing the parts again after a gap of some years confirms my gut feeling that they overdid the effect.

There's no torpedo, but for external stores the kit provides a pair of 250 Kg bombs on an external rack. The fins are quite thick, so the bombs will look much better if you replace them with plastic card.

The transparent parts are excellent. There's no option to open the canopy, but the parts are commendably clear with neatly defined frames. The small rear fuselage windows are cleverly designed to drop in from the exterior, saving a lot of messing about with masking.

All that resin...

Hasegawa supply a complete new "front end" in resin for the B6N-1. Well, not quite complete, because the old styrene Kasei engine is still used. The only photo I've found of the Mamoru doesn't show the crankcase, so I don't know how different the two 14-cylinder radials looked in real life.

The resin parts are fair, but I have to say they don't match the quality of the rest of the kit. I was initially concerned that the cowling looked too oval on the rear edge to match the circular backplate, but once the engine clicks in place it actually fits very neatly. What is rather perplexing, though, is what appears to be a scar on the exterior where the master (or sub-master) part has been cracked and repaired at some stage. It really should have been picked up on and corrected better.

The cooling gills on the sample's backing plate are a little ragged on one side and there is a small air-bubble which will need repairing, while the new propeller blades show clear swirls as though the resin has been mixed inconsistently.

A new spinner is supplied, which looks slightly less bulbous than the original (although the difference is so subtle, I might be deceiving myself there). This will need careful preparation, as the casting block is on the front to allow allow it to assemble like the styrene version.

Finally, there are a neat pair of exhausts (slightly hollowed, but you could easily drill them deeper still) and an oil cooler intake.

Instructions and decals

The assembly guide is well drawn and clearly laid out, as we've come to expect with Hasegawa. Colour suggestions for Gunze Sangyo paints are keyed to most details throughout.

Decals are provided for a pair of Tenzans:

1. 13-382, 601st Naval Flying Group, Aircraft Carrier Zuikaku, Singapore, Spring 1944
2. 31-364, 531st Naval Flying Group, 1943

The silk-finished decals look to be excellent quality, with pin-sharp printing, particularly evident on the cockpit instruments. No stencils are included, beyond red fuel tank covers and propeller warning stripes.

Conclusion

Hasegawa's B6N1 is a really interesting model, but I haven't marked it as highly as I expected on account of the resin parts that don't match the overall quality of the rest of the sample kit. I hope I was simply unlucky and that they are normally better, but I can only mark on what I have in front of me. I presume Hasegawa out-source for their resin parts and, on the basis of this example, I think they need to tighten the quality control. Despite that, experienced modellers shouldn't be too put out by the extra work required, and the resulting early "Jill" will make a very attractive addition to any 1:48 collection of Japanese aircraft.

Please remember, when contacting retailers or manufacturers, to mention that you saw their products highlighted here - on AEROSCALE.