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koivis
01-25-2007, 10:57 PM
Does anybody know why Ki-84 is 90 kph faster at 6000 meters than N1K2-J, and 40 kph faster at sea level? IIRC they had the same engine, Nakajima Homare Ha-45-21. Or was the N1K2 version some kind of "low altitude tuned"? And why, overall N1K2 feels so slow compared to Ki-84? I know it's slower, but didn't expect the difference being this big.

Here's the speeds, tested at Crimea, 100 % fuel
Plane---0 m-----around 5-6K
Ki-84---580-----685
N1K2-J--550-----595

To add more into this... if N1K2 is as fast as "factory" figures imply (maybe too slow?), why is J2M3 and J2M5 so fast, military power speed for J2M3 is 584 kph at 5450 m. Ingame: 645 kph!!! And, the opposite, again, "the best Japanese fighter" (lol), Ki-100 goes as fast as was it's speed at MILITARY POWER. In fact, Ki-100 is only a bit faster than Zeros are now. And Zeros didn't have "Water-methanol injection", and only had 1130 hp, compared to Ki-100's 1500 hp. (Only very late A6M7s had a little methanol boost, maybe 1200 hp, but were also heavier than earlier models, thus negating the extra power.)

To sum it up:
Ki-84, J2M3/5: OK, faster than "official" non-WEP speeds (especially J2M5, which is REAL good at high altitudes)

N1K2-J, Ki-100: as fast, or, what is even worse, SLOWER than the almost "cruise" power figures, found in every book/website. There is "WEP" modelled ingame, but it only boosts these two into their "Military" performance levels. So it seems they lack the "real" WEP injection totally.

Any opinions about these, I know the last patch is coming soon!

shinden1974
01-25-2007, 11:45 PM
The kI-84 AND J2M3/5'S Performance is based on tests done by the US and others. This performance exceeds the commonly quoted figures we see.

the source for this air data is probably TAIC 1, an air intelligence briefing from '45('46?) that sadly doesn't include the N1K2-J in most copies in circulation.

It's important to realize that this performance is subject to an intense debate. The discussion of the octane fuel used and whether the tested engines were built for a higher octane fuel or the americans modified the engine is enough to fill several pages of one thread.

Another important thing to remember is that no one knows for sure what happened during these tests and most statements about the tests are vague quotes such as "superbly maintained". As a maintenance person myself, this is a pretty meaningless statement as far as increasing performance is concerned, If an airframe is maintained 'superbly', it operates at 100% power and efficiency no more no less. This statement probably refers to the support personnels' capabilty in keeping a foreign aircraft flying than anything alse.

The N1K2-J probably performed very well in it's stateside tests as well. In some places I've read it was the fastest of all tested japanese aircraft, but I have not the source for it. Some publications have listed a speed over 400 mph. My only source for this is Mike Spick's illustrated directory of fighters, which quotes a speed of 416 Mph (plus higher sea level and climb rate numbers) and states the these numbers come from US tests. Unfortunately I've never actually seen the data from these tests, and I doubt Oleg will increase the speed based on these numbers alone. Who knows though, I'll email a proposal and see what happens, I've never seen the J2M5 test either. If the speed were increased the hellcat's should be as well, it's way too slow compared to much historical data, like the N1K2-J the hellcat's speed is based on commonly available data, which is often wrong.

JG52Karaya-X
01-26-2007, 01:13 AM
Originally posted by koivis:
And, the opposite, again, "the best Japanese fighter" (lol), Ki-100 goes as fast as was it's speed at MILITARY POWER. In fact, Ki-100 is only a bit faster than Zeros are now.

Well the Ki-100 certainly was not the "best Japanese fighter". I know its stated that way in many books, but then again those are the same "copied from others without checking primary sources" that state the Bf109K had 2x15mm in the cowling and an Mk103...

Truth is, the Ki-100 was a tad better than the Ki61, speed-, climb and agility-wise. However there was still so much to be desired and for the most part the Goshikisen was just a bullseye for the allied fighters in '45.

As already said the Ki84 is modelled after US trials which used much higher graded fuel than what the Japanese had so it is questionable if the Hayate we have is actually representative of what a plane in front-line service could achieve.

Marcel_Albert
01-26-2007, 02:25 AM
Originally posted by JG52Karaya-X:
As already said the Ki84 is modelled after US trials which used much higher graded fuel than what the Japanese had so it is questionable if the Hayate we have is actually representative of what a plane in front-line service could achieve.

Actually , it is not mate , let me explain you by a short summary http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

The engine of the Ki-84 was designed/built to deliver the expected power with the fuel they had , which was a lower octane fuel than the fuel the USAAF used for the tests .

However a higher octane fuel does make a difference , for an engine that has been built to accept a quality of fuel with higher octane , in an American engine , giving her fuel with too low octane could damage the engine for technical reasons i cannot explain well in English , you can hear small detonations when it happens .

For the case of the Ki-84 engine , the fact that you use higher octane fuel on it doesn't change anything AFAIK , it's still the same rate of air/fuel mix injected in less than 1 second going in the carburator , same rate of compression ..... it really doesn't change anything because the engine is not designed to accept higher octane fuel , engines need a minimum octane indice , but using a higher octane than what the engine has been designed for is useless , trust me this is for sure http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

JG52Karaya-X
01-26-2007, 05:00 AM
Thats what I dug up from the depths of my HD:

http://img.photobucket.com/albums/v639/Karaya/Ki84_482_1102719583_286_1088100577.jpg

http://img.photobucket.com/albums/v639/Karaya/Ki84_482_1102719617_286_1088100766.jpg

http://img.photobucket.com/albums/v639/Karaya/Ki84_482_1102719651_286_1088100520.jpg

http://img.photobucket.com/albums/v639/Karaya/Ki84_482_1102719685_286_1088100833.jpg

The fuel means probably 92 octane!? Unfortunately no mention of the manifold pressure. The US Report gives a max. topspeed of ~680km/h whereas the Japanese sheet states 624km/h. The trial between the Seafire and the Frank is not to be taken that seriously as the CSU on the Ki84 failed and therefore the engine did not put out full power (as stated in the document).

tigertalon
01-26-2007, 06:25 AM
Yohei Hinoki, a 12kill ace of IJA:

"It was easy for us to shoot these P-51s down, for their sole defensive manoeuvre was to perform a circular turn. The Ki-100 had a superior turning circle in comparison with the P-51, and we simply cut inside their defensive turns."

After an engagement of P-51s on July 16th, 1945:

"We destroyed 11 enemy aircraft, but lost three pilots in return. Considering that our small team was only newly assembled, and fighting against such a large group of enemy aircraft, the loss of three pilots was not so bad. We owed this result principally to our aircraft, which we called the Goshikisen."

Vipez-
01-26-2007, 09:21 AM
Originally posted by JG52Karaya-X:
Thats what I dug up from the depths of my HD:



http://img.photobucket.com/albums/v639/Karaya/Ki84_482_1102719685_286_1088100833.jpg



Interesting, says in the end "Frank has been reported carrying a fixed tail gun, firing aft." Does anyone have any info about KI84 carrying a gun firing backwards?

JG53Frankyboy
01-26-2007, 09:50 AM
perhaps Maddox games should have give the
Ki-84-Ia a Ha-45 Model 11 or 12 engine - that would propably have a max speed of ~630km/h.

and the Ki-84-Ib the actual (4.071) performance with its Ha-45 Model 21

that would have give missionbuilders a wider choice of using the Frank..............



the J2Ms, well, i was so surprised when they appeared in the game. i would have never expected such a performance ! i never read about such a performance.


the Ki-100.............. reliability of the engine and easy to fly do almost not count in a game http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif
but for me its a dog , i not expected an "berplane" , but as its now http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif
i would have expected a better climb, more speed at sealevel, and a little bit better turn........


the N1K2-Ja, i think its well modelled - beside its Damage Modell - thats a little bit too tough.

R_Target
01-26-2007, 10:05 AM
Originally posted by JG53Frankyboy:
the J2Ms, well, i was so surprised when they appeared in the game. i would have never expected such a performance ! i never read about such a performance.

Me neither, but I did pick up a book a couple of months ago with a TAIC data sheet for the Raiden (Dec. '44) which shows speeds of 350mph@SL and 405mph@17,000 ft. It doesn't say whether it's an estimate or a test though. Possibly the lower speeds frequently seen are for Military power only?

JG53Frankyboy
01-26-2007, 10:18 AM
well, as always its a question of wich sources/Datas the gamedeveloper choosed and/or how he interpreted them.
i belive thats the most difficult work when doing a historical flightsim..............

and i think the data bibliothek of Maddoxgames is huuuuuuuuuuuuuuuuuuuuuuuuge , with a lot of different datas for one and the same plane http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif

PropJoe_187
01-26-2007, 11:52 AM
>rubs eyes<

Did I read that correctly???

"Frank has been reported with a tailgun, firing aft"???? http://forums.ubi.com/images/smilies/blink.gif

I've never heard of such...

JG53Frankyboy
01-26-2007, 12:01 PM
Originally posted by PropJoe_187:
>rubs eyes<

Did I read that correctly???

"Frank has been reported with a tailgun, firing aft"???? http://forums.ubi.com/images/smilies/blink.gif

I've never heard of such...

we, living nowaday, with all infos available fast and easy, have to think 60 years back........... there were not much reliable information availabe what the enemy used.
the enemy was more like an alien, espacially in the airwar.

harryklein66
01-26-2007, 01:32 PM
Originally posted by R_Target:
Me neither, but I did pick up a book a couple of months ago with a TAIC data sheet for the Raiden (Dec. '44) which shows speeds of 350mph@SL and 405mph@17,000 ft. It doesn't say whether it's an estimate or a test though. Possibly the lower speeds frequently seen are for Military power only?

http://img.photobucket.com/albums/v296/harryklein/J2M.jpg

shinden1974
01-26-2007, 03:33 PM
If anyone has an airdata sheet for the N1K2-J I'd love to see it. I've never seen any sheet for the speed often quoted (369/370 mph max) or any other speed for that matter.

Marcel albert is right, which is why there is speculation that the US testers modified the engine. I think closer to the truth is that engine was spec'd for a fairly high octane and regular frontline fuel hurt performance (and probably contributed to the poor maintenance of these engines). But who really knows for sure?

It's a little weird following pacific war aircraft to see the J2Ms (often said to be a piece of junk) perform much better than the N1K2-J. The J2M is usually said to have stopped progression due to the superiority of the shiden in most reading I've done on the subject. Of course the J2M being junk is not true in the game or real life probably.

The Homare engine is a very powerful engine and just from a power to weight perspective should deliver great speed before we even discuss the effects of aerodynamics. IRL this engine often failed to make this full output power, but if we were to model the effects of maintenance, it would cause a considerable amount of crying in the other theaters of the war as well.

VW-IceFire
01-26-2007, 04:35 PM
Regarding the Ki-100 being the Japanese's best late war fighter this largely comes from factors unrelated to speed or climb performance. The Ki-100 was largely reliable, easy to land and taxi due to a wide track undercarriage, and generally was able to dive with American planes (generally not better but was regarded as being quite good in a dive). All that plus being lighter and having some better range than the Ki-61 and you can definitely see why the Japanese liked this one.

Versus the Ki-84 which was definitely higher performance but not as good in the turn, unreliable engines that either didn't perform or didn't perform at full potential, airframe problems and so forth.

Lets also keep in mind that in 1945 the most numerous Japanese fighter in-combat was still the A6M Zero. It should have been the A7M but that plane was hopelessly delayed by dithering over the powerplant and other details.

PikeBishop
01-29-2007, 05:36 AM
Dear All,
Remember also that the late war japanese fighters fought against the Russians also, so perhaps Oleg has access to other figures from captured Russian examples to look at other than the U.S. ones.
Best regards,
SLP

alert_1
01-30-2007, 03:59 AM
J2M3 has power/weight ratio, wight/wing area ration very close to la5FN/La7 and it looks lke more streamlined desing. It SHOULD have performance very close to the soviet fighters...

koivis
01-31-2007, 06:06 AM
Originally posted by alert_1:
J2M3 has power/weight ratio, wight/wing area ration very close to la5FN/La7 and it looks lke more streamlined desing. It SHOULD have performance very close to the soviet fighters...

Well, so does the N1K2, and still it has a top speed of only 595 kph. Sure it was almost 400 kg heavier and a bit larger than Ki-84. But 90 kph slower? Come'on. The Hellcat was 1700 kg heavier than N1K2, one meter larger wingspan, yet only 200 hp more power, and top speed still 610 kph? Which is more streamlined? Just compare those planes.

And Ki-100, 113 kg lighter, 75 cm larger wingspan, 1500 hp compared to 1990 hp, and full 110 kph slower than Ki-84! Unbelievable! Something is clearly wrong with these two planes.

Tater-SW-
01-31-2007, 08:00 AM
Originally posted by tigertalon:
Yohei Hinoki, a 12kill ace of IJA:

"It was easy for us to shoot these P-51s down, for their sole defensive manoeuvre was to perform a circular turn. The Ki-100 had a superior turning circle in comparison with the P-51, and we simply cut inside their defensive turns."

After an engagement of P-51s on July 16th, 1945:

"We destroyed 11 enemy aircraft, but lost three pilots in return. Considering that our small team was only newly assembled, and fighting against such a large group of enemy aircraft, the loss of three pilots was not so bad. We owed this result principally to our aircraft, which we called the Goshikisen."

I'll believe that when I see the US loss reports for that day showing anywhere near a dozen combat losses of P-51s. Maybe it's true, maybe it's not, but japanese claims without real data, particularly late war, are pretty suspect.

R_Target
01-31-2007, 08:09 AM
AFAIK the N1K2 has no high blower stage for the supercharger, so it will hit it's top speeds below 15,000 ft. It's certainly quick at low and medium altitudes.

Tater, see here (http://506thfightergroup.org/missionjuly16.asp).

shinden1974
01-31-2007, 03:11 PM
Originally posted by R_Target:
AFAIK the N1K2 has no high blower stage for the supercharger, so it will hit it's top speeds below 15,000 ft. It's certainly quick at low and medium altitudes.

It does:http://www.enginehistory.org/Japanese/nasm_research_4.htm#Homare21
same exact engine as the Ki-84 thus the questions about why is the Ki-84 so much faster with the same engine and good aerodynamics supposedly (the George had a laminer flow wing) The Japanese had no problem with the regular 2 stage supercharger, it was the three-stage mechanical turbo-supercharger that was giving them fits.

chris455
01-31-2007, 03:59 PM
Actually , it is not mate , let me explain you by a short summary http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

The engine of the Ki-84 was designed/built to deliver the expected power with the fuel they had , which was a lower octane fuel than the fuel the USAAF used for the tests .

However a higher octane fuel does make a difference , for an engine that has been built to accept a quality of fuel with higher octane , in an American engine , giving her fuel with too low octane could damage the engine for technical reasons i cannot explain well in English , you can hear small detonations when it happens .

For the case of the Ki-84 engine , the fact that you use higher octane fuel on it doesn't change anything AFAIK , it's still the same rate of air/fuel mix injected in less than 1 second going in the carburator , same rate of compression ..... it really doesn't change anything because the engine is not designed to accept higher octane fuel , engines need a minimum octane indice , but using a higher octane than what the engine has been designed for is useless , trust me this is for sure http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Very true, and an accurate description (for once) of what hi-test fuel can and cannot do- http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

R_Target
01-31-2007, 04:07 PM
Oops, I should've been a little more clear on that point. What I meant was lack of two-stage two-speed (or "three stage" as it's called in IL2) supercharger.

BigKahuna_GS
02-01-2007, 12:16 AM
PikeBishop
Dear All,
Remember also that the late war japanese fighters fought against the Russians also, so perhaps Oleg has access to other figures from captured Russian examples to look at other than the U.S. ones.
Best regards,
SLP
__________________________________________________ _______________________________________________



Would that be similar to the "trusted" japanese docs sent to Oleg that said the A6M Zero rolled 3-4 times faster than the NACA test docs ? These japanese docs made the Zeke the fastest propeller driven fighter of WWII. Especially over 375mph, it rolled faster than the 190, P51, and the hydraulic boosted airleron P38. Well years of flight tests, pilot reports and history indicate that the Zeke's controls started to stiffen up at a little over 200mph and continued to progressively get worse as speed increased.

The IL2 Ki84 is not representative of the 1944/45 japanese fighter serving in japan at that timeframe. It over performs buy a large percentage compared to the real aircraft.


_

PikeBishop
02-02-2007, 02:55 AM
Dear Kahuna,
Well I think that nomatter where one looks one will always find biased data on ALL sides. The art is to be able to sift out which is real and which is not (e.g.Korean Mig15/F86 kill/loss ratio's quoted at 16:1 were in fact only 2:1) . I think that Oleg has it right and the game does reflect what were the results in any combat between specific types. This game can only go so far in reproducing the balance on the design stratergies of each country. You should also remember that real pilots never had access to the performances of new types encountered as we do and therefore know the weak points of aircraft before we even start. Remember also that "maintanence problems" of some sort or another plagued All types and not just the Japanese.....you just don't hear much about it.
Best regards,
SLP

koivis
02-08-2007, 10:36 AM
Real topspeeds of J2M3, N1K2, Ki-84 and Ki-100 at ALTITUDE WITH MILITARY POWER (not WEP):

J2M3 585
N1K2 595
Ki-84 630
Ki-100 580

As you see, with MIL power Ki-100 was almost as fast as J2M3. Is this the case in game? NO!
Also, N1K2 was FASTER in mil power than J2M3. Is this the case ingame? NO!

We are talking about errors as big as 50 kph here. The problem is, that there seems to be NO test data with full WEP power for these two undermodelled fighters (N1K2 and Ki-100). So we can't accurately say how much extra performance they need. http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif

BigKahuna_GS
02-08-2007, 12:32 PM
Pikebishop-Well I think that nomatter where one looks one will always find biased data on ALL sides. The art is to be able to sift out which is real and which is not (e.g.Korean Mig15/F86 kill/loss ratio's quoted at 16:1 were in fact only 2:1)

Well I think I just found some more biased data http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

(e.g.Korean Mig15/F86 kill/loss ratio's quoted at 16:1 were in fact only 2:1)

Trying not steer this thread away but never heard the claim 16:1 and 2:1 is definetly way off the mark. The most accurate I have seen was somewhere around 6-8 to 1. Do a forum search as the best posting with info from both sides was by Skychimp on this subject--very informative.

shinden1974
02-08-2007, 07:07 PM
yes we are wandering off...

Exaggerated kill claims on all sides is a simple fact and often doesn't have much to do with someone trying to 'blow up' their numbers. It has a lot to do with the chaos of air combat and 'sounds good to me' record-keeping.

The Japanese had severe problems with exaggerated kill numbers, much of it having to with the fact that the Japanese military didn't keep careful kill records and a fair amount of victory disease. Maybe we can let this OT pointless who killed how many piss contest die now.

I'm actually hoping you'll elaborate on your earlier post though, Kahuna. Obviously someone found some japanese propoganda data for the A6M and turned it in to oleg, But with the Ki-84, it's the JAPANESE docs giving the Ki-84 the slower speed. It's the allied test data that gave the Ki-84 it's advanced performance in-game.

That's what I was talking about earlier...there's much speculation that somehow the US had enhanced the performance. I honestly don't want to rehash the octane debate, but I've never seen any proof that any enhancement was done other than better fuel. I've read a lot of BS about it, but by what standard do we use the japanese docs? by your own standard of accuracy (japanese docs cannot be trusted) the Ki-84 is just right! Is there other Ki-84 test data? I'd like to see it.

IMO you're right and the KI-84 (and J2M3) should show the performance it had historically and historically I believe these aircraft were not so fast...but the air data available leaves them where they are.

koivis
02-08-2007, 10:48 PM
I better clear this up... Japanese gave ALL their performance figures using military power, not WEP. Therefore all their speed figures are a bit too low, and the most quoted 630 kph figure is for early model of Ki-84 with 200 hp less power. I have no doubt that the plane, if properly maintained and all working could do 680+ as it currently does, without any engine "tuning".

The point of this thread is not Ki-84 or J2M, but the other two: N1K2 and to some extent Ki-100 are too slow. (Again, if they match their MIL power values ingame, it isn't enough, they still have WEP modelled, but somehow the performance isn't.)

J2M should be (or should have been) modelled after THESE (http://www.ww2aircraft.net/forum/attachments/engines/34518d1160399221-japanese-engine-specs-testing-japanese-engine-performance.pdf) test results. The plane was very streamlined, and good climber but now it seems to be more of turn-fighter than energy fighter which it was.

Changing fuel to better doesn't actually give it much additional power, just makes it more able to more reliably achieve the power, and also capable of higher boost levels. But one thing is sure, if you read that document, the power levels used in American tests were basicly same as japanese ratings.

I'm trying to desperately find some REAL maximum figures for N1K2-J and Ki-100. I've seen N1K2-Js max speed quoted as 417 mph / 670 kph, which seems reasonably fast and therefore must be a post-war test figure.

EDIT: please also read this interesing discussion at: WW2aircraft.net (http://www.ww2aircraft.net/forum/aviation/performance-japanese-aircraft-inflated-deflated-3179.html)

LEBillfish
02-09-2007, 01:25 AM
No expert by far but here goes on what I know of fuel from racing....

First off, the LOWER the octane number the easier it is for the fuel to ignite. Try using a very high octane fuel (ever premium) in an old low compression lawn mower, boat motor etc., and you'll find it runs terribly. Yet put too low an octane in a high compression engine and you may find you get detonation.

In a perfect "never" achieved for long condition, you will burn exactly the amount of fuel you put in each firing and it will burn fast enough to have done so before the exaust valve opens.......So too high an octane can hurt performance. Yet too low in contrast in that if the fuel fires too early you're not getting the best condition it actually expanding as the piston tried to compress it instead of just a moment before (what timing is for).

Now superchargers make pressure, trying to force the fuel and air into the cylinders. One result of that extra fuel air is the volume is increased over that the piston would draw in itself or at least maximizes it. So it is almost as though increasing what we think of as the compression ratio (YET is NOT) yet can have the same results........That is why say in cars, an engine you may have changed the pistons from 8:1 to 10.5:1 compression ratio to gain performance you may need to drop to 7:1 to use a supercharger or quite simply you'll blow gaskets or other things.

Compression of fuel alone can cause detonation or the fuel to actually ignite. As compressing air causes heat, plus you most likely have carbon in there which gets hot and stays it like an ember.........So to resolve the problem of spontaneous combustion, you increase the OCTANE as it will not ignite so easily, hence allowing you to determine when. Yet again to high an octane and you can't as it does not as well.



So what does all that crud mean........It means you do not select the engine for the fuel, you select the fuel for the engine.....OR.....You design your engines to work with the fuel you want to use.

High octane fuel alone does NOT make an engine have more power...Yet allows you to do different things to increase that power.

No doubt the japanese designed their engines to work with 92 octane fuel (or may of been 96 will need to check)......That would limit them on some of what they could do for performance, yet does not mean they could not achieve the same performance.

The quality of the fuel does make a difference yet mostly in impurities that hinder ignition or foul cylinders and valves so quickly detonation from carbon begins to occur.

Now don't take that as gospel as I could be all wrong yet is how I remember it. Point being though don't sweat the fuel, concern yourselves with test results.....and DON'T think TAIU was so silly as to use higher or lower octane fuel to test planes as they were trying to determine what they would encounter, not try and make the plane better or worse and is why the fuel found in and around the plane was always made note of.

PikeBishop
02-09-2007, 04:11 AM
Dear All,
That Mig15/F86 kill ratio I was not aware of, but suffice is to say that the ratio was not as high as was claimed. What I do think is important is that in a war situation a pilot when encountering a new enemy type often never knew how or why he managed to lose an enemy machine......did he out-roll it, outdive it, or was he faster at that altitude than it?..........or was the enemy aircraft low on fuel or out of ammo or just lost sight of him and so gave up the chase. I think that the US pilots must have had an awful time with the 43's and M2's until an M2 was captured after 6 months of war. I also did not realise that the performance figures for the japanese aircraft were only without WEP which could well explain the discrepancey because it is clear to me that the late war japanese fighters were at best difficult to beat and had excellent performance.
In the game we are in hindsight constantly aware of all the fighters weaknesses and we should realise what it must have been like having to face all the uncertaincies in WWII air combat.
Best regards
SLP

TheBandit_76
02-09-2007, 09:17 AM
Hmm, I once put some drained AV fuel from a friend's aerocommander into a rotary RX-7. Ran like a striped ape.

lrrp22
02-09-2007, 11:03 AM
Originally posted by shinden1974:
But with the Ki-84, it's the JAPANESE docs giving the Ki-84 the slower speed. It's the allied test data that gave the Ki-84 it's advanced performance in-game.

Shinden,

Therein lies the problem, the TAIC numbers used for the in-game Ki-84 are *not* based on post-war U.S. test data. The in-game numbers are based on best-case estimated performance numbers that originally appeared in the March 1945 TAIC manual. In fact, they are identical to the March '45 data. Despite many claims to the contrary, there is no evidence that any comprehensive post-war tests were conducted on the Frank.

LRRP

shinden1974
02-09-2007, 08:32 PM
I see lrrp22. searching here earlier I see you were in some heated discussion about the Ki-84 years ago.

nothing's changed since then, which data should have been used? There's no reason to go one way or the other...considering the lack of proof, why is the historically 'correct' option always the slowest option?

I always find that interesting in threads like this...there's no evidence to support any airspeed figure, the often quoted speed comes from unverified japanese docs with no test data...the other speeds come from allied 'test' data that may or may not be a generous estimate...so the only correct conclusion is to use the slower number...why? you wonder why people roll their eyes at this. It's sounds like the old japanese planes are **** BS. (not a racism accusation by the way, simply an old bias in aviation entusiast circles that have a passing interest in the PW...see Oleg).

I think you have an honest urge to get to the truth, but I think this is one of those cases where we will never have any hard data. Maybe we need to just set a model of the airframe up somewhere, run speed tests at various simulated altitudes in a wind tunnel and call the results the correct ones, it would be better than what we have now! I wonder if Oleg has ever considered simulating such a test by computer, it would go a long way to solving problems like this...

Badsight-
02-10-2007, 01:35 AM
Originally posted by 609IAP_Kahuna:
The most accurate I have seen was somewhere around 6-8 to 1. Do a forum search as the best posting with info from both sides was by Skychimp on this subject--very informative. then you havent looked very hard

its been gone over in-depth at this forum - after reviewing kill & loss records for both sides , a rate of 4.5-1 in favour of the Saber is the most accurate figure your ever going to be able to claim

& the La-7 is 30 Km/h faster @ SL than the Ki-84 , on less Hp . 140 Hp less

the Brits got 400 mph out of their captured example , & that was with a faulty rpm govenor which meant they didnt run it to max RPM . . . .

. . . & we all know what 300 extra RPM did for the P-38 .

basically it wasnt impossible for the Ki-84 to have gone over 400 Mph . captured japanese airmen even claimed their Hayates went faster than the TAIC figures , & we know that japanese manufacture max speed figure were not the maximum possible settings

KIMURA
02-10-2007, 06:02 AM
Well said Fishy and Marcel Albert. Just increasing of Octane does not result in an increase of power(kW). That's a myth, maybe created by authors and became copy/paste thoughout the time. Sure if an engine is not optimised and setup then you'll get some marginal power increase but not like turning a VW into a Porsche.
a/c engines were optimized at a specific fuel grade that was available to the troops - as Fishy already stated. So for the Homare 21 92 Octane. Also the TAIC manual does referring to 92 Octane for the tested aircrafts there. Just filling the 145/130 into the fuel tanks of Japanese a/c does not result in better performance.
I think (just a will guess) the US tested on Clark Field with Japanese fuel they captured there. The Ki-84 (S-17) later was transferred to the US and the engine was reworked there and became modified. It's also surprisingly that the Ha-45 ran @ 48@Hg (92 Octane) to produce nearly 2000hp, where as Allied engines ran higher MP's for the same output.

Karaya about the Ki-100 as best Kitai-fighter. Surely on paper the Ki-100 was far off being the best, but the pilots who flew it stated the Type 5 being the best. I guess the Ki-100 a fighter a pilot could dream of. Forgiving,good handlinh, good performance, good armament and reliability. I guess many game pilots just rating an a/c after paper specs, but that's not the way real pilot do I guess they rated an a/c how it handles and the chance to get home alive and often not the best performer that was.

JG52Karaya-X
02-10-2007, 12:39 PM
About the fuel: I just pointed out that higher octane fuel was used by the US in their trials, if it meant any difference I dont know.


Originally posted by KIMURA:
Karaya about the Ki-100 as best Kitai-fighter. Surely on paper the Ki-100 was far off being the best, but the pilots who flew it stated the Type 5 being the best. I guess the Ki-100 a fighter a pilot could dream of. Forgiving,good handlinh, good performance, good armament and reliability. I guess many game pilots just rating an a/c after paper specs, but that's not the way real pilot do I guess they rated an a/c how it handles and the chance to get home alive and often not the best performer that was.

Yes, plane handling certainly also was a big factor, especially as the number of experienced combat pilot had drastically decreased up until '45 when the Goshikisen entered service. Its reliability was certainly also an important trait, keeping in mind that many Ki84 had severe troubles with even getting their engines running and/or had to return to base with mechanical problems, but still the performance of the Ki-100 was nothing special by the time it was delivered to the troops. You have to compare it to its contemporary adversaries, the F6F, F4U, P38, P47 and P51, in case of the latter we are speaking of a speed margin of more than 100km/h, even the F6F (the slowest of these US fighters) will not have much of a trouble to hunt down and/or seperate from the Ki-100. From a serviceability and ease-of-handling point of view the Goshikisen probably was the best Japanese fighter of that time but still I wouldnt want to be facing the US fighters in one, could turn out to be quite unhealthy.

IMHO the Ki-100 would have been a decent fighter in '43, but in '45 it didnt have any ground of competition anymore.

LEBillfish
02-10-2007, 03:13 PM
Originally posted by TheBandit_76:
Hmm, I once put some drained AV fuel from a friend's aerocommander into a rotary RX-7. Ran like a striped ape.

I've heard such tales too and can tell you for a FACT having stupidly put 106 octane (a texaco rarity even above 104) years ago into a 79 1/2 RX7 that it took draining the tank to get it to run again.

That said.................On to the Ki-100:

The Ki-100 was NOT and end all aircraft by anymeans. It was slower then the Ki-61, yet retained it's handling (which btw here is off as it was reputed to be more agile by far then P40's yet just slightly less then Ki-43's). It had great difficulty reaching the altitudes it needed to, etc. etc..

It was a bandaid fix. Like taking a Triumph TR6 and putting a Dodge B body (charger) fornt end on it so you could use the dodge engine. In fact, they did not "Build" Ki-100's as Ki-100's, they took Ki-61-II's, cut off the nose, and jerry rigged on the front half of a navy fighter which if you'll note is akwardly wider then the fuselage of the Ki-61/100.

It was not a better plane, it was a make due with what you have on hand bandaid job.

e8n1
02-25-2007, 09:50 AM
As was stated earlier the TAIC speeds were estimates based as engineers best case speeds. Any discussion of improved fuel or other improvements during test flights is relatively meaningless.

S17 (the Ki-84) was tested there but nowhere I have found any of the test results from most any of the aircraft that were tested at Clark. They also tested a second Ki-84 (S10) at Clark. I believe that aircraft crashed.

I've talked to the commander of the TAIC unit at Clark on several occasions about this topic. He said that they filed reports on all the tests that took place there. They were filed with the Navy who in turn would have sent them to Washington. Thus far there is no evidence that they ever made it that far.

In the tests that they did they weren't as interested in straight out performance as they were with function. What I mean by this is that their pilots weren't thrilled to find out what the aircrafts maximum airspeed was simply because it may endanger them. They were more interested in finding the weaknesses of the aircraft and how they performed against various allied aircraft.

This same fellow also worked at the bureau that put out the TAIC manual (he was an aeronautical engineer) as one of the guys that also did the estimates before he was assigned to lead the group in the Pacific.

I doubt that we will ever know the real hard numbers on speed but it is always an interesting debate.

-Dave

darkglamJG52
02-26-2007, 11:27 AM
Originally posted by tigertalon:
Yohei Hinoki, a 12kill ace of IJA:

"It was easy for us to shoot these P-51s down, for their sole defensive manoeuvre was to perform a circular turn. The Ki-100 had a superior turning circle in comparison with the P-51, and we simply cut inside their defensive turns."

After an engagement of P-51s on July 16th, 1945:

"We destroyed 11 enemy aircraft, but lost three pilots in return. Considering that our small team was only newly assembled, and fighting against such a large group of enemy aircraft, the loss of three pilots was not so bad. We owed this result principally to our aircraft, which we called the Goshikisen."

US reports says 1 P-51D lost(John W. L. Benbow) + 2 or 3 with damage.

http://506thfightergroup.org/missionjuly16.asp

harryklein66
03-02-2007, 09:03 AM
Originally posted by JG52Karaya-X:
http://img.photobucket.com/albums/v639/Karaya/Ki84_482_1102719651_286_1088100520.jpg

http://img.photobucket.com/albums/v296/harryklein/J2M.jpg

someone noticed that the top speed at overload+wep are very close to the top speed that are often quoted +-620Km/h for the Ki84 and +-600km/h for the J2m3 ?

Kocur_
03-02-2007, 09:25 AM
May I have question about not so late Japanese fighter? Are 580kmg @ 3800m for Ki-44I and 605kmh @ 5200m for Ki-44II (taken from Famous Airplanes No 16) THE top speeds or are those "almost top" speeds i.e. not achieved at "WEP" (or "110%"). If the latter is correct - what would be absolute top speeds of that plane?

harryklein66
03-02-2007, 10:01 AM
Yup it's an interesting question that can be applied to all the other AC

If some one can translate this ? : http://img.photobucket.com/albums/v296/harryklein/Ki_44II.jpg

ICDP
03-02-2007, 05:51 PM
Harryklein this is referring to the Ki44II and the 605kph matches the "maximum" speed given for this aircraft in Japanese Aircraft of the Pacific War by Rene Francillon. The 620kph figure is probably closer the the actual top speed since most literature tends to give the lower numbers as maximum speeds rather than the higher numbers.

Why is it that an Fw190A3 with around 1,700hp and 8,700lb take-off weight is widely accepted as a 400+mph aircraft. Or a Spitfire MkIX with Merlin 66 rated at 1,720hp and a take-off weight of 7,450 is good for 408mph. Yet the Ki84-1a with 1,800hp and 7,900lb in weight is a expected to be lucky to get 390mph. The 1,800hp rating is for the early Ki84's, later versions were rated at 2,000hp. The truth is there is no logical reason to expect a <span class="ev_code_RED">properly</span> built Ki84 to be a sub 400mph aircraft. It doesn't take an aerodymanic genius to figure out that the sub 400mph figure for the Ki84 doesn't add up.

harryklein66
03-02-2007, 05:54 PM
http://forums.ubi.com/images/smilies/agreepost.gif

PS: you can read Japanese ?

Kocur_
03-03-2007, 12:51 AM
Originally posted by ICDP:
Yet the Ki84-1a with 1,800hp and 7,900lb in weight is a expected to be lucky to get 390mph.

While I dont have knowledge to try to argue about actual figure, I'd like to point out a factor not mentioned above, i.e. wing area. Ki-84's 21m^2 puts it in Spitfire ballpark, so if one would make comparisons the latter should be taken for them, rather than Spitfire's "competitior", which had far smaller, less draggy wings and was always faster-per-power - Bf 109. And Japanese designers did try, apart from Ki-44, to maintain rather low wingloading. So I'd say, that if Ki-84 speed should be compared with say Fw-190 with similar power available, I would expect Frank to be slower, due to those 2,7m^2 more.

ICDP
03-03-2007, 02:16 AM
Harry sorry I can't read Japanese. I do know the symbol before the 44II in the text means Ki. So it is obviously referring to the Ki44II fighter which according to my literature had a top speed of 605kph. The 620kph in the text I assumed was referring to the higher speed with full "combat" power. I can't know this for sure but am simply making a guess.

Hi Kocur,

I gave the speeds for both the Fw190 and the Spitfire MkIX in my comparison. I know that there is more to top speed than power and weight but nonetheless the later Ki84 with 2,000hp should logically be able to reach well over 400mph. I honestly have no problem believing that a later ki84 built to spec should reach 427mph as it does in the sim.

Lets compare the Ki84 with the F6F and F4U-1, both were much heavier than the Ki84 and had larger wing area with slightly higher wing loading. The power loading of the Ki84-1a (1,800hp) was around 25% better than both the USN fighters. The F4U-1 was capable of around 417mph top speed and the F6F was good for 399mph at top speed (2,250hp for both fighters). With this in mind how can it be accepted that a well built Ki84 with more power to weight and less drag than both of these fighters was slower? That is not even considering the later Ki84's with the 2,000hp engine. Granted the build quality of the late war Japanese aircraft was poor but the sim doesn't model these problems.

Kocur_
03-03-2007, 02:48 AM
I know that there is more to top speed than power and weight but nonetheless the later Ki84 with 2,000hp should logically be able to reach well over 400mph.

I perfectly agree!


I honestly have no problem believing that a later ki84 built to spec should reach 427mph as it does in the sim.

Like I said I dont have 'my' figure, but that looks probable, especially considering, that apparently Homare kept the power up to quite high alt for PTO at least, as data from the website (http://translate.google.com/translate?hl=en&sl=ja&u=http://www.warbirds.jp/kakuki/sanko/kakengine.htm&sa=X&oi=translate&resnum=1&ct=result&prev=/search%3Fq%3Dhttp://www.warbirds.jp/kakuki/sanko/kakengine.htm%2B%26hl%3Den%26lr%3D%26sa%3DG) suggests (ctrl+F for "Honor 21" in "The japanese military compilation").


To my tiny knowledge power and drag rule the top speed. Powerloading would affect acceleration, but not necessarily the top speed, as proves say CR.714, about as fast as MS.406 (484kmh vs.490kmh, and actually would be faster probably if that 450PS Renault kept that power as high as HS12Y of Morane did with its 860PS), but with far worse powerloading of 3,9 kg/PS, compared with roughly 2,9PS/kg of Morane.

Fork-N-spoon
03-03-2007, 03:17 AM
Originally posted by Kocur_:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I know that there is more to top speed than power and weight but nonetheless the later Ki84 with 2,000hp should logically be able to reach well over 400mph.

I perfectly agree!


I honestly have no problem believing that a later ki84 built to spec should reach 427mph as it does in the sim.

Like I said I dont have 'my' figure, but that looks probable, especially considering, that apparently Homare kept the power up to quite high alt for PTO at least, as data from the website (http://translate.google.com/translate?hl=en&sl=ja&u=http://www.warbirds.jp/kakuki/sanko/kakengine.htm&sa=X&oi=translate&resnum=1&ct=result&prev=/search%3Fq%3Dhttp://www.warbirds.jp/kakuki/sanko/kakengine.htm%2B%26hl%3Den%26lr%3D%26sa%3DG) suggests (ctrl+F for "Honor 21" in "The japanese military compilation").


To my tiny knowledge power and drag rule the top speed. Powerloading would affect acceleration, but not necessarily the top speed, as proves say CR.714, about as fast as MS.406 (484kmh vs.490kmh, and actually would be faster probably if that 450PS Renault kept that power as high as HS12Y of Morane did with its 860PS), but with far worse powerloading of 3,9 kg/PS, compared with roughly 2,9PS/kg of Morane. </div></BLOCKQUOTE>

There are a lot of asumptions and over simplification going on. From all that I've read, two different aircraft can have the same hp, same weight, same dimentions yet they will have very different performance. Will both aircraft have the same performance? No! F4U and F6F are good examples, one is listed as being 30+ mph faster than the other. Despite the fact that the F4U-1D and F6F-5 have very similar numbers on paper, one is 30+ mph faster than the other. I've never seen 399 listed for the F6F. Despite the way in which 399 for the F6F has been thrashed about the internet for the past seven or eight years, nobody has brought forth hard evidence to support such claims.

There's a lot more to acceleration than power loading.

There's a lot more to turn performance than wing loading and power loading.

You cannot just look at similar numbers and then with one sweep of a broad brush say, "they should have very similar performance."

The P-51B is much heavier than the Spitfire Mk IX, has a much higer wing loading, and the P-51 has less hp than the Spitfire Mk IX yet the P-51B is faster than the Spitfire MkIX.

Even in some of the very simplistic comparisons, 392 Ki-84 and 408 for the Spitfire Mk IX aren't that different. Their performance is within 4% of each other, that's not a significant difference and is entirely possible.

Kocur_
03-03-2007, 03:29 AM
There are a lot of asumptions and over simplification going on.


The P-51B is much heavier than the Spitfire Mk IX, has a much higer wing loading, and the P-51 has less hp than the Spitfire Mk IX yet the P-51B is faster than the Spitfire MkIX.

He, he! Which Spitfire Mk.IX and at what alt? http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif Just joking - to underline alt as a powerful factor - comparing speed results without mentioning alt is indeed gross and extremely popular oversimplification.

ICDP
03-03-2007, 03:45 AM
Hi Fork-N-Spoon,

I am not even close to understanding aerodynamics but I am aware that two different designs have widely differing speeds even with similar power. This is why mentioned the F4U and F6F in my post to demonstrate that two aircraft of similar weight & power could have very different top speeds. It is obvious that the F6F has more drag overall than the F4U-1 and that is the reason it is 20mph slower. I then added the Ki84 into the mix with lower drag and higher power to weight than both the F6F and F4U. It was a smaller, lighter aircraft with slightly lower wingloading but better power to weight ratio. At least to a layman like myself this points to an aircraft that should have no problem hitting 400+mph. Also bare in mind that I am not even remotely referring to acceleration or turn performance. I am using powerloading to determine that the Ki84 had more excess power available than both USN fighters. I am using a combinations of all of these numbers to determine that the Ki84 was no more draggy than the F4U-1 or F6F. Should it not therefore be logical to expect the Ki84 to reach similar or especially in the case of the F6F even better performance.

This is not over simplification but simply applying logic to reach a conclussion. Correct me if I am wrong in this conclusion.

Fork-N-spoon
03-03-2007, 04:29 AM
Beginning in 2004, I grew tired of both this game and this forum. I've quit playing the game, but continued on in the forum. I've determined that there's no point in debating. You're right, the Ki-84 had pretty colors, looked cool, thus it should do 600 mph. I surrender and I'm deleting this bookmark.

There's one other similarity that I've noticed. Both the Hurricane and Spitfire had many similarities, both even had identical markings, I think that they both had identicle performance.

:\/

P/S I'm having a breakdown you see...

ICDP
03-03-2007, 04:51 AM
Originally posted by Fork-N-spoon:
Beginning in 2004, I grew tired of both this game and this forum. I've quit playing the game, but continued on in the forum. I've determined that there's no point in debating. You're right, the Ki-84 had pretty colors, looked cool, thus it should do 600 mph. I surrender and I'm deleting this bookmark.

There's one other similarity that I've noticed. Both the Hurricane and Spitfire had many similarities, both even had identical markings, I think that they both had identicle performance.

:\/

P/S I'm having a breakdown you see...

Wow, great reaction. You will see that in all of my posts I was pointing out that it doesn't add up that the Ki84 was sub 400mph. I was using numbers from other aircraft to support my assumption. They key word here is assumption. At no point did I present my assumption as fact I simply stated that logic tells me it should be 400+mph. Now you react with childish BS that I somehow want the Ki84 to be capable of 600mph!!!.

I have already prior to your childish tirade stated that no two aricraft were alike depsite having th exact same powerplant and similar weight (F4U v F6F). I have already acknowledged that there is more to determining top speed than power and weight. The fact that I have given figures for four very different designs of aircraft that have speeds of 400-420mph seems to be lost on you.

Oh and I have posted this many times to show the F6F listed top speed of 399mph. Now you can say you have seen an official document saying the F6F was capable of 399mph. I have also seen graphs in AHT showing the same top speed.

http://i17.photobucket.com/albums/b58/ICDP/Fig5.jpg

Bellator_1
03-03-2007, 05:15 AM
The Ki-84 could at the very least reach 422 mph, and an excellent condition example running on the right fuel could probably do 375 + mph at SL and 435 + mph at 20 kft - aerodynamically the design is very clean.

US test results varied from 422 - 427 mph at FTH with 100/130 grade fuel (Or was it 130/150 ?), which is a good way from the 87 - 92 octane fuel used by the Japanese - therefore it is rather obvious that the captured examples didn't perform as well as the ones in service which were in good condition.

The climb rate achieved in the US tests was 4,300 ft/min.

e8n1
03-03-2007, 06:20 AM
Bellator 1,

I was wondering if you could provide your sources for the below statement?

-Dave

>> The Ki-84 could at the very least reach 422 mph, and an excellent condition example running on the right fuel could probably do 375 + mph at SL and 435 + mph at 20 kft - aerodynamically the design is very clean.

US test results varied from 422 - 427 mph at FTH with 100/130 grade fuel (Or was it 130/150 ?), which is a good way from the 87 - 92 octane fuel used by the Japanese - therefore it is rather obvious that the captured examples didn't perform as well as the ones in service which were in good condition.

The climb rate achieved in the US tests was 4,300 ft/min.>>

Bellator_1
03-03-2007, 06:57 AM
Ofcourse e8n1;
http://aycu40.webshots.com/image/11959/2002192202386990547_rs.jpg

Do you want the rest of the report as-well ?

e8n1
03-03-2007, 07:12 AM
Again, the number you quote are theoretical. They are only engineered number they are not actual test data.

If you could get a hold of any test data from either Clark Field or from the post war tests run on the Frank it would be more meaningful but still not 100% accurate.

-Dave

koivis
03-03-2007, 07:27 AM
I notice you all have somehow missed the two links I gave in a previous post:
japanese-engine-specs-testing-japanese-engine-performance.pdf (http://www.ww2aircraft.net/forum/attachments/engines/34518d1160399221-japanese-engine-specs-testing-japanese-engine-performance.pdf)
performance-japanese-aircraft-inflated-deflated (http://www.ww2aircraft.net/forum/aviation/performance-japanese-aircraft-inflated-deflated-3179.html)

And I say this again, the point of this thread is not Ki-84, because the documents above suggest that it had the performance that it has in game, if it was properly maintained.

Now some of you say, "well most of the planes were in bad condition and used lower quality fuel than what the engine was designed for". Yes, that's true, but then, also planes like early LaGG-3, were basicly in similar situation, suffering from bad airframe quality or engine difficulties which seriously hampered their performance.

Quote from LaGG-3: (Wikipedia...)

"Some aircraft supplied to the front line were up to 40 km/h (25 mph) slower than they should have been and some were not airworthy."

You'd like your LaGG-3 to have 40 km/h slower speed than it now has??? But then, the current N1K2-J somehow HAS slower speed than it should have. The only problem is that I don't have any real performance curves for the N1K2-J because it was not properly tested by Americans, or I haven't found any data for it.

REAL japanese MIL power speeds at 6000 meters:
Ki-84-I (Ha-45-11/12)--630
Ki-84-I (Ha-45-21)-----670<---- this is actually for wooden prototype Ki-84-II, but it was even a bit heavier than the -I
N1K2-J (Ha-45-21)------595

Current ingame speeds for Ki-84-1a and N1K2-J:
Plane---0 m-----6000 m
Ki-84---580-----685
N1K2-J--550-----595<---- this is WRONG, it's same as the real MIL power value, while Ki-84 is a tad faster than the MIL power value (as it should be)

As these planes had EXACTLY the same engine, their performance curves should be closer. The current 90 km/hi difference at 6000 meters is ridiculous.

harryklein66
03-03-2007, 09:41 AM
http://img.photobucket.com/albums/v296/harryklein/N1_01.jpg
http://img.photobucket.com/albums/v296/harryklein/N1_02.jpg

J_Anonymous
03-03-2007, 11:59 AM
Originally posted by harryklein66:
Yup it's an interesting question that can be applied to all the other AC

If some one can translate this ? : http://img.photobucket.com/albums/v296/harryklein/Ki_44II.jpg
"The climb rate improved, and the maximum speed improved by 25 km/hour as well, to reach 605 km/hour. However, it didn't quite meet the required specification of 620km/hour at 5400m."

harryklein66
03-03-2007, 12:02 PM
Thank you very much http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

A6M2b_ZERO21
03-03-2007, 12:55 PM
I am a Japanese.
The text of KI 44 was translated.
Since it is translation by translation software, there may be a strange portion.
__________________________________________
A gunsight is a glasses type.
The hook for spinner starting was added and the form of a spinner was also changed in connection with this.
Although it was the form as the built type of a prototype, and an increase experimental model where the wheel cover of an early production machine was the same, in the production machine of the second half, the lower panel was moved to the body side.
Armaments are two dishes of type 89 7.7mm fixed machine guns to the body.They are two dishes of type 1 12.7mm fixed machine guns (HO 103) in wings.For the number of carrying cartridges, the number of 7.7mm guns is 500 each, and 12.7mm gun is 250 shots each.
In addition, there are also two dishes of 7.7mm guns and data which make that by which model 1 KO(Ia) and the body also changed the thing of two dishes of 12.7mm guns into a 12.7mm gun into wings model 1 OTSU(Ib) in the body.
Although 4 dishes of 12.7mm gun type may have been planned, a possibility that saw from the number of production and such repair was carried out is very low.

- Double reversal propeller test prototype
The double reversal propeller which changes one set of a 1 type second-half production type motor into Ha 41 PESHI for double reversal propellers, and is called PE 7P-1

* The text of the 1st line has broken off here.

__________________________________________________ _______________________________

- Increase experimental model in model 2 (KI44II)
The thing whose propeller is the diameter of 3.00m in connection with engine change and for which it ended and と was also changed into the three Hamilton standard type propeller,The lubricating oil cooler was changed into the nest type of a bee from the annular type,The fuel tank was changed into the self ceiling type,Since weight increased by improvement and wings load increased, landing speed increased and landing became still more difficult.
The rise performance was improving, and although the maximum speed also carried out improvement in 25 km/h and reached 605 km/h, it did not come to fill a demand called 620 km/h (5400m).
Mass production was started in November around June, 17 that basic examination was completed.

* 17 years are name of an era of Japan.
* Showa 17 = A.D. 1942

- Type 2 model 2 single seat fighter (KI44II)
Formal December, 17 adoption. It is classified into two models (IIa), model 2 OTSU (IIb), and model 2 Hay (IIc) according to armaments.

* The text of the 2nd line has broken off here.

__________________________________________________ ________________________________
From the full load 2764 to 2993kg
For the number of production, the serial number is after 1354 at about 393 sets.

* Judging from text order, the number of production of model 2 OTSU is seemed.

- Model 2 HEI (KI44II HEI): The gun of wings also made the body gun HO 103, by the model which carried a total of four dishes of 12.7mm guns, the gunsight was changed into the optical image type and the canopy was also improved. The serial number is after 1750 and is manufactured 500 or more sets.

- Model 3 (KI44III)
KI 44 -- a development start -- since there was no motor suitable those days, Ha 41/Ha 109 was equipped, but since small Ha 45 of a high output completed after that, the model 3 (KI 44III) which equipped Ha 145 as an improvement proposal in the second performance builds a prototype -- having . No. 1 will be completed in June, 18. Practical use examination was completed in December of the same year.

* Ha 145 is one of the kinds of Ha 45 (Ha 45-43).
* Also in a unification name (Ha 45), there are an army name (Ha 45 Type 4) and a navy name (HOMARE) in a Japanese engine at Arisa and others.
* Ha 145 is an army name.

A wingspan is increased by about 70cm. Wings area was increased to 19.0 square meters, and also increase area also of the tail is carried out and a propeller is changed into a four-sheet standard type. It was increasing to full load 2886kg.
Although model 3 OTSU of three models of four dishes of 20mm machine guns, two dishes of 20mm machine guns, and four dishes of 37mm machine guns was planned, when the experimental model was completed, the next fighter KI84 is...

* The text of the 3rd line has broken off here.
__________________________________________

As for the Japanese table, the plan value of N1K1-J and the numerical value of the in-house test of Kawanishi are written on the data immediately after this contribution.

Guess value:
Top speed 321 knot / 2500m 348knot/6000m
Climbing power 2 minute 7 second / 2500m 5 minute 15 second / 6000m
Cruising capacity With no publication
Practical use ceiling 11250m

Measured value in a company :
Top speed 315 knot / 3000m 333knot / 6000m
Climbing power 2 minute 50 second / 2500m 6 minute 20 second / 6000m
Cruising capacity Full power 30 minute + cruising (210 knots) 3 hours
Practical use ceiling With no publication
Note: Calculate a guess value by the weight of 3800kg.
As for the lower small table, the number of production is written.
*Name-of-an-era 17 years of Japan = A.D. 1942

Translation is to here.

Since it is not updated in many cases even if it is behind improved by the measurement data of a Japanese army which I regard as it being measurement by military power, although the measurement conditions currently taken out to N1K2-J 620 km/h in the case of a performance comparison examination with J2M3 are not known, is the speed of data also of the thing which is data in early stages of an experimental model in many cases the late cause?
For example, in the official score of Japan of KI84, it can take out with output restrictions only to 1800H.P., and a certain thrust type exhaust pipe is not attached to a mass-production machine, either, but it is measurement by military power.

harryklein66
03-03-2007, 02:44 PM
Thank you very much for the Translation http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif.

In the last part do you mean that the Japanese data give the performance at military power for the prototype, pre serie or early serie model, and they were not updated even if later modifications improve or decrease the performance ?

A6M2b_ZERO21
03-03-2007, 05:22 PM
Only record to military power leaves an army and the navy fundamentally to an official score.
In Japan, it was used by the battle only to military power.
Using full power was forbidden except the takeoff.
However, use of war emergency power was permitted in the war last stage.
There is almost no record of war emergency power by such reason.

In Japan, even if it performed reconstruction which improves performance afterwards, new data was not put on official data.
Therefore, most of the official data of a warplane of Japan is the thing of an experimental model.

In the case of Type 4 fighter "HAYATE" (ki84)
Ha 45 (HOMARE 21) engine is about 2000H.P.
However, 1800H.P. restriction was applied.
This continued till the beginning of 1945.
There is no thrust type exhaust pipe which is effective in gathering speed in built-a prototype type Ki84.
Record of top speed is record of military power as well as an old Japanese army plane.
Even if it was an experimental model owing to the damage caused by bombing etc., the good engine of quality was not necessarily obtained.
It may not have been obtained even by 1800H.P. for the above-mentioned reason.
The official data measured on these various conditions is 624 km/h and 630km/h.
Although the experimental model of ki84-Ib also had record of 660 km/h, a change was not made for the official score.

N2K2-J is also measured on the almost same conditions as ki84.

Bellator_1
03-03-2007, 06:37 PM
Originally posted by e8n1:
Again, the number you quote are theoretical. They are only engineered number they are not actual test data.


Really ? Care to elaborate on that cause I've not yet heard of technical reports as these containing much calculated results without making notice of it... (Like the Tojo II)

http://aycu17.webshots.com/image/9696/2006370989715273672_rs.jpg

R_Target
03-03-2007, 07:04 PM
Originally posted by Fork-N-spoon:
I've never seen 399 listed for the F6F. Despite the way in which 399 for the F6F has been thrashed about the internet for the past seven or eight years, nobody has brought forth hard evidence to support such claims.

http://img180.imageshack.us/img180/7527/taicf6fti9.gif

e8n1
03-03-2007, 07:06 PM
"Really ? Care to elaborate on that cause I've not yet heard of technical reports as these containing calculated results..."

Sure. I had a chance to interview the Captain that was in charge of TAIC at Clark. When asked about the TAIC manual data basically he told me that these were theoretical "engineering" numbers. Previous to commanding the unit in the SW Pacific he was one of the engineers that calculated these numbers.

Another Item on this. The TAIC manual that is being quoted us the March update of the December 1944 "Provisional Data."

In December of 1944 they had not actually seen the aircraft as noted in the general data notes:

"Performance figures should be taken as estimates but they do give an indication of the expected performance of new Japanese Fighters." At this point the max mph was listed at 422.

In the March 1945 update when they had photographed and measured samples of the aircraft the wing dimensions changed and the speed estimates climbed to a max of 426mph.

Now you would think this is because they captured and flew the aircraft before the March 1945 information.

Not so. Clark Field was captured and a base of operation was setup in February of 1945. By the time they began flying aircraft it was nearly April 1945. Information also did not travel back to Washington quick enough for this to be included in the update of March 1945. It went to fleet and then on up the chain.

The numbers in the TAIC manual are estimates based on new measurement information not based on actual flights.

When I asked the captain directly if they updated any of the manuals based on test data he said flat out "no". One of the reasons for this was that by the time all the tests had taken place the information was basically meaningless and the next model was out. BTW March of '45 was the last update that the Frank appeared in.

Also as I believe I stated earlier, test data can be skewed. Different pilots are willing to take different risks with different test results. Different aircraft are better restored than others. Engineering generally remains constant.

Hope this helps.

-Dave

R_Target
03-03-2007, 07:11 PM
I was wondering why the March TAIC sheet is blank under "General Data."

e8n1
03-03-2007, 09:46 PM
That's one I can't answer. It could be because it is a second entry for the Frank (with the first being the December 1944 entry) or it could be because these are replacement pages for the manual. I really don't know.

-Dave

Bellator_1
03-04-2007, 03:24 AM
With a 1,900 HP engine I definitely don't see why this bird shouldn't be capable of 430 + mph, and Japanese pilots have reported speeds of this magnitude and higher.

harryklein66
03-04-2007, 05:46 AM
Originally posted by A6M2b_ZERO21:
Only record to military power leaves an army and the navy fundamentally to an official score.
In Japan, it was used by the battle only to military power.
Using full power was forbidden except the takeoff.
However, use of war emergency power was permitted in the war last stage.
There is almost no record of war emergency power by such reason.

In Japan, even if it performed reconstruction which improves performance afterwards, new data was not put on official data.
Therefore, most of the official data of a warplane of Japan is the thing of an experimental model.

In the case of Type 4 fighter "HAYATE" (ki84)
Ha 45 (HOMARE 21) engine is about 2000H.P.
However, 1800H.P. restriction was applied.
This continued till the beginning of 1945.
There is no thrust type exhaust pipe which is effective in gathering speed in built-a prototype type Ki84.
Record of top speed is record of military power as well as an old Japanese army plane.
Even if it was an experimental model owing to the damage caused by bombing etc., the good engine of quality was not necessarily obtained.
It may not have been obtained even by 1800H.P. for the above-mentioned reason.
The official data measured on these various conditions is 624 km/h and 630km/h.
Although the experimental model of ki84-Ib also had record of 660 km/h, a change was not made for the official score.

N2K2-J is also measured on the almost same conditions as ki84.

Thank you for the explanations http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

koivis
03-04-2007, 04:35 PM
Originally posted by harryklein66:
http://img.photobucket.com/albums/v296/harryklein/N1_01.jpg
http://img.photobucket.com/albums/v296/harryklein/N1_02.jpg

Now this is what I'm talking about! The first REAL performance figures for N1K2-J I've ever seen... Remember, that ALL "official" Japanese documents show top speeds which are tested with military powew, which in their terminology means a bit higher than max. continuous (allied term), but much less than max. power (allied term=WEP).

So, the speed figures for N1K2-J should be as follows: 551 kph (342 mph) at 0 m (i.e. as it is now), and 655 kph (407 mph) at 6000 m (far more than it's now. The 655 kph figure is more in line with current performance of J2M and Ki-84. Have you noticed how the N1K2-J has troubles keeping up with anything (EDIT: any 1944-45 American fighter plane, except F6F Hellcat) over 1000 meters? (plus, it overheats amazingly fast, but that doesn't bother me, actually I like that feature http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif )

If this could still be fixed... http://forums.ubi.com/images/smilies/11.gif
(we're talking about 50+ kph (over 7 percent) speed BUG here!

EDIT: just mentioning: currently P-51D is over 120 kph faster at 3000 meters than N1K2-J. 120 kph. N1K2-J has 1990 hp engine, vs P-51D's 1720 hp. Yes, P-51D weighs a bit more and has a laminar flow wing, and more streamlined apppearance (liquid-cooled V-12 engine). But, still... 120 kph???

e8n1
03-04-2007, 04:50 PM
The source you are citing on the George is TAIC manual December 1944. Again the numbers aren't "real" numbers. This was provisional at the time. A George wasn't captured and flown until around April 1945.

-Dave

harryklein66
03-04-2007, 05:20 PM
The TAIC is indeed an estimation, and should be take for what it is.

But the the first document is :

Originally posted by A6M2b_ZERO21:
As for the Japanese table, the plan value of N1K1-J and the numerical value of the in-house test of Kawanishi are written on the data immediately after this contribution.

Guess value:
Top speed 321 knot / 2500m 348knot/6000m
Climbing power 2 minute 7 second / 2500m 5 minute 15 second / 6000m
Cruising capacity With no publication
Practical use ceiling 11250m

Measured value in a company :
Top speed 315 knot / 3000m 333knot / 6000m
Climbing power 2 minute 50 second / 2500m 6 minute 20 second / 6000m
Cruising capacity Full power 30 minute + cruising (210 knots) 3 hours
Practical use ceiling With no publication
Note: Calculate a guess value by the weight of 3800kg.
As for the lower small table, the number of production is written.
*Name-of-an-era 17 years of Japan = A.D. 1942

shinden1974
03-04-2007, 10:47 PM
Originally posted by koivis:
Now this is what I'm talking about! The first REAL performance figures for N1K2-J I've ever seen... Remember, that ALL "official" Japanese documents show top speeds which are tested with military powew, which in their terminology means a bit higher than max. continuous (allied term), but much less than max. power (allied term=WEP)...

look closely: That's an N1K1-J or george 11, so if an estimate on the N1K2-J was ever done, it's probably a little faster (416 mph as sited in some source?)...estimates of course.

e8n1...since you interviewed the TAIC personnel, did they give an indication of how they estimated the speed? was it comprehensive taking into account the known frontal area, NACA data with engine speed and many other engineering factors, or just a guesstimate? Sometimes an estimate is better than a known 'fact'.

HarryKlein66...where did you get that TAIC report, I've never been able to even find it...pretty rare data you got there, ever send it to Oleg? think it's pf@1c.ru

shinden1974
03-04-2007, 10:54 PM
Originally posted by harryklein66:
The TAIC is indeed an estimation, and should be take for what it is.

But the the first document is :
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by A6M2b_ZERO21:
As for the Japanese table, the plan value of N1K1-J and the numerical value of the in-house test of Kawanishi are written on the data immediately after this contribution.

Guess value:
Top speed 321 knot / 2500m 348knot/6000m
Climbing power 2 minute 7 second / 2500m 5 minute 15 second / 6000m
Cruising capacity With no publication
Practical use ceiling 11250m

Measured value in a company :
Top speed 315 knot / 3000m 333knot / 6000m
Climbing power 2 minute 50 second / 2500m 6 minute 20 second / 6000m
Cruising capacity Full power 30 minute + cruising (210 knots) 3 hours
Practical use ceiling With no publication
Note: Calculate a guess value by the weight of 3800kg.
As for the lower small table, the number of production is written.
*Name-of-an-era 17 years of Japan = A.D. 1942
</div></BLOCKQUOTE>

388 mph? think this is the WEP figure for the N1K1-J? might be right.

Bellator_1
03-05-2007, 02:41 AM
The N1K2J did 595 km/h on max continuous power, so its entirely possible it did ~ 650 km/h on WEP.

The Ki-84I did 630 km/h on max continuous power, so the same aplies for it being capabale of 700 + km/h on WEP.

A6M2b_ZERO21
03-05-2007, 04:24 AM
Since he has noticed the mistake of translation of the value of the in-house test of Kawanishi, it corrects.

Mistake: 333 knots / 6000m
Correction value: 330 knots / 6000m
-------------------------------------

The speed of the official data of N1K1-J is 584km/h.

In N1K1-J to N1K2-J, reexamination of about the same design as a new style machine is performed rather than reconstruction.
It is changed except wings and a cockpit.
The body was made thin, it only carried out having stored all the guns in the inside of wings, and speed improved only by about 10km/h by official data.
I feel the doubt in this.

e8n1
03-05-2007, 05:51 AM
e8n1...since you interviewed the TAIC personnel, did they give an indication of how they estimated the speed? was it comprehensive taking into account the known frontal area, NACA data with engine speed and many other engineering factors, or just a guesstimate? Sometimes an estimate is better than a known 'fact'.

They had a team of 2-3 different people working on different aircraft (they worked on multiple at one time). The team consisted of different specialists. If I recall (I'd have to go back and relisten to the interview again) one guy was an aeronautical engineer, one was an engine specialist and they have a drafting/design person that did the "artwork" for the books.

One of the people that was stationed in Washington was a French fellow who worked in the Japanese aircraft industry pre-war in the area of aircraft powerplants.

The groups would work mainly on photos to do their main calculations. Some of the photos were as simple as overhead shots from 20,000 feet while others were from crashed jungle wrecks.

-Dave

A6M2b_ZERO21
03-05-2007, 08:43 AM
The maximum speed of N1K1-J can specify it as 611 km/h by the full missions builder
Did Oleg and others know existence of the in-company test of Kawanishi?

330 kt is About 611km/h

However, it can direct in N1K2-Ja only to 585 km/h.

harryklein66
03-05-2007, 09:59 AM
http://img.photobucket.com/albums/v296/harryklein/N1K1_01.jpg
I think this illustrate the difference we where talking before
N?1 is a Prototype ( I think ),
N?2 look like a serie model, or maybe a pre-serie?, notice the air intake under the engine cowling, the single exhaust pipe collector, the gun sight is mounted (Edit this is not a gun sight but the left hand of the pilot... http://forums.ubi.com/images/smilies/1072.gif ), but there is no wing gun.
N?3 have propulsive effect exhaust pipe.


Originally posted by A6M2b_ZERO21:
In N1K1-J to N1K2-J, reexamination of about the same design as a new style machine is performed rather than reconstruction.
It is changed except wings and a cockpit.
The body was made thin, it only carried out having stored all the guns in the inside of wings, and speed improved only by about 10km/h by official data.
I feel the doubt in this.
Yes 10km/h only sound strange

Can you help on this ? :
http://img.photobucket.com/albums/v296/harryklein/N1K_01.jpg
http://img.photobucket.com/albums/v296/harryklein/N1K_02.jpg

harryklein66
03-05-2007, 10:24 AM
Originally posted by shinden1974:
HarryKlein66...where did you get that TAIC report, I've never been able to even find it...pretty rare data you got there
the TAIC report as the Japanese data sheet come from GAKKEN Vol.24, you can oder them from specialised aviation sites.

If you are interested in the subject I recommend you, the MARU Mechanism of Military Aircraft, and the BUNRIN DO series.
Even if you can't read Japanese (as I :/ )
they are very interesting book as they have a lot of very good quality pictures, and a lot of technical drawing and blue print


ever send it to Oleg? think it's pf@1c.ru
As the TAIC data are estimations, and the japanese data are from a prototype which did not have all the modification added to the AC,
I don't think it can be usefull.

A6M2b_ZERO21
03-05-2007, 10:59 AM
Yes, as for the place to which you point, the plan value is written.
The plan started N1K1 as a sea plane.
It estimated, when about 100 km/h speed improved only by removing float in using N1K1 as a land fighter.
It was presumed from there having been A6M2-N and about 100km/h of speed differences of A6M2.
Furthermore, it was expected that 70km speed increased by changing engine into 2000H.P. from about 1500H.P.
Thus, it was guessed that the speed of N1K1-J was about 650 km/h.

A6M2b_ZERO21
03-05-2007, 01:02 PM
As for the upper table, a definition and weight of the term of the general tools of N2K2-J are written.

However, in part, since it is indistinct, there is also a place where decipherment of a character is difficult.
If you want to surely know the contents, it will translate, but it stops now.
For a lower table,
The upper left stage is the sea fighter [KYOFU] model 11 (N1K1}).
upper row right is the locality fighter [SHIDEN] model 11 (N1K1-J).
lower-berth left is the performance plan value of the [SHIDEN] model 11.
lower-berth right is the locality fighter [SHIDEN] model 21 [SHIDENKAI] (N1K2-J).

An item is the from a top.
maximum speed (kt/altitude)
Cruising speed (kt/altitude)
*(only a plan value take-off run distance(m))
Landing speed (kt)
Rise time (m / minute, second)
Cruising capacity (nm/hour) (a top is regular and the bottom is exaggerated load)
*Only a (SIDEN) model 11 is radio, radio return equipment, and those with a drops tank.(Second
exaggerated load)
Practice ceiling (m)

harryklein66
03-05-2007, 05:01 PM
Ok thanks http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif , sorry I'll make a better scann of the first table.

If I've understand correcty,from the lower table, the weight of the N1K1 is 3860 Kg a normal load, and the N1K2 is 4870 Kg at normal load.
That may explain why the difference in recorded performance is so small between the N1K1 and N1K2 depending on what make the N1K2 heavier.

KIMURA
03-06-2007, 07:34 AM
Originally posted by ICDP:
Lets compare the Ki84 with the F6F and F4U-1, both were much heavier than the Ki84 and had larger wing area with slightly higher wing loading. The power loading of the Ki84-1a (1,800hp) was around 25% better than both the USN fighters. The F4U-1 was capable of around 417mph top speed and the F6F was good for 399mph at top speed (2,250hp for both fighters). With this in mind how can it be accepted that a well built Ki84 with more power to weight and less drag than both of these fighters was slower? That is not even considering the later Ki84's with the 2,000hp engine. Granted the build quality of the late war Japanese aircraft was poor but the sim doesn't model these problems.

A good power load alone does not tell which a/c is faster that's a myth. The thing that counts is thrust and that depends on the prop-area/fuselage area ratio, propeller speed, propeller load, propeller efficiency.

On that the Corsair was superior to the either Ki-84 or N1K2-J.

Here some figure playing.
F4U-1D stats with:
1677kW (2250HP)2700rpm
Gear ratio 0.5
Engine momentum: 6211Nm
Prop hub momentum: 12422Nm
Propeller momentum@ r0.8 = 7783Nm at green aera(10351Nm @ r0.8 of the Ki-84 VDM (brown area)
Prop circular speed 282m/s

Ki-84-I Ko stats with:
1491kW (2000HP) 3000rpm
Gear ratio 0.5
Engine momentum: 4970Nm
Prop hub momentum: 9940Nm
Propeller momentum@ r0.8 = 8283Nm
Prop circular speed 235m/s


Had some minutes left to build up the situation on CAD for better showing. I took some side view of either a/c and scaled to correct measure.

At first look of calculation the Corsair seems weaker, as a result of the bigger lever arm of the bigger prop. But on 2nd look on the numbers you'll notice the Corsair has the bigger momentum at the given area of the Hayate showed with brown area on the Corsair prop and red area on the Ki-84 prop.
The green area on Corsair shows the ratio same r=0.8 ratio of the red area of the Hayate.
It seems also that the Corsair has the smaller fuselage face surface. Not to speak of the superior prop/fauselage ratio.

http://mypage.bluewin.ch/a-z/kimura-hei/compare.jpg

koivis
03-06-2007, 10:21 AM
Originally posted by KIMURA:

It seems also that the Corsair has the smaller fuselage face surface. Not to speak of the superior prop/fauselage ratio.


Umm... the as both fighters had tight-fitting cowlings, what makes you think that Ki-84 had smaller fuselage face surface??? Nakajima Ha-45 had diameter of 1180 mm, this gives the engine an area of 1,09 square meters, compared to P&W R-2800, 1340 mm, 1,41 square meters. I know that that isn't necessarily the same thing as actual fuselage face area.

I say this about 1000th time: ALL Japanese official speed values were measured using militart power. This means that the first version of Ki-84 with 1800 hp Ha-45-11 engine had top speed of 630 kph at 6000 meters. BUT the actual power with was not 1800 hp, 1800 hp was the WEP value at sea level. The rated military power at altitude was 1440 hp for Ha-45-11 (@ 5700 m) and for improved Ha-45-21 1625 hp (@ 6100 m). That's an improvement of 12 %. Now what was the WEP rating at those altidutes, respectively? The American test report posted earlier gives 1850 hp @ 5450 m which is 28 % more than the power required to achieve 630 kph (Ki-84-Ia), and 14 % higher than N1K2-J's MIL rating for 595 kph.

NOW, I'm I'm not totally wrong, it's easy to calculate new top speeds for aforementioned fighters using these values. So, HWG:
(Ki-84)
cubic root(1850 / 1440) x 630 kph = 685 kph

See? Very close to what we have now... http://forums.ubi.com/groupee_common/emoticons/icon_rolleyes.gif

(N1K2-J)
cubic root(1850 / 1625) x 595 kph = 621 kph

which is
1. a bit faster than F6F Hellcat (as it should be)
2. still slower than F4U Corsair http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Ok, why not try this with different fighters:
(J2M3)
cubic root(1785 / 1560) x 585 kph = 612 kph

Hmm... now, either the Japanese value is incorrect, or current ingame modelling of J2M is totally incorrect. (I'm guessing the latter) http://forums.ubi.com/images/smilies/shady.gif

(N1K1-J, only AI)
cubic root(1850 / 1625) x 585 kph = 611 kph

(Ki-61-I)
cubic root(1100 / 1085) x 590 kph = 593 kph

Conclusion:
N1K2-J is 26 kph (or 4 %) too slow at second blower stage (same applies to N1K1-J also)
J2M3... well, seems to be too fast by about 30 kph
Ki-84 is ok.
Ki-61-I is ok.
Ki-100, well I haven't seen any WEP power data for Ha-112-II, so any info is welcome.

A6M2b_ZERO21
03-06-2007, 10:26 AM
The upper table was also translated.

Explanation of each state

Full load
Main part(A pipe type bomb dropping machine is included)
Fixed loading thing(Parachute,Carbon dioxide bottle,Direct connection dynamo,Rechargeable battery
,Control box?)
Loading thing(Pilot,Arms,Fuel,Lubricating oil,Machine-gun firing control equipment,Oxygen breathing apparatus)

All consumption states
The state which consumed arms, fuel, and lubricating oil from the regular state.

light weight state
The state which consumed arms, fuel, and lubricating oil 50% from the regular state

Regular state
It is equipped fully with all the arms except a bomb, return direction measurement equipment, and the arms for training(However, 20mm machine-gun cartridge each gun of 200 shots).
The state which carried fuel and lubricating oil so that it might become 3800kg
The state which carried a full load in the regular state of fixed fuel[*first excess weight state?]

Second excess weight state
The state which equipped First excess weight with 1 type sky No. 3 radio return direction measurement equipment and a drops tank

Third excess weight state
The state which equipped Second excess weight with two No. 25 bombs

*No. 25 bomb = 250kg bomb
*No. 1 bomb = 10kg bomb

The item of a table becomes
"Regular excess state[regular weight state or full load?]"
"First excess weight state"
"Second excess weight state"
from the left.

It becomes
"20mm machine gun x4"
"Bullet 200 x4"
"Discharge equipment"
"Gun site"
"Bomb dropping machine"
"No. 25 bomb"
"Type 3 sky No. 1 telephone"
"Type 1 sky No. 3 return equipment"
"Oxygen breathing apparatus"
"Drops tank"
"Body front part fuel tank"
"Body rear fuel tank"
"fuel tank in wings"
"Drops tank"
"Methanol"
"Lubricating oil"
"Fixed loading thing"
"Main part weight"
"Pilot"
"All weight"
from a top.

*The text was translated as much as possible literally.
The state where there is nothing to explanation can be started, or there are two drops tanks.

JtD
03-06-2007, 10:41 AM
I'd just like to thank you for taking the time to translate the documents. It is pretty rare to get this close to Japanese documents. Much appreciated. http://forums.ubi.com/images/smilies/25.gif

ICDP
03-06-2007, 10:46 AM
Thank you for taking the time to explain this KIMURA. Not sure if I am wrong here but I was assuming the better power to weight ratio of the Ki84 meant access thrust available. Should this not mean more thrust to help top speed? I wasn't using power to weight to show acceleration but thrust available. If this is wrong then I will shut up http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Also does anyone know if the Ki84 had more drag than the F4U and F6F?

P.S. A big thank you to A6M2b_ZERO21 for translating the Japanese documents. http://forums.ubi.com/images/smilies/25.gif

A6M2b_ZERO21
03-06-2007, 11:02 AM
Originally posted by koivis:


(J2M3)
cubic root(1785 / 1560) x 585 kph = 612 kph

Hmm... now, either the Japanese value is incorrect, or current ingame modelling of J2M is totally incorrect. (I'm guessing the latter) http://forums.ubi.com/images/smilies/shady.gif



I have not seen the speed of J2M3 be 585 km/h by the data seen in Japan
The performances of J2M3 which I know are as follows.
596kph / 5450m
611kph /6000m

Bellator_1
03-06-2007, 11:29 AM
KIMURA,

Remember both the Ki-48 and N1K1-2J features a four blade prop while the Corsair has a three bladed one - except for the later versions ofcourse which has four blades.

Also where did you get the gear ratio figures from ? The reason I'm asking is that generally when you use a smaller prop you make up for that by having it spin faster, so the gear ratio would definitely have been different for the Ki-84 and N1K1-2J compared to the Corsair.

harryklein66
03-06-2007, 12:00 PM
Many thank again for the translation, if on day I can help you on something, it will be with great pleasure http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

A6M2b_ZERO21
03-06-2007, 12:48 PM
If I've understand correcty,from the lower table, the weight of the N1K1 is 3860 Kg a normal load, and the N1K2 is 4870 Kg at normal load.
That may explain why the difference in recorded performance is so small between the N1K1 and N1K2 depending on what make the N1K2 heavier.
Seemingly, in N1K1-J to N1K2-J, about 100kg is heavy.
However, there are also many dIt seems that it became heavy a little by bulletproof strengthening although it became light by the miniaturization.
ata with the lighter N1K2-J by the weight except bulletproof
If weight increase of this extent it may become faster, but...

harryklein66
03-06-2007, 01:25 PM
I have look some drawings of the N1K1 and N1K2, and it appears that the N1K2 have bigger fuel tank, I think this explain difference in weight.

A6M2b_ZERO21
03-06-2007, 05:46 PM
Originally posted by harryklein66:
I have look some drawings of the N1K1 and N1K2, and it appears that the N1K2 have bigger fuel tank, I think this explain difference in weight.
As for N1K1-J and N1K2-J together as for the built-in fuel tank it is the same at 716 liters
Supposing the tank of N1K2-J looks large, I will think that the thickness of the rubber of a self sealing will increase.
As long as the data which you presented are seen, both the plan value of N1K1-J and Regular excess state of N1K2-J think that this weight that is 3800kg would be the measurement weight of N1K series.
There are also data of "full load = regular weight."
Since the numerical value of a full load changes considerably with data, I do not understand true measurement weight.
* There is even various about 4200kg from 3700kg.

KIMURA
03-07-2007, 02:06 AM
Originally posted by Bellator_1:
KIMURA,
Remember both the Ki-48 and N1K1-2J features a four blade prop while the Corsair has a three bladed one - except for the later versions of course which has four blades.
Also where did you get the gear ratio figures from ? The reason I'm asking is that generally when you use a smaller prop you make up for that by having it spin faster, so the gear ratio would definitely have been different for the Ki-84 and N1K1-2J compared to the Corsair.

Hi Bellator
The figures I took from 3-side view from the net with poor to average quality. I'll have another work on it and rescan at home from Aero Detail Ki-84 and F4U for more accuracy. The Ki-84 Hayate (pre series of 100 a/c) suffered from bad propeller with very bad efficiency. The Ki-84-I serie got them replaced by a better one. But I guess that one was still below the Hamilton standard prop the US-a/c used.
About the thing the prop area/fuselage ratio. The thing is that a/c designers tend to apply a big as possible prop for a good ratio to the fuselage face surface, but also have attention for ground clearance of the prop. The Corsair is a good example on that. The greater that ratio the greater the efficiency, because the smaller the area the thrust flows against the cowling face area.
The other controversy about let the prop spinning faster. Fact is, that the faster an a/c should go the slower the prop has to spin. Yes you read correctly. Later and faster fighters and today's racing a/c too had slower spinning props to with bigger AoA on the prop blade. That means that the prop blade speed had to be maintained in an efficient speed range. Prop blade speed is the result of spinning speed and a/c helix speed. The faster the helix speed should be the slower the spinning speed has to be. Example of that. Racing Mustangs do fly with standard Hamilton props but with gear ratio of about 0.35:1. Compare to 0.5:1 of the war days. The Prop circular speed was put down to (IIRC) 220m/s compared to the 300m/s of the WWII gear ratio. Same on any other a/c that takes place on racings. The racing teams increase AoA (engine momentum) and decreased prop revolution.
Same the tendency on WWII engines of the last generation. R-2800 (C-series) had an increased rpm by 100 revs but a lower gear ratio of 0.45:1 compared to the B-serie with a gear ratio of 0.5:1. B-series had a hub speed of 1350rpm, whereas the later C-series made some 1260revs.

KIMURA
03-08-2007, 04:19 AM
Had some time left and corrected the appear and sizes for better match with RL. As template I took Aero Detail scans.
http://mypage.bluewin.ch/a-z/kimura-hei/compare1.JPG

In that view you can see 2 blue circles in any of these face views. The outer circle describes the propeller area, the inner the to expecting face surface ( cowling area) of the fuselage.

For comparison here the data I gathered:
F4U1-D
Propeller area: 125'036cm²
cowling area: 13'460cm²
Thrust area: 111'576cm²
Ratio propeller/cowling area 9.289:1

Ki-84-I Ko
Propeller area: 73'061cm²
cowling area: 9'269cm²
Thrust area: 63'792cm²
Ratio propeller/cowling area 7.882:1

http://mypage.bluewin.ch/a-z/kimura-hei/compare2.jpg

harryklein66
03-08-2007, 03:47 PM
Originally posted by A6M2b_ZERO21:
As for N1K1-J and N1K2-J together as for the built-in fuel tank it is the same at 716 liters
Supposing the tank of N1K2-J looks large, I will think that the thickness of the rubber of a self sealing will increase.
As long as the data which you presented are seen, both the plan value of N1K1-J and Regular excess state of N1K2-J think that this weight that is 3800kg would be the measurement weight of N1K series.
There are also data of "full load = regular weight."
Since the numerical value of a full load changes considerably with data, I do not understand true measurement weight.
* There is even various about 4200kg from 3700kg.

I have found some table in the Maru, i think they indicate the fuel quantity for the N1K1 and N1K2 (but i'm not sure ) I'll post them tomorrow, I hope this will help

Bellator_1
03-08-2007, 08:32 PM
KIMURA,

First of all let me compliment you on your graphics, excellent ! http://forums.ubi.com/images/smilies/25.gif

However if the prop is smaller you do infact usually increase prop rpm (same goes for the racers), increasing the critical AoA of the blades is another method and ofcourse a great advantage to have and does increase speed.

Remember Prop RPM = Engine RPM / Gear ratio.

Also remember a bigger prop sucks more juice out of an engine than a smaller one, which means keeping rpm's in climbs or turns will be a problem, so no, bigger is not always better when it comes to props.

harryklein66
03-09-2007, 02:46 PM
http://img.photobucket.com/albums/v296/harryklein/N1K_03.jpg
http://img.photobucket.com/albums/v296/harryklein/N1K_04.jpg

A6M2b_ZERO21
03-10-2007, 09:34 AM
Locality fighter "SHIDEN" Model 11

Name SHIDEN Model 11
Form Middle wing Single support Single engine Drawing-in landing gear
Crew member 1 person

Main size

Full-width (m) 12.00
Total length (m) 8.855
Total height (m) 4.058

Weight

Dead weight (kg) 2710

The a mount of loading

light load (kg) 703
Regular weight(kg) 1040

First excess weight

With no bomb (kg) 1181
With a bomb (kg) 1211

Second excess weight (kg) 1536

Full load

light load (kg) 3413
Regular weight(kg) 3750

First excess weight

With no bomb (kg) 3891
With a bomb (kg) 3921

Second excess weight (kg) 4246

Load

Wing loading (kg/m2) 159.5
Horsepower load(kg/HP)      2.21


Engine

name HOMARE Model 21
Quantity 1

Horsepower

Takeoff power 1990

altitude best

First stage Military/Altitude 1825HP/1750m
Second stage Military/Altitude 1625HP/6100m

Number of rotations (r.p.m)

Military 3000
Take off 3000

Manifold pressure (mm)

Military 300
Take off 450

Reduction gear ratio 0.5

Fuel

Specific gravity 0.725
Type Aeronautical 91 gasoline

Propeller

Form Metal 4-sheet SUMITOMO V type Oil pressure constant velocity propeller
Diameter (m) 3.3
Variable range 39.7 degrees or 43 degrees
Weight (kg) 203

Fuel tank capacity

Items

Left and right inside wing (l) 180 x2
Front and back inside body (l) 210+165
Drop tank (l) 400

Total (l) 1135

Main wing

Wing type LB620515-6075
Wing area (m2) 23.5

A6M2b_ZERO21
03-10-2007, 09:36 AM
Locality fighter "SHIDEN" Model 21 General particular sheet *From SIDENKAI instruction manual
Up to KAWANISHI of No. 5100

Name  SHIDEN Model 21
Form  Single engine low wing Mono Wing Drawing-in landing gear
Crew member  1 person

Main size

Full-width (m) 11.990
Total length (m) 9.346(Horizontality)
Total height (m) 3.960(Horizontality)

Weight

Regular Full load (kg) 3800
Dead weight (kg) 2710
The amount of loading (kg) 1090

Load

Wing loading (kg/m2) 162
Horsepower load(kg/HP)       2.3

Engine

Name x quantity NK9H x1

Power

Take off (HP) 1990

First military (HP/Altitude) 1860/1750

Second military (HP/Altitude) 1625/6100

Number of rotations

military (r.p.m) 3000

Take off (r.p.m) 3000

Manifold pressure

Military +300
Take off +500

Reduction gear ratio 0.5

Propeller

Form VDM 4-sheet metal constant velocities
Name N1K2J-P2
Diameter (m) 3.3

Fuel tank capacity

front part in the body (l) 270
rear in the body (l) 260
inside wing (l) 93 x2
Drop tank (l) 400
Methanol tank (l) 140
Lubricating oil tank (l) Oil 56 Air 4

Main wing

Wingspan (m) 11.990
Wing type LB620515-6015512
Wing area (m2) 23.5(It includes inside the body)
Chord length (m) 2.070
Setting angle (Angle) 4.0(Fuselage center)
top anti-angle (Angle) 6.0(It sets and is 30% line)
Twist angle (Angle) 3.25(The end of the wings which can be set)
Aspect ratio 6.13

Flap ? *It is difficult to read

Width (m) 2.605 x2
Average chord length (m) 0.56
Area (m2) 1.45 x2
Movement angle (Angle) 30
Operation Takeoff and dogfight(Envelope system)

Aileron

Width (m) 2.639 x2
Average chord length (m) 0.47
Area (m2) 1.233 x2
Flat opposition ratio 26.7%
Movement angle (Angle) Back 19?10'

Tail wing

Horizontal stabilizer

Span (m) 4.50
Chord length (m) 1.52(Body center)
Wing area (m2) 4.516
Setting angle (Angle) +1.0(Vis-a-vis the thrust line)

Elevator

Span (m) 2.157 x2
Chord length (m) 0.440(Max)
Wing area (m2) 0.556 x2(The trim to include)
Average ratio -

Movement angle

Air (Angle) Raising 21? Lowering 19?10'
Take off (Angle) Raising 33? Lowering 30?

Elevator trim

area (m2) 0.090 x2
Movement angle (Angle) Raising 17? Lowering 10?

Fin and rudder

Span (m) -
Total height (m) 1.90(Thrust line upper part)
area (m2) 1.59(Up to No. 100)
Setting angle (Angle) 0

Rudder

span (m) 0.55(Max)
Total height (m) 2.080
area (m2) 0.81(trim is included)
Movement angle (Angle) 17?30'

Rudder trim

area (m2) 0.068
hand transmission ratio 10:4
ovement angle (Angle) nose right 14?left 6?10'

Body

Length (m) 7.792(engine mount,rudder is included)
Span (m) 1.740(fixed fillet is included)
height (m) 2.640(fin and rudder is included)

Landing gear

Main oleo

Distance (mm) 180
Internal pressure (kg/cm3) 18

Main wheel

Diameter x width (mm) 600 x 175
Regular use atmospheric pressure(kg/cm3) 18

Main oleo * Why is there one more?

Distance (mm) 100
Internal pressure (kg/cm3) 26

Tail wheel

Regular use atmospheric pressure(kg/cm3) 200 x 75 (Solid)

Axle interval (m) 3.855

Three-point stillness angle (Angle) About 13?

harryklein66
03-10-2007, 11:44 AM
Thanks for the translation http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Well, so the N1K1 and K2 weight almost the same at empty weight and regular weight.

for the oleo part, I think the 2nd one is maybe the tail wheel one.

A6M2b_ZERO21
03-14-2007, 12:10 PM
The engine of Ki-84 is the same as N1K2-J.
for N1K2-J is not for low altitude.
Because the fuselage being different, is the same engine, if it makes the graph, you probably will draw the similar line.

From the measurement with USA of Ki-84-Ia it tried calculating at ratio.

Ki-84-Ia

TAIC
(Second-half mass-production type)

NORMAL 7940lb(3602Kg)
20000ft(6096m)(WEP) 427mph(687Km/h)
23000ft(7010m)(Military) 426mph(686Km/h)
21325ft(6500m)(Military) 418mph(673Km/h)
20000ft(6096m)(Military) 412mph(663Km/h)
18378ft(5600m)(Military) 405mph(652Km/h)
(Military)1695hp 20000ft(6096m)
(WEP)1850hp 17900ft(5456m)


The guess value of the speed for every height of record of Japan which did based on the above-mentioned record

IJA
(Increase experimental model No.4)
21325ft(6500m)388mph(624Km/h)
*It is measurement condition unclear, but it presumes record with the military and the full load from the fact that the above-mentioned record becomes official record
Main part weight 2698kg
Full load 3890kg

Take off 1800H.P.
20000ft(6096m)(WEP) 396mph(637Km/h)
23000ft(7010m)(Military) 395mph(636Km/h)
21325ft(6500m)(Military) 388mph(624Km/h)
20000ft(6096m)(Military) 382mph(615Km/h)
18378ft(5600m)(Military) 376mph(605Km/h)

The guess value of the speed of the measurement weight of Japan carried out based on the difference of measurement weight

Take off 2000H.P.
20000ft(6096m)(WEP) 405mph(651Km/h)
23000ft(7010m)(Military) 404mph(650Km/h)


N1K2-J is calculated from the above-mentioned guess value.

N1K2-J

IJN
18378ft(5600m) 370mph(596km/h)
*It is measurement condition unclear, but it presumes record with the military and the full load from the fact that the above-mentioned record becomes official record
Main part weight 2710kg
Full load 3800kg

Take off 2000H.P.
FULL LOAD 3800kg
20000ft(6096m)(WEP) 398mph(641Km/h)
23000ft(7010m)(Military) 398mph(640Km/h)

take off 1800.H.P
20000ft(6096m)(WEP) 390mph(628Km/h)
23000ft(7010m)(Military) 389mph(626Km/h)
21325ft(6500m)(Military) 382mph(615Km/h)
20000ft(6096m)(Military) 376mph(606Km/h)
18378ft(5600m)(Military) 370mph(596km/h)

It turns out that there are not necessarily Ki84 and a big difference.
Why did it seem that it is late 30km/h or more? The direction of N1K2-J of it was because the measurement altitude was low.

18378ft(5600m)(Military) 370mph(596km/h)

20000ft(6096m)(WEP) 370mph(595km/h)


Although it thought that the N1K2-J was heavier, in fact in a full load, there is almost no difference.
N1K2-J Maximum loading just is heavier.

Weight with about the same, the same engine. wings area of N1K2-J is larger. At high altitude the one where the wing area is large maneuverability to be good is profitable. But, inside the game as for N1K2-J high altitude performance feels more badly than Ki-84.
If an altitude is raised, he will have a feeling whose engine power is quickly lost as compared with Ki-84.

Both engine is visible to what is completely different within a game.

------------------Ki-84----N1K2-J
mixture-----------Auto-----Manual
Supercharger
change altitude---2500m----4000m
maximum
Manifold pressure +680 --- +500

*Real Ha-45-21 (HOMARE 21)
Supercharger change altitude: 3500-4000m
mixture: Auto (It can designate change as the manual)
maximum Manifold pressure: +500mm

Within a game, it is thought that the N1K2-J is heavier.
To attached Aircraft guide
It is written as "High wing loading".
At the almost same weight as Ki-84, to the wing area being larger the...

I think that wing load is the comparatively lighter one. (162kg/m2)



There is still a part in which it has made a mistake although it is not related to speed.
It is an auto combat flap.

This is made very skillfully, G sensor and a speed sensor correlate, and a flap angle moves for becoming the optimal.
When the operation switch of the automatic combat flap is turned on at high speed applying big G a little only it moves, but at low speed it moves largely even with horizontal flight.

Inside the game the automatic control cancellation switch of the automatic combat flap has not been attached.
Since only G sensor is attached it will operate in the scene which is not meant even when it is high-speed. It is a very obstructive function.

KIMURA
03-15-2007, 05:28 AM
Originally posted by Bellator_1:
KIMURA,

First of all let me compliment you on your graphics, excellent ! http://forums.ubi.com/images/smilies/25.gif

However if the prop is smaller you do infact usually increase prop rpm (same goes for the racers), increasing the critical AoA of the blades is another method and ofcourse a great advantage to have and does increase speed.

Remember Prop RPM = Engine RPM / Gear ratio.

Also remember a bigger prop sucks more juice out of an engine than a smaller one, which means keeping rpm's in climbs or turns will be a problem, so no, bigger is not always better when it comes to props.

Belator

I did not referred to RPM but on prop circular speed, that's not the same.

Bellator_1
03-16-2007, 04:56 PM
Originally posted by KIMURA:
Belator

I did not referred to RPM but on prop circular speed, that's not the same.

Well the faster the prop spins the higher the circular speed. So although the bigger prop achieves a higher tip speed pr. revelution the smaller prop makes up for this by going faster and being less prone to loss of RPM under stress.

KIMURA
03-22-2007, 08:35 AM
Originally posted by Bellator_1:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by KIMURA:
Belator

I did not referred to RPM but on prop circular speed, that's not the same.

Well the faster the prop spins the higher the circular speed. So although the bigger prop achieves a higher tip speed pr. revelution the smaller prop makes up for this by going faster and being less prone to loss of RPM under stress. </div></BLOCKQUOTE>

Well Bellator
The momentum equation proves that your statement of stress behaviour is not correct, if we're talking about the same engine which has to produce the same amount of thrust. If a prop behaves better or worse under stress depends on Kilowatt (horsepower) at a given radius of the prop. Having a prop circular speed of 260m/s (but a different rpm of the small and large prop), an engine of 1470kW and the same output of thrust, the large area prop and the small area prop behaves exactly the same under stress.

koivis
03-22-2007, 02:26 PM
KIMURA, I totally understand your drawings and calculations. But I have one question: if two propellers have same dimensions, but other has 3 and the other 4 blades, they run a same rpm, which produces the most thrust? I believe that Ki-84 & N1K2-J had considerably smaller prop only because it had 4 blades, compared to F4U-1's 3. Am I right?

Also, with almost the same hp, less overall drag, and less weight the N1K2-J had a REAL topspeed of around 611 kph @ 6000 m (with WEP), compared to F4U's 630+ kph at that height. Does this difference come from the less efficient propeller?

A6M2b_ZERO21
10-05-2007, 12:35 PM
I noticed a clear mistake of N1K2-J.
It was decided that N1K-J is adopted as a carrier-based plane from delay of development of A7M.

Attaching arresting hook to N1K3-J and N1K4-J, the test of taking off and landing was done with the aircraft carrier.
The result was very good.

Minimum standard of takeoff of the Japanese navy around 1944 is ground run 70m at wind velocity 14m/s(50km/h).

I tried in aircraft carrier Shokaku.
The rate of the aircraft carrier: 50km/h
Takeoff start position: About 70 m
(A deck is about 240 m, so it's about 70 m around the bridge from the front.)
Fuel: All 100%

A6M2-21
250kg Bomb : It can take off.

A6M5
250kg Bomb : It can take off.

D3A1
250kg Bomb + 60kg Bomb x2 : It can take off.

J2M3
60kg Bomb x2 : It can take off.

Ki-84-Ia
250kg Bomb x2 : It can't take off.
200L Drop tank x2 : It can't take off.
100kg bomb x2 : It can take off.(Just barely.)

N1K2-Ja
250kg Bomb x2 : It can't take off.
100kg bomb x4 : It can't take off.
400L Drop tank : It can't take off.
60kg bomb x4 : It can't take off.
100kg bomb x2 : It can't take off.
60kg bomb x2 : It can't take off.
Without loading : It can take off.(Just barely.)

The performance of the engine doesn't change N1K3-J and N1K4-J from N1K2-J.
Moreover it increases in the weight for reinforcement armed.

That indicated good takeoff performance.

The engine performance of N1K2-Ja is worse than the real thing.
(In particular, acceleration performance.)

MSA007
10-23-2007, 07:15 AM
Sorry for my bad English...I am a Chinese.I read a Japanese book about Ki84. Something is intresting like ki84 alway could get high octane fuel(100 in Philippine/95 homeland) to make the complicated Ha-45 engine operated well.Other planes(ki61/44/43) only have 92/87 supply in homeland defense.

So I think fuel is not a big problem on ki84.Besides I believe the real top speed of ki84 in WW2 should be 660 not 687 because the U.S. tested ki84 wasn't full load and had no painted.

blindpugh
10-23-2007, 12:00 PM
Originally posted by Marcel_Albert:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JG52Karaya-X:
As already said the Ki84 is modelled after US trials which used much higher graded fuel than what the Japanese had so it is questionable if the Hayate we have is actually representative of what a plane in front-line service could achieve. I agree more octane rating dont mean more power in an engine built for low octane fuel

Actually , it is not mate , let me explain you by a short summary http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

The engine of the Ki-84 was designed/built to deliver the expected power with the fuel they had , which was a lower octane fuel than the fuel the USAAF used for the tests .

However a higher octane fuel does make a difference , for an engine that has been built to accept a quality of fuel with higher octane , in an American engine , giving her fuel with too low octane could damage the engine for technical reasons i cannot explain well in English , you can hear small detonations when it happens .

For the case of the Ki-84 engine , the fact that you use higher octane fuel on it doesn't change anything AFAIK , it's still the same rate of air/fuel mix injected in less than 1 second going in the carburator , same rate of compression ..... it really doesn't change anything because the engine is not designed to accept higher octane fuel , engines need a minimum octane indice , but using a higher octane than what the engine has been designed for is useless , trust me this is for sure http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>

LEBillfish
10-23-2007, 03:25 PM
Originally posted by blindpugh:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Marcel_Albert:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JG52Karaya-X:
As already said the Ki84 .... I agree more octane rating dont mean more power in an engine built for low octane fuel

Actually , it is not mate , .....it really doesn't change anything because the engine is not designed to accept higher octane fuel , engines need a minimum octane indice , but using a higher octane than what the engine has been designed for is useless , trust me this is for sure http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE> </div></BLOCKQUOTE>

Not exactly true as I mentioned pages back in this thread.....Higher the octane the more difficult it is to induce combustion. That's the point of higher octane, as with the higher compression ratios, the pressure alone will ignite the lower octane fuel similar to a diesel.

So too HIGH of an octane in an engine designed for lower octane will make it run poorly. Even higher octane and it won't at all..........Don't even bother with all the stories of putting racing fuel, av gas and so on into street production auto engines....They're all b.s.. If you want a test go find some high octane fuel and put it in your lawn mower...You'll find if it runs at all it will poorly, and sooner then you realize will be fouled.


Point blank..........TAIU tests were designed to give a quick heads up of what we were up against. They were performed with planes that were most often scraped and abandoned by the Japanese, and then put back together by those with no concept of how to work on them "precisely"......Lastly, they were flown by people who 1. Didn't want to waste their life pressing a hunk of junk remade into a plane. 2. did NOT know what the proper way to fly them was 3. Did not get the chance to learn either due to time or failure of the plane (good ex. the Ki-61-Ko tested which only had 3 careful flights before the engine siezed.

Take all your data....Compare it, throw out the extremes then look it over........That's the problem both in the sim and with many books you'll even find, they single source and most often from one of the least qualified.

In the end this a moot point.....Sadly Japanese planes in the sim are how they'll stay.