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Best/worst mass-produced late WWII fighters
GastonMarty
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Quebec, Canada
Joined: April 19, 2008
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Posted: Wednesday, January 29, 2014 - 06:36 PM UTC

There was a recent series of post on Hyperscale commenting the rankings offered by Robert Farley on the "National Interest or Real Clear Politics" website. I didn't think much of them (particularly how broad they were), so I thought I would do my own, since I did re-design a game around a specific period over fifteen years of research, and I had never really considered ranking them...

The game design I used has fairly crude mechanics, which can only "summarize" the prolonged turning battles that are so common in European late WWII dogfights, but I still feel the game's Data Cards give an appropriate comparison within their limitations... (I did all the graphics, including the small 1/144 scale side views, given the horrible accuracy of most small side views!):

http://boardgamegeek.com/filepage/97109/advanced-air-force?

The ranking below considers propeller fighters designed for air superiority, and a priority is placed for medium-low altitude air superiority at the exclusion of other considerations. Only propeller types with over 1000 in service during WWII are considered, except for the Ki-100 (a development of the Ki-61), which I felt deserved inclusion. This does not include range as a major consideration, unless drastically short. The time period considered is strictly from early 1944 to the end of war, so only types predominantly associated with that period, in the specific role of air superiority below very high altitudes (below B-17G bomber interceptions, but somewhat closer to typical B-24 cruising altitudes: 20-24 000 ft.).

It is important to note I considered most test flight evaluations of the period to be not predictive of in-combat performance. Surprisingly often, their conclusions are the exact opposite of observable real-life combat tactics, a prominent example being the US Navy's evaluation of the FW-190A, whose conclusions are the exact mirror opposite of the Soviet 1943 "Red Fleet" front-line tactical evaluation article: I think based on the US Navy's FW-190A combat experience, it is wiser to go with the Russians on this one... The quality of evaluations tends to be even poorer in tests involving foreign-built fighters, but it can also extend to domestic fighters: Several US evaluations claim quite confidently that the Merlin-engined P-51 out-turns in low-speed sustained turns the P-47D (at least one German test pilot makes similar claims in favour of the Me-109G over the FW-190A!)... The reality of combat is very consistently in the opposite direction, regardless of who is piloting, and the margin is often surprisingly large, all things considered...

One exception on the Allied side is a 1944 test comparison of the FW-190A and the P-47D, done in Italy by US front-line fighter pilots: Extremely detailed and accurate, and very congruent with combat accounts. As is the German KG 200's evaluation of an underpowered needle-tip prop Razorback P-47D: "The P-47D out-turns our Bf-109G" ("On Special Missions: KG 200"): Abundantly congruent with thousands of actual combat reports, including at low speeds and low altitudes... In fact, the P-47D is documented as matching, or out-turning, in level turns, the Me-109G near the ground ("on the deck") even when carrying two 1000 lbs underwing bombs while dogfighting (Osprey, P-47 Thunderbolt units of the 12th Air Force, p. 32)... The Me-109G and the Merlin P-51, on the other hand, are so closely matched that 15 minutes turning matches (45+ consecutive 360s to the same side) are not unheard of, including one claimed of 30 minutes(!)... Me-109Gs out-turning slowly P-51s is also not unheard of, if the P-51 does not use flaps, or, more importantly, if it does not reduce its throttle after speeds have reached their lowest point (as opposed to lowering the throttle to slow down when going too fast, which is not the same thing). Typically, the P-47D will reverse a tailing Me-109G in one minute (roughly 3X 360) at any altitude, and there are numerous combat accounts to support this... I know of no instances of the Me-109G sustaining low-speed turns better than the P-47D...

To rank the fighter types, the proper place of dive and zoom tactics is considered realistically: In reality "dive and zoom" was mostly confined to the use of a high speed dive from a superior altitude, typically followed by a short sharp turn rather than a zoom... Dive and zoom is notably rare in late war Western Front skies...

Contrary to the widespread assumption that most WWII fighters were shot down unawares from behind, in practice it doesn't take reading thousands of combat reports to see that this is not common at all... Even the supposedly blind Me-109 is rarely caught unaware... Diving attacks followed by zooms are even rarer, and seem confined to specific types in specific theaters: P-38s vs Japanese fighters in the Pacific, Me-109Gs versus Russian types on the Eastern Front, or versus slower-climbing British types on the Mediterranean Front, and, most remarkable of all, the Spitfire Mk IX/XIV versus Luftwaffe types on the late-war Western Front... A centralized armament, or at least far-reaching powerful guns, seem a pre-requisite for effective diving air-to-air attacks, which tend to be easily foiled by turning, and don't give much of a chance to "pepper" the targets for a long while with multiple hits from a stable distance...

It is very obvious, from hundreds of accounts, that the Spitfire M IX's "redressing of the balance" vs the FW-190A was achieved mainly by using superior altitude to generate high speed dives, followed with short sharp turns: The use of diving speed from a higher altitude is more obssessive on the Spitfire than in most others types (the Russians tried to adapt the Spitfire to their usual level turning tactics by removing its outer guns, to no avail)... By contrast, the P-47 is hardly ever used in dive and zoom, although it could do it, and it is instead almost exclusively engaged in prolonged turning tactics in actual combat (and there are thousands of easily available combat reports to support this). The same is true of the FW-190A, although occasional attempts to use high speeds rather than its low-speed maneuverability end up being, predictably, more to the FW-190A's detriment...

The FW-190D-9 is below the "1000 in sevice" threshold, but is notable for its poorer low-speed sustained turning performance compared to its radial predecessor, a well-known fact among Luftwaffe pilots. Despite this, it often looks quite good in combat by using, repeatedly, gravity-aided short-lived "oblique" turns, which its much better climb rate helped in performing to hold its own in maneuvering combat (the Me-109G often did the same, especially the later better-climbing models). Nevertheless, a 1946 Allied evaluations found: "Any advantage this type (D-9) may have over BMW-engined versions is more than offset by its poorer handling characteristics"

From best to worst in sequence:

Best:

1-FW-190A -Superior sustained low-speed turn rate, especially if the throttle is reduced and the stall correctly "held" on the ailerons (of which there was a choice of 3 styles, and even field-mounted hinge spacers, for this purpose), superior firepower, roll rate, dive performance. Very good top speed and excellent durability. Very poor high speed high-G unsustained turn rate, especially to the right. Extremely poor dive pull-out performance. Largely unsuitable for dive and zoom tactics, but could zoom well, once, from level flight speeds not preceded by dives...

2-P-47D -Excellent sustained low-speed turn rate, excellent firepower, superior durability, dive performance and very good high speed handling. Superior top speed except at lower altitudes. Very poor climb rate, improved moderately at low altitudes by the later paddle-blade prop. The poor climb rate was mitigated by a very good zooming ability, not affected too much by "sinking" when pulling out from a dive, unlike the FW-190A...

3-Ki-100 -Superior sustained low-speed turn rate, outstanding combined turning and climbing performance, good firepower. Poor speed.

4-F6F Hellcat -Excellent sustained low-speed turn rate, excellent vertical maneuverability, superior durability. Good climb rate. Poor speed until the later F6F-5.

5-F4U or FM-2 Wildcat: -Wildcat has the superior sustained low-speed turn rate of all US fighters, but has a poor speed and climb rate. The F4U has good speed (excellent in the F4U-4), superior durability and dive-bombing abilities. Poor climb rate and average zoom. Faster rolling than the F6F, it proved nevertheless less forgiving in sustained low-speed turning combat, and has slightly lower performance in hard high-G turns as well. Excellent climb rate in the F4U-4, especially compared to the much more numerous earlier F4Us, which were also inferior to the Hellcat in this respect.

6-P-51B/C/D: -Superior speed and range. Poor low-speed sustained turning ability if the throttle is not heavily downthrottled, with partial flaps and prop pitch settings set to coarse at low speed. Very good high speed unsustained high-G turning ability. Excellent zooming but average climb rate if not using "Purple Passion" 150 octane fuel, with at least + 21 lbs of boost (late 1944 mostly). Poor durability to hits. Poor (to extremely poor in in B/C) outer-turn gun reliability when turning hard: This was due to wing flex on an untested gun installation, a fundamental problem somewhat alleviated but never solved. Gun jamming rate was over three times the contemporary early 1944 jamming rate of the same guns in the more rigid P-47 (500 mrbf vs 1800 in April), improving to only twice poorer in the later P-51D models, as they both improved (1200-1400 vs 3100 in June), probably mostly due to to the shift in operations to lower altitudes in mid 1944 (source: "Ordnance and armament, VIII Fighter Command Statistics, 18 September 1944"). The P-51's average climb rate was hugely helped by the "Purple Passion" 150 octane fuel, and this climbing ability was augmented by its very good zooming ability. A close match to the Me-109G in handling, despite much higher weights.

7-Spitfire Mk IX: -Best propeller-driven low-altitude climb rate of WWII (better than available to the Mk XIV at low altitudes) if 150 octane "purple passion" fuel and +25 lbs boost used. Average to poor low-speed sustained turn rate, but a forgiving stalling ability allows shooting "across the circle" in a full three-axis control stalling condition ("wings rumbling"), giving the perception of tight low-speed turns... Excellent 20 mm gun destructiveness allows fast success in short unsustained snapshots, compensating for handling deficiencies... Fairly good high speed unsustained high-G turn; close to P-51 and probably better than an un-trimmed Me-109G. Far, far superior to FW-190A... Poor roll rate except at very low speeds or high altitudes, getting even worse at high speed and in later WWII models. Outstanding high altitude diving speed due to high Mach number, but below average diving ability in denser low-altitude air (on par with Me-109G, except still suffering briefly from initial negative G engine output loss when pushing the stick, unlike the Me-109G). Despite this, much better suited for high speed "dive and zoom" combat than sustained low-speed maneuvering combat.


Worst (still from best to worst):

1-P-38L or Me-109G: -P-38L has unacceptable high-altitude diving performance for a fighter (pull-out assisting surfaces of later models are only for safety, and do not change the very low Mach speed available from high altitudes). Poor low-speed roll rate despite aileron boosting (but outstanding roll rate at high speed with boosting). Average to poor sustained turn rate (but very good high-G unsustained initial turn-in). Extremely high maintenance and initial costs. Poor durability to hits. Superior climb rate, and even more so for its superior zoom and excellent speed, like most US late war types. A good dive and zoom type, but only at low altitudes... A mixed bag, but seen as a "relief" by Luftwaffe pilots, at twice the cost/maintenance/training outlay...:

US P-38L evaluation:
-Controls inaccessible. Many switches could not be reached with harness locked - including auto override switches.
-Too much mechanical equipment for one man to operate in combat.
-Bad visibility to sides and down. Instrument panel and windshield too far away.
- Poor coordination of control forces and effectiveness, combined with weak directional stability make it a poor gun platform, and its maneuverability is so low as to preclude its use in modern combat.
-Would not consider this a modern fighting aircraft.

1944 Fighter pilot conference:

Worst cockpit: Most votes - P-38

Adolf Galland:
"P-38s were not difficult to handle in combat. Many, many P-38 pilots are angry with me about this statement, but it's true. "



Me-109G has poor fuel endurance, poor firepower in basic configuration, yet, despite these compromises favourable to lighter weights, still suffers from a below average sustained low-speed turn rate (if the throttle is not reduced). Moderate diving speed is limited by aileron flutter. Good unsustained high-G turning ability, especially if trimmed tail-heavy, and quite a good climb rate (although no better than an overboosted Merlin P-51 vs the basic G-6). Later MW-50 boost could not be used in prolonged climbs or dives without destroying the engine... Outstanding high-speed dive pull-out performance if trimmed tail-heavy (better than P-51). Excellent zoom. Very well suited for dive and zoom tactics, just like the P-38, but can retain this tactic higher... In many ways the consumate dive and zoom fighter. Gunther Rall: "They complemented one another: The FW-190 was like a saber, the Me-109 like a rapier."

2-Typhoon -Poor roll rate, diving ability, and climb rate. Good low-altitude speed and excellent firepower.

3-Ki-43 Oscar. Poor firepower, but better than it appears owing to special explosive ammo. However, the available 900 rpm rate of fire was almost halved by the prop synchronisation, owing to the synchro-adverse Browning design... Very poor speed owing to lower octane than IJN fuels until 1944(!)...

4-A6M5 -Very poor durability to hits (worse than Ki-43!), very poorly conceived and weak firepower that did not allow for a single point of aim, or good shot coverage (much improved on the later five-gun models). Poor top speed, despite that being actually 20km/h higher than usually claimed (about 585-590 km/h with overboost).

5-Yak-9 -Poor firepower, speed, diving ability, and also maneuverability in long-range models. Durability questionable under fire. Good climb rate.

6-Ki-61. Poor reliability and low speed. Average climb rate. Outstanding initial zoom, and quite good turn rate to left in the first 1200 made. Well suited to both turn-fighting and dive and zoom, but hampered by its low speed and climb rate.

The second half of its production, the Ki-61-I Kai Tei(d), was largely unserviceable as a fighter, with 600 lbs more weight with the same power... It was used almost exclusively as a spare parts provider to keep the lighter and faster "short nose" versions going, or was widely expended as a Kamikaze aircraft(!)... Half the production was thus largely a waste of ressources... Incredible but apparently true...

7-Macchi MC 202 -Poor firepower, poor speed and poor climb rate.

8- N1K1 "George". Poor reliability, poor climb rate, poor speed. Good sustained turn ability (if the butterfly flaps worked!), but abyssmal unsustained high-G initial turning ability in the mid-wing N1K1 version, which was 2/3 rds of all N1Ks produced... In high-G unsustained turns, a harsh transition into the turn could induce "auto rotation", where the aircraft stalled in an uncontrollable condition that could rotate on any of three axis in succession, and which usually killed the pilot... This was alleviated on the low-wing N1K2, a version that also elliminated the extensible landing gear reliability issues. Excellent but short-lived firepower in the N1K1, the shooting endurance being improved in the N1K2. Both versions were much better suited to dive and zoom tactics than turning engagements, but were hampered in this by their mediocre to average climb rate.

9-Worst mass-produced fighter of the later WWII period, no contest, was the Ki-84 "Frank": This mostly not due to inherent design: 70% were unserviceable on delivery, and often had to be flown to frontline depots with a maximum available speed of 400 km/h (250 mph), where the overworked depots tried to turn them into serviceable fighters... These ferry flights were considered extremely dangerous... Entire squadrons remained "on paper" only, while waiting for flyable aircrafts...

Very impressive theoretical straight-line performance (actually faster than the P-51D below 20 000 ft., even with Japanese fuels) meant the aircraft was rushed into a massive production programme, just at the time the skilled labour exemption from draft was curtailed... With its very late-war production ramp-up, this type was the most heavily affected by the cancelling of the skilled labour draft exemption. The result for the Ki-84 was the well-deserved Japanese nickname "pilot killer"... Even the sturdily-designed landing gear had such unpredictable heat treatment it would often collapse...

When working correctly, the aircraft itself was still not as impressive as it appeared on paper, being of average maneuverability, even though it had superior acceleration, climb rate and speed. It certainly had an inferior low-speed sustained turn rate to the P-47N (though it might have held its own with the P-51D, if the Mustang was not downthrottled), and quite heavy controls at high speeds... Suitable mostly for dive and zoom tactics not often available when defending: Diving and climbing is of little help if you are below... The Ki-43 was more useable even late in the war, and supposedly produced more kills than all other Japanese fighters combined (according to the Osprey book on Ki-43 aces)... Japanese evaluations determined that one Ki-100 could take on three Ki-84s with a fair chance of winning, even when starting from the same altitude...: One on one, it was no contest at all, even after switching pilots, and the Ki-100 was widely recognized as by far the best Japanese fighter produced in WWII (Aeroplane magazine article of November 2005, p. 61-77)... It could have been available two and a half years earlier... The Ki-43 was duly noted as a more challenging opponent than the Ki-84... The Ki-100 was effectively a Ki-43 with the firepower, and some of the acceleration performance, of a Ki-84, and was thus considered vastly better than either...

This roughly sums up what I found in researching for the boardgame over the past few decades...: Not at all what I expected to find I have to say... Sorry if one of your favourites is poorly ranked: I tried to be as objective as possible within a narrow focus, and I like them all...

Gaston
amegan
#243
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Posted: Wednesday, January 29, 2014 - 10:42 PM UTC
Interesting, but surely the purpose of developing combat tactics is to enhance the abilities of the aircraft you have to fly, and to avoid, if possible, the situations you can't win. For example there is a passage in The Big Show where Clostermann has to get away from a 190, and he knows that if he can reach 12000ft, where thev second stage of the Merlin supercharger kicks in, he will lose the 190 easily, and so it proves. Any aircraft design is a compromise and the designer designs for a particular requirement expressed by the service requiring the machine. This may leave the aircraft with undesirable characteristics in the role in which it eventually serves. The Typhoon is a good case, designed as a high altitude intercepter with controls optimised for high altitude, the engine proved incapable of achieving high altitudes and it became a low altitude fighter bomber, but with the same miserable ailerons. The major role of the Typhoon became ground attack and it would normally fight other aircraft only in self defence. The Spitfire was a 1936 design intended for 350mph, in the late war diving at 440mph it is not surprising it suffered aileron reversal effects as the ailerons twisted the wings not designed for those speeds. From the middle of the war the wings were clipped to improve low level handling, to adapt the aircraft to a role that it wasn't designed for. Undoubtedly, the conditions changed as the war went on with Allied fighters required to carry more and more load while German and Japanese fighters were able to benefit from light fuel loads and a lesser requirement to carry bombs, to improve handling and flight characteristics. Personally I would want to fly an aircraft suitable for the task required, and the word "fighter" is far too general, it has to be split down into smaller categories, interceptor, escort, fighter-bomber, lowlevel air superiority, each has to deal with other where the envelopes cross, but their purposes are different. The Spit and 109 were both designed as interceptors and both made poor escorts, neither carried enough fuel or ammo. The Mustang was not a good interceptor, poor climb rate, but large fuel and ammo load makes it the best piston escort ever. The 190A was an excellent air superiority fighter as was the P-47, both would have serious deficiencies as escorts, (the P-47 had a low critical Mach number so couldn't be dived hard at high altitudes, the 190A also had poor handling characteristics at high alititudes). It is interesting that determined pilots and good tactics could make even mediocre aircraft yield results far above their apparent capability, witness Finnish results in the Winter Wars using some very indifferent aircraft types. This must come back to tactics suiting the aircraft.
GastonMarty
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Posted: Thursday, January 30, 2014 - 09:18 AM UTC

Your assumption that the P-47D had a poor available Mach number is based on an Eric Brown test of an early P-47B. For some reason this poor maximum dive speed aerodynamic issue was completely solved in subsequent models, and the P-47D could reach similar or better Mach figures to the P-51 or even the FW-190A, at around 0.81 (for 0.84 on the FW-190A). The Spitfire had 0.89-0.92, but still had moderate available dive speed at low altitudes because wing buffetting made Mach irrelevant, Mach limits being higher to the point of irrelevance for most WWII prop types at low altitudes.

For an escort fighter you need range and maybe high altitude performance, but of these two range is (in theory) irrelevant to the tactics needed to achieve air superiority, and you still need air-to-air combat maneuverability if your escorting duties are going to be useful... Similarly, being an "interceptor" is not going to be of much use if you cannot maneuver well enough to defeat the challenge of the escort fighters...

There is only two basic ways to use a fighter for air superiority: Hit and run from a superior altitude, and sustained turn fighting, hit and run being essentially the crutch, and sometimes the saving grace, of otherwise objectively inferior fighters, hence the order of their appearance in my list.

I would say climb rate is about the only positive discriminating element that would segregate these two fighting styles between fighter types, and even that element was not always predictable to the aircraft designer...

WWII aircraft designers did not know how to design a fighter for an air superiority role: Their knowledge was insufficient to even predict if they were building a hit and run type or a turnfighter...

This is blindingly obvious in how they turned out: Heavy aircrafts such as the P-47D and FW-190A were obviously designed for high speed hit and run, and yet they were the best turnfighters in the Western Front, and used as such... Light aircrafts such as the Spitfire and the Me-109 were obviously intended for maneuverability, yet were better used as hit and run types... They simply could not design for a role, and few fighters remained in the role the designer had intended...

A well-known quote from a high ranking US official illustrates this best: "The P-51 was designed for low-altitude ground attack, the P-47 for high altitude escort: Given how they ended up, it's a wonder we won the war!"

It could be said that their understanding of what they were building was too poor to allow tailoring a design to a role: The eventual role was instead tailored to the design's performance outcome... Even then, to gain air superiority there was only two basic and complementary fighting styles, and the predominant one in the age of guns was still turn-fighting by some margin: This was in part due to the low lethality of guns (2% hit rate) which required peppering the target for a while...

Gaston