Spitfire mk VB/Seafire vs Zero

[ponsford]

Regarding F4F-3 versus F4F-4, from F4F Performance Trials :

Detail Specification For Model F4F-3 Airplane
Gross weight: Normal fighter, (110 gallons): 6895 lbs., Overload fighter, (147 gallons): 7432 lbs.
High speed at sea level: Normal fighter: 278 mph. Overload fighter: 277 mph
High speed at max. critical altitude 22,000 ft.: Normal fighter: 326 mph. Overload fighter 336 mph (that looks like an error to me)
Time to climb to 20,000 ft.: 7.6 minutes

F4F-3 #1845 / #1848 R-1830-76
Full load weight: 6260 lbs / 7065 (7300 at take off)
Max speed at critical alt.: 331 at 22,000 ft. / 331 at 21,000 ft.
Time to climb 20,000 ft. ` 10.5 minutes / 10 minutes

Detail Specification For Model F4F-4 Airplane
Gross weight: Normal fighter, (110 gallons): 7426 lbs., Overload fighter, (144 gallons): 7972 lbs.
High speed at sea level: Normal fighter: 275 mph. Overload fighter: 274 mph
High speed at critical altitude 19,400 ft: Normal fighter: 318 mph. Overload fighter: 316 mph.
Time to climb to 20,000 ft: 12.7 minutes.

F4F-4 #4058 R-1830-86
Gross weight: 4 gun: 7370 lbs., 6 gun 7921
Vmax at critical altitude (19,400 ft): 319 mph (7370 lbs)
Time to 20,000 ft: ~12 minutes

Whether -3 or -4, the Wildcat’s performance doesn’t seem to me to be in the same class as any contemporary Spitfire mark.

[renrich]

JD, your points are well made but I think that the early Martlet which was originally scheduled for France and wound up in the FAA had only the four 50s and was quite successful against the Condor. In the early going in the pacific the performance of the F4F3 was more on par with the A6M but when the F4F4 replaced the F4F3 with two more guns, less ammo per gun and the folding wings, that additional weight really hampered the performance and the only way the USN pilots survived was by superior tactics and because of the ruggedness of the AC. I believe that the RAFs insistence on the 6 guns was based on their belief that a certain number of hits(statistically) was needed to bring down a bomber and the overall level of gunnery training in the FAA or RAF was not, at that time, equal to that of the USN. A number of the kills for F6F3s were against the big Kawanishi flying boats which were pretty rugged unlike some of the IJN fighters and the 4 -50s were ample. The thing to remember is that in an AC of the Wildcat's size and HP, 400 or 500 pounds made a big difference in rate of climb and overall maneuverability. That is the reason that the FM2 went back to the 4-50s. If you remember, the early F8Fs had only 4-50s also to save weight.

[ponsford]

I’ve read through this thread twice now and was unable to find any figures on the Zero or Spitfire V from flight tests or manufactures’ data bearing on aircraft performance characteristics such as speed, climb, roll rate (excepting the NACA chart) & turn. I can’t believe that’s really the case after 10 pages of discussion. Could someone please point out to me where in this thread basic performance data of the Zero is cited, i.e. max speed at SL & Critical alt, climb in ft/min, roll rate, turn in deg/sec at specified alt? I must have missed it. Frankly I think the Spitfire – Zero comparison is less interesting than a F4F – Zero comparison. In my view, based on performance data of the Spitfire from trials and what I understand Zero performance to have been, the Spitfire is a class better in performance than the Zero with the exception of turn. The F4F and the Zero, on the other hand, may be closer in performance, at least in basic performance characteristics such as level speed, climb and roll. Without the numbers, however, how can one say?

Ok, on my third read through I found this from parsifal:

Specification of A6M2 Navy Type 0 Carrier Fighter Model 21:
One Nakajima NK1C Sakae 12 fourteen cylinder air-cooled radial, rated at 940 hp for takeoff, 950 hp at 13,780 feet.
Performance: Maximum speed 331 mph at 14,930 feet. Cruising speed 207 mph. Initial climb rate 4517 feet per minute. Climb to 19,685 feet in 7 minutes 27 seconds. Service ceiling 32,810 feet. Normal range 1160 miles. Maximum range 1930 miles. Radius of turn with entry speed of 230 mph was 1118 feet. Entering a 180 degree steep turn with an entry speed of 230 mph, the fighter could complete the turn in 5.62 seconds, with an exit speed from the turn of 189 mph. At slower speeds, the turning radius was 612 feet. Normal positive g-load factor was 7g, with a safety factor of an additional 1.8g. Normal negative g-load factor was 3.5g, with a safety factor of an extra 1.8g.

Thanks parsifal. At least we have something now to compare. The 4517 ft/ min climb figure seems doubtful though... Do you know the source for those figures parsifal?

[parsifal]

Hi Richard

I happen to believe that the decision to put six guns and folding wings on the Wildcat was the right one, notwithstanding what i consider to be a very marginal drop in performance.

Firstly the design work for the F4F-4 was done before the US had really become that aware of the Zero. And packing the maximum amount of firepower against strike aircraft was the right decision. Being able to shoot down the attack aircraft has to be the number one priority for a carrier based fighter, not shooting down enemy fighters. If the strike aircraft get through, , and damage or sink the carrier, the whole Task Group is then placed at risk. The fighters of themsleves are expendable.

And as things happened to turn out, the F4F-4 was still competitive against the zeke. It was built like a brick dunny and could out dive and I believe out roll a zeke. Even though a zeke was not strong, it could still absorb some punishment, and having 6 guns instead of four meant that you only needed to keep the zeke in your sights for 2/3 the time that it might take an F4F-3.

Now the wing folding was critical to US success. It meant that overnight their standard Fighter component on their carriers went from about 18 fighters, to over 30. By comparison, the Japanese carriers were embarking about 18-24 Fighters, so the US went fom parity, to superiority in the numbers department. This proved crucila in the 1942 battles

I would also hotly dispute that the USN flyers were that much better than FAA pilots at shooting. Ther was no comparison in the flight training of an FAA pilot to your standard garden variety RAF Jock. It took over a year to train fleet air arm crews, at the beginng of the war the RN was receiving just 16 pilots per year (although this changed rapidly. Whilst I have heard that the USN practced deflection shooting to amuch greater extent than any body else, USN training times for their aircrew were nowhere near as thorough as the early war FAA. Later on, as the need for numbers grew, the FAA did drop its standards, so the later 1942 FAA pilots were not quite as good, but in 1940-42 (warly), the FAA boys showed exceptional skill in the air. As an example, though not an air combat issue, just 18 swordfish, attacked and disabled 3 Italian Battleships, in the middle of the night. Compare the damage they did, to the Japanese in PH, and the amount of damage per aircraft for the british aircraft is FAR in excess of that achieved per a/c by the IJN pilots

[John Davies]

Originally Posted by renrich

......the overall level of gunnery training in the FAA or RAF was not, at that time, equal to that of the USN. ........ The thing to remember is that in an AC of the Wildcat's size and HP, 400 or 500 pounds made a big difference in rate of climb and overall maneuverability. .

True; and Johnnie Johnson would probably have agreed with you, (I've quoted him in an earlier post) and he certainly knew what he was talking about. And yes, you are quite right, UK authorities did work on a pretty crude statistical notion of how many bullets you needed to spray into the target area to ensure a kill. I can't help wondering if they made a clear distinction between rifle calibre and .50 weapons?

However, it is also worth remembering that a good many FAA pilots were trained in the USA by the USN. Hanson ("Carrier Fighter") gives an account of his basic and advanced training, if I remember rightly at Penescola. (I don't have my copy to hand ATM). So maybe some of them were taught how to shoot?

I take your point about the undesireability of adding weight to a small fighter. I'd still emphasise that if you have to add weight, a fairly outboard position in the wings is one of the worse places to do it.

Seafire squadrons in the Pacific theatre were authorised to remove both the wingtips and the outer .303 MGs from their aircraft, leaving one cannon and one MG (probably as an insurance against cannon feed jams) on each side. This combination simulataneously increased roll rate and reduced stick forces. Since the basic Spitfire airframe was highly manoeverable to begin with, the results must have been fairly startling. But it all goes to show that weight far out in the wings of a fighter is NOT a good idea!

The decision whether or not to adopt this modification was left at squadron level, and not all of them did it. But the fact it was so much as considered suggests to me that even the Merlin-55 equipped Seafire LIIIs and FIIIs needed every edge they could get against the Zero. They had a pretty impressive performance. They were highly manoeverable aircraft, with an impressive rate of climb, angle of climb, and rate of accelleration. The tactics Brown describes in "The Seafire" of keeping the speed well up above the Zero's best fighting range, and proceeding in a series of near-stall turns, obviously worked, to judge from combat reports. But even so, the FAA clearly treated the Zero with considerable respect.

Which leads me to the obvious conclusion that if the pilots of a pretty advanced development of the Merlin-engined Seafire had to work hard at it to get a decisive advantage over the Zero, then anyone who went up against a Zero in a Wildcat had to be a real hero!

[John Davies]

While we’re on the subject of the Wildcat, here’s a bit of light relief……

All taildraggers swing a bit on takeoff, but the Wildcat more than most. This was due to a combination of a big torquey radial, a narrow undercarriage, a short fuselage and a fin (“vertical stabiliser” in American) and rudder that could have been bigger, and indeed were enlarged in the later ones.

So before you open the throttle you wound in a lot of rudder trim to compensate. Now the fun starts….

The rudder trimmer in the early Wildcats (and for all I know in all of them) worked in the opposite to the natural sense; i.e you wound the wheel to the left to apply right trim and vice versa. There was also a trim indicator, which did go round the right way, which meant that when the trim wheel was being wound one way, the indicator was going the other way. Are you confused yet?

Of course, from time to time the inevitable happened, and some luckless sprog wound in a handful of trim not to compensate for but to accentuate the swing. Once the throttle was opened, no pilot in the world had a leg strong enough to force the rudder pedal over against the combined forces of swing and mis-trim, and he would very soon find himself facing the way he had just come.

Some very spectacular incidents resulted. Apparently some pilots actually managed to take off in this manner. I never heard of an accident in which anyone was killed. Grumman built their aircraft very strongly! However, it was a bit unfair on other users of the airfield. It never, to my knowledge, happened afloat, because no pilot is going to do that more than once, so it tended to happen during training ashore.

In a way, it’s kind of comforting. It shows that British designers did not have a monopoly of mutton-headed anti-ergonomic cockpit design.

[Glider]

Originally Posted by ponsford

I’ve read through this thread twice now and was unable to find any figures on the Zero or Spitfire V from flight tests or manufactures’ data bearing on aircraft performance characteristics such as speed, climb, roll rate (excepting the NACA chart) & turn.

This may help with the Spitfire V for speed and climb

Spitfire Mk VB W.3134 Report

[renrich]

I have read that the Wildcat was very easy to groundloop in a landing on dry land but the arresting gear on a carrier helped in that respect. According to Lundstrom, I believe, the design of the F4F4 was undertaken after the USN knew about the Zero performance. Some of the USN pilots said the F4F4 flew like a loaded torpedo plane! No question that the folding wings was the correct decision so as to get more VFs on board. The FAA may have been well trained but again according to Lundstrom the prewar gunnery training of the USN was superior to all other air forces and the overall training of the USN and IJN was the best in the world. Lundstrom-" In terms of actual flying hours, the Navy's aviation program in the mid 1930s probably offered the most comprehensive training schedule of all the world's air forces." In the USN, the 1935 syllabus was a one year course involving 465 hours of ground school and 300 hours of flight. In 1939, it was recommended that the syllabus be shortened to seven months with 207 flight hours. The syllabus began after a month at a flight school with ten hours of instruction where if the student was apt, he soloed. ( I soloed after ten hours of dual. When I got up in the air, I looked at the empty right seat and asked the Lord to please let me get back on the ground again safely.) The VF wings before 1940 averaged from 3500 to 1500 flight hours. The VF wings in 1940 averaged 1000 to 600 flight hours. The VF wings 1941 averaged 600 to 300 hours. The VF wings in 1942 averaged 300 flight hours. If the six guns was the correct decision for the F4F4, why did they go back to four guns on the FM2 and why the four guns on the F8F?

[HoHun]

Hi Parsifal,

>So according to these sources, I think you are right, the performance is better in the older mark. The exceptions appear to be max ceiling.

I'd say this is probably a misquoted data point then. Ceiling is tied rather closely to flying weight, with the lighter aircraft enjoying a clear advantage if everything else is unchanged.

Regards,

Henning (HoHun)

[HoHun]

Hi John,

>On the other hand, if you are an FAA pilot keeping the Fw200 Condors off the North Atlantic convoys in winter, manoerverability doesn’t matter so much. Firepower, however, does.

Good point - from Brown's books, I'd say the British were really impressed by the Fw 200's fighting abilities early in the war, so the six guns might have been necessary (or at least highly desirable) from their point of view.

>Adding an extra gun and its ammunition, on each side, in effect increasing the weight devoted to armament by 50%, will greatly increase the roll inertia that a control input from the ailerons has to overcome in order to initiate or stop a roll.

Hm, this would be right only if the six-gun fighter had indeed had 150% of the ammunition supply of the four-gun fighter, but it seems that the lightly-armed variant carried more ammunition, so the difference was not as great as it might have been.

But you hit the nail on the head with the differentiation between roll rate and roll acceleration - this is an important detail often missed in performance discussions!

Regards,

Henning (HoHun)

[HoHun]

Hi Ponsford,

>I’ve read through this thread twice now and was unable to find any figures on the Zero or Spitfire V from flight tests or manufactures’ data bearing on aircraft performance characteristics such as speed, climb, roll rate (excepting the NACA chart) & turn.

With regard to Spitfire data, see:

WWII Aircraft Performance

F4F data:

Untitled Document

A6M data is hard to find - the best guess would be the TAIC intelligence summary for which I don't have an online resource. It seems that climb rate does not match the published engine ratings in that TAIC chart, though.

In general, there is only so much you can learn from un-processed data because of the variability of data from multiple sources, or even contradictions within a single source occassionally. That's the reason for conducting a quantitative analysis that leads to "generic" data, like this one:

http://www.ww2aircraft.net/forum/pol...tml#post364448 (F4F Wildcat versus P-40E Tomahawk)

(If the direct link doesn't take you right to the correct post, it's #25 in the linked thread. The P-40 data is from Perils P40 Archive Data )

>Frankly I think the Spitfire – Zero comparison is less interesting than a F4F – Zero comparison.

I don't know how the F4F came to play such a big role in this thread, but it's in fact a Seafire vs. Zero discussion

Regards,

Henning (HoHun)

[JoeB]

Originally Posted by HoHun

1. Since Joe decided not to accept my offer to consider his post never

2. In reality, the markedly inferior performance of the F4F vs. the A6M is a well-documented fact, and the good combat record of the USN was achieved in spite of that inferior performance.

3. Note that Joe uses the term "combat effectiveness" as if it were a property of the aircraft on the same level that performance is a property of an aircraft. As the results of combat - the only way to measure "combat effectiveness" - are dependend both on men and machines, and on the men and machines of the opposing side as well -, this is a misconception,

4. So how comes he thinks he can get away with a poorly-hidden insult on my honesty here?

With regard to possibly contradicting data ... those who have actually sorted through different data sets while analyzing performance are aware that there is much conflicting data around, and that it is a routine occurrence to have something contradicting something else. Quantitative analysis is an excellent tool to sort out such contradictions.

1. Huh?
2. No actually 'markedly inferior" is not documented. To again refer to a reference you've been told about, have said 'maybe I should read' but obviously haven't read, see Lundstrom's discussion of the early informal and formal F4F v captured (Ryujo's from the Aleutians) Zero in late 1942 ("First Team in the Guadalcanal Campaign" p 534-5). The first tests concluded the F4F was slightly faster. The next ones, probably more carefully conducted, gave the general result with which we're famillar now (or should be): the two were around equal in speed at sea level, then Zero relatively slightly faster up to 19k ft (best speeds less than 20mph apart); both trials agreed the Zero was somewhat better in a continuous turn (not a lot, not as much of an advantage as over the P-40), Wildcat rolled substantially better at high speed, F4F dived a little better or same, Zero climbed substantially better in general. Not markedly inferior even in those basic stats.

Anyway you made that comment wrt to F4F v P-40 not F4F v Zero. It's definitely not 'well documented' that the F4F was 'markedly inferior' in performance to the P-40E, that depends what area of performance you emphasize between two a/c more dissimilar than the F4F and Zero were.

3. There are separate individual plane factors. Those consist in turn of measureable aerodynamic performance (speed, sustained turn rate, radius, etc) and other (armament, ruggedness, cockpit visibility behind or for gunnery, favorable handling for gunnery? etc). There is overall combat effectiveness of the plane. There is combat effectiveness of a fighter unit equipped with the plane.

The second thing, overall combat effectiveness of the plane itself, would be illustrated as follows: randomly select similarly trained test pilots of similar background. Assume you could convince them to seriously try to kill each other in real air combat in various scenario's, not a race, and not just a mock dogfight. Let them go at it and see what happens. The more the effectiveness difference, the higher the kill ratio. The separate individual plane characteristics will determine which plane is more effective in that 'all else equal' situation but there is no way to calculate the kill ratio upfront just using the performance stats. IOW a single index of effectiveness and the individual stats are related things but not the same thing. Of course the effectiveness of a unit equipped with the plane is another thing, no confusion or misconception about that except maybe by you.

4. If your graphs say the F4F turned a lot worse than the Zero and head to heads said not as well but not big difference, I'll go with the trials (though trials of captured a/c aren't 100% certain either). And again if you really don't want to debate don't, but 'I'm on ignore' then you launch into another long response with lots of ad-hominem, what does 'ignore' mean then ?

Joe

[ponsford]

Thanks for the link Glider:

Spitfire VB
Max speed: 371 mph at 20,100 ft.
Climb: 3250 ft/min at 15,200 ft.
Time to 20,000 ft. 6.4 minutes

Thanks for the links HoHun. I appreciated your analysis of the F4F and P-40. Have you done a similar analysis for the F4F versus Zeke? I would find that of interest.

Here’s an interesting online article on Zero performance:
ZERO-SEN Model 21 Performance: Unraveling Conflicting Data by Richard Dunn

Speeds summarized fwiw:

Zero 21:
(1) 316 m.p.h. at 16,570 ft. (Taylor, p.253);
(2) 316 m.p.h. at 16,400 ft. (General View, appended chart)
(3) 321 m.p.h. at 20,000 ft. (Mikesh, p. 123)
(4) 326 m.p.h. at 16,000 ft. (Reardon, p.113)
(5) 331.5 m.p.h. at 14,930 ft. (Francillion, p. 16)
(6) 332 m.p.h. at 16,570 ft. (Caiden, p. 158)
(7) 336 m.p.h. at 19,685 m.p.h. (Green, p.46)
(8) 345 m.p.h. ( Sakai , p.48).

Dunn is pushing Sakai’s figures. I’m not entirely convinced by his argument.

More US Zero data below:

Informational Intelligence Summary No. 85: Flight Characteristics of the Japanese Zero Fighter
Max speed sea level: 270 mph
Max speed critical height: 326 mph
Climb sea level: 2750 ft/min.
Climb 15,000 ft: 2380 ft/min.

Zero-2 A6M2, USAAF Material Command (Actually Navy figures from San Diego)

Vmax sea level 277 mph
Vmax 16,000 ft 335 mph
Climb sea level 2710 ft/min
Climb 15,000 ft 2480 ft/min

Mitsubishi Type 0 MK2-SSF Hamp Airplane, AAF No. EB-201 Flight Test Engineering Branch

All flight tests were performed at rated power and no data is available at maximum emergency power, 2600 RPM and 40" Hg. manifold pressure.

Maximum speed at high critical altitude = 15,300 ft. (2400 RPM and 36" Hg. man. press.) = 308 MPH

Rate of climb at sea level (2400 RPM and 36" Hg. man. press.) = 3260 ft/min.
Rate of climb at low critical altitude, 7000' (2400 RPM and 36" Hg. man. press.) = 2980 ft/min.

TAIC Report No. 17, Combat Evaluation of Zeke 52 with F4U-1D, F6F-5, and FM-2
Max speed: 335 mph at 18,000 ft.

TAIC 38: Zeke 52

Max speed at sea level: 291 mph 44” HG
Max speed at critical alt. 19,400 ft.: 326 mph 44” HG.

[ponsford]

Originally Posted by John Davies

Which leads me to the obvious conclusion that if the pilots of a pretty advanced development of the Merlin-engined Seafire had to work hard at it to get a decisive advantage over the Zero, then anyone who went up against a Zero in a Wildcat had to be a real hero!

Hi John: I take your point and tend to agree with the gist of it. It would take balls... or numbers, discipline and good tactics.

[ponsford]

Originally Posted by parsifal

The zero Mk 2 had the following statistics

Specification of A6M2 Navy Type 0 Carrier Fighter Model 21:

Performance: Maximum speed 331 mph at 14,930 feet. Cruising speed 207 mph. Initial climb rate 4517 feet per minute.

Hi parsifal: After reading Dunn's article I presume your figures are from Francillion? That 4517 ft/min must be a typo. That can't be right. It's just too far removed from other available data sets to be believable.