Tuesday, March 3, 2015

Mitsubishi A7M3(-J) variant of the Reppu

The A7M3 has cooling lips aside the engine, depicted in most drawings of the A7M3 version.

The proposed A7M3 variant of the Reppu and the land based sub-variant (the A7M3-J) were to be powered by the Mitsubishi MK9C eighteen cylinder radial engine that was rated at 2,250 hp on take-off, 1,800 hp at 5,000 metres and 1,660hp at 8,700 metres. Armament comprised of six wing-mounted Type 99 Model 2 20mm cannons (for the A7M3) and four wing-mounted 30mm Model 5 cannons and two rear-fuselage mounted obliquely firing 30mm Model 5 cannons. The dimensions of the A7M3 and the A7M3-J were supposed to be identical to their predecessors however the weights and also the wing loading of these models were different to those of their predecessors. For the A7M3 model, the weight when empty stood at 3,392 kg and when loaded it was 5,040 kg, while the wing loading was 163.3 kg per square metre. For the A7M3-J model, the weight when empty stood at 3,955 kg and when loaded it was 5,732 kg, while the wing loading was 183.1 kg per square metre.

The Combined Fleet website says carrier fighter but, oddly, other sources say that the A7M3 (Model 23) was based on the airframe of the A7M2 (Model 22) but without the wing-folding mechanism.
Either way, the A7M3 was powered by a Mitsubishi MK9C (Ha-43-31 with three-stage two-speed compressor - 2,250 hp T/O, 2,000 hp at 1,800 m, 1,800 hp at 5,000 m, and 1,660 hp at 8,700 m). Armament was increased to six 20 x 101 mm Type 99 Model 2, all wing-mounted.
By contrast, the land-based A7M3-J was to be longer (presumably ahead of the firewall), have greater wing area, and would be powered by a turbocharged engine (Mitsubishi Ha-43-11 Ru). Armament was to be six 30 x 122 mm Type 5 cannons (2 x oblique fuselage-mounted, 4 x wing-mounted).
Other sources say that the A7M3 and A7M3-J were both powered by Mitsubishi MK9Cs, differing only in the armament fitted.




  1. I thought the short-nosed A7M3 had the MK9S.
    Anyway this model was insurance in case the redesigned A7M3-J hit a snag.
    In hindsight, I think the A7M3 should have preceded the full-on high altitude redesign into combat. It was a compromise but it had better climb and still had much better altitude performance than the A7M2 or any other Japanese fighter! Why delay it to post-war? The Reppu was already the most delayed fighter of th war, since 1940.
    Packing 6x20mm cannons was enough to leave a mark too. Japan didn't have an extra 6 months.

    The MK9 engine should have been produced underground, not where the sole factory could be bombed, as it was of course.
    It was so reliable it was also slated to power the Ki 84 as well as the A7M. More than one MK9 factory was called for in my opinion. How many late-war Japanese fighters had a reliable engine in strong numbers?
    The Navy brass already wasted a year delaying the Reppu before the earthquake setback. The 1940 start didn't get serious for 2 years when it should have been only 1-1/2 years because of the A6M2 and 3.
    The Reppu was the Zero replacement. The A6M5 was with no engine upgrade was obsolete, but was made (5,000) pending the Reppu, by default. Compliments of the Navy brass, resources were mis-spent.

    Next, They locked horns with the Jiro Horikoshi and forced the unreliable NK9 underpowered A7M1 which disappointed as he predicted. This cost the MK9 engined Reppu 6 months again. They already were proven wrong by Jiro with the underpowered A6M5/6 Zero, but they didn't learn to trust him. So he built the A7M2 and won them over with a demonstration flight to restart the Reppu program again. The A7M3-J took a year and still only had a non working mockup for inspection in 1945. Enough delays! Get the A7M2 on the carriers first, while they are still afloat!! This should have been done in late 1943! Had the Navy been as savvy as the Army, it could have happened. Their Ki 84 was the contemporary of the A7M and they were kicking butt already in 1943. 3,500 Nakajima Hayates were produced vs 1 Reppu by the end of WW2. Besides, Nakajima made most of the A6M Zeros for Mitsubishi at the same time. The A6M5 Zero 52 was highest priority for the Navy, when the A7M2 Reppu should have been.

    The Marianas turkey shoot should have had the 1,560 hp Ha-112-II engined A6M5s (A6M8) and less turkeys. Maybe even some A7M Reppus for carrier defense.

    Can you imagine B-29s intercepted by 3,000+ A7M3 Reppus?
    6 wing cannons could've done a job on the heavies.
    And go toe to toe with P-47N and P-51D escorts.
    The A7M2 had automatic combat flaps like the N1K Shiden, giving the Reppu a 12 sec full circle turn time like the 1942 A6M3 Hamp!
    The A7M3 Reppu had more agility as well as more firepower than the US fighters and it was well protected, all at the same time.
    The Reppu fighter was praised by Saburo Sakai for good reason.
    But very few pilots would ever fly it because of delays, most of them unnecessary.

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