Do we have any encounters of P51s with A6Ms?

[VBF-13]

You might need a whole new plane for those engines. Just fitting the Ha-112 ( Kinsei 62) required deleting the cowl gun/s.

The Ha-41 was the earliest but used a single speed supercharger. the Ha-109 was probably the best bet after the Kinsei engine. It was only 4 in (110mm) bigger in diameter than the Sakae and 130 kg heavier than a Sakae 21 (which was 60kg heavier than a Sakae 11/12) and the Zero had been originally designed around the Mitsubishi Zuisei engine which was slightly smaller and lighter than the Sakae.

Problem for the Japanese was ANY engine change would cut into the range/radius of the Zero. Could a bigger engine allow enough fuel to make up for the increased consumption? A number of Zeros were lost when they changed form the Sakae 11/12 to the 21 due to smaller fuselage tank and increase fuel consumption.

Once the Japanese are on the defense it doesn't matter quite as much.

I see. These mechanics are well-beyond the scope for me. I wonder if I can infer this much on where they really needed to go. There are some who still think the F6F was just a souped-up F4F. I'm not saying, here, but I think you know what I mean. The fact is, the F6F was a radically-different machine. I hear you saying, outfitting these A6M5s, was like trying to outfit the F4Fs. I hear you saying, the Japanese Navy really needed a radically-different machine.

Of course, neither Japan, nor anybody, really, had the capacity to go there, as the U.S. had. I'm just saying, that's what they needed. They needed that new-generation fighter. I understand, now, also, why Mitsubishi didn't just throw bigger engines into these airframes. It tried, as you pointed out, in the A6M8, but it knew that was easier said than done. Had Japan not been going down at the time, I'm thinking it could easily have measured-up to the challenge.

 

[parsifal]

The A6M5 is often referred to as an A6M3 with strengthened wings to permit faster diving. This isin fact is quite untrue. The later versions of the A6M3 were the first types with the wing strengthening and in fact th later A6M3s and A6M5s had the same dive capabilities. moreover, the Mark 5 retained same engine, but nevertheless had some improvement in aircraft speed and performance

This aircraft was a development of a proven failure and was a far more modest update compared to the ambitious A6M4, the "A6M5" or "Model 52", featured a thicker skin and rounded, non-folding wingtips, as well as a new exhaust system that provided a slight amount of additional speed from exhaust thrust. The A6M5, or "Type 0 Carrier Fighter Model 52", went into production in the fall of 1943, and demonstrated a noticeable improvement in performance. Its top speed of 351mph made it competitive to the 360 mph (or so in the tropics) of the earlier F6fs (that invariably were pretty badly worn and therefore unable to reach full design speeds)

Two sub-variants followed. The "A6M5a", or "Model 52a", had even thicker wing skinning, and cannon with belt feed instead of drum feed in the wings. The belt feed allowed the ammunition for the cannons to be increased from 100 to 125 RPG.

The "A6M5b", or "Model 52b", incorporated an armor glass windscreen and a fuel-tank fire extinguisher to reduce the aircraft's inclination to immediately burst into flames when hit. The A6M5b also replaced one of the 7.7 millimeter guns in the cowling with a 13.2 millimeter Type 3 machine gun, a license-built Browning.

The "A6M5C" or "Model 52c" added armor plate and larger fuel tanks with self-sealing, and featured one 13.2 millimeter gun in the cowling, plus a 20 millimeter and 13.2 millimeter gun in each wing, for a total of five guns. The A6M5c first flew in September 1944. The A6M5 series machines were the most heavily produced Zero variants, with at least 5,000 built.

The A6M5c was just an interim fit until the more powerful Sakae 31A engine, which featured water-methanol power boost, was ready for service. The first Zero with such an uprated engine, the "A6M6c" or "Model 53c", performed its initial flight in November 1944. It was similar to the A6M5c except for the new engine and self-sealing wing tanks. Production was performed by Nakajima. The Sakae 31A engine provided noticeably improved performance, when it worked properly, but under the pressures of war Japanese manufacturing quality was in steep decline.

in late 1944, the Imperial navy finally gave approval to use the powerful Kinsei engine in place of the Sakae. The result was the A6M8, which offers an interesting comparison to the Hellcat, but by the time of its introduction there were simply so few good pilots left, and the USN heavily outnumbered the Japanese. The A6M8 was a redesigned and enlarged Zeke that showed some rather impressive design elements.

The Kinsei offered 1,340 HP (another source says they were 1560hp), giving it a top speed of almost 360 MPH. All fuel tanks were self sealing, and it also carried on board automatic extinguishers as well. The two wing mounted drop tanks developed for the A6M7 were enlarged to 360 litres it had a As stated, Horikoshi had wanted to use the Kinsei engine from the beginning, but the IJN had regarded it as too powerful. The larger engine dictated elimination of the 13.2 millimeter gun mounted in the cowling, with the four guns in the wings retained, and an improved fuel-tank fire extinguishing system was fitted. The A6m8 was armoured to withstand 0.5in MG fire. It could carry 1102 lb of bombs or 8 rockets. The A6M8 carried as standard eight 10kg anti-air rockets, that had been found useful againts the B-29s.

Time to 20K was 6min 50 secs, which is not bad. It had a good dive speed as well, ive read around 460mph

 

[VBF-13]

Parsifal, if I don't get back to you it's because my head exploded after reading your last two posts. Really, this is fascinating detail. I'm definitely going to have to give these re-reads. Well done.

 

[cherry blossom]

I think that Mitsubishi wanted to install the Kinsei in the Zero as soon as they realized that it was possible. However, possibly they only realized that this was an option after examining a Fw 190 in 1942 or even 1943. This is separate from the issue that they had proposed a Kinsei powered aircraft in response to the original 12-shi requirement before designing the A6M1. The Kinsei 60 series of engines was first run and flown in 1942. The Ki-46 III was powered by such engines but production was very slow and the Ki-46 II and III were both produced in 1943. I have a dim memory of hearing that the problem was that the fuel injection equipment for the Ha 112-II ( Kinsei 60 series) was produced by hand craftsmanship rather than a mass production process. The first navy application of the Kinsei 60 series was the D4Y3, which entered service in early 1944 (?). Again, the Fw 190 was important in showing that a radial could replace the inline engine of the D4Y2.

q‹ó‹@ƒGƒ"ƒWƒ"ˆê——E"ú–{ŒR has some details on various engines. It suggests that the 1560 hp was a take off rating with the 1340 hp being a military power at 2100 metres. At least the take off rating required methanol water injection.

Using that data, we can compare various possible power plants:

Sakae-21, Length 1630 mm, Diameter 1150 mm, Dry weight 590 kg
Kinsei-62 Length 1660 mm, Diameter 1218 mm, Dry weight 675 kg
Homare-11 Length 1690 mm, Diameter 1180 mm, Dry weight 830 kg
Ha 109 (Ha 34-11) Length 1575 mm, Diameter 1263 mm, Dry weight 720 kg.

Apart from its weight, the Homare was unreliable in early 1944 and Mitsubishi claimed that a Homare 22 only gave 1,300 hp at altitude in the A7M1 compared to the specification of 1750 hp at 6450 metres. There is some independent support for Mitsubishi as the P1Y2 was fitted with theoretically lower powered Kasei 25 engines because of problems with the Homare. Knowing the history of bitter competition between Mitsubishi and Nakajima, it is not surprising that Mitsubishi did not propose using the Homare.

Was the Ha 109 the best answer? With 37.5 litres displacement against 32.3 litres, it was slightly more powerful than the Kinsei 62 at altitude, did not use water/methanol injection or fuel injection and thus could presumably have been produced in quantity. It might have allowed mass production of a Zero with A6M8 like performance from the middle of 1943. However, we can guess that a larger displacement and lower compression ratio engine would use more fuel than the Kinsei even before calculating the effects of it being wider and heavier.

 

[GregP]

You can ignore Martin Caidin except for the entertainment aspect. He is notoriously inccurate.

 

[VBF-13]

I think that Mitsubishi wanted to install the Kinsei in the Zero as soon as they realized that it was possible. However, possibly they only realized that this was an option after examining a Fw 190 in 1942 or even 1943. This is separate from the issue that they had proposed a Kinsei powered aircraft in response to the original 12-shi requirement before designing the A6M1. The Kinsei 60 series of engines was first run and flown in 1942. The Ki-46 III was powered by such engines but production was very slow and the Ki-46 II and III were both produced in 1943. I have a dim memory of hearing that the problem was that the fuel injection equipment for the Ha 112-II ( Kinsei 60 series) was produced by hand craftsmanship rather than a mass production process. The first navy application of the Kinsei 60 series was the D4Y3, which entered service in early 1944 (?). Again, the Fw 190 was important in showing that a radial could replace the inline engine of the D4Y2.

q‹ó‹@ƒGƒ"ƒWƒ"ˆê——E"ú–{ŒR has some details on various engines. It suggests that the 1560 hp was a take off rating with the 1340 hp being a military power at 2100 metres. At least the take off rating required methanol water injection.

Using that data, we can compare various possible power plants:

Sakae-21, Length 1630 mm, Diameter 1150 mm, Dry weight 590 kg
Kinsei-62 Length 1660 mm, Diameter 1218 mm, Dry weight 675 kg
Homare-11 Length 1690 mm, Diameter 1180 mm, Dry weight 830 kg
Ha 109 (Ha 34-11) Length 1575 mm, Diameter 1263 mm, Dry weight 720 kg.

Apart from its weight, the Homare was unreliable in early 1944 and Mitsubishi claimed that a Homare 22 only gave 1,300 hp at altitude in the A7M1 compared to the specification of 1750 hp at 6450 metres. There is some independent support for Mitsubishi as the P1Y2 was fitted with theoretically lower powered Kasei 25 engines because of problems with the Homare. Knowing the history of bitter competition between Mitsubishi and Nakajima, it is not surprising that Mitsubishi did not propose using the Homare.

Was the Ha 109 the best answer? With 37.5 litres displacement against 32.3 litres, it was slightly more powerful than the Kinsei 62 at altitude, did not use water/methanol injection or fuel injection and thus could presumably have been produced in quantity. It might have allowed mass production of a Zero with A6M8 like performance from the middle of 1943. However, we can guess that a larger displacement and lower compression ratio engine would use more fuel than the Kinsei even before calculating the effects of it being wider and heavier.

I'm looking into this A6M8. This is awesome. My takeaway is they had the right fit in this hopped-up A6M. Just, by that time, the show was over. Too little, too late.

 

[Shortround6]

Pretty much. They needed the A6M8 in 1943 not 1945.

It wouldn't have changed the outcome, just the timing and the cost.

 

[VBF-13]

Pretty much. They needed the A6M8 in 1943 not 1945.

It wouldn't have changed the outcome, just the timing and the cost.

It looks to me like they'd have pretty much been a wash up against our F6Fs and F4Us. I heard what you suggested earlier in that these pilots didn't really require miles and miles of experience in these aircraft to put on a good fight in them. I was told by guys who flew the F6Fs, in particular, one who was at Saipan, that combat "experience" only frightens you more. The thing is, get the tactical training in. On that requisite, I don't know if you're aware of this, but the Navy had a rule, you don't goof off in these aircraft. Still, that's all they did. It kept them sharp, right on the edge, and that's where the Navy wanted them. I heard quite a few stories on that, from a Marine F4U making an emergency landing at the wrong base with telephone wires wrapped around a wing and the Hawaiian police hot on its tail, to Navy FM2s diving on Hawaiian sailboats and rolling them over with the propwash. The hot-dogging was never officially endorsed. This was the United States Navy Department, after all. But everybody knew the score. They're in the moment of truth, they peel off and make their dives, you throw out the book. This is no practice drill. You want them on that edge, loose, unabashed, ready to take the risks, unafraid to push their aircraft to the limits, and then some. Call it the unofficial rule.

 

[Balljoint]

It looks to me like they'd have pretty much been a wash up against our F6Fs and F4Us. I heard what you suggested earlier in that these pilots didn't really require miles and miles of experience in these aircraft to put on a good fight in them. I was told by guys who flew the F6Fs, in particular, one who was at Saipan, that combat "experience" only frightens you more. The thing is, get the tactical training in. On that requisite, I don't know if you're aware of this, but the Navy had a rule, you don't goof off in these aircraft. Still, that's all they did. It kept them sharp, right on the edge, and that's where the Navy wanted them. I heard quite a few stories on that, from a Marine F4U making an emergency landing at the wrong base with telephone wires wrapped around a wing and the Hawaiian police hot on its tail, to Navy FM2s diving on Hawaiian sailboats and rolling them over with the propwash. The hot-dogging was never officially endorsed. This was the United States Navy Department, after all. But everybody knew the score. They're in the moment of truth, they peel off and make their dives, you throw out the book. This is no practice drill. You want them on that edge, loose, unabashed, ready to take the risks, unafraid to push to their aircraft to the limits, and then some. Call it the unofficial rule.

My recollection of the guys who stayed in after the war fits this description. During Soldier Field flybys from the upper seats I could see down in the cockpit including the lighted instruments while they were flying towards the closed end of the bowl. Also, at the dedication of O'Hare –it was a grass AAF field- they trenched the field with their prop wash during high speed runs.

They hosted some of our model plane meets at Glenview Naval Air station. Great guys. They showed us their planes and explained and flew demonstration of combat tactics.

 

[VBF-13]

That's getting down pretty low, Balljoint, if you could see that. Fantastic. But that's how it was. My dad was in the reserves after the war and he had to check out F6Fs periodically out of Glenview. Where would they go in them? Who knows? I never got around to finding that out. I know he buzzed his block and did a little performance once to a standing ovation out there, they lived in Cicero. Mostly, he said, there wouldn't be any complaints.

 

[parsifal]

Zeke was a great plane, until it met the hellcat. kinda says volumes about just how good the hellcat was.

The A6M8 would have evened up the playing field, but the hellcat would still hold some advantages. Peformance at altitude, dive speed, overall airframe strength, would have to go in favour of the F6F. Goes double for the P-51. im not saying the Zeke was obsolete, just outclassed. Once the yanks got into their stride, this was never going to change

 

[sgtleehead]

McGuire , 2nd highest scoring US pilot died after his plane stalled when he and 3 others attacked a lone Zero. 1945. Out of the encounter - two lightnings downed and the zero flew off. In the right hands, even then, a potentially very dangerous plane. Know your enemy!.

Low speed dogfight - Zero. High speed Corsair or Tempest.

Interestingly - Adding more power to an air-frame doesn't necessarily guarantee more speed or performance. Loads of factors in play of course - but a more modern air-frame with a more powerful engine would normally prove a better alternative. KI84 and Kawanishi N1K. Both superb planes and still maneuverable.

 

[BiffF15]

SgtLeeHead,

I thought McGuire stalled and spun it in from failure to jettison his external fuel tanks? While the Zero pilot could claim that as a kill, it's more an example of pilot error.

I was also under the impression that the 38 with maneuvering flaps down at low airspeed could turn almost as well as a Zero in part due to it's symetrical torque (of the motors). Anyone else have any info or opine on this?

Cheers,
Biff

 

[Garyt]

Goes double for the P-51. im not saying the Zeke was obsolete, just outclassed. Once the yanks got into their stride, this was never going to change

I'd think the KI-84 is a good argument against this statement.

Climb and speed roughly equivalent to the top end US fighters - and it could not turn with a Zeke, but it was not bad. And this was accomplished with struggles for quality control in the manufacturing (bombing had a fair amount to do with this, as well as of course shortages due to the sub attacks on the merchant marine), and with less than high quality fuel. Had armor for the pilot, self sealing fuel tanks and heavy armnament.

I've read when tested after the war with high octane fuel, US pilots could get to 426mph in level flight.

 

[tomo pauk]

SgtLeeHead,

I thought McGuire stalled and spun it in from failure to jettison his external fuel tanks? While the Zero pilot could claim that as a kill, it's more an example of pilot error.

I was also under the impression that the 38 with maneuvering flaps down at low airspeed could turn almost as well as a Zero in part due to it's symetrical torque (of the motors). Anyone else have any info or opine on this?

Cheers,
Biff

The P-38 entry in the 'US hundred thousand' book pretty much agrees re. bolded part.

I'd think the KI-84 is a good argument against this statement.

Climb and speed roughly equivalent to the top end US fighters - and it could not turn with a Zeke, but it was not bad. And this was accomplished with struggles for quality control in the manufacturing (bombing had a fair amount to do with this, as well as of course shortages due to the sub attacks on the merchant marine), and with less than high quality fuel. Had armor for the pilot, self sealing fuel tanks and heavy armnament.

I've read when tested after the war with high octane fuel, US pilots could get to 426mph in level flight.

US ground crew was fueling up the Japanese aircraft with 91 oct fuel. Such fuel was used mostly on trainers and transport aircraft. Quirk was to acquire the Ki-84 with it's engine in good, let alone excellent condition. US wartime reports credit the Ki-84 with 420+ mph. Here, Japanese aircraft section.
More about the Ha-45 here.

 

[eagledad]

Gentlemen,

According to the book, Possum, Clover Hades, The 475th Fighter Group in World War II by John Stanaway, McGuire and his flight actually engaged a Ki-43 Oscar and not an A6M. However, initially the flight identified the Japanese aircraft as an A6M5.

The Ki-43 was flown by A/O Akira Sugimoto of the 54th Sentai. McGuire stalled his Lightning trying to get the Oscar off the tail of Capt Ed Weaver's P-38. McGuire's aircraft crashed with his drop tanks still attached.

Eagledad

 

[parsifal]

This is one of the entries in that book that i find very hard to accept.

At 250 mph the A6M2 Zero 21 did a 1118' radius 180 degree turn was done in 5.62 seconds. For slower turns the radius was 612'. Normal positive g-load factor was 7g, safety limit was 8.8g; and normal negative was 3.5g with a safety factor of another 1.8g or 5.3g limit. Wing loading was 22 lb/sq. ft. Stability was neutral around all three axis, controls were light and beautifully harmonized. Stall was gentle and complemented it's slow speed dogfighting prowess. However as speed and altitude increased this diminished especially above 26,000'. Initial climb rate was 4517 fpm, not bad for 940-950 hp 19,685' was reached in 7 min. 27 sec. Power loading was 5.59 lb/hp.

Not as sure of the p-38, but it is generally regarded as a poor dogfighter, except by its zealot supporters. According to Chuck Hawks and another warbirds forum "Without employing the MANEUVER flaps, the P-38 did not turn as well as most other US planes. It had the largest minimum turning radius of all fighters. For comparison, it's minimum turning radius was about twice that of the FM-2 Wildcat. The flaps helped decrease turning radius at the expense of speed. The MANUEVER flaps helped, but still did not make the P-38 into legendary dogfighter"

"Regarding the turn radius of the Lightning in a dogfight, the P-38 had a trick up its sleeve that the others did not. It was the "cloverleaf" (no, not the same as used by the RAF bombers to avoid nightfighters) maneuver.

The P-38 had wonderful slow-speed stalling characteristics. It could be stalled and recovered losing almost no altitude and not entering a spin as so many single-engined fighters did. In a steep-banked, turning fight, the pilot could actually pull the Lightning into a momentary stall which resulted in a tightening of the turn radius for a short interval. Then, he would recover whereupon the greater turn radius would be re-established. It was during those short intervals that he could pull inside his adversary and give him a burst of those concentrated guns.

Viewed from above, if a complete circle was flown during which this stalling tactic was performed several times, the track of the aircraft through the air resembled a "cloverleaf," hence the name of the maneuver".


The trouble with this later quote is that to get to that magical situation, the P-38 had to be below 180mph. At that speed, the Zeke would complete its turn in a 612feet, and did it in about 3.5 seconds. In the time it took for the P-38 to complete its "magical manouver", the Zeke would be inside its turn, allover it like a dog on heat, and the P-38 in a world of trouble. Ther was only one manouver that virtually guranteed a kill....Keep the speed up, get the height, dive and use speed to get the hell out of dodge. any other claim about the zeke should be treated with the disdain it deserves. Never, repeat never, try and dogfight with a zero. The Hellcat was the best US type to attempt this, and even then, a pilot was giving away a lot by trying to turn with a zeke at low speed.

 

[Garyt]

US ground crew was fueling up the Japanese aircraft with 91 oct fuel. Such fuel was used mostly on trainers and transport aircraft. Quirk was to acquire the Ki-84 with it's engine in good, let alone excellent condition. US wartime reports credit the Ki-84 with 420+ mph. Here, Japanese aircraft section.
More about the Ha-45 here (Nakajama HA-45 Hamore engine).

Interesting, also the link to the Hamore discussion.

Looks like the Ki-84 made 426mph with lower level octane fuel that it was designed for.

I wonder what it would have done on the 100 octane it was designed for...............

 

[GregP]

Parsifal,

Either somebody's pulling your leg or you made a math error.

180 mph is 264 feet per second (Actually 236.989 feet per second, but you get the idea).

A circle with a diameter of 612 feet has a circumference of 3,845.3 feet, so the distance around 180° is 1,922.7 feet.

At 264 feet per second, and assuming he doesn't decelerate at all, it takes 7.28 seconds to cover the distance and complete the turn.

Besides that, VERY few aircraft could exceed 20° per second turn rate, and 180° divided by 3.5 seocnds is more than 51° per second, which has NEVER been done in a fixed wing aircraft in a level unstalled turn, even by a Harrier using VIFFing.

The math says your above figures are a tall tale that sounds good but doesn't wash. Physics doesn't lie. I'm assuming a typo in your figures since you are usually spot on. This is NOT an attack. Just trying to get it straight.

About the P-38, since maneuvering flaps aided the turn. they were routinely used by P-38 pilots in combat once fitted. Another trick they could use was asymmetric thrust to help the turn rate. It works in a P-38. Didn't turn it into a world-class dogfighter, either, but did surprise many Japanese pilots.

As far as being all over a P-38 like a dog in heat goes, it was quite the reverse in the real war. P-38's shot down 1,700 Japanese aircraft with very few losses in the PTO. That tells P-38's they didn't dogfight with Zero at 180 - 250 mph or the results would have been quite dfferent.

 

[tomo pauk]

Interesting, also the link to the Hamore discussion.

Looks like the Ki-84 made 426mph with lower level octane fuel that it was designed for.

I wonder what it would have done on the 100 octane it was designed for...............

I'm not sure that it was designed for 100 oct fuel, standard Japanese fuel was 91 (or 92) octane. The lack of better fuel was to be circumvented via using water injection, in order to delay the onset of detonation.