The Other Japanese Fighters

[Robert]

Whoops, I meant the D4Y and M6A being possibly related. Makes some sense, since they both come from manufacturers of IJN a/c.

Both were in fact manufactured by Aichi.

Yokosuka was not a manufacturing concern, rather it was a Naval Arsenal, design and flight test center that had a limited production capability. The bulk of Yokosuka aircraft were built by other manufacturers.


The D4Y project originated out of experience with the Heinkel He 118V4, the IJN had planned to produce a modified version but the aircraft disintegrated in flight, by late 1938 the project to produce a better aircraft using the 118 as the basis was assigned to the Dai-Ichi Kaigun Koku Gijitsusho at Yokosuka, the team was led by Chief Eng Masao Yamana . The first of five D4Y prototypes built by the Dai-Ichi Kaigun Koku Gijitsusho was completed in November 1940 and made its first flight the following month. Serial production was assigned to Aichi (1,818 produced) and the Dai-Ichi Kaigun Kokusho (11th Naval Air Arsenal) at Hiro (215 produced).

Based on the timelines for development and the fact that Aichi was the major producer of the D4Y, it is very likely that the D4Y influenced the design of the M6A.

Jon

Yes, the D4Y and M6A were related:

From Monogram Close-Up 13:
The original basis for the design [of the M6A Seiran] evolved around the advanced carrier-based dive bomber D4Y1 Suisei (Judy) which had just started rolling off Aichi's Eitoku plant in southwestern Nagoya City that spring [1942]. The hope was that the Suisei, with some modifications, could be adapted for submarine use. In this capacity it was to be named Keisei. The conversion was found to be impractical, however, as was the attempt to have interchangeability of major assemblies between the two aircraft.
Although features of Judy were carried into the basic design of Seiran, a near total redesign became necessary in order to perfect a foldable airplane to fit into the eleven- foot six-inch diameter hangar tube of a submarine. This requirement became the point of departure of the design.

As posted on my website.

[ysi_maniac]

Ki-43 Hayabusa with Merlin


... and minor details

[famvburg]

Where's the radiator?

[ysi_maniac]

In the not included wings.

[RussC]

I would almost wonder if the IJAAF would have insisted Kawasaki mount the Merlin like the Daimler Benz in the "Tony" and slope the cowling down up front giving more pilot visibility. It would mean going from carbs to injectors though. A light airframe like the Hayabusa would scream along with a Merlin up front.

[sequoiaranger]

>I would almost wonder if the IJAAF would have insisted Kawasaki mount the Merlin like the Daimler Benz in the "Tony" and slope the cowling down up front giving more pilot visibility. It would mean going from carbs to injectors though. <

The reason the Hein (and He-110, and Bf-109, and Re-2001/5) cowling(s) slopes down is that the DB engine is an "inverted-V" engine whereas the Merlin is an "upright-V". You can just "turn the Spitfire cowl upside-down" for shape of the cowling, but that does nothing for the shape of the engine and it wouldn't fit in the downturned cowling!!! Look at where the exhausts are and that tells you where the cylinders are---they are "up high" on the Merlin, and "low" on the DB engines!

The Spitfire cowl on the Ki-34 *LOOKS* "cool" in side-view, but remember, too, that the Hayabusa had a round, radial engine, and a round fuselage. The Spit had the narrowest cowl that would snug up against the INLINE engine---there would be mega-gaps on the side of the fuselage, in reverse of the Suisei/Ki-100 engine exchange. But---maybe THERE are your radiator intakes!!!

[rickshaw]

If you introduced fuel injection to the Merlin, would it be possible to invert the engine?

[PR19_Kit]

Rolls-Royce would have had to do a lot more work on the Merlin to get it to work well inverted.

The oil scavenge system would need a complete redesign for a start, and I suspect many other aspects would not be working at their best upside down. And for what? The only obvious improvement would be to better the visibility of the Spitfire pilots while taxi-ing or on the approach, and they'd already figured good ways round both of those problems anyway. Hurricane, Defiant and bomber pilots didn't seem to mind the shape so much.

[rickshaw]

An exercise in whiffery of course...

[ysi_maniac]

The Spitfire cowl on the Ki-34 *LOOKS* "cool" in side-view, but remember, too, that the Hayabusa had a round, radial engine, and a round fuselage.

You are right. I am currently trying to mate Fokker D.XXI fuselage and Hurricane engine. It is laborious but ... we are whiffers! In the other hand, Hayabusa's fuselage is round but quite narrow.

[sequoiaranger]

Last year I made such a beast, using an old Nichimo Ki-61 nose/forward fuselage to mate up to a Hasegawa Ki-84:



Here is an "in-progress" shot that shows the blending of the two fuselages. The Ki-61 fuselage had to go back as far as the cockpit where the Hayate fuselage slimmed down enough for a match-up:



I "Germanized" it with wing cannon gondolas and bulged-cowling guns as a bomber-destroyer variant.

So a "Spitfire-nosed" Hayabusa would probably be similar!

[ysi_maniac]

Beautiful indeed!!

[RussC]

I'll second that. A really superb build. 

[ysi_maniac]

With Klimov engine

[sequoiaranger]

That's *SO* Yak-9!!