Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: Vermillion on November 10, 1999, 05:49:00 PM
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Ok, just finished the Max Level Speed test for the Aces High N1K2-J Shinden.
Protocol: Aircraft was loaded with full fuel and ammo. Climbed to 1,000 ft, and set to auto level trim. Aircraft was allowed to accelerate till speed was stable (MIL power), and after 30 seconds, IAS mph speed was recorded. WEP was applied, and after speed was stable for 30 seconds, IAS mph speed was recorded. This process was repeated at 3,000ft, and every 3,000ft thereafter to 33,000 ft.
Results
(http://web.mountain.net/~arringto/ah/n1k2-speed.gif)
As can be seen from the chart, the tested IAS is averaging only 75%-85% of the IAS expected.
This result is consistent with the results of the N1K2 Climb test that I presented last week. Which also averaged only 75%-80% of the expected results.
(http://web.mountain.net/~arringto/ah/n1k2-climb.gif)
Conclusion: One of several possible problems are occuring here. 1.) The data on the AW Performance Charts that I'm basing the testing on (expected results), it total trash. or 2.) We may have a problem with the the FM of the N1K2 (If so, I would guess in the power department since both climb and speed are approximately equally effected, but pure guess though)
Pyro, could you at least tell me if the historical data is in the ballpark ??
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Vermillion
WB's: (verm--), **MOL**, Men of Leisure,
"Real men fly Radials, Nancy Boys fly Spitfires ;) "
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Vermillion,
I'll do the same with the C.205 when she'll roll out of the factory (compared with the few official data we have). Tell me if you wanna tha data in Excel format.
Greets,
Gatt
4th Stormo CT
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The only data I have gives it a top speed of 369mph and a climb to 6000m in 7 min 22sec
loaded weight: 8800-9000 lbs
From 2 sources, including the USAF museum (from website)
I dunno about those AW charts, Verm...
Firstly, they've converted whatever the original data was into knots so there could be a conversion factor error there and looking at the specs at the top doesn't seem to reflect the actual test conditions. For example, the P-47 and P-51 are listed at their gross weights where there's no way they would be as fast or climb as well as those charts say.
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Verm,
I second wells' feelings concerning those AW performance charts. Do you have any other information available?
Actually, once the FM is finalized (if that can ever really be - what was that phrase? Oh, "The older I get, the better I was." Think that applies well to our perception of WWII aircraft, especially our own fav's), we should probably focus more on making performance charts wrt AH, so that others can get pertinent information for the aircraft represented.
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129 IAP VVS RKKA
[This message has been edited by leonid (edited 11-11-1999).]
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Guys, just to check too see if there was a conversion error or something else going on, I checked the AW chart against the P-51 and Spitfire, for just a few data points. (1k, 5k, 10k)
The P-51 was almost dead on at 1,000 ft at the tested weight listed on the AW charts. Expect 362 mph, Tested WEP at 356 mph. Thats less than a 2% error, well within conversion and tested data read errors.
The Spitfire was even closer at 1,000 ft. The AW Spitfire, which had the Merlin 61, had an expected IAS mph of 330. My WEP tested value was exactly 330.
So while the individual data on the N1K2 may be suspect, the charts themselves seem to match very closely to the AH performance for at least the Spit and Pony.
Unfortunately Wells, no I don't have any better data. Hell, I challenge anyone to produce any better data, supporting or contradicting, because I would love to see it myself. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif) The N1K2 is one of my favorite aircraft, and data is very hard to get.
I however exclude single point measurements from secondary source table top reference books. We all know how inaccurate that can be, and how an error in a single book can propagate down thru hundreds. Remember the 15mm Cannon debacle for the 109?
Just for an example take that 369 mph number. What if it was originally knots, and was erroneously reported as mph, and the error propogated. That could make the top speed at altitude aprox 420 mph, which is the approximate speed of the 190D, which has a similar weight and less horsepower than the N1K2. And if you look the AW Chart for the N1K2 and convert IAS knots to TAS mph, again its in that 420 ballpark. What a coincidence !! (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
Now, thats not what I am saying happened, just illustrating that we can only rely on primary source data, especially on some of these rare aircraft such as the N1K2.
Thats why I asked Pyro, if the data was totally off, and then if so I would shut up (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif)
And then again, its possible that there is an error in the FM. Remember Gatt found one on the La5, which was too fast.
Just reporting my best data vs tested results (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif) Its all up to Pyro after that.
PS: Yes Leonid, I would be happy to help out on a set of charts for AH game performance. Organize a group of testors and I will participate.
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Vermillion
WB's: (verm--), **MOL**, Men of Leisure,
"Real men fly Radials, Nancy Boys fly Spitfires ;) "
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Error propogation:
Top speed = 400 mph.
Convert to km/h for Euro book: 1.61 x 400 = 644 km/h.
USA guy picks up Euro book, writes book using 644 km/h. 644 x .62 = 399 mph.
Repeat until number is totally hosed. (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)
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The data I have looks pretty good to me. It looks to originate from a primary source. Speed is given in knots, altitude in meters etc. The conversion factors are right on as well. Here's the data for the N1K2
Power: 1825 hp @ 1750m
1625 hp @ 6100m
Speed: 321 kt @ 5600m
Time to climb to 6000m: 7 min 22 sec
From what I understand, the engines did not develop the rated power of 1990 hp.
I will play with some numbers and see if the data is reasonable.
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Pyro, could you at least tell me if the historical data is in the ballpark ??
That a million dollar question. I'm very curious to know how HTC calculate data for a/c like the N1K2 or the C.205, their data being so rare to find out. Any hint PYRO?
Ok, ok dont mind, I'm asking too much ... (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)
Cant wait for testing the C.205 anyway.
Greets,
Gatt
4°Stormo Caccia
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Here's what I came up with. Assuming the speed and power data that I quoted is correct and using a loaded weight of 4000kg (from same source), I get a climb rate of approximately 14.2 m/s (2800 fpm) @ 19000'. This is pretty close to the green line in Vermillion's chart (expected value), however, if I use 4300 kg as the loaded weight (such as is listed in the AW chart), then the climb rate drops to 12.7 m/s (2500 fpm) at 19k, which is much closer to the red line (tested value). From this, I tend to think that the climb rate is too low in AH as well, although the speed is probably ok.
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From E. Brown "Duels In The Sky" ISBN 0-87021-063-7
Max Speed 407 mph at 19000f
Climb 4.000 ft\min
Brown has his opinions:
"Mustang IV Versus George 12
In this battle, a small edge in speed and maneuverab'l'ty belonged to the Mustang, but it had little margin for error. Its high rate of roll, giving the advantage both in attack and defense, should be the deciding factor in this cat-and-mouse game.
Verdict: The Mustang could use its all-round advantage to good purpose, but the pilot would have to work hard for victory."
danish
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While offline I see several new posts.Though I might be braking the law I might as well bring some more from Brown ;=).
"KAWANISHI NIK2-j GEORGE 12
This low midwing, single-scat fighter was developed from the Rex fighter seaplane and looked like the American Republic Thunderbolt. It was of all-metal structure with flush-riveted, stressed skin, and all controls were fabric covered. The cockpit was set over the trailing edge of the 39-ft, 4-in wing and was fitted with a blister-type canopy.The pilot had armor protection.
Model 12 had an uprated 2,000-hp Nakajima Homare 21, an eighteen-cylinder, two-row radial engine with a two-speed supercharger and ejector exhausts. It drove a four-blade, constant-speed airscrew. The fuel tanks in the fuselage were self-sealing.
Rate of climb was 4,000 ft/min. The aircraft is reported to have had barely positive stability arolind all three axes, light and effective controls, and a rate of roll somewhere between that of the Zeke and the Tojo. It does not appear to have been quite as maneuverable as the Hellcat more on par with the Corsair.
The predecessor model 11 with a top speed of 315 knots (363 mph), had been much used in the defense of Formosa. Model 12 had a maximum speed of 353.5 knots (407 mph) at 19,000 ft. Range was 929 rim (1,070 statute miles).
Armament consisted of four 20-mm wing cannon and two 7.7mm machine guns in the fuselage, synchronized to fire through the airscrew.
Assessment: The George 12 was a high-quality, high-performance fighter that appeared too late and in too few numbers to influence the course of the air war. It was well armed and protected-the Japanese having learned from their combat experience against the Americans."
Wells: the low engine output you report, was that a result of declining industrial quality?If so the concensus on these boards have been to accept the "what if" top notch quality - as you know better than anyone ;=)
danish
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Thanks for the info Danish!
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It does not appear to have been quite as maneuverable as the Hellcat more on par with the Corsair.
I hate the term "maneuverable." To my understanding, in the hands of a good pilot, the F4U was much MORE maneuverable than the F6F. Better zoom, better roll, higher top speed, at least equal in initial dive I'd suspect. To me, a turning circle does not equate to maneuverability. Damn I hate the use of that term! It's fewkin' useless... if not outright counterintuitive.
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Wells - I had a brief discussion with Manx at the con. He can read Japanese and has quite a library. He indicated that the Ki-44 was probably the fastest Japanese fighter in the field because the Homare (Ki-84 and N1K engine) did not live up to its ratings.
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My info tells me the N1K2 does 363 MPH.
Mino
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Ok guys here is an example that I was thinking of the other day, about the differences in secondary "references".
Look in just about any book, and see what the top speed of the Ki-84 is, remembering it has the same engine as the N1K2.
Complete Book of Fighters, lists the Ki-84's top speed at 388 mph, at 22,000 ft.
Janes Fighting Aircraft of WWII, lists it at 426 mph, at 23,000 ft.
Francillon's, Japanese Aircraft of WWII, in the technical section lists it as 392 mph at 20,000 ft.
And most of the others books we use as references lists the Ki-84 in that 380-390 range. So most of us would discount the Jane's number and claim the 380-390 number as "correct".
But then if you read Francillons description section at the very end, he tells of how a captured Ki-84 was tested at the Middletown Air Depot, in Pennsylvania, in 1946. In this test the Ki-84 reached a speed of 427 mph at 21,000 ft.
So which is right?
Even Francillon who's book is considered one of the definite desktop references on Japanese WWII aircraft, contradicts himself and ends up with a supporting number for each range of max speeds.
This is why I'm very leary of discounting the AW chart data, which supposedly comes from primary source data, for data we dig out of secondary source desktop reference books.
Even the best of these types of books contradict themselves.
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Vermillion
WB's: (verm--), **MOL**, Men of Leisure,
"Real men fly Radials, Nancy Boys fly Spitfires ;) "
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Another option is to compare to an aircraft of similarity where more data is known. (ie F4u, F6f)
The R-2800 puts out 1650 hp @ 21k and the Homare 1625 hp @ 20k (pretty darn close).
The F4u has substantially more wing area than the George (drag), and the George is at least as aerodynamic as an F4u. There's nothing really obvious sticking out on the George that would slow it down significantly. There's no reason it shouldn't be as fast as an F4u. However, it does seem to have a much smaller diameter propeller than the F4u and that will reduce efficiency a bit. I measure 3.3m for the George compared to 4.0m on the F4u.
This reduced thrust efficiency is offset by having less wing area and there's no reason not to expect the George to hit 400mph.
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Is it possible that the 380-390 rating is based upon the performance that the Japanese got out of it (keeping in mind their fuel and engine problems), and that the 420-ish rating is a result of what the Americans got out of it in post-war testing (using better fuel)?
And, if so, which one should be depicted?
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SnakeEyes
o-o-o-
=4th Fighter Group=
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Exactly SnakeEyes
That very well could be the problem.
In these games in the past, every aircraft is modeled as in "perfect" condition, so in my opinon you would use the higher results.
Even the American aircraft are modeled off of perfect test aircraft, under perfect maintenance, with good gasoline.
The US planes in the field wouldn't perform up to that rating either, so Its my opinon that you would have to do the same for other nationalities.
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Vermillion
WB's: (verm--), **MOL**, Men of Leisure,
"Real men fly Radials, Nancy Boys fly Spitfires ;) "
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Tis true... of course my argument would be that, if the enemy planes were that close to ours in terms of performance, we would have sped P-47N & Ms, P-51Hs, Tempests, and F8F-1s to the field much faster than we did. Of course there's a very large contingent that refuses to accept these aircraft for various reasons.
Shrug... I suppose it's just a huge pet peeve of mine. My thought is that if you're going to model an aircraft that had substantial flaws in a manner that make that plane perform to its theoretical ideal, it only seems fitting to include the aircraft that would have theoretically been rushed to the front to counter such a threat.
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SnakeEyes
o-o-o-
=4th Fighter Group=
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arrrgghhhh.... tho it pains me
<punt>
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Vermillion
WB's: (verm--), **MOL**, Men of Leisure,
"Real men fly Radials, Nancy Boys fly Spitfires ;) "
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Part of the reason the Super Hot allied aircraft weren't rushed to the front was....
Cause they weren't needed.
On The History Channel the other night they talked of the Allied numbers of better than 10 to 1 over the Luftwaffe.
I have heard, that in the Pacific there were like 60 to 1 odds, of course in range to strike Japan were closer to 3 to 1. (Theatre wise you include South East Asia, Australlia, Indochina, China, the Phillippines, the Marianas, Etc. there were a lot of planes in the Pacific, but they weren't all a direct threat to Japan.)
I guess the thing we need to know here is what Pyro and HT used for reference material.
My guess (Er, should I have said that?)
take all the numbers you can find, add them together, and then divide by the number of numbers you initially used. That is how you get an average.
I certainly hope that he didn't use AW Charts, cause that would be plagurizing from another sim.
I have no data on the performance of Japanese Aircraft, wish I had a source and it was different from yours.
Personally I would go with the Janes Numbers.
So, er, um, Pyro, HT, What numbers did you use?
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"I could feel the 20MM Cannon impacting behind me so I made myself small behind the pilot armor" Charlie Bond AVG
lkbrown1@tir.com
http://www.tir.com/~lkbrown1 (http://www.tir.com/~lkbrown1)
Very Opinionated Person.
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Well I know Pyro didn't use the AW Charts for two reasons.
One is that there isn't enough data there to make a FM without doing alot of guessing.
Two, is that the AW charts were made from data that is readily available in the US from FLight Tests of captured Georges. So he didn't need too.
The Airforce & the Navy both had a George they flight tested and they're currently in their respective musuems.
So if you know which documents to request from them, you can get the info from the government thru Freedom of Information Act requests (FOIA). But the trick is knowing what the documents are. I would love to order copies of these original documents.
But I agree Downtown, I would just like a yes or no on the issue of, Is the chart data correct or is the FM correct ?
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Vermillion
WB's: (verm--), **MOL**, Men of Leisure,
"Real men fly Radials, Nancy Boys fly Spitfires ;) "
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Hey Verm,
I can't answer for how another game models their planes. I have seen a TAIC report on the N1K1 that showed performance similar to what you cite, but it's just an intel report where they try to ascertain the enemy's capabilities. In the particular report on the N1K1 that I read, they found a wrecked George in the Phillipines and examined it. They then made some estimations about the planes speed, climb, ceiling, range, payload, etc. It's not based on flight-tests or anything like that. It's just first line intelligence and I imagine they erred on the high side to make sure they don't get a nasty surprise.
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Doug "Pyro" Balmos
HiTech Creations
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Thanks Pyro appreciate the information.
PS: Whats the TAIC acronym? Don't recognize that one.
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Vermillion
WB's: (verm--), **MOL**, Men of Leisure,
"Real men fly Radials, Nancy Boys fly Spitfires ;) "
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FYI, there was a recent article in `Flight Journal' Magazine, written by a former Grumman Test Pilot. He reported on flying the Hellcat and the Corsair. I suggest anyone interested in comparing the two, read it (I believe it is available in back issues, and the article was within the last 4 or 5 issues. Just look for the one with the article about the Grumman testpilot.)
http://www.flightjournal.com/ (http://www.flightjournal.com/)
Navy Taste Test
Feature by Corky Meyer
December 1998, pg. 44
(Hellcat vs. Corsair)
Up is not Always Easy
Feature by Corky Meyer
April 1999, pg. 56
(When the noise stops and gravity takes over)
Hope that helps.
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TAIC = Tactical Air Intelligence forgot what the last word stands for. They published a bunch of intel reports on estimated enemy plane capabilities.
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Doug "Pyro" Balmos
HiTech Creations