Best Fighter in the Pacific and CBI Theaters in 1942

[HoHun]

Hi Claidemore,

>HoHun?? In looking at your climb rates on page 1 of this thread, you have the P40E at 16m/s at sea level (3149 ft/min). All the stats I've seen list the P40E as 2100 ft/min.

Good catch, thanks! I was still listing the P-40E at 56" Hg erreneously (as I had made a mistake modifying an existing Gnuplot script for the PTO/CBI comparison).

The curve for the P-40E at 44" Hg does in fact yield 11.22 m/s at sea level, which converts to 2209 fpm, so that it's fairly close to the 2100 fpm you expected.

>You have the F4F at 2952 ft/min and it's usually listed around 2000 ft/min.

As one or two Grumman fans have requested in other threads, I've begun to include the the lighter and better performing F4F-3 into the comparisons instead of the heavier F4F-4.

BuAer data for the F4F-4 at Military power at a weight of 7975 lbs is 2480 rpm (12.6 m/s). The lighter F4F-3 is obviously going to climb more rapidly, so my calculated 15 m/s figure looks good. Of course, if you have data specific for the F4F-3, it would be valuable for cross-checking my calculation.

Regards,

Henning (HoHun)

 

[HoHun]

Hi again,

As power available also has an impact on turn rate, here the turn rate chart again with the P-40E at 44" Hg as advertised.

Regards,

Henning (HoHun)

 

[JoeB]

The remote control lower turret on early E models was a Sperry.

The successful manned belly turret in later B-17E's and all F's and G's was Sperry. The early unsuccessful remote control one was made by Bendix.

Joe

 

[FLYBOYJ]

The successful manned belly turret in later B-17E's and all F's and G's was Sperry. The early unsuccessful remote control one was made by Bendix.

Joe

The Swamp Ghost > Photographs - Lower Bendix Turret

 

[HoHun]

Hi Mike,

>That leads me to my current front runner, the F4f Wildcat. It was slower than the Curtiss or Bell, maybe a little faster than the Zero.(or equal ) But it had altitude ability that the other American fighters did not.

Hm, actually in the scope of the comparison, we're comparing the US planes to the A6M3 which had a two-speed supercharger drive that gave it a much higher top speed at altitutde than the A6M2 with its single-speed supercharger. The difference is really a bit like that between Spitfire V and Spitfire IX

The A6M3 according to my calculation is as fast as or even faster than most Allied fighters it faced in 1942, except for a narrow mid-altitude band (the "valley" between the two supercharger speeds' power peaks) where the P-40 is somewhat better because it has its power peak right there.

You're spot on with regard to the F4F-3's altitude capability, tough. Above 9 km, it surpasses in the P-40E in every aspect of performance, including speed. Unfortunately, the A6M3 still surpasses the F4F-3 by a similar margin ...

Regards,

Henning (HoHun)

 

[JoeB]

1. I will get Fortress in the Sun.

2. Having said that - Odyssey of a B-17 The Swoose - by Herbert Brownstein contradicts Salecker by stating that the remnant (a 'dozen') survivors of 19th BG DEI retired to Australia and continued combat ops - headquartered at Mareeta - and flew missions against northern New Guinea targets and Rabaul - staging out of New Guinea. May 6 appears to be the approximate date the Swoose became a Ferry ship. Clearly this book contradicts Salecker's assertion that no more B-17D's were used in combat after February 11.

3. In the meantime it was a B-17D that rescued MacArthur from Mindanao on 11 March. That definitely was a 'combat mission' under any definition

4. Brownstein goes on to say that the first few B-17E's started arriving in Australia to replace B-17Ds in March and the Swoose was selected and cleaned up in April, 1942 - then assigned to Brett. The Swoose remained armed and averaged 150 hours/month mostly flying to advanced based such as Port Moresby.

5. It is unclear when the last B-17D combat mission in which bombs were dropped or armed recon was performed by the 19th BG but it was after March 1942.

1. You'll see how specific the info is, and how I'm not inferring much but rather how he gives the specific a/c tail numbers.

2. There's no contradiction because all but 3 of those a/c were B-17E's, ones the 19th had received already as replacements prior to end of DEI campaign. Salecker gives the fate of each of the 35 original B-17D's in the FEAF, and no more pre-E's were sent out to Australia as replacements, all replacements were E's. Only 3 of the D's still survived by the end of February:
40-2072: redesignated transport after combat damage 12/25, final fate unk.
40-3079: redesignated transport, lost in accident at Daily Waters, Australia March 14
40-3097: originally "Ole Betsy", sent to Australia for overhaul in January, received all 4 engines and the tail from 40-3091, renamed "The Swoose", half swan/half goose. Saw no more combat (as in bombing) missions, Salecker footnotes this to Brownstein's book.
(also the Japanese restored 40-3095 to flying condition)

The other 26 B-17's in Australia at the beginning of March, right after evacuation of Java, were all E's: 16 evacuated from Java (he lists the serial numbers in a footnote), and 10 of the 14th Recon Sdn (of 12 originally assigned to Naval TF 11, then redesignated 40th RS in April). That unit began raids against Rabaul Feb 22, while the Java campaign was winding down.

"Soleil Levant sur l'Australie" by Bernard Baeza, which covers all Japanese and Allied combat air ops against and from Australia also says of the 19th BG that by March the few pre-E models were no longer used on combat missions but for transport and liaison.

3. The B-17 which picked up MacArthur was, per Salecker and other sources, was 41-2447, San Antonio Rose II, a B-17E; as was 41-2429, the other plane on that mission, both of the 19th BG.

4. The statement about E's only equipping the 19th from March is clearly wrong from a variety of sources and photo's showing them in Java, a/c assigned to both 7th and 19th BG there (7th later absorbed into 19th). Salecker's statement of Feb 11 as last B-17D combat, as in bombing, mission is footnoted to a primary record "Diary, 19th BG in Java". And by March Swoose wasn't an example of a B-17D but one of only two left in the theater.

5. So, if it hinges on transport missions to Port Moresby being 'combat' then the 2 B-17D transports which survived after March may have flown 'combat missions'. What the 19th's diary and Salecker clearly mean is bombing missions, and I don't see evidence those handful of D's were used after Feb 11 on bombing missions, with Salecker and Baeza both saying they weren't, and Salecker also detailing the missions against Rabaul in spring 1942, by B-17E's.

Joe

 

[MikeGazdik]

HoHun, we are on the same page as far as the F4F and Zero , I think. I was comparing the F4F to the American Army fighters in that one paragraph.

Can you make a graph or chart of the combat radius or range of each of these aircraft? I know the Zero would be king here, I would be curious how the others compared to each other.

I think the range of the Zero made it a good offensive weapon. Coupled by the fact that the American Army fighters were slow to climb, it only gave the Japanese a greater advantage......unless the Wildcat was on scene.

That being said, I think the better overall speed of the P-40 and P-39 and better diving abilities gave them the advantage in an escort type role, where they were with dive bombers or level bombers. Even with the poorer altitude capabilities of the Warhawk or Airacobra, once a fight was engaged in an escort situation, the altitude of the scrap would likely lower and I think the advantage favors the U.S. Army fighters.

 

[renrich]

The P39 because of it's short range and poor altitude performance was hopeless as an escort fighter in the Pacific. It's only real use was as a ground attack fighter bomber. The Wildcat was a better escort fighter than either Army fighter because of overall performance at altitude. The P400, because of oxygen system problems could not even be used above 15000 feet.

 

[claidemore]

Hi HoHun,
The climb rates for the F4F-3 were still bothering me, so as you suggested I looked for some other documents to shed some light on it. Found the attached pdf. (primary source document! woohoo! )
F4F-3 (no 1845) with two .30 fuselage guns and two .50s, weighing in at a very light 6262 lbs shows initial climb about 12.7 m/s while the heavier (no 1848 ) with 4 wing .50s @7300 lbs shows about 10.4 m/s.

 

[renrich]

Page 473, Dean, "America's Hundred Thousand," "the fastest and lightest Wildcat was the early F4F3 which touched 335 mph at 22000 feet. In addition the climb rate of the early F4F3 was over 3300 FPM at SL, very sprightly performance for the time." This was with military power. That is Mfr. data and at a weight of 7150 pounds. That is with 360 pounds of ammo and 660 pounds of fuel in what is called fighter mission load. I believe that is with SS tanks and some armor.

 

[HoHun]

Hi Claidemore,

>The climb rates for the F4F-3 were still bothering me, so as you suggested I looked for some other documents to shed some light on it. Found the attached pdf. (primary source document! woohoo! )

Wow, good find! That illuminates the F4F better than what I had before!

>F4F-3 (no 1845) with two .30 fuselage guns and two .50s, weighing in at a very light 6262 lbs shows initial climb about 12.7 m/s while the heavier (no 1848 ) with 4 wing .50s @7300 lbs shows about 10.4 m/s.[/QUOTE]

Hehe, if I plug a constant 1000 HP and 7300 lbs weight into my calculation and then select the speed for best climb, I get 10.39 m/s at high gear full throttle height But I won't claim my calculation is accurate to 0.1 %, the good fit owes a lot to coincedence.

Why was I comparing the climb rate at high gear full throttle height? Well, let's examine the four diagrams for No. 1848:

Upper left hand: Climb rate, supposed to be constant below high gear full throttle height, as can be cross-checked by the perfectly straight time to altitude graph in the same diagram. Note: The two-stage, two-speed R-1820-76 with its ability to bypass the auxiliary stage supercharger at low altitude would realistically have a three-step climb graph. Someone has added such a three-step chart with faint pencil lines, and though it's not really legible, it looks as if he has labelled the addition "BuAer", indicating that he was possibly taking his data from the Buereau of Aeronautics Aircraft Characteristics Sheet.

Upper right hand: Engine power curve in the vicinity of high gear full throttle height, with rated power indicated as 1000 HP. As the full throttle height (critical altitude in US terminology) is that given for the top speed case in the main text of the report, this is obviously with ram effect, and the difference to the upper left hand diagram for the climb case is thus explained. Note: The test aircraft did only indicate 981 HP instead of 1000 HP on the torque meter in flight, as pointed out in the main text of the report.

Lower left hand: Speed at high gear full throttle height as a function of power. The main text gives the top speed of No. 1848 as 330 mph, but here we can see that the test aircraft with 981 HP apparently achieved only 329 mph. That might look like cheating, but remember that the engineers were not trying to find out the peculiarities of No. 1848, but rather how a typical F4F-3 with the engine power exactly on specs (or perfectly average, as it was normal for engines to have a bit more or less power than specified) performed.

On the bottom right hand, we see the airspeed indicator calibration curve which is not terribly interesting for us right now.

Going back to the upper left hand diagram, we can conclude now that it is a generic diagram for the engine operating at a constant power of 1000 HP as measured by the torque meter, which would require the engine to be throttled back in supercharger low gear, and not be operated at constant manifold pressure even in high gear, as it was the practice in combat.

The only point where military power and test power coincede is at high-gear full throttle height, and that's where I get the deceptively accurate fit of 10.4 m/s you report versus the 10.39 m/s my calculation yields.

However, I still have to improve my F4F-3 model so that it reaches the 330 mph pointed out by the report. It is a bit short of this currently because I based it on the F4F-4's drag, and while the F4F-4 is often criticized for the extra weight it put on, the report you found shows that it also put on a bit of extra drag along with the weight - the extra gun barrel opening is an obvious source of some of that drag, and the small gaps in the wing skinning necessary for the folding wings are another. If I reduce the F4F-3 model's drag to make it represent the cleaner variant, that will increase climb rate a tiny bit so that my calculation will no longer be as close to the historical data, but 0.2 to 0.3 m/s higher.

My original F4F-3 graph was calculated for MIL power, based on the R-1830-86 data from the BuAer standard aircraft charactersistics chart for the F4F-4. The F4F-3 uses the R-1830-76, but as far as I can tell from the data on AEHS Home, the two engines are identical with regard to the parameters that determine performance. MIL power is 1200 HP/2700 rpm @ sea level, 1150 HP/2700 rpm @ 11500 ft, and 1040 HP/2550 rpm @ 18400 ft. This does yield a contradiction to the F4F-3 report which shows a full throttle height of just 15500 ft for high gear, but that also seems to contradict the 21000 ft full throttle height in level flight. No idea how to resolve this one, and there is one like this in almost every flight report :-/

My original F4F-3 graph was also calculated for 7065 lbs instead of the 7300 lbs of the F4F-3 report, but as the F4F-3 report gives exactly these 7065 lbs as "full load weight", this was probably a good choice. The difference to the 7300 lbs in the report was responsible for some of the excess climb rate you were noticing, though. (I made it a habit to note the weight on the charts, but the F4F part of the chart was so old that I hadn't done that yet, and while assembling the various curves I did not go back into my calculation to look it up. Now you know anyway

Regards,

Henning (HoHun)

 

[varsity078740]

The successful manned belly turret in later B-17E's and all F's and G's was Sperry. The early unsuccessful remote control one was made by Bendix.

Joe

Joe:

I respectfully disagree. The Bendix remote lower turret was used on early
B-24Ds and B-25B thru early G models. They were retactable, and had a sighting system built into and viewed through the body of the turret It was not a successful design as such but was later improved and adapted as the chin turret for B-17s. Early B-17Es had a Sperry non retractable turret that
was an entirely different design and used a seperate periscopic sighting station viewed through a bubble, aft of the turret.

Duane

 

[slaterat]

I voted for the Zero. Its weaknesses are well documented , but in early 42 it had enough performance to overcome them. Of the allied rides its close, all have similar advantages regarding the Zero, ie dive speed and toughness. However, I would chose the Hurricane over the Wildcat or the P 40. It was pretty essential for all three of them to need an altitude advantage to defeat the Zero and the Hurricane has the best climb rate of the three.

Slaterat

 

[Doughboy]

I chose the Zero, because of its speed and maneuverability.

 

[HoHun]

Hi again,

>However, I still have to improve my F4F-3 model so that it reaches the 330 mph pointed out by the report. It is a bit short of this currently because I based it on the F4F-4's drag, and while the F4F-4 is often criticized for the extra weight it put on, the report you found shows that it also put on a bit of extra drag along with the weight - the extra gun barrel opening is an obvious source of some of that drag, and the small gaps in the wing skinning necessary for the folding wings are another.

Here is the comparison again with the improved F4F-3 data and the P-39D data finally added.

Regards,

Henning (HoHun)

 

[HoHun]

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[HoHun]

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[Vincenzo]

Merlin's P-40 there weren't in pacific in '42?

 

[syscom3]

Thanks Hohun.

 

[lesofprimus]

Gotta go with the Zero-sen in 1942....