J2M Raiden

[krieghund]

People please. I understand the Hellcat trumps the J2M in combat and apparently in conversation popularity now. I know well enough about the Hellcat already. tnhe purpose of this thread was to get opinions on whether or not the J2M could be put up against planes other than its typical USA opponents

HOLD THE PHONE!!! My previous posting FIGHTER COMBAT COMPARISON ; F6F-5 vs J2M3 combat comparison report between the F6F vs J2M3 here: http://www.ww2aircraft.net/forum/fli...2m3-26637.html (F6F-5 vs J2M3) I believe answers the question that the J2M3 kicks butt!

However, this comparison is not equally paired up. The two fighters are designed for two different missions. The Raiden can't do the Hellcat's mission and the Hellcat is not as good as the Raiden for the point defense interceptor mission. I believe the better match up would be the Ki-84 against the Hellcat or even the N1K1-J as they would have been encountered more frequently.

To plainly answer your question, the J2M3 when functioning adequately would be superior to anything in the US inventory from medium to low altitudes until the advent of the Bearcat or the Seafire 47. This relates to the performance of the aircraft and doesn't address maintenance difficulties, training shortfalls, and other mitigating factors at the time of the Raiden's introduction. If you wish to use those factors then the question is answered by history already.

 

[renrich]

I find it extremely doubtful that the Raiden, based on performance numbers was superior to the F4U4. At SL it could do 380 mph which according to Dean, AHT, was the best that any US WW2 fighter could do and at altitude it could get almost 450 mph. At combat power and SL it's climb rate was almost 3900 FPM. It was a superb gun platform, had a very high roll rate and was a great maneuvering fighter( not talking about rate of turn.) It could carry six 50s with lots of ammo and the F4U4B carried four 20 mms with lots of ammo.

 

[Sagittario64]

once again my point has been missed. i know how the hellcat and raiden stack up against each other. what im wanting to know is, if a yak was superior to it or was a 109 inferior to the raiden? pitch these and other european aircraft against the raiden.

 

[CORSNING]

krieghund,
Thank you for posting the sight on manuals. Awsome find buddy. I punched it up and shelled out the best $31 spent in quite a while. Thanks again, Jeff.

renrich,
The F4U-4 maximum TASs were 383mph/S.L. climbing to 464mph/20,600ft. See www.wwiiaircraftperformance.com. Click on F4U and scroll to the bottom and click on F4U-4 performance summery. The -4 initial climb: 4,770fpm gradually climbing to 4,825fpm just over 10,000ft. The J2M3's (according to 105B) maximum speeds were 359mph/S.L. climbing to 417mph/16,600ft. (F4U-4 at 16,600ft= 433mph). The Jack 21's initial climb: 4,835fpm climbing to 5,000fpm just over 4,000ft. U.S. pilots that flew the J2M3 praised its handling up to 325mph. I do not know exact roll rates of the J2M but in the compairison against the Hellcat it was found to have quicker response. I do not have exact figures but have formed the opinion that at low and medium altitudes and speeds these two fighters were close enough in performance that the pilot skill and luck would be the determining factor in a close in dogfight. At high speed or high altitude the fight would be a whole different game where I believe the F4U-4 would hold a fair advantage.

Sagittario64,
My files are at home so I'm going to have to use my memory (this ought to be good). The Yak-3P with 3 x B-20 cannon did operate against the Japanese in the closing months of the war. It could climb initially: 4,450fpm and had a maximum speed of 401mph (16,400ft.?) and a sea level speed of 350mph (?) The VVS considered it to have a roll rate equalling the FW-190A and at medium and high speeds (up to about 360mph) to be able to outturn most anything. It was considered to have a very high combat speed (see N. Golodnikov). It was a very quick and responsive aircraft. If pilots of each aircraft used their planes best qualities I believe the outcome of combat would be close. If you would like to learn more about the Bf.109's capabilities check out Kurfurst's sight. Its an awsome sight filled with 109 information. I am going to refrain from posting my opinion of the Bf.109's capabilities because I have only recently started to research it's capabilities and there are a lot more people on this sight with much greater knowledge of this aircraft at this time.

 

[vanir]

Just tossing out there off the top of my head, the 109 will get trumped in every area except two: performance generally above 6000 metres, and dive. Every other area you'll have to work very hard, but all late war fighters from every belligerent nation are competitive with only a few exceptions. Spits, US types, Russian, German, Japanese all very very good planes. The problems, the advantages, they were industrial and achieved by strategic superiority for whatever reason, sometimes luck, sometimes disadvantage.

 

[renrich]

Corsning, your post really illuminates how performance tests vary from one source or another. I think the different numbers are the result of different test conditions, load, exterior conditions, climatic differences, perhaps fuel, individual aircraft, etc. My figures I quoted came from Dean, AHT, which I regard as kind of the bible on WW2 US fighters. The handling qualities come from Boone Guyton, Vought test pilot and Linnekin, "80 Knots to Mach Two," who flew the F4U4 operationally, as well as the F6F5 and F8F. He rates the Corsair, overall, the better handling AC over the Hellcat and Bearcat. To me, with equal pilot skill, the numbers indicate that the Jack would be at a disadvantage at all the above.

An anecdote, which illustrates how important pilot skill was in ACM. Guyton, who probably had more time in a Corsair than anyone living and who was an ex USN pilot flew in a mock dogfight in 1944, against a Marine ace in another Corsair. The Marine had the standard 10 gallon water tank for WEP where as Guyton had a 60 gallon( from memory) tank. Guyton tried every thing he knew and the Marine waxed him every time.

 

[CORSNING]

renrich,
I agree with you 100%. I believe the Corsair had the edge overall in the horizontal plane and the J2M3 had a slight edge in the vertigal (at lower levels).
When I research a particular A/C, I strive to find out the absolute limits of a combat ready A/C in interceptor/air superiority mode. The amount of boost level used and everything you mentioned all have a direct outcome on the final performance figures. I have always felt if you are going to compare an interceptor (Yak-3, Spit XIV, J2M3, Ki.44...etc.) to a fighter bomber or escort fighter (P-51, P-38, P-47, F4U-4..etc.) it can only be apples to apples if you equip the latter in their lightest combat mode without pylons and shackles. This unfortunately is not how they met in combat but is a more true representation of the individual A/C's comparative performance. Many fighter A/C were handicapped because of the necessities of war (FW-190G) and the gunship Bf-109s. Utilization was everything in a battle in order for victory. What happened where in WW2 I leave to the historians. I am more interested in what the aircraft was actually capable of IF it was properly manufactured/maintained. The Ki.84 had to deal with a lower grade of fuel. I strive to find out its true capabilities in good condition with this fuel and not all the conditions it had to suffer under (poor construction by unskilled workers, poor maintenance from lack of parts). I would really like to get my hands on a technical performace report of the Ki-44-IIIa with the 2,000hp. Nakajima Ha. 145. It had an increased wing (204.514sq.in) and enlarged tail surface. The Ki-44-II had a max. climb of 4,286fpm at 6,888ft. the -III must have been a sky rocket............Ahaaaaaaaaa, I went and got off topic, didn't I......sorry.

 

[CORSNING]

vanir,
Now you went and did it. You got me curious about the 109 so I strolled over to the Kurfurst sight (awesome by the way) and looked up the 109K-4. Best I can tell the true limits of the K-4 in combat ready gear is as follows: Max. Speed: 377mph/S.L. 396/3280ft. 413/6560ft. 423/9840ft. 432/13,120ft. 442/16,400ft. 452/19,352ft. 447/19,680ft. 449/22,960ft. 437/26,240ft. Max. Climb: 4,723fpm/S.L. 4,880fpm/2,625ft. 4822/3,280ft. 4,625/6,560ft. 4,428/9,840ft. 4,310/13,120ft. The 109 used MW-50.
The Bf.109K-4 had a definite maximum speed advantage at all altitudes and good handling up to 325mph (max. combat speed?) Its climb was close enough for close in fighting at very low altitudes and it eclipsed the climbing ability of the J2M3 just over 6,000ft. The Jack may have outturned the 109 under 20,000ft. but the leading edge wing slats of the 109 must have made it close.

Sagittario64,
Sorry I got carried away. Any plane can beat another fighter if the pilot skill difference is great enough or if a pilot is taken by surprise. But on equal terms, and if the pilot uses the best abilities of his aircraft you can cross off the Hurricane, Typhoon, Lagg-3, La-5FN, IAR.80, D.520, Mosquito, Yak-1, Yak-7 and probably the Mig-3 as being contenders with the J2M3 or even J2M2. The performance levels are too great. I'll have to do more digging to comment on the Spitfire 14, FW-190D, Yak-9U, Tempest, 2005 and MC.205. I read the post on the P-38L vs J2M3 and I believe the contest between them was a lot closer than the conclusion of that post noted.

 

[vanir]

The epitomised performance figures for the K-4 are commonly swung favourably by enthusiasts of this bird and given for the 2000PS engine at 1.98ata of which no conclusive evidence exists being in service, and it was not cleared for service until the last few weeks of the war. Most units operating the K-4 were at airfields that were only receiving B4 fuel, and operated them alongside Doras. They had to be the 1850PS 1.8ata version.
Two airfields notably operated K-4 in March 45 and were receiving C3 fuel only, they operated alongside Fw-190A/F types. These may very well have been the 1.8ata 1850PS motor as it could use either fuel interchangeably and nobody has yet provided evidence that they indeed operated at 1.98ata.

So you need the figures for the DB-605DB engine for K-4 aircraft, at 1.8ata overboost calibration. Still from aces, what I've arrived at is Erla G10, fastest of the wartime 109, around 425mph often seen in the field or about as fast as a Mustang but of course they have completely different handling personalities and flying qualities. Räll said the Erla G10 had no trouble exceeding 400mph, but it was the only one which could. Still, if someone said what about the K he very well might've said, oh yes the K too. That's the thing about personal stories.

K models were heavier than a G-10 in clean fighter configuration in any case from all repute. A dutch team did a nice research project on Erla G10 and late series G14/AS using the 605ASB motor (which is virtually identical to a 605DB but has a different blower). K models were serially fitted with all the rustätze equipment, just not the external fittings unless you specified the installation (but they actually could be fitted or swapped in the field where the Gustavs had to have it done at the factory despite nomenclature). No idea what else but it's pilots who said it was lighter and fastest and they're pretty believable. Oh I think the K had more oxygen bottles in the starboard wing too, like twice as many. The Dutch confirmed reports before such evidence existed and all we had was the word of the vets, so that's doubly convincing.

 

[CORSNING]

Thanks for the info vanir. See there, you proved my point. There are several people on this sight that know a heck-of-a lot more about the Bf.109 than I do. I'm more of a Russian, Japanese and U.S. aircraft type of guy.

 

[renrich]

Here is another factor which most of us either ignore or either are unaware of. The R2800 powered a lot of US AC including the Corsair, Thunderbolt and Hellcat. The Corsair was in combat in February, 1943, the Thunderbolt in April, 1943, and the Hellcat in August, 1943. The R2800 was a good engine, almost legendary for power, ruggedness and reliability. The vast majority of pilots at the 1944 Fighter Conference picked the R2800 as their favorite. The P47, when it became operational was plagued with many problems. A lot of them crashed. The Corsair had many teething problems, including engine issues. A number of times test pilots had to abandon burning Corsairs or were forced to dead stick land or were killed.

Get this! In March, 1943, (look at the dates when the above fighters went into combat) Boone Guyton and Vought were still trying to ferret out the problem which caused number thirteen cylinder in the R2800 to overheat, seize up and blow the engine. The engine in the Corsair, number 02157, Guyton was flying was all instrumented. At 25000 feet a full power run was begun. Guyton leveled off at normal power and began a shallow dive to 24500 to shorten the time spent at military( not combat) power. After four minutes, military power, he was approaching the speed designated for the test. The temperature of number thirteen was nearly 260 degrees, the limit. A little shudder, he grabbed the throttle, prop control, the engine blew, oil covered the canopy, the plane caught on fire. He thought he could make the runway but did not quite make it. He was in the hospital three months and was lucky to live.

Here is the point. The R2800 turned out to be a good engine but in 1943, it still was troublesome and our fighters were flying with it. Eventually that problem with number thirteen was eliminated and the F4U4 could with water injection use 75 inches of MP, safely. On this forum, we talk about this or that wunderairplane, the TA152 and many others and we quote all these performance figures we get from books or online. Maybe those performance figures are true or maybe not. But could those performance numbers be produced in production airplanes with production engines, over and over again, safely? If not, comparing those wunderairplanes to the proven models does not make much sense.

 

[fastmongrel]

Get this! In March, 1943, Boone Guyton and Vought were still trying to ferret out the problem which caused number thirteen cylinder in the R2800 to overheat, seize up and blow the engine.

renrich what was the problem with the 13th cylinder and how was it sorted. Also how were the cylinders numbered.

 

[renrich]

FM, in his book, he did not describe what the problem other than it overheated, was, or how it was corrected. He had several engines blow while he was flying the Corsair. From memory I believe number thirteen was on the aft bank of cylinders. His book," Whistling Death" is a good one. Guyton was six feet four inches and was a star football player in college. The engine had lots of teething problems during the development of the airplane and the Corsair kind of blazed the trail for the later use of that engine in fighters since it was among the first AC to use the engine and both Vought and Pratt and Whitney were owned at that time by United Aircraft.

 

[GregP]

Sagittario64,

There is no account of a J2M Raiden going up aginst the Me 109 or other German fighters. The data on the J2M that remains is self contradictory. Many sources cannot agree if the climb rate was 2950 feet per minute, 3900 feet per minute, or 4800 feet per minute. These same self-contradictory sources don't even say if the quoted climb rate is the initial climb rate, climb rate at, say, 5000 feet or 25000 feet, and the rate of roll is not published anywhere I have been able to uncover with any degree of relaibility.

Our museum does have a Raiden, and it is a very good-looking aircraft. That doesn't mean we have a reliable flight test report on iot that details the real-life performance of it. I have heard talks given by pilots at the time who said that some of the evaluation pilots were VERY biased and didn't report accurately on the performance of captured equipment because they wanted history to think otherwise. So, we were warned not to believe all the flight test evaluation reports.

That leaves me in a bit of a quandry. Which tests ARE a reflection of real performance? I don't even believe we have more than a very few tests of the J2M to look at.

What we have left is a description of the basic aircraft weight and power, the fact that it used a rather short, 4-blade propeller, and a few combat reports.

I, for one, decry simulators becuse many people seem to feel the sims are a good indiction of real performance! Not ture. The sims give a decent indication of the equations used by the progrtammer, and if we cannot find a real performance analysis, what makes you think the programmer could? Sims are games, pure and simple, and have nothing whatsoever to do with flying a real warbird. I sometimes fly WWII simulators for fun, and you can easily pull full aft sick at high speeds. Thry that ina real warbird and you will break the plane or break up first.

I'm afraid this question, which is interesting to me, will have be left in the area of conjecture. What we DO klnow is that the Raiden was a pretty good performer when it was running well. We also know that probability of any particular Raiden running well at a point in time when it needed to do so was less then stellar. Still, a good design from the designer of the Zero, that was put into production less than completely successfully, through no fault of the designer.

 

[krieghund]

It would appear the only way to get an accurate performance would be to use a software program such as "Basic Aircraft Performance" by Sid Powers (KERN International, Inc) which requires the input of all physical parameters of the aircraft in question. Of course it was originally designed to compute jet aircraft performance but it does an excellent job of drag prediction. It just takes so bloody long to input the parameters and it is a Basic language program.

I have included the output samples from this program, One for the J37 Viggen and a Cessna 172.

 

[barney]

renrich what was the problem with the 13th cylinder and how was it sorted. Also how were the cylinders numbered.

I don't know what the problem was with the 13th cylinder either. However, in a general sense, I believe I can explain what was going on.

The Pratt Whitney R-2800 was the first air cooled engine to produce more than 100 horse power per cylinder. Engineers in the 30's believed that 100 horse power per cylinder would never be achieved. The problem was cooling. That, and back when the design of this engine was begun, the quality of the fuel was not good. But, mostly, it was cooling. You have to have sufficient fin surface to dissipate the heat.

So, on a tightly cowled engine, as was the case with the F4U, air for cooling would be at a premium and careful baffling would be required. I can imagine problems arising here as bugs were worked out.

 

[CORSNING]

I coudn't locate any report specifically directing the overheating problem of the R-2800 to the 13th cylinder (that doesn't mean it doesn't exist). I do know that a lot of the cooling problems were corrected by replacing the cast cylinder heads with forged heads allowing deeper, closer-pitched cooling fins. Ganged slitting saws following cams were used to creat the correct depth and pitch for the fins. This substatially increased the cooling fin area and heat rejection capability of the engine.

 

[Sagittario64]

Greg and corsning i thank you for your professional opinions. It seems that there are too many factors to come close to a definitive conclusion, the validity of test data included.

 

[CORSNING]

Sagittario 64,
Sorry I took so long to get back to your original question. I have moved all my files and books to a new room in my house and they are a complete mess. The holidays took a lot out of me also.
I pulled what I had on the Spitfire Mk.XIV and did a side by side comparison against the J2M3. The Jack 21 compares favorably up to about 20,000ft. The Griffin Engine just proved to be too much after that. I used power figures from the Griffin 65 at +18 boost sinse that was the boost used from January 8, 1944 to March 21, 1945. The Jack has the advantage in power loading 3.77 lbs./hp vs. 4.15 lbs./hp. The Jack has the advantage in wing loading 33.89 lbs./sq.ft. vs. 35.1 lbs./sq.ft.
Don't have time now to post all the figures, but if your interested I could post them this weekend. I'm still trying to find all my info on the Tempest, MiG, La-5FN, La-7., Yak-3 9U and MC 202.

 

[GregP]

Renrich,

From several pages back (sorry, I was moving ...) the WWII pilots would know if the data got transmitted because they got answers from back home of disbelief. How would they know the performance? Easy, they fought with them and could either catch or not catch the enemy, climb with or not climb with the enemy, etc. Their talks are of the lecture variety, not Q&A, but if you come down when we have these pilots give their talks, you can always ask them yourself.

One of our guest speakers was Corky Meyer, Grumman test pilot. He says the F6F and the F4U performed almost identically. They had the same engine, same prop (at least in the F4U-1 variant) and equivalent frontal area. The only real difference was the fact that Vought use ram air and Grumman did not due to concerns about carb icing. According to Corky, it you flew an F4U-1 and an F6F-3 side by side at identical power settings, they would cruise right together except in the main stage due to ram air in the Corsair. He says if you ran them in any other stage, side by side, at the same power one or the other would usually gradually pull away, and it wasn't always the same aircraft.

He stated categorically that the Vought Corsair had what he called an "optomistic pitot-static system" and always indicated a bit faster than the Hellcat even when they were flying side by side.

Many of the veteran WWII pilots from the Pacific have a great respect for the late-war Japanese aircraft. I say "respect," not affection ... I see someone above quoted the J2M3 as having a climb rate of 3900 fpm. We have heard anywhere from 2950 to 4800 fpm from WWII combat veterans for the Jack, and they said it was "very fast and could disappear vertically with ease." I believe the 370 mph was, in fact, a sea level speed at conservative power. It could easily have been a major player in Europe if deployed there ... just my opinion. Yours may vary.

The J2M, Ki-84 and Ki-100 were as good as anything we had. Ask anyone who fought them; I have and that's what they said. Add the N1K-2J Shiden to the list, too ... the only great fighter developed from a floatplane.

Vanir touched on something that has been my thought for a LONG time. Top speed is not exactly important. Combat speed is important. Top speed is almost never actually achieved. Combat speed and the ability to climb and dive to engage or disengage combat is important, as is maneuverability. Top speed is for factory test pilots. Almost nobody else pays any attention to it. Military pilots almost never attain the listed top speed without facing difficulty for aircraft abuse. The Military wants to fly their planes for a long time, not wear them out in a few flights. It's Ok to pull some g's but, if you over-g a plane, you are in for a tough time from your commander.

Take the McDonnell F4 Phantom. Officially it is a Mach 2.5 aircraft, and can do that if you configure it right, fly it clean except for a couple of sidewinders, and follow a specific flight profile. In real combat, it is a Mach 1.6 - 1.8 airplane. Big difference, huh? And most Phantom pilots never SAW Mach 2.5 ... they saw Mach 1.6 - 1.8 or so, max. particularly if carrying drop tanks. Ever see a pic of a Phantom without drop tanks? If so, not many. It's fuel flow is like a small creek.