Mitsubishi A7M Reppu / SAM
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Mitsubishi A7M Reppu / SAM

The design by Mitsubishi of a carrier-based fighter to supersede the A6M Zero-Sen had been planned by the Japanese navy as early as 1940, but was frustrated, by the company's involvement in urgent development and- production programmes. It was not until 1942 that design of the M-50 Reppu (hurricane) began, but the continuing pressure on Mitsubishi for developments of the ABM meant that it was not until 6 May 1944 that the first prototype, which by then had the company designation Mitsubishi A7M1, was flown for the first time. A cantilever low-wing monoplane with retractable tailwheel landing gear, the A7M1 soon revealed excellent flight characteristics, but as predicted by Mitsubishi the type's maximum speed on the power of the installed Nakajima NK9K Homare 22 engine was below specification. Further testing was abandoned until availability of the 1641kW Mitsubishi MK9A radial engine made it possible to build seven A7M2 prototype and service trials aircraft, the first prototype being flown on 13 October 1944. Clearly a potent fighter that could meet Allied opposition on equal terms, the Reppu had a maximum speed of 630km/h at optimum altitude and was ordered into production as the Navy Carrier Fighter Reppu Model 22. Unfortunately, by then it was too late for the Japanese navy, Allied air attacks and an earthquake limiting production to only one aircraft. Development of similar land-based fighters was planned under the designations A7M3 and A7M3-J, but neither was built before the war ended.

Mitsubishi A7M Reppu / SAM

 ENGINE1 x Mitsubishi MK9A, 1650kW
    Take-off weight4720 kg10406 lb
    Wingspan14 m46 ft 11 in
    Length11 m36 ft 1 in
    Height4.28 m14 ft 1 in
    Wing area30.86 m2332.17 sq ft
    Max. speed620 km/h385 mph
    Cruise speed410 km/h255 mph
    Ceiling10900 m35750 ft
 ARMAMENT4 x 20mm cannons, 2 x 250-kg bombs

Mitsubishi A7M Reppu / SAMA three-view drawing (752 x 1049)

Comments1-20 21-40
Ron, 22.01.2016

The A7M3 aternative was not such a major redesign. It used a mechanical 3 speed supercharged MK9S in the existing A7M2 frame and still gained most of the high altitude prowess of the 3-J long nose version. A7M2: 390 mph @ 21,650'; A7M3: 400 mph @ 28,543'; A7M3-J: 403 mph @ 32,800'; A8M: 410 mph. All but the A7M2 are estimated.

Ron, 22.01.2016

A7M2 WoF: 3.453 (43 rps, mixed guns). Same as A6M8.
4.267kg/s (33 rps) 4x20mm @ 500 rpm each.

A7M3: 9.600kg/s (75 rps) 6x20mm @ 750 rps each. Best compromise.

A7M3J/A8M: 9-11kg/s (26-30 rps) 4x30mm @ 400-450 rpm each 15Kg/s counting dorsal twin 30s.
6.800kg/s (50 rps) 4x20mm @ 750 rpm each.

Ron, 22.01.2016

The 13.2(x99mm cartg) Type 3 HMG is close to the MG 131 13.1mm but with higher velocity @ 795 mps and much heavier 49-52g bullet. Range: 900m. RoF 800 rpm.

The Type 99-II Type 4 hasdecent velocity of 759 mps equal to the MG 151/20, but much slower RoF: 500 rpm but again a much heavier 128g shell and better range: 1000m. So it is closer to the US Hispano.
The 99-II Type 5 is equal to the much heavier Hispano Mk V. Both have a 750 rpm RoF.

The 70g 30mm(x122mm cartg) Type 5 is between the slower, long range 141g MK 103 and the short range but faster 60g MK 108. It has a heavier 345g shell and 900m range. A winning compromise. The much lighter Army 50g H0-155 has the same 900m range and 400-450 rpm but a much lighter shell.

So there is nothing inferior here. The firepower is free of the short range of the MK 108 and the double weight of the MK 103 or the unreliability of the US Hispano, with a heavier projectile in each case, and with a good range.

So all the Reppu versions have good to great punch.

All of them have decent high muzzle velocity and top throw weight. RoF on the A7M2 with mixed guns is slow for the 20mm while adequate for dogfighting and retaining lighter Zero agility. But the A7M3 with 6x20mm fast cannons is awsome.
The A7M3-J/A8M with 4x20mm fast or 4-6x30mm slow big cannons are good for intercepting B-29s.

Ron, 21.01.2016

I've seen 410 mph estimated speed for the replacement of the Reppu, the A8M Rifuku with the Nakajima Ha-44-13 2350 hp engine. So, I would go with the 2400 hp Ha-44-21. It had the A7M3-J larger wing and the 4x30mm Reppu body, up-engined to be called Rifuku. I've also seen it with 4x20mm 750 rpm 1000m range cannons. I also like the A7M3 Reppu with 6 of these wing-cannons for volume of rounds per sec. These rounds are 128g shells almost equal to the Hispano 130g and much heavier than the H0-5 shell of the Army cannon.

Ron, 21.01.2016

The A7M2 Reppu had the same firepower as the A6M8 Zero plus the tight turn of the A6M3 Zero 32: 360 turn in perhaps 12 seconds with the Shiden style automatic combat flaps.

I still see the Type 99-II called low velocity by many. It had a firing range comparable to the Hispano! These folks are obviously confused with the early 99-I. Big difference!

I like the A7M3 for the faster 20mm cannon Type 99-II Type 5 with the 750 rpm RoF. Much better than the unreliable M2 Hispano and equal to the RAF MK V Hispano 20mm cannons.

Ron, 15.01.2016

The Russian report on the Reppu A7M2 mentions it was armed with 4 (500 rpm) Type 99-II Type 4 cannons. So maybe the A7M3 had faster (750 rpm) Type 99-II Type 5 cannons.

In 2/1944 the major redesign was started for the A7M3-J using the turbocharged MK9A-Ru for high altitude.
(this took a whole year to reach mockup inspection 2/1945 and still no prototype).
The A7M3 was a back-up in case it failed. It too was land based but since the A7M3 was based on the A7M2 frame, it could be done much quicker if started first with minor modification using the 3 speed supercharged MK9S. This would still get most of the altitude prowess of the long nose redesign without losing the time.

The sole engine plant at Daico was bombed, delaying MK9 engines. Why was the Zero replacement dependent on just one engine factory with B-29s around? If only there were several factories, this Mitsubishi engine wouldn't have held up the works for the Reppu.

So with these 2 points the Reppu may have seen action.

1. Prioritize the A7M3 first since it was competent up high vs other Japanese interceptors. 6x20mm cannons are adequate. What US plane can match that?

2. Crank up the volume of MK9 engine output at multiple sites, maybe underground too!

Not that the outcome could be changed for WW2, but at least the more timely potential of the Reppu A7M3 could have gone a few rounds instead of looking like perhaps the most mismanaged program of the war (late 1940-45).
The A7M3 had better estimated climb than the long nose A7M3-J and the pattern of fire would be denser for dogfighting too.

Ron, 12.01.2016

The obvious typo was meant to read A7M2 in my last post, not A6M2. Sorry.
I trust you knew the A6M2 didn't go 400mph like the A7M2 in level max speed. I make my share of typos.

Ron, 12.01.2016

The A7M1 was dropped in favor of the A7M2 with 2,200 hp.
It turn very well with the automatic combat flaps.
The only US fighter that could equal it in W/L and P/L and go as fast was the F6F. But the new F8F was more of a contemporary. The Bearcat could beat the A7M but it had a clear advantage in firepower. The A7M3 could challenge B-29s with 6x20mm wing cannons. The 750 rpm new Type 99-II Type 5 was in production since 5/1945 so it could have a leathal punch hard to beat. The longer nose A7M3-J packed 6x30mm long range cannon. Even better to tackle bomber raids. Unlike most Japanese fighters, it was good up high too. The A6M2 was test flown and climbed to 6 km in about 6 minutes. It went about 400 mph. even if the dive speed was reduced to 490, it was a worthy competitor. It had a more conventional 4x20mm armament that was still more reliable than the M3 Hispanos on some F8Fs. Most US fighters had the 12.7mm HMGs. No comparison! The Reppus Ace was it's bite.

Ron, 08.01.2016

516 mph was the target dive speed (830 kph) for prototype.

Some say the Reppu could turn better than the late-war Zero. That would be around 12 sec 360 circle like the A6M3.
I like to use this sight to assemble new data I find about planes, more than to argue with other aviation enthusiasts about nationalism etc... Other sites are better for that.
We all have favorite planes. I like to be open minded to find talented designs wherever they may be. When I see a worthy plane tied up by officials at the expense of engineers, it needs to be exposed. I like to explore the potential of planes and temper it with reality by others of like mind and love for aviation.

The Reppu design team certainly had their share of frustration. But they did have a promising design. 2,200 hp gets my attention. The earlier engine was too weak for this fighter at this stage.

Armydicked, 05.07.2012

People, can we dispence with the racism? So the Japs 'Japped' us at Pearl Harbour? Just like LTG Washington 'Japped' the Hessians at Valley Forge?!!!

Casual Observation: During WWII, E-V-E-R-Y country was guilty of milking a platform that should have been retired long ago. The A6M2 Zero was a brilliant 1939 design that reached pinnacle termination in 1941 and a new design should have been initiated. Instead, the Japanese wasted resources on the A6A3, A6M5, A6M6-8 which, with a power plant double that of the A6M2 was only 17mph faster? Japan had the Heinkel He100D and the Focke-Wulf FW190A1/3 which, with better power plants would have matched the P-47/P51D.
Don't laugh---Germany continued improving there Messerschmitt Me109 (1935) which reached pinnacle termination with the Me109F (1940)---its Me109G-K resulted in progressively worse aircraft to 1945. America committed the same act of stupidity with the Curtis P-36/P-40, the P-40 being a P36A with a mounted inline engine. The P40C hit pinnicle termination in 1940 and the subsequent P40 D-N Warhawks dragged the obsolessant design into JAN1945!!! FYI, the British adored their P-40s (used as desert ground attack aircraft) and begged Curtis to continue cranking out the near worthless AirCraft.

People freak at what it must have been like being a P51D pilot and being forced to take on a Jet fighter like the Me262A which was 100+ mph faster. Try being a Japanese pilot in a A6M7 Zero (340mph) going up against swarms of No. American P51Hs (487mph) that were 140mph faster!!!

Tom Barron, 04.07.2012

The Japanese lost this war before it even began.
When they attacked Pearl Harbor their embassy in Washington had received a top secret signal that they were to drop off a declaration of war at the US State department.
The signal was so highly classified that they could not disclose it to anyone without the right clearance.
So the diplomas had to type up the declaration of war themselves.
None of them could type worth a damn, and when you are doing something as historical as declaring your country's leaders had decided to go to war, well, everything had to be just so, letter perfect, and no erasures allowed!
So they typed and tried and tried again and this little farce went on for so long, that by the time the ambassador had clean copy to present and got his top hat and hauled his ass over to talk to Corny Hull, well, by that time the carrier strike force was already doing their thing in Hawaii, and the Japanese, 'ah, so, we decided we would rather fight you than put up with your imperialist demands that we give up what we gained by force of arms just on your arrogant say so! En garde!' and immediately followed up by a killing blow to the US Navy fleet at Pearl Harbor.
That 'we declared war on you honorably' just before the guns went bang might have cut some ice as far as their 'limited objectives' war goals were, and perhaps this would have resulted in some negotiations in mid 42 happening, but that undeclared war attack really screwed the pooch there for the Japanese. They were the Yellow Peril and America was just as racist as were the Japanese and the Germans. That attitude went through one hell of a change after they took Singapore, Hong Kong, the Philippines, Java, and the Zero was doing combat ranges of nine hundred miles away from their bases. They had extremely well trained pilots, but they were only graduating a hundred Naval Aviators a year. At Midway they lost three hundred pilots.
They had their heads up their butts with 'we know..' stuff that simply was not so. The American's were fat and cowardly and didn't have the back bone for a long prolonged fight, just as the Japanese were near sighted buck toothed short little little gardeners who were only clever at copying more advance western designs. (How many of you know about which plane(s)the Zero was supposedly based on?)
America caught one hell of a break when she got to read the Japanese codes. The Japanese were simply too arrogant about their own superiority. Sakai, the great Japanese ace, was one of seventy five selected out of fifteen hundred for pilot training, and of that group, only twenty five won their wings. The Japanese military was the most brutal of all of the armies and navies of the twentieth century, and I think you would have to go back to Sparta to find as military a culture. That brutal selection process chose their commanders and they followed a medieval of warfare where the worst dishonor one could have was to surrender in combat. They treated their captives in so bad a way that the only way that America would have negotiated is if they did not hear about the Bataan Death March. The eastern and western codes were two different things entirely. Succor the wounded? Just kill them so they don't slow you down!
The idea that a lack of skill with a type writer might have effected how World War II went in the Pacific War sounds ludicrous, but there it is. The Japanese military were hell bent on fighting to the very last man standing,and they simply would not listen. If a plant manager told a military officer that due to lack of materials or skilled labor they could not deliver the fighters, he'd be beaten until hospitalized. (That happened at Mitsubishi, by the way.)
The atomic bomb, horrible as that weapon was and is, did save a lot more lives that most people realize even now. Does anyone remember those 'really dumb' balloons that Japan sent over on the jet stream that set off a few forest fires in Washington and Oregon way late in the war? One of those weapons that only someone clutching at straws and living in a day dream would even bother with, and how dumb could they get, right? Well, the forest fires were reported in the press, and that allowed the Japanese to figure out where their balloons were winding up. In China, they had been testing biological weapons and once they had the range, guess what the real payload of those silly balloons was? We now have a policy of equating biological and chemical weapons as being the equivalent of nuclear weapons and it's the stated policy of the United States that if someone attacked us with biological warfare, they get nukes in return.
Speaking of nukes, Hanford is in Washington state, and I image that if a plague got started, it would have screwed up production of the atomic bomb. You also have the naval yards there where ships would pull in for long yard periods and men would take leave and head out for all parts of the country. Gee, if only we'd ...

kildlawyrs, 14.05.2012

Any one who honestly believes that this fighter could have changed the war's outcome in any meaningful way, should ask themselves, "Where would America's military power have been six months after Hiroshima?"

As with the Germans, with the Japanese it was a classic case of , Too little, too late.

Bush Pilot, 09.05.2012

The Japanese gambled it all on a short war? Let's consider how unlikely a negotiated surrender could be expected to actually happen.

1. Japanese undeclared war attack on US at Pearl Harbor.

2. Japanese torture/slaughter hundreds of thousands of Chinese.

3. Japanese torture/execute thousands of civilians/captured enemy prisoners.

Conclusion: Nothing is going to stop the sleeping giant and it's allies from crushing these merciless warmongers, regardless of which fighter was developed and put into action whenever and with hot shot pilots or not, etc. developed by Japan. WWII era Japanese officers could give lessons on how to motivate your enemy to do anything to beat you and never be willing to negotiate.

Ron, 21.03.2012

That MK9A 2200 hp motor could have given other Japanese fighters some much needed speed while the war was still on.
At least the IJNAF. Can you imagine a 400 mph Zero in 1944, or a Shiden-Kai with 2200 hp instead of the unreliable Homare, or in place of the Raiden's unreliable 1800 hp Kasei 23.
I think the Army Ki 100 was too slow with the 1500 hp Mitsubishi 62 engine, almost as slow as the A6M8. So if Kawasaki could stomach a 1500 hp Mitsubishi navy motor, what about the 2200 hp one! can you imagine letting all Japanese fighters test that engine in 1943-44. No more unreliable J2M3, Ki 61-II, N1K1/2, and of course Ki 84! They could use the extra power too (especially the Ki43). The A6M5 could have been well armored and sturdy with that bad boy under the hood and fool everyone and in quantity. As it was the A6M5 still had what? 1130 hp in 1944-45, while the Reppu engine waited and waited and missed out. Mitsubishi should have demonstrated their MK9A and K engines and quit with the 1130 hp motor already. Let the Navy authorities see the light. 1942-3 was gone. The US wasn't accommodating the A6M5 at this late date. The most numerous fighter of Japan was being relegated to suicide missions. They were fairly good at it too.
As soon as Horikoshi locked horns with the Navy over the Reppu, he should have let loose with a tried and true Zero with real strength and hp! Just as a stop gap at least. Maybe they would have said no, but I doubt it.
Even the smaller MK9K with 2000 hp would have brought the A6M5b up to world class performance in spring 1944. Think of 5,000 of those running loose. The Zero with armor and high velocity armament (plus a new 13.2 mm MG to compliment the other 3 weapons). Thicker skin to raise dive speed to 460 mph. This 5b version deserved more than 1130 hp. The Reppu was supposed to be ready by now but nooo! So, demonstrate a Zero special! And climax the show with a Raiden special! Corsairs and Hellcats, Lightnings and Mustangs, and MK VIII spitfires would have their hands full.
Don't keep making 5,000 obsolete A6M5/6/7s. If the Navy pilots miss the low hp, let them fly old Oscars and Nates.

Ron, 19.03.2012

Jiro Horikoshi had to be one frustrated designer!
The Japanese Navy was farsighted enough to issue a 16-Shi specification in 1940 to replace the Zero with the Reppu but withdrew it, then revived it in April 1942 to a 17-Shi spec! There goes a year or so right off the bat!
Next Jiro insisted on the 2200 hp MK9A or B engine being developed for the necessary performance, but the Navy 'elected to postpone its engine selection'. In September the Navy instructed Mitsubishi to install the 2000 hp NK9K instead! The A7M1 was the result in April 1944 complete with hydraulically folding wings for carrier stowage (what carriers?). As a result of its poor performance May 6 1944, as Horikoshi warned, it was suspended by the Navy.
Finally they listened and authorized his MK9A installation. After a redesign for this larger engine, the A7M2 flew October 13 1944. At last the Navy found a successor to the A6M Zero! But by now nothing but misfortune befell the program; earthquakes, B-29 bomb raids, test crashes, US fighter sweeps. Unnecessary delays from the start. It should have been in service long before. Even with the 2000 hp engine the A7M1 in 1943 combat could have been in place of the prolific A6M5 altogether. 357 mph was better than 351. Then, in place of the 348 mph A6M6 Zero, the A7M2 with the more powerful engine reaching 390 mph would have rivaled the army's fleet-footed Nakajima Hayate.
The Japanese Navy was its own enemy as if the USA wasn't enough. Guess they thought they were better engineers than Jiro Horikoshi and his team at Mitsubishi.

Klaatu, 13.08.2011

They say that a company ought to begin designing their next fighter by the time the current one is being introduced into squadron service. Consequently, if the Zero went into service in 1940, then that's when Mitsubishi ought to have begun working on it's replacement, the Reppu. However, they didn't begin work on it until 1942, and the first prototype didn't fly until half way through 1944. Under those circumstances, it really wouldn't have made any difference how good the plane turned out to be, it was inevitable that it was going to be a case of too little and too late.

bombardier, 24.05.2011

Had it been built in numbers it would have been much harder for the Allies to win the war

Ben Beekmasn, 26.02.2011

I agree with those who say the war's outcome would have been the same whether the Japanese used the A7M Reppu, the Nakajima Ki-84, the Kawasaki Ki-100, the Mitsubishi J2-M3 or any other advanced airplane in quantity. The United States was at the same time also developing more powerful, faster, longer-ranged etc. aircraft which would overcome anything they met in combat as did the Hellcat and the Corsair. And with the huge manufacturing capacity of the Americans, a small country like Japan having the geographical size of California wouldn't have a chance at winning a protracted conflict. Indeed, the Japanese were well aware they couldn't win a long war. Their strategy from the beginning was to grab so much territory at the outset that the Allies would see the futility of trying to win it all back and would ask for a negotiated peace. The negotiations would result in Japan returning those territories they didn't really need (as in the Phillipines) but acquiring other territories that were rich in oil and natural resources (such as in the Dutch East Indies). Top Japanese militarists must have been astonished when it became apparent that the U.S. and England/Australia intended to pursue a long, costly, war to recover everything the Japanese had taken. Those Japanese Generals and Admirals who had spent time in the West, in London, Paris, Washington etc., must have known by mid-1942 that it was a war they couldn't possibly win. The militaristic spirit of "bushido" that these older upper-level officers had by than so thoroughly inculcated in the lower officer ranks made it impossible to stop their own war machine. The "youngsters" wanted to fight on regardless of the number of casualties. That is, until the atomic bombs came along and put an end to all arguments.

joel, 10.12.2010

anyone who thinks that this aircraft would have changed history is dillusional. It would have expedited the new generatation of American aircraft like the F8F and the F80 if the A7M would have been produced in great numbers. I doubt the timeline would have changed much. The Focke-Wolfe 190 was still probably a better airplane.

Dominic, 04.10.2010

Guys, remember that the Ki-84 "Hayate" was equal to the Hellcat and Corsair in all respects, they just never got to fight at full potential due to a lack of skilled pilots and horrible fuel. Same with the Kawanishi N1K-J Shiden.
The A7M, if piloted by pilots with skill equal to their American counterparts, would've laid waste to anything the Allies could've put in the air in 1945. Period.

1-20 21-40

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