Integrity of Japanese planes

[Kweassa]

I remember an argument I had with some of the fellow Rooks a few days back. Obviously, someone was pretty displeased of how a Ki-84 followed him on a 450mph dive.

 Naturally, being a good-natured Rook, I told him that the Ki-84 is good upto just about that point before it falls apart. Then, all hell broke loose as the complaints on Japanese planes burst out here and there.

 I was quite surprised at the amount of misconception the people had about the Japanese planes. For some reason, they think every Japanese plane is an origami plane made out of ricepaper, structurally frail and weak, inherently slow, and solely stressing on turn maneuvering alone. Basically, they were treating all Japanese planes like the A6M2 Zero type 21.

 But ofcourse, since I was no expert myself, all I could do was repeat some of the facts as I've seen in the a/v forums.


1. The A6M zero being 'weak at dives', is not due to its basic structural frailty, but rather due to the fact that it used skins of insufficient strength. An aircraft is held together not only from the inside, but outside as well - as the skin bind and holds the structure tightly together.

2. As it turns out, the earliest Zekes of the war tended to shed its skins during high-speed dives, which would result in critical failures in it structure.

3. This tendency, was already overcome by '42, when aircraft skins were stregthened thoroughly. The A6M5 of '43 was already able to withstand considerably higher speed dives than its predecessors.

4. Japanese planes were not typically weak or frail. The Zekes were notoriously weak in internal protection due to the fact that it lacked protection for the pilot and the fuel tanks. The victories scored agaisnt Zekes were not because the plane would fall apart when shot, but rather because the plane just tended to catch fire a lot.

5. When adequate protection was added to the new lineup of fighters produced after '42, the Japanese planes had sufficient protection as any other plane during the war.

6. While Japanese planes did share an amount of common design philosophy, especially the noticeable emphasis in maneuverability, those planes were not just made to turn. They produced many excellent and promising designs.

7. The reason the Japanese planes were slow and maneuverable, was not because the Japanese liked it that way - but simply becase; a) the level of engine development relatively lacked behind its European allies, b) the war effort was staggering behind. Quality problems and short supplies led to numerous failures and troubles, noticeably with the engines, and many of the planes were hardly achieving their optimal performance which the design might allow.

8. Thus, while nothing but imagination, if they had better engine tech, or a steady supply of better fuels, the Japanese planes would probably be fast AND maneuverable.

9. The Ki-84 was an excellent design on par with the best of what the allied had to offer.


 ...


 If anyone sees something wrong with the facts I currently remember, or anything to add please do so. My point is that while lacking generally in speed, design wise the Japanese planes were every bit as potent as Allied planes and there's no reason to say that any of the Japanese planes in the game are overmodelled. Even the 'UFO Nikis' - as nowadays I hardly see any Niki doing any 'bullshi*' maneuvering.


 I also have a question - why does the Ki-84 fall apart at over 450mph anyways? Is there any kind of document which notes this tendency to manifest in real life planes? What was the cause for it? The Ki-84 looks pretty much structurally sound overall, and I quite don't understand why it'd disintegrate at high speeds.

 Is it some kind of quality problem that's being modelled in AH2?


ps) If that be so, I say some planes, like the Typhoon perhaps, needs an equal does of the same treatment with their structural integrity. Tail-end falling off at high-G pullouts, anyone?

[Karnak]

The Ki-84, like all late war Japanese aircraft, suffered greatly form poor quality control.  I think that is why it had trouble in high speed dives.

As to the basic design, it is fully on par with aircraft like the P-51D, P-47N, F4U, Fw190D-9, Spitfire Mk XIV and La-7.  It would have been an absolutely great war plane with some work on it by American or German teams, as it was it was merely very good.

(I say German and American because they were the only countries that really focused on the ergonomics of making the pilots job easier so as to enable him to fight better)


The problem many Americans have is that they want a "Marianas Turkey Shoot" when facing any Japanese fighter, and they fail to consider anything beyond the aircraft.  They completely ignore the relative skills of the American and Japanese pilots in that action, and they do not consider their skills in the game relative to the skills of the player in the Japanese fighter.  In other words in the game skills are equal overall whereas in reality the skills and tactics were nothing remotely like equal.

[Kweassa]

The Ki-84, like all late war Japanese aircraft, suffered greatly form poor quality control. I think that is why it had trouble in high speed dives.

 Is this for real?

[Karnak]

The Japanese manufacturing capabilities took heavy hits from both enemy action and idiotic domestic policies.  This led to a very significant decline in the quality of Japanese aircraft.  The Germans also saw such a decline, but later and not quite as bad, though closer than the rabid Luftwaffe fans will admit too.

[HoHun]

Hi Kweassa,

>I remember an argument I had with some of the fellow Rooks a few days back. Obviously, someone was pretty displeased of how a Ki-84 followed him on a 450mph dive.

>3. This tendency, was already overcome by '42, when aircraft skins were stregthened thoroughly. The A6M5 of '43 was already able to withstand considerably higher speed dives than its predecessors.

Relying on H. P. Wilmott, "Zero A6M":

The late-model A6M3 Model 32 had new wings with a thicker gauge skin to allow increased dive speeds. The dive speed limit for the A6M5 was 660 km/h. (I assume this is IAS. For comparison: The Me 109E was placarded at 750 km/h.) I'm not quite certain the aforementioned A6M3 had the same dive limit as the A6M5 had a different wing. The A6M5 Model 52a featured another increase in sking gauge, allowing a dive speed of 741 km/h. (Guess it's 740 km/h with a rounding error from to-and-fro conversion :-)

The Model 52b tried to address the issues of lacking firepower, lacking pilot protection and propensity to catch fire by adding:

- One 13.2 mm machine gun instead of one of the 7.7 mm machine guns
- A 51 mm reinforced glass windscreen (apparently of simple design)
- CO2 fire extinguishers for the fuel tanks

The Model 52c went even further:

- Replacement of the cowl guns by 13.2 mm wing guns outboard of the cannon
- Armour below the pilot's seat (apparently, the first armour on the A6M)
- Self-sealing rear-fuselage tank (apparently, the first such tank on the A6M)

The A6M7 was a dive bomber variant with a strengthened tail, which was necessary to withstand the stress of power dives. (Explaining the limit on the fighters.)

The A6M8c Model 54c/Model 84 featured:

- Kinsei engine
- All fuel tanks self-sealing
- Improved fire extinguishers

My conclusion: The A6M was a bit behind with regard to self-protection in comparison to Western fighters.

>5. When adequate protection was added to the new lineup of fighters produced after '42, the Japanese planes had sufficient protection as any other plane during the war.

I believe the quality of the Japanese self-sealing tanks was not up to the same standard as the contemporary western tanks. However, this seems to be a little-researched topic, and western tanks may not be uniform either.

>6. While Japanese planes did share an amount of common design philosophy, especially the noticeable emphasis in maneuverability, those planes were not just made to turn. They produced many excellent and promising designs.

The design philosophy of the Japanese Army is exemplified by the series of Nakakjima fighters. The Ki-27 set the standards with regard to manoeuvrability, but the Ki-43 was already built primarly for speed (and its manoeuvrability was heavily criticized at the time). Later, the Ki-43 was fitted with a good amount of pilot armour. Its successor, the Ki-44, signified a paradigm change since it was designed as interceptor and fit into the footprint of the Me 109 quite accurately, though featuring a powerful radial engine. It was hoped the Ki-44 would retain some low speed manoeuvrability, though the contrast to the previous type was marked. The Ki-84 was the results of the lessons learned with the Ki-44 and on one hand reverted to the larger dimensions of the Ki-43 (with a more powerful engine, of course), while on the other hand, it was changed over the Ki-43 and Ki-44 in its emphasis on good high-speed handling. (That's what I read into one of Mitsu's posts here :-) The Ki-44 appears to have had a very aggressive elevator that was dangerously light at high speeds, with the tendency to overstress the (sound) airframe. In short, the design philosophy of the Ki-84 probably was not far from what the western air forces where using for their aircraft, too.

Regards,

Henning (HoHun)

[Kurt]

Integrity of Japanese planes

I have never been lied too by a japanese airplane, they do just what they say they will, which means they have more integrity than most people I meet.

[Krusty]

heh, cute, Kurt

As to Japanese planes being weak, I don't have any books to quote like HoHun, but I will say this: Why does a 190F8 shed its wings if you pull up from a vertical dive very hard? Why does a B26 lose its ailerons, rudder, and elevator at very low speeds? Why does a P38 lock up and need to be trimmed out of a dive? Why the 109 in the same situation?

The Ki-84's diving speed is what it is. It is not weak, it is not strong, it just "is". Historically the structure proved less sound in certain situations than did some other air craft.

That doesn't mean the Ki84 was structurally unsound, it just means they designed it one way, and it was limited because of the way it was put together.

And for those that think the Ki84 can't dive well, try it. You can WELL exceed 450, and the only thing you'll lose is a rudder

[FTJR]

And the elevators.. My question is why do both have to let go at the same time.

[Charge]

http://www.avweb.com/news/columns/185354-1.html

"Most of the airplane is built of T-7178 aluminum, a top-secret variety developed by the Japanese for the purpose. It is lighter and stronger than the normal aluminum we used at the time, but more brittle. If you push anywhere on the skin with your thumb (gently, please!), it feels like a heavy-duty tin foil."


-C+

[Flayed1]

I know that we have the KI-84-IA in game but the tail acts like one of the KI-84-II type planes with the wooden rear fuselage and fittings that they started making because of their dwindling reservs of strategic light alloys.   If this version we have is modled after the aluminum tail section I would hate to see how one with the wooden tail would act in a dive.

[HoHun]

Hi Krusty,

>The Ki-84's diving speed is what it is. It is not weak, it is not strong, it just "is". Historically the structure proved less sound in certain situations than did some other air craft.

Do you mean there is historical evidence, or do you mean that is your assumption?

Regards,

Henning (HoHun)

[Knegel]

Hi,

since the majority of japanese fighters was Ki-43´s and A6M´s, most of their problems get transferred to all japanese planes.

Afaik only the Ki-84 and specialy Ki-44 was similar heavy wingloaded like the allied fighters, but the Ki84 still was on the lower end of the scale(similar to the SpitfireIX).

Since the dragload is pretty important while a highspeed dive and the wingarea cause a main part of the drag, i guess even the Ki-84  wasnt able to dive with the P51 or P47 at highspeed, at least it must have had more problems than the FW190A, despite the structural problems.
I guess the initial diveacceleration of the Ki-84 must have been outstanding, but at highspeed the light weight, relative big wings and radial engine layout got to be a problem.

The structural and highspeed drag problems of the Ki-43-I and A6M2 also got fixed a bit by a shorter wingspan (smaler aspectratio) in the Ki-43-II+III and A6M3/5 . This have a shorter leverage as result and a better drag at highspeed(though they lost at medium/slow speed, what minimized the range), but this planes never got close to the dragload of the US planes.

Althought the thinking in the japanese HQ did change, it still wasnt consequent enough to provide the Vmax and divespeed of the P51´s and P47´s, but they got much closer to this performences and the climb and turnadvanatge made them to similar dangerus planes like the Zero vs the earlyer US planes.

What i always found to be strange is that the japanese HQ saw the advantage of the Me109E4 and Ki-44(the only more heavy wingloaded japanese fighter) that late or never in the needed way.
While fitting the more strong engine into the Ki-61´s they tried to increase the wingare, cause they thought the Ki-61 already was heavy wingloaded. Only after they got structural problems with the big wing they did use the old Ki-61 wing.

The Ki-44 made its maiden flight in 1940 and was available in 1942 and was for long time the only japanese fighter to be able to intercept the B29(with 4 heavy MGs, ouch ouch ouch).
Iam pretty sure, with the Ki-44 instead of Ki-43´s the AVG would have had more problems.

Are the following numbers right or do someone have better datas?

10.500 produced A6M´s,  8.209 was A6M2´s(2300 A6M3+5 sounds a bit few to me)
5,900 Ki-43´s, 716 Ki-43-I's
1200 Ki-44-II+III´s(smal number of Ki-44-I´s)
3.300 Ki-84-I's and Ki-84-II's
3.000 Ki-61-I's
1500 N1K1 + 2

And do someone know which was the main engine used in the Ki-84??

I have three different versions of the Ha-45 listed.

Ha-45-11(Nk9b), 1690HP/2900rpm/2000m, 1460HP/2900rpm/5700m

Ha-45-21(NK9H), 1860HP/3000rpm/1800m, 1620HP/3000rpm/6400m

Ha-45-21(no data), 1875HP/3000rpm/1800m, 1695HP/3000rpm/6100m


btw, at highspeed dives for now i dont had much problems to leave the AH Ki-84 behind, but of course if someone get slow, close to a Ki-84, the initial acceleration advantage of the Ki-84 will hinder you to get to highspeed without to get shot down.

Greetings, Knegel

[Kev367th]

Kweassa - You from all people should know that the Tiffy tail shedding was only prevalent early on.
By the time the 4 bladed prop was fitted (like ours) it had been eradicated.

http://www.clubhyper.com/reference/typhoonpropsf_1.htm

[MiloMorai]

Originally posted by Kev367th
Kweassa - You from all people should know that the Tiffy tail shedding was only prevalent early on.
By the time the 4 bladed prop was fitted (like ours) it had been eradicated.

http://www.clubhyper.com/reference/typhoonpropsf_1.htm

Another of those overblown ww2 myths.

[Kweassa]

Kweassa - You from all people should know that the Tiffy tail shedding was only prevalent early on.
By the time the 4 bladed prop was fitted (like ours) it had been eradicated.

 That was kinda my point. I am already aware that the problems were fixed by the time the Typhoons as depicted in AH2 were performing in the theater. However, the point is that the various accounts and testimonies clearly indicate the early Typhoons had a considerable amount of structural problems associated with the tail plane.

 The recommendation to not trim the elevator plane up to recover from potentially dangerous dives, as a forced level-out via trim would put a pressure on the tail plane which it cannot take, thus resulting in structural failure, says a lot about how this particular plane might be handled as fighter/bomber. In other words, despite its excellent low-alt speed performance, using that speed in combat maneuvering which would frequently slam high G conditions upon the plane was not recommendable. In that aspect it is fully understandable why the Typhoon was not regarded as highly as a fighter as it was a fighter/bomber.

 Frankly, I think AH2 should model two Typhs separately - the early Typhoons of '41~'43, and the late Typhoons after that, and slap a perk on the latter.