# P-39 or P-40 for rest of war?



## Jerry W. Loper (Apr 9, 2010)

You're the officer in command of a small country's fighter defense squadrons. Let's say the country is Australia and the date is December 1941 or January 1942. The crazy Japanese just bombed Pearl Harbor and are running rampant in the Pacific. For the rest of the war, your squadrons will be provided an adequate supply of American single-seat fighters. The catch is, they'll be either P-39s or P-40s (all the different models of each main type will become available). The responsibility of the squadrons under your command will just be defense of your country, not advancing against Japan. Which type would you pick?


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## Colin1 (Apr 9, 2010)

If the constraints are

single-stage Allison technology
interception only

then it's got to be the P-39. It was faster than any version of the P-40 and was more powerfully armed.

Range will still be an issue, even for interception, Australia is rather large.


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## timshatz (Apr 9, 2010)

Colin has hit the nail on the head with the problem both aircraft give you. Range. Neither has anything worth talking about. Not even sure which is better but I would guess it would be slightly better in the P40. But, that besides, I would go with the P40. It was still in service with the Allied Forces (USAAF, RAAF and RNAF) long after the P39 was relagated to second line allies (France, Italy, ect.) and the Soviets. There had to be a reason for that. 

Either way, it's gonna be a rough war for Australia if all they have is the P40 or P39


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## Nikademus (Apr 9, 2010)

The Russians preferred the P-39 over the P-40 and used it right up to the end of the war.


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## michaelmaltby (Apr 9, 2010)

Assuming that Japanese bombers are not attacking from high altitude, I would select the P-39. The key would be emulating the Soviets -- strip off the wing guns to save weight and operate with just the nose cannon and machine guns. Get close.

MM


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## Glider (Apr 9, 2010)

P40 all the way. The P39 had nasty spin habits its favourite being a flat spin and had significant COG problems. Such were these that in theory it was dangerous to fire the nose gun ammunition in that the plane shouldn't be flown without it in place.
In addition the P40 was a decent fighter at lower altitudes and was way ahead of the P39 in GA. Taking the wing guns off the P39 would leave it poorly armed, as the 37mm was at best marginal for air to air combat with a low mv and slow ROF.

Photo attached re the ammo, apologies to those who have seen it before


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## Thorlifter (Apr 9, 2010)

As much as it hurts to say, I'd have to go with the P-39. A bit less range, but faster, better armed, much better rate of climb. And who knows, if it was the front line fighter for Australia, it may have prompted a little better engine, especially if altitude was an issue with getting to the attacking bombers. 

But that's only if one of it's primary roles was bomber defense. If we are talking about using it primarily as a air superiority or a dog fighter, it's absolutely the P-40.


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## michaelmaltby (Apr 9, 2010)

Thorlifter - agreed 

MM


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## Colin1 (Apr 10, 2010)

Thorlifter said:


> But that's only if one of it's primary roles was bomber defense. If we are talking about using it primarily as a air superiority or a dog fighter, it's absolutely the P-40.


The P-39 could climb all over the Bf109E
If the Aussies did go ahead and do some work on the engine, who's to say it couldn't have climbed all over the Bf109F?


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## tomo pauk (Apr 10, 2010)

If we are allowed to use only the real planes, P-39 would've been my choice.

If we are allowed to modify (in a realistic way) either design, I'd go with P-40. 
The engine position allows for non-problematic engine change (Merlin 60 series would've been no-brainer, but we can consider Bristol Hercules, R-2600, R-2800 etc), it would have been easily lightened, version with just 4 x 0.50in would've had enough fire power for fighter's job, it was regarded as a sturdy plane, and the combat range was decent.


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## michaelmaltby (Apr 10, 2010)

A cannon is essential - the 37 mm Olds was problematic - but for close in work (as the Soviets practised) 2 50's + 37mm concentrated in the nose would be very effective against Zero's (when unavoidable) but mostly against the Betty's and other Japanese bombers that would be flying in to Oz.

Tomo - if you can "modify" the P-40  can I modify the AiraCobra - why not a Merlin?

MM


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## Shortround6 (Apr 10, 2010)

tomo pauk said:


> If we are allowed to use only the real planes, P-39 would've been my choice.
> 
> If we are allowed to modify (in a realistic way) either design, I'd go with P-40.
> The engine position allows for non-problematic engine change (Merlin 60 series would've been no-brainer, but we can consider Bristol Hercules, R-2600, R-2800 etc), it would have been easily lightened, version with just 4 x 0.50in would've had enough fire power for fighter's job, it was regarded as a sturdy plane, and the combat range was decent.



"Merlin 60 series would've been no-brainer"

It would have required a considerable amount of work. Perhaps more than was available at the time. 

Australia would have to make this decision at the end of 1941?

Merlin 60 series is still on the bench. Merlin 60 is heavier than the Merlin XX in the 40F and needs an inter-cooler stuffed somewhere in the plane. It could be done, see P-40 Q but you need an awful lot of redesign with the enemy knocking on the door. And then you are stuck with the P-40 airframe. You are stuck with it anyway in this thread but why put first rate engines in a second rate airframe?

Bristol Hercules does no good at this point in time. Engines come from England (you can forget license manufacture) and they don't have enough (unless you can kill bomber Harris).

We are already going over your 3rd engine choice and the 4th is even worse.

Have the Aussies demand P-40Fs and have done with it. 

Japanese planes may be light but cutting your bomber interceptors to 4 guns doesn't seem to be the answer.

"michaelmaltby"

can I modify the AiraCobra - why not a Merlin?

What does it get you, besides production problems?

Single speed single stage Merlin isn't going to change performance that much from existing P-39.
Two speed single stage Merlin can raise your combat ceiling by around 5,000ft. 
Two speed-two stage Merlin (60 series) is out. It won't fit without redesigning the plane.


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## michaelmaltby (Apr 10, 2010)

"... Two speed single stage Merlin can raise your combat ceiling by around 5,000ft. "

That's better than nothing - the Zero has the unmodified P-39 at a disadvantage as it currently stands.

But I'm NOT advocating modification  -- just lose the 30 cal's in the Cobra wings.

MM


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## tomo pauk (Apr 10, 2010)

Shortround6 said:


> "Merlin 60 series would've been no-brainer"
> 
> It would have required a considerable amount of work. Perhaps more than was available at the time.
> 
> ...



Of course, no Merlin 60s 'till 1943, but that's where the things would've gone likely 
Till then Merlin 20s would do.



> Bristol Hercules does no good at this point in time.



Same as Melin 60s, but perhaps as early as 1942.



> Engines come from England (you can forget license manufacture) and they don't have enough (unless you can kill bomber Harris).



I can do that as I can alter anything in past 



> We are already going over your 3rd engine choice and the 4th is even worse.



Here we disagree completely 



> Have the Aussies demand P-40Fs and have done with it.



You can't never had enough of engine power 



> Japanese planes may be light but cutting your bomber interceptors to 4 guns doesn't seem to be the answer.



The issue was getting to the altitude (even for not-so-underpowered Spit V, above Darwin eg.), not that 4 x 0.50in were not enough (eg. on Wildcats).


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## davebender (Apr 10, 2010)

The P-40 was perfectly capable of defeating most Japanese aircraft during December 1941. It's a fairly new design so I would expect performance improvements in future P-40 models. The P-40 was relatively easy to fly, which is critical for all those new green pilots. U.K. pilots already have considerable experience with the P-40 by December 1941 and reports have been generally favorable.


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## Juha (Apr 10, 2010)

Hello
first of all, Glider, thank for the photo, I had seen previously only the original official b/w photos on ammo mags of P-39.

Difficult to say which one, Soviets thought P-39 clearly better than P-40, in Western AFs opinion was the opposite. IMHO removal of the wing armament didn’t make P-39 too weakly armed against Japanese a/c, 2 heavy mgs was enough against Jap fighters and with 37mm, it needed careful maintenance to work properly with some small mods in ejection tube, Jap bombers could be rather easy targets. Soviets didn’t complain, at least not much, on the cannon.
Westerners clearly liked P-40 more and at least it was easier to fly. The two heavy mgs in nose of the early P-40s was enough for Jap fighters and the later with 4-6 heavy mgs in wings had enough firepower for Jap bombers. So IMHO so-so, but I’d pick up P-39, really a subjective choice.

Juha


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## Glider (Apr 10, 2010)

I don't doubt that the 37mm would be lethal against bombers of any nation, after all they don't move around much and are a lot bigger. The twin 0.5 in the nose is sufficient against early Jap fighters but some of the later ones were more robust. However if you are up against any other nation then it would be on the light side.

Give the bombers an escort and the P39 would be in trouble.

Neither did well at altitude its a question of degree. I admit to not knowing a lot about the P39's performance to be able to make a knowledgable statement.


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## Markus (Apr 10, 2010)

P-40, no doubt at all. Both are faster than an A6M/Ki-43, have esentially the same engine with the same critical altitude but the P-40 has a better range and the latest version(-F) has a Merlin engine that gives her a better performance at higher altitudes. Considering the impressive altitudes the Japanese bombers operate at I´d very much like to get my hands on a few hundered P-40F.


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## michaelmaltby (Apr 10, 2010)

".... Give the bombers an escort and the P39 would be in trouble...."

I'm not sure that's true. The Soviets based much of their P-39 tactics on fighting in the "vertical axis". The P-39 is faster, more powerful and a wee bit heavier than the Zero. Using the P-39 to advantage comes down to tactics - the same way that the Chenault AF used P-40 tactics against the Japanese.

Like Juha, I find my preference for the P-39 "subjective" - it's the right machine for pilots with a certain style. Yeager never fought in the P-39 but he really like to fly it. 

The Russians never "officially" complained to Bell about the deadly "flat spin" but when the Soviet test pilot was in Buffalo (the story goes ) he threw a P-39 into a flat spin and then recovered.

Maybe the Russians were just "grateful" for modern, well-made stuff - 

MM


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## Shortround6 (Apr 10, 2010)

Problems with P-39 in 1941-42 is that early installations of the 37mm were bad. Problem with ejection chute. Gun was good for 1-2 shots and then jammed. 
2 synchronized .50cals is not the hottest armament. The big Browning did not take to synchronization well and rate of fire fell from around 800rpm to under 500rpm. although that does extend the firing time of 200rpg the P-39 carried.
Maybe they should leave the .30s in the wings.
Cut the .30 ammo to 400rds per gun?


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## davebender (Apr 10, 2010)

The shorter range of the P-39 would be a serious issue in the Pacific (i.e. where Australia is located). It would not be as much of a problem in the European war.


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## Colin1 (Apr 10, 2010)

davebender said:


> The shorter range of the P-39 would be a serious issue in the Pacific (i.e. where Australia is located). It would not be as much of a problem in the European war.


Both types would have range issues in the Pacific
one of the constraints imposed by the OP was mainland defence only

In the ETO you'd be trading one set of problems for another, the single-stage Allisons would not be able to compete with the Luftwaffe


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## Thorlifter (Apr 10, 2010)

Colin1 said:


> The P-39 could climb all over the Bf109E
> If the Aussies did go ahead and do some work on the engine, who's to say it couldn't have climbed all over the Bf109F?



True Colin, but the scenario is for Australia. Their primary advisary would have been the Zeros, G4M's, and Oscars, not Luftwaffe fighters.

As I noted, I gave a big advantage to the P-39 over the P-40 in regards to rate of climb.


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## Colin1 (Apr 10, 2010)

Thorlifter said:


> True Colin, but the scenario is for Australia. Their primary adversary would have been the Zeros, G4Ms, and Oscars, not Luftwaffe fighters.
> 
> As I noted, I gave a big advantage to the P-39 over the P-40 in regards to rate of climb.


My point
not clearly made, was that the P-39 had it over arguably the best fighter in Europe at the time for manoeuvrability and the best fighter in the Pacific for speed.


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## vanir (Apr 10, 2010)

Australia did evaluate both, the P-39D's were assigned to "intercept" duties near Canberra (82 Sqn) whilst P-40 training squadrons were sent north and west. I believe the main factors in settling on the P-40 was ease of pilot training and conversion to the type and it was assumed this was the most likely model to experience continued development in the 'States. In fact from what I've read if it wasn't for the Russians the P-39 would've passed out of production before the N series.

Also gettings parts for the Merlin was difficult in Australia, it was very far away from Britain and primary strategic materiel for them and in the States Packard production fell short as it was. We used something like a dozen total Merlin engine P-40's through the whole war and always relied on the Allison. Parts were available without having to set up local manufacturing. The main reason we took the Beaufighter was because we started making Hercs, I believing taking on licensed Merlins would've been harder.

I do believe the F-series Allison should've been fitted with a two-speed Merlin XX style supercharger from the start, the reason it wasn't was bureacratic. I mean aside from the whole high altitude, turbosupercharged thing, just making the F-series more like the Merlin XX for supercharger performance, after all the Packard was a Merlin XX.

In any case I'm with the RAAF on this. The P-40 was by far the better choice. My personal preference, as a pilot? The P-39.


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## michaelmaltby (Apr 10, 2010)

We are talking about defending Australian airspace - first and foremost - right??. The BofB with France being more than a few klics over the channel.

But the Japanese are NOT the LW. Their planes aren't up to German standards - overall - and their missions are long range.
To respond to these conditions the RAAF pilots faced with the realities of the sitution and the P-39 would have to adapt.

Both the P-39 and P-40 are less than ideal - so was the Brewster Buffalo - and we know what the Finns did with that. 

MM


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## Shortround6 (Apr 11, 2010)

vanir said:


> Also gettings parts for the Merlin was difficult in Australia, it was very far away from Britain and primary strategic materiel for them and in the States Packard production fell short as it was. We used something like a dozen total Merlin engine P-40's through the whole war and always relied on the Allison. Parts were available without having to set up local manufacturing. The main reason we took the Beaufighter was because we started making Hercs, I believing taking on licensed Merlins would've been harder.



Have you got a reference for the Australian Herc?

I believe Australia did make licensed Merlins, but perhaps not until the very end of the war or just after?


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## Glider (Apr 11, 2010)

Colin1 said:


> My point
> not clearly made, was that the P-39 had it over arguably the best fighter in Europe at the time for manoeuvrability and the best fighter in the Pacific for speed.



I am sorry but that doesn't fit in with my understanding. If the P39 was that good the RAF would have been yelling for more instead of getting rid of them as fast as possible.

There was a tactical comparison held between the Me109, P39 and Spit V in July 1941 and the report was presented in September 1941. 
Briefly below 20,000ft the P39 was superior in the level against the Bf 109E(speed and manoevrability) but above that the P39 lost its advantage of speed. The Bf109E could always climb faster than the P39. 
*Note* - It should be remembered that in mid late 1941 the P39 would be facing the 109F which was a significant improvement on the 109E

Against the Spit VB, 
Speed - at 13,000 ft the P39 was 18mph faster, at 15,000ft they were matched, at 20,000 ft the Spit was 35mph faster, at 24,000 ft the Spit was 55mph faster.
Climb - The Spitfire always outclimbed the P39
Turn - The Spitfire outurned the the P39 but it was close.
Take Off - The P39 had a ground run of 2,250ft the Spitfire 1,590ft.

Also the aircraft wasn't ready for combat. If the USAAF considered them to be ready it says a lot for the lack of testing that had been done. 
The list of problems included
a) The oxygen couldn't be turned on from the cockpit!!
b) The Gun Sight had to be changed so the pilot could see clearly out of the front of the aircraft
c) Ammunition Tanks for the 0.30 guns had to be changed as they distorted
d) The IFF had to be moved as it blocked the view to the rear.
e) Incorrect wiring had to be replaced
f) When the nose guns fired the carbon Monoxide levels in the cockpit could reach lethal levels.
g) Maintenance of guns was very difficult, all guns were inaccessible in particular
..i Time taken to remove the recoil mechanism of the 0.50
..ii problem with loading and unloading the 0.30
..iii allignment of the ammunition tanks
h) on firing tests the 0.30 jammed 36 pct of the time, the 0.50 22 pct of the time the 20mm worked perfectly.
I) Compass problems
j) Guns couldn't be fired at night as it destroyed the pilots night vision
k) Reserve fuel feed failure

So in summary the P39 was far from being the best fighter in Europe. The Spit V was better apart from speed at low altitude and the 109F was at least as good as the Spit V. Even the 109E could take care of itself above 20,000ft and 
By the time the P39 was available in numbers the Germans have the Fw190 and 109G entering service and the RAF the Spit IX, any of which was way ahead of the P39.


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## vanir (Apr 11, 2010)

> Have you got a reference for the Australian Herc?



After checking my memory with local records I stand corrected, the Beaufighter was license produced locally but the engines imported, I was certain I'd read somewhere the reason we produced the Beaufighter was because we were making Bristol engines (at Fisherman's Bend iirc) for other aircraft and it was readily adapted to license produce Hercs.
Not so after checking our local aviation museum sites, who clearly state they were all imported.

We did use Bulldogs in the RAAF/maybe we did make some other Bristol engine so perhaps that source was stating an assumption as fact. I should've checked.


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## Shortround6 (Apr 11, 2010)

vanir said:


> We did use Bulldogs in the RAAF/maybe we did make some other Bristol engine so perhaps that source was stating an assumption as fact. I should've checked.



I have read that even Bristol was using main bearings imported from Sweden for the Hercules (both by plane and by converted MGBs) as they couldn't get bearings of the quality they wanted from British sources. Not to cast aspersions on the Australians but it seemed doubtful that they could have solved the bearing supply problem (or the sleeve valve problem) on their own.

As far as the sleeve valves go there is a story about how six Sidestrand centerless grinders were diverted from delivery to a P&W plant in Kansas, put aboard the Queen Mary and rushed to England for Napair's use in making sleeves for the Sabre engine during the early crisis in it's manufacture. P&W was not happy

There is more to making engines than having a set of plans.


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## vanir (Apr 11, 2010)

Certainly so, from local metallurgy to everything else. Too true.


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## Colin1 (Apr 11, 2010)

Glider said:


> I am sorry but that doesn't fit in with my understanding...


Glider
there's nothing wrong with your understanding, you are quite right on all points
I didn't, however, claim that the P-39 was the best fighter in Europe, I stated that it was as manoeuverable as the best fighter in Europe. Note that I have not magicked the P-39 into two-stage supercharger land either, this is at the best altitude for the P-39, not the Bf109E.


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## davebender (Apr 11, 2010)

Yipes! We had problems with P-40s operating in the Philippines and the P-38 problems are well known. Makes me wonder about the quality of U.S. Army Air Corps leadership during WWII.


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## Markus (Apr 11, 2010)

On the PI it was logistics. Primitive bases, loooong supply line, brand new fighters(P-40B/E), green pilots, few spare parts.


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## Glider (Apr 11, 2010)

Colin1 said:


> Glider
> there's nothing wrong with your understanding, you are quite right on all points
> I didn't, however, claim that the P-39 was the best fighter in Europe, I stated that it was as manoeuverable as the best fighter in Europe. Note that I have not magicked the P-39 into two-stage supercharger land either, this is at the best altitude for the P-39, not the Bf109E.



I understand but we wil have to agree to disagree on choices. You take the P39 and I will take the 109F.


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## davebender (Apr 11, 2010)

That's directly connected to leadership as the majority of American military shipping was in the Pacific during the fall of 1941. Somebody established the wrong transportation priorities.

HyperWar: Strategic Planning for Coalition Warfare, 1941-42 [Appendix G]
*Nov 30, 1941*
529,164 DWT in the Pacific vs 249,350 DWT in the Atlantic.


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## Markus (Apr 12, 2010)

davebender said:


> That's directly connected to leadership as the majority of American military shipping was in the Pacific during the fall of 1941. Somebody established the wrong transportation priorities.
> 
> HyperWar: Strategic Planning for Coalition Warfare, 1941-42 [Appendix G]
> *Nov 30, 1941*
> 529,164 DWT in the Pacific vs 249,350 DWT in the Atlantic.




That reflects the view of the Japanese not attacking before mid-42. Besides, it was not so much how much but what was shipped that was wrong. "Swedish" P-35A instead of the proven P-36, B-17 instead of AA-guns and radar sets...

Back to the topic:

I took a look at "America´s 100,000" and both the P-39D and the P-40E seem useless as interceptors. The Japanese routinely operated at 25,000ft. It takes a P-39D 15 minutes to reach that altitude and ideally a fighter should start the attack from a few thousand feet above the target. Climb times for Warhawks are even worse, even for the F-version. So both planes would be used as medium altitude fighters and fighter bombers. The P-40 is the less complicated and more readily available of the two.


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## michaelmaltby (Apr 12, 2010)

"... The Japanese routinely operated at 25,000ft"

True - but attacks often were mixed - bombers _and_ dive bombers - the fighters stayed with the DB's (strafing and civilian terrorism) which brings them down to the prime altitude of the P-39's - 10,000 - 11,000 feet - vertical plane)

I posted earlier that the RAAF would have to devise "tactics" to suit the P-39's strengths: it is fast at low altitude, climbs well, has limited range but carries a 500 lb external payload.

*"Tactics*" : (fictional, of course )

1. -- Be air born quickly from widely dispersed strips. Reach 10,000 and assume climb-launch-attack attitude

2. -- Launch unguided, fragmentation rockets with timed fuses (for 25,000') at the bomber formations from about 10,000 feet. (The rockets are from an Austrian-developed "dispenser system" holding 8 missiles  mounted on the center-line hard-point of the P-39.). The dispenser is very basic and disposable 

3 Stay below 11,000' to take on the dive bombers, fighters and "wounded" bombers as they descend. (remember the Japanese bombers don't have SS gas tanks or armor) with the 37mm and the 2 50's in the nose.

Australia had the resources and industry to develop such a rocket dispenser system if they had been *forced *to fight with the P-39, IMHO. 

MM


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## Glider (Apr 12, 2010)

I notice that a number of posts have said that the P39 was good in the climb. If the P39D took 15 mins to get to 25,000 ft and its my belief that the A6M2 made 20,000 in around 8 mins, then to put it briefly it sucked.

Is my understanding correct ie that the P39 was very poor in the climb or have I got it very wrong?


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## davebender (Apr 12, 2010)

Both Hawaii and the Philippines had operational radar on December 7, 1941. In both cases they detected the Japanese air raids at a considerable distance. 

Everyone knows about the Pearl Harbor radar SNAFU. Here is a good description of the Philippine radar and their equally screwed up communications system.
From Shanghai to Corregidor: Marines in the Defense of the Philippines (Defenses of Manila Bay)


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## michaelmaltby (Apr 12, 2010)

Glider my numbers may be flawed but I'm reading (P-39) 3,333 rate of climb vs; (Zero) 2,812 feet per minute

I think the fact that the Soviets re-wrote their tactics to stress the vertical (under 10 - 11, 000 feet) with the P-39 is an indication that at low altitude it was no "dog" "-)

"... 15 mins to get to 25,000 ft " --- 8 minutes to get to "fighting" altitude with my tacrics. 

MM


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## Markus (Apr 12, 2010)

Glider said:


> I notice that a number of posts have said that the P39 was good in the climb. If the P39D took 15 mins to get to 25,000 ft and its my belief that the A6M2 made 20,000 in around 8 mins, then to put it briefly it sucked.
> 
> Is my understanding correct ie that the P39 was very poor in the climb or have I got it very wrong?




Depends. The P-39D´s climb rate was ~2,500 ft/min up to 12,000ft -the engine´s critical altitude -then the climb rate dropped to less than 1,000ft/min at 25,000ft. This translated into climb times of four, ten and fifteen minutes to 10, 20 and 25,000ft. The improved birds the Russians got could do it in three, seven and ten minutes but that´s not going to happen before 1943. 

Several websites say the A6M had a climb rate of 3,100ft/min and since she had a two-speed supercharger the critical altitude of the engine is likely to be well above 15,000ft. One source says an early Zero reached 20,00ft in 7.5 minutes. 

What bothers me is info that P-39 in Port Moresby ran for the sea when the Japanese attacked as they could not climb above them in time. (E. Bergerud: Fire in the Sky)


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## Nikademus (Apr 12, 2010)

Glider said:


> I notice that a number of posts have said that the P39 was good in the climb. If the P39D took 15 mins to get to 25,000 ft and its my belief that the A6M2 made 20,000 in around 8 mins, then to put it briefly it sucked.
> 
> Is my understanding correct ie that the P39 was very poor in the climb or have I got it very wrong?



I think it depended on the tactical situation. Dmitry Loza's "_Attack of the Airacobra's_" describes the development of high speed tactics that stressed Vertical maneuvers. The key points stressed were, "Altitude, speed, maneuver, fire" If the Cobra's kept their speed up and/or could dive down on their opponents they would be able convert it to quick altitude changes.


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## Nikademus (Apr 12, 2010)

Markus said:


> What bothers me is info that P-39 in Port Moresby ran for the sea when the Japanese attacked as they could not climb above them in time. (E. Bergerud: Fire in the Sky)



Believe part of that had to do with lack of early warning thx to the Owen Stanley mountains masking their approach. Zeros flew high cover and would tend to have alt advantage + the defenders would be at their most vulnerable while clawing for altitude. One difference i noted comparing Soviet and US experiences was that while the Airacobra would be comfortable in a turning fight against the Germans that would not be the case against Zeros, + Zeros can also quickly climb. If the Airacobra had a good burst of speed going and altitude was even, it would be in a much better position. Believe one or two A6M's were burned that way over Lunga. (Zeros down near ground level....P-400 comes blitzing in with all guns blazing at high level speed....boom)

A major change in tactics initiated within the 216th Fighter division while fighting the Kuban air campaign (mainly with Airacobra's along with a few Kittyhawks and Yak-1's) was dispensing with the old prescribed doctrine in regards to speed. It was too low, making the Soviet pilots patrolling more vulnerable. Higher speed was stressed along with pairs flying at different altitudes. The Soviet pilots would further increase their speed by trading altitude slowly. (essentially they adopted German Rotte and Scharm groupings)


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## Shortround6 (Apr 12, 2010)

michaelmaltby said:


> Glider my numbers may be flawed but I'm reading (P-39) 3,333 rate of climb vs; (Zero) 2,812 feet per minute
> 
> I think the fact that the Soviets re-wrote their tactics to stress the vertical (under 10 - 11, 000 feet) with the P-39 is an indication that at low altitude it was no "dog" "-)
> 
> ...



There are questions as to which P-39 you are comparing. 3 different engines. Early engine had 1150hp for take-off and low altitude with about 1125-1150 at 12,000ft. The next engine (in K&Ls) was good for 1325hp take off and still 1150 at 12,000ft but in WEP was good for 1590 at 2500ft. 3rd engine had 9.60 gears for the supercharger and traded low altitude power for height. 1200hp for take off and 1125 at 14,600ft WEP of 1420 at 9500ft. This engine was in the M, N, and Qs.
One book gives time to 25,000ft for a "D" model as 14.0 minutes while an "N" model could do it in 11.9min. 
The real kicker beiing that it took the "D" 4.9 min to get from 20,000ft to 25,000ft while the "N" took 6.1 minutes to get from 15,000 to 25,000. 
Russians also ditched the wing .50s and their ammo quite often.


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## billswagger (Apr 12, 2010)

Im also thinking that the location of battle is likely to include war ships and a large part of the defense would be to have the capacity to ward off any navy to prevent invasion or bombings, and in that case you'd need a P-40. It had a combat radius of 400 miles with a bomb load, and 700 miles in a fighter configuration. 

In that respect, i don't see the Japanese having the capability to fly high altitude missions where the P-40 couldn't also engage an attacking fleet. 
The Japanese planes had the range but their ships would need to remain outside the range of the P-40s striking distance and this might actually mean a high altitude offensive from the Japanese was impossible. With the P-40 offering more maneuverability and adequate fire power to stop anything the Japanese could throw at them.

I think if the mainland were some how breached and the Japanese had captured an airbase and were able to operate from a portion of Australia then the P-39 may be more applicable. It would be needed to engage at higher altitudes and it had much better speed than the P-40, which is why the Russians spoke so highly of it. It was really the first plane that let them fight on somewhat more even terms with the Germans. 
In this respect, the P-39 would be more suitable to stop multiengined bombers flying at higher altitudes and fast enough to avoid having to engage with enemy escorts. 
Other than that, the P-39s superior speed is not that much of an advantage over the P-40 because the Zero was slower than both, and what the P-39 made up for in climb lacked in turning ability. Its my belief that an army could not rely on the P-39 alone against the Japanese, but i couldn't say the same for the P-40, So, im thinking the P-40 is gonna be the better bird for this battle. 




Bill


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## Colin1 (Apr 12, 2010)

billswagger said:


> In this respect, the P-39 would be more suitable to stop multi-engined bombers flying at higher altitudes and fast enough to avoid having to engage with enemy escorts
> 
> Other than that, the P-39s superior speed is not that much of an advantage over the P-40 because the Zero was slower than both,
> 
> and what the P-39 made up for in climb lacked in turning ability


What advantage would the P-39 offer the Australians over the P-40 for higher-altitude work?

I don't recall the A6M being decisively slower than the P-40 at any stage up to late 1943/early 1944, when the A6M had other US fighters to worry about anyway.

The P-39 was not lacking in turning ability, unless you're comparing it with the Japanese fighters where most Allied fighters fell short.


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## Glider (Apr 12, 2010)

Can I thank everyone for their replies to my question. The consensus seems to be that the P39 had a speed advantage over the Japanese at all altitudes and could dive away from trouble. Its turn was good but not up to Japanese standards and its climb was average at lower altitudes and dire over 15,000.

For the P39 to have a chance depends on the Japanese attacking at low altitude and not twigging on to the problems the P39 had at altitude. If the Zero's are escorting bombers at say 20 - 25,000 ft then the P39 would be fighting for altitude with the Zero's diving on them. The only choice for the P39 would be to dive away and they would find it difficult to impossible to regain any height without getting shot to bits.

The various ft/min figures are interesting but often forgotten is that in a combat situation the angle of climb is at least as important as the rate of climb. The Zero clmbed at a very steep angle and few if any fighters at the start ofthe war could stay with them and if you cannot match the climb then you may well not be able to get your guns on target. Even if the P39D could climb at 3,000 ft/min then it can only do that for seconds or it wouldn't take 15mins to get to 25,000ft which averages out at about 1,600ft min.


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## michaelmaltby (Apr 12, 2010)

"... and not twigging on to the problems the P39 had at altitude". You know that's impossible. They *captured *Allison-powered US fighters.

MM


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## renrich (Apr 12, 2010)

Billswagger, don't know where you get the combat raius of the P40 but you are not even close. A landbased A6M barely had a combat radius of 500 miles. The P40 would be doing good to have a 175 mile CR.


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## Jabberwocky (Apr 12, 2010)

renrich said:


> Billswagger, don't know where you get the combat raius of the P40 but you are not even close. A landbased A6M barely had a combat radius of 500 miles. The P40 would be doing good to have a 175 mile CR.



Truth is somewhere in between actually:

Going off the RAAF P-40 data sheets:

Range (NOT radius):
Internal fuel:

P-40E: 675 miles
P-40F: 815 m
P-40K: 670 m
P-40M: 695 m
P-40N: 550 m

With External fuel:

P-40E: 1,110 miles
P-40F: 1,085 m
P-40K: 975 m
P-40M: 985 m
P-40N: 875 m

Typically, combat radius is ~35% of absolute range, so best radius for the P-40 would be about 390 miles for the P-40E with full internal and external tanks, for a P-40E. Worst is just 305 miles for the P-40N.

With just internal fuel, best combat radius is about 285 miles for P-40F (Merlin was slightly less thirsty than the Allison at cruise, only by about 5-10% though, depending on altitude). Worst is just 190 miles, again for the N.

Personally, I'd rather the P-40 than the P-39. While its performance is not quite as good, the aircraft can be more easily adapted for the Merlin, so you always have the potential of sticking a two speed, two stage Merlin in later in the war. Later war P-40L/P-40Ns were already pushing 360-370 mph with Merlins or higher alt rated Allisons, like the -81/-83.

You could go for a two aircraft solution: Longer ranged Merlin powered P-40s for high alt work (+16,000 ft), short ranged Allison powered versions with more power down low for low alt work and fighter bombing.

Range is better than the P-39's (by about 20-30% usually). This is important in Australia and later in the PAcific, where fighters will have to cover a lot of ground.

The P-40's ruggedness also lends itself to ground attack better. Ultimate bomb-load for the P-40 was 1,500 lbs, including 2 x 250 lbrs on each wing.

Its also less of a maintenance hog, and its easier to service.

Armament APPEARS heavier on the P-39, but the 37 mm was very unreliable and more a detriment than an asset. The P-40s 4/6 .50 armament is fine to deal with any likely opponent, with the possible exception of the heavy flying boats.


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## Glider (Apr 13, 2010)

michaelmaltby said:


> "... and not twigging on to the problems the P39 had at altitude". You know that's impossible. They *captured *Allison-powered US fighters.
> 
> MM



I know


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## Shortround6 (Apr 13, 2010)

Jabberwocky said:


> Personally, I'd rather the P-40 than the P-39. While its performance is not quite as good, the aircraft can be more easily adapted for the Merlin, so you always have the potential of sticking a two speed, two stage Merlin in later in the war. Later war P-40L/P-40Ns were already pushing 360-370 mph with Merlins or higher alt rated Allisons, like the -81/-83.
> 
> You could go for a two aircraft solution: Longer ranged Merlin powered P-40s for high alt work (+16,000 ft), short ranged Allison powered versions with more power down low for low alt work and fighter bombing.



I have my doubts about a two stage Merlin in a P-40, the engine may fit but you ave to stick the intercooler radiator somewhere.

P-40Es and Fs could already hit 360mph.


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## tomo pauk (Apr 13, 2010)

The 'in-between' solution to improve P-40 performance would've been installation of Merlin 40 series With 1400-1500 HP that seems the most expedient, and was very much feasible as early as mid 1941 (so the Aussies can get that at least in mid 1942 in their P-40s). 

The single-stage Merlin 40s were perhaps possible for P-39, but P-40 would've take it without too much rework.


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## billswagger (Apr 13, 2010)

Colin1 said:


> What advantage would the P-39 offer the Australians over the P-40 for higher-altitude work?
> 
> I don't recall the A6M being decisively slower than the P-40 at any stage up to late 1943/early 1944, when the A6M had other US fighters to worry about anyway.
> 
> The P-39 was not lacking in turning ability, unless you're comparing it with the Japanese fighters where most Allied fighters fell short.



The A6m was as much as 30mph to 50mph slower than the P-40 depending on altitude and variant. 

The P-39 was reported in Russian interviews to be significantly faster at 6000m than the P-40, It was also better in the vertical for this reason, however the Russians also maintained that the P-40 was better in the horizontal and a dogfight in the P-39 was to be avoided. I can only assume this means the P-39 was not particularly good at turn fighting, 

It also looks like i misinterpreted the ranges for the planes but the ideology is the same. 


Bill


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## MikeGazdik (Apr 13, 2010)

I think another important consideration is the willingness of the supplier (U.S. Army Air Corps) to provide needed aircraft. History shows they gave up on the P-39 early, whereas they kept the P-40 for issue to thier own air forces.

I think this would lead us again to the P-39 being released for export / Lend-Lease much sooner than the P-40. At least in much greater numbers.


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## Timppa (Apr 13, 2010)

Jerry W. Loper said:


> The responsibility of the squadrons under your command will just be defense of your country, not advancing against Japan. Which type would you pick?



P40, especially the P-40F (Merlin) submodel. Reasons:
- P-40F has significantly more range than any P-39 submodel.
- P-40F has slightly better high altitude performance.
- P-40 is much less prone to stall/spin, which is important in high altitude combat. Also it makes is less accident prone. Any commander hates losing pilots without enemy firing a shot.
- P-40 armament of six reliable .50's is very adequate against any Japanese aircraft. The 37mm cannon of the P-39 had some jamming problems, also it is a short range weapon due to low muzzle velocity.


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## davebender (Apr 13, 2010)

Formosa to Manila is about 550 miles. Historical evidence suggests A6M2s of the IJN 11th Air Fleet managed that trip several times with enough fuel remaining to engage the American defenders in combat.


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## bobbysocks (Apr 13, 2010)

how many P 40s/P39s were in still used in combat by 1944? a wealth of the US 40s were used for advanced fighter/gunnery training in GA or FL.


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## Vincenzo (Apr 13, 2010)

billswagger said:


> The A6m was as much as 30mph to 50mph slower than the P-40 depending on altitude and variant.
> 
> Bill



maybe but over 6000 meters Zero were fastest, and also at P-40 FTH 50 mph slower afaik it's too for contemporary P-40 and Zero


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## Colin1 (Apr 13, 2010)

Vincenzo said:


> maybe but over 6000 meters Zero were fastest, and also at P-40 FTH 50 mph slower afaik it's too for contemporary P-40 and Zero


I agree
I've never seen any evidence to suggest that a P-40 variant was ever 50mph faster than an A6M variant, the greatest speed differential between the two fighters was in the early incarnations of both types; the P-40B was around 34mph faster than the A6M2 and this at altitudes favouring the P-40. 

The P-40 most likely to cut it against the A6M at altitude, the P-40L (or F, if you can stand the 4mph drop in max speed).


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## tomo pauk (Apr 13, 2010)

Agree with Colin Vicenco.

Think we could consider the P-40N as a competitor vs. Zeros too. It was able to top 600 km/h, admittedly on a modest altitude.


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## Colin1 (Apr 13, 2010)

tomo pauk said:


> Think we could consider the P-40N as a competitor vs. Zeros too. It was able to top 600 km/h, admittedly on a modest altitude.


The P-40N was a howler
quite how Curtiss could get a P-40L to 368mph @ 20,000ft then succeed it with a model that could manage 378mph @ 10,000ft is a mystery; it baffles me that it was made in greater numbers than any other variant at a time when P-40 production should have ceased.

Contemporary of the P-40N was the Ki-84, offering near-400mph performance at twice the height of the N.


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## Shortround6 (Apr 13, 2010)

Colin1 said:


> I agree
> I've never seen any evidence to suggest that a P-40 variant was ever 50mph faster than an A6M variant, the greatest speed deficit between the two fighters was in the early incarnations of both types; the P-40B was around 34mph faster than the A6M2 and this at altitudes favouring the P-40.
> 
> The P-40 most likely to cut it against the A6M at altitude, the P-40L (or F, if you can stand the 4mph drop in max speed).



I can sure take the 4mph drop in max speed, considering it was at 5,000ft higher than the Speed from the "E" model. at around 22,000ft the "F" was actually about 20-30mph faster than an "E" although the "E" was 10-20 MPH faster from sea level to over 15,000ft.

"F"s start coming of the production line in the beginning of 1942. It might be interesting to see what an "F" or "L" model could have done if given the "N" treatment (Mag wheels, aluminum radiators, and so on) Although the armament reduction was carried a little too far.


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## billswagger (Apr 13, 2010)

Vincenzo said:


> maybe but over 6000 meters Zero were fastest, and also at P-40 FTH 50 mph slower afaik it's too for contemporary P-40 and Zero



which is why in the context of the previous paragraphs i wrote, the P-39 would be the better plane. Given the range of the battles and the fact japan would be fighting from sea, Zeros aren't likely to be flying at 6000m. 




Colin1 said:


> I agree
> I've never seen any evidence to suggest that a P-40 variant was ever 50mph faster than an A6M variant, the greatest speed deficit between the two fighters was in the early incarnations of both types; the P-40B was around 34mph faster than the A6M2 and this at altitudes favouring the P-40.



There is evidence.You are thinking of top speeds at full throttle heights, plus the Allison was discovered to have a greater potential at lower altitudes. The P-40E could run at 70" boost under 10,000ft which gave the bird a considerable jump on low flying Zeros. 

Its not like the Zero was the only plane to contend with, either.

Eric Schilling of the AVG was able to give a run down of top speeds at medium altitudes where most combat was flown:
"The P-40B was. . .
40 mph faster than the AM6-2 (21) Zero. 
50 mph faster than the Hyabusa, or Ki-43.
70 mph faster than the fixed gear I-96.
195 mph faster than the cruise speed of the Ki-21 Sally.
130 mph faster in a dive than any Japanese fighter.
3 times the roll rate of the Zero."

There is little mention of the Ki-44 through 100, including the ki-84 and ki-61, but my thinking is that these planes would be operating at higher altitudes, per their design, but competing with a later model P-40K,M or N was more likely to be fought at lower altitudes where the P-40 met on even terms or even held a speed advantage. 

I think the P-40 was still known to have many positive traits where its turn characteristics were more desired than the Mustangs in some parts of the Pacific. Had the fights been at higher altitudes, then i think it would've been a different story. 
It may have also been because the Mustang was seen as an easy target because of its radiator which for some reason didn't plague the P-40 the same way. At least the literature suggests the Allison was well armored, and perhaps the the location of the radiator was less susceptible than the Mustangs. (front vs lower rear) 

For me, its the P-40 turn characteristics that win it over the P-39 to answer the OP. The P-39 had a different center of gravity which set it up for a nasty stall and was not able to turn the same way, despite being faster than the P-40, The P-39 still had a place in lower altitude combat and the cannons could be very destructive to bombers, but if i had to choose one it would be the 40. 


Bill


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## Shortround6 (Apr 13, 2010)

If the Australians have to a make a choice in Late 1941 or Early 1942 (DEC-Feb) it won't be a P-40B or C. Both have been out of production for a number of months. Unless of course, they are forced to fly well used handme downs.


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## Nikademus (Apr 13, 2010)

billswagger said:


> Dave Schilling of the AVG was able to give a run down of top speeds at medium altitudes where most combat was flown:
> "The P-40B was. . .
> 40 mph faster than the AM6-2 (21) Zero.
> 50 mph faster than the Hyabusa, or Ki-43.
> ...



Dave Schilling? Do you mean Eric Schilling? Not the most reliable source from what i've read.


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## billswagger (Apr 13, 2010)

Nikademus said:


> Dave Schilling? Do you mean Eric Schilling? Not the most reliable source from what i've read.



dang it. yes Eric Schilling, and i also question some of the things he says but the numbers here are actually close enough to quote.



Bill


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## Vincenzo (Apr 14, 2010)

billswagger said:


> There is evidence.You are thinking of top speeds at full throttle heights, plus the Allison was discovered to have a greater potential at lower altitudes. The P-40E could run at 70" boost under 10,000ft which gave the bird a considerable jump on low flying Zeros.
> 
> Its not like the Zero was the only plane to contend with, either.
> 
> ...



for Schilling i'm agree with Nikademus

for speed: so P-40E go to 350 mph at sea lavel (put that A6M3 go to 300 mph)? or go a 385 mph at 10000 ft (put that A6M3 go to 335 mph) ?


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## Timppa (Apr 14, 2010)

billswagger said:


> which is why in the context of the previous paragraphs i wrote, the P-39 would be the better plane. Given the range of the battles and the fact japan would be fighting from sea, Zeros aren't likely to be flying at 6000m.
> Bill



According to this description of one raid against Darwin, The Japanese fighter escort was at 31,000 feet (9450m), and the bombers were at 26,000 feet (7900m).
The day the planes "all fell into the sea": Darwin Raid 54-2 May 1943. | Goliath Business News
AFAIK these altitudes were not exceptional.


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## Vincenzo (Apr 14, 2010)

Vincenzo said:


> maybe but over 6000 meters Zero were fastest, and also at P-40 FTH 50 mph slower afaik it's too for contemporary P-40 and Zero



i want partially correcr this the merlin engined P-40s was faster of Zero also at high quote but never of 50 mph (max around 30 mph)


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## claidemore (Apr 14, 2010)

In hindsight the P40N and F are both pretty good airplanes vs the various Japanese planes. 
However, at the point of making a decision to use one type to wars end, we would be looking at P40E and P39D. Below is a comparison chart of the types Australia had access to. Available here:Perils P40 Archive Data
Using that particular chart in a staff meeting to make a decision, the Spitfire VC is going to be picked! 
For purposes of the question in this thread though: given the distances involved in that theatre, and the slim perf advantage of the P39, the P40 would be my choice because of better endurance and range on internal fuel. Drop the tanks, fight for 10 minutes, and then make it back to base.

{why pick Spit VC when range is my determining factor for picking P40? The Spit has significant performance advantage, 35 mph vmax, +6000 ft celing, half the time to climb to 20k. Which is why you shouldn't have one type, different missions require different planes.}


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## billswagger (Apr 14, 2010)

Timppa said:


> According to this description of one raid against Darwin, The Japanese fighter escort was at 31,000 feet (9450m), and the bombers were at 26,000 feet (7900m).
> The day the planes "all fell into the sea": Darwin Raid 54-2 May 1943. | Goliath Business News
> AFAIK these altitudes were not exceptional.



That was an interesting read. I guess the capability was there, but it doesn't seem like such high altitude efforts were very effective. 

Most of the damage done by the Japanese involved attacks on shipping with the use of submarines. 





Vincenzo said:


> i want partially correcr this the merlin engined P-40s was faster of Zero also at high quote but never of 50 mph (max around 30 mph)



The 30-50mph speed difference was a generalization, and dependent on variant and altitudes. A P-40E is closer to 50mph faster than an A6M2, and a P-40B is still faster than an A6M3. You can look up exact numbers if you want to beat me up over exact numbers. 
Comparing top speeds is really apples to apples when you consider the disparity in dive speeds, which is what made the P-40 so much faster than the a6m in the first place. On top of that, the P-40 was decisively faster than the A6M in level flight.


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## Vincenzo (Apr 14, 2010)

afaik P-40B was not faster of A6M3, and P-40E is closer to 50mph faster of A6M2 only if this don't go a max power (2550 rpm +250 mm Hg)


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## tomo pauk (Apr 14, 2010)

Is there a table that lists speeds of various Zero marks available online?


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## Colin1 (Apr 14, 2010)

tomo pauk said:


> Is there a table that lists speeds of various Zero marks available online?



______________________________*A6M1_________A6M2_________A6M3_________A6M5_________A6M7*
*Engine:____________________*Zuisei 13_________Sakae 12________Sakae 21_________Sakae 21________Sakae 31a
*TO hp:_____________________*780_____________940____________1130____________1130__________1130
*Loaded weight:______________*5,155lbs_________5,313lbs_________5,609lbs_________6,025lbs________6,600lbs
*Wing loading lb/sq ft:_________*21.3____________22.0____________24.2_____________26.3__________28.9
*Power loading lb/sq ft:________*5.9_____________5.4_____________5.7______________6.1___________6.7
*Max speed:_________________*316.3mph________331.5mph_______338mph__________351mph________337mph
*@ altitude:_________________*11,800ft_________14,930ft_________19,685ft_________19,685ft________20,992ft
*Rate of climb:_______________*7 min 15sec to____5 min 50sec to____7 min 19 sec to____7 min 1sec to____7 min 58sec to
_____________________________16,400ft_________16,400ft________19,680ft__________19,680ft________19,680ft
*Ceiling:____________________*n/k_____________33,780ft_________36,240ft__________36,240ft_______33,390ft
*Range:____________________*n/k_____________1,930___________1,447_____________1,194_________943


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## michaelmaltby (Apr 14, 2010)

"... how Curtiss could get a P-40L to 368mph @ 20,000ft then succeed it with a model that could manage 378mph @ 10,000ft is a mystery; it baffles me that it was made in greater numbers than any other variant at a time when P-40 production should have ceased."

Colin1 I agree - the whole P-40 story is a bit of a "mystery". The company was publicly (in the stock market sense of the word public) active during the war - it imploded in on itself almost immediately after war end - the attitude about Curtiss wartime achievement is "cynical" (no "star" in their livery) but overall *they clearly new how to "build" mass produced planes*. The P-40, the Commando C-46, the Hell Diver, and a bunch of specialty stuff.

I tried googling "Donovan Berlin" but can find nothing on the internet. Colin1 what do you know about the mysterious Mr. Berlin 

MM


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## Vincenzo (Apr 14, 2010)

Colin1 said:


> ______________________________*A6M1_________A6M2_________A6M3_________A6M5_________A6M7*
> *Engine:____________________*Zuisei 13_________Sakae 12________Sakae 21_________Sakae 21________Sakae 31a
> *TO hp:_____________________*780_____________940____________1130____________1130__________1130
> *Loaded weight:______________*5,155lbs_________5,313lbs_________5,609lbs_________6,025lbs________6,600lbs
> ...



this are from Francillon?

i've not source to support but after years looking data on web the speed of A6M2 it a bit too slow (335/345 afaik) the speed of A6M3 it's too slow (350/360 afaik) and M5 a bit too slow (355/365 afaik). the M5 with same engine of M£ go 13mph fast in this table i think a bit high for only the individual exhaust stubs


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## Colin1 (Apr 14, 2010)

michaelmaltby said:


> I tried googling "Donovan Berlin" but can find nothing on the internet. Colin1 what do you know about the mysterious Mr. Berlin


Not a great deal
Ralph Damon transitioned (along with the company) from President of Curtiss-Wright Airplane Company to VP and General Manager of Curtiss Aeroplane and Motor Company in 1934, moving to Buffalo NY in the process. In the same year the USAAC put out a circular for a new single-seater fighter for a competition to be held in 1935. They (the USAAC) were looking for something that offered a 'significant advance' over the P-26.

Damon, having seen CW lose one fighter contract to Boeing and an attack aircraft contract to Northrop saw this as an opportunity to win some significant Air Corps business.

He hired Donovan Berlin, who was the Chief Engineer at Northrop prior to leaving the company. Berlin's portfolio whilst at Northrop consisted of programs such as the all-metal, low-wing monoplanes that Northrop had made throughout the 30s. He too, moved to Buffalo and commenced work on the new fighter for the Design 75 program.

The Model 75, as it became known, was once again an all-metal, low-wing monoplane but structural support and bracing were all internal. It had an enclosed cockpit and retractable landing gear; though not revolutionary, it was a break from the past.

I've no idea why Berlin left Curtiss-Wright, it doesn't appear to be well documented but I did come by a book in the middle of last year, currently sitting patiently on my shelf for its turn at the reading table:

Curtiss-Wright
Greatness and Decline

Louis R Eltscher
Edward M Young

ISBN: 0-8057-9829-3

It's a book about Curtiss-Wright, make no mistake, it's not about P-40s or any other CW model but I'm hoping it will offer me insight into the shenanigans going on at Curtiss-Wright at the close of WWII.

I'll see if it throws up any light on the life and times (and fate) of Mr Berlin.


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## michaelmaltby (Apr 14, 2010)

Thanks Colin1 - I love the P-39 and read Lawrence Bell's biography for the same reasons - I got a couple of nuggets from the book. Larry Bell wanted to give Soviet pilots who flew P-39's ZIPPO Lighters  but that idea was vetoed. He once said that he might as well push all the P-39's Bell built into the lake for all the "feedback" he got from the Russians on how they actually USED his planes. 

Did Berlin DO anything after WW2?

MM


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## tomo pauk (Apr 14, 2010)

Thanks indeed, Colin 

The 1st mark available to the Aussies would've been P-40E; some 15-25 mph faster then M2 M3. The RAAF would've had to wait till the dash-N arrives (mid/late '43?), being faster than those two marks by 50 mph indeed. The M5 M6 would've halved that though, plus their speed was achieved at greater altitude, meaning that if RAAF boys were to intercept a major raid, they would've had really a troublesome time to do that. 
Not unlike the air raids vs. Darwin, where Spits V struggled many times.

Perhaps the P-40F (Merlin XX, two-speed supercharger vs. single speed in Allison) would've been the best solution? With 350 mph @ 20kft it would've been pretty speedy, not giving any advantage in horizontal speed category, and many of weight-reduction measures applied to the P-40N would have make it slightly faster, but also much more better climber.


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## Colin1 (Apr 14, 2010)

michaelmaltby said:


> Did Berlin DO anything after WW2?


I have no idea whatsoever what Berlin did after the war, I have never found anything on his post-war career.

This link rang a very vague bell, I posted it a while ago and faintly remembered an opening piece about Berlin's exit from Curtiss-Wright; it just seems that it's not well documented

http://www.ww2aircraft.net/forum/aircraft-pictures/curtiss-p-40-pictorial-history-19032.html


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## tomo pauk (Apr 14, 2010)

FWIW, here are the figures for P-39. The altitude of the max speeds achieved, I'd say those were achieved at altitudes ranging from 12,5kft (for earlier models) to 15kft (for later models) :


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## Juha (Apr 14, 2010)

Hello Vincenzo
Colin's data is more or less identical to Japanese specification card for Zero types from A6M3 Model 32 onwards, but there has been discussion on what the speed figures really are. Are the figures max speeds in western sense or are they the speeds quaranteed by the manufacture.

Juha


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## michaelmaltby (Apr 14, 2010)

"... until he left its employ in December 1941."

Thanks for the great colinlink, Colin1. A lot of work went into that.

By his departure date at CW in '41 - I'd say he went over to GM-Fisher and joined a failed-before-it-started venture 

MM


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## Colin1 (Apr 14, 2010)

michaelmaltby said:


> Thanks for the great link, Colin1. A lot of work went into that


lol oh I definitely remember the link generally
the pics were awful - dark as hell and still not that sharp even after I cleaned them up
Still, I don't suppose they were taken with 2009 in mind...


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## michaelmaltby (Apr 14, 2010)

The P-40 - like the Hawker Hurricane - is one of those "obsolete when the war started" planes that just kept "competing".
And the P-40 was certainly more advanced than the Hurricane ... but similar longevity. The Soviets liked neither the Hurricane nor the P-40 .

MM


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## Vincenzo (Apr 14, 2010)

Juha said:


> Hello Vincenzo
> Colin's data is more or less identical to Japanese specification card for Zero types from A6M3 Model 32 onwards, but there has been discussion on what the speed figures really are. Are the figures max speeds in western sense or are they the speeds quaranteed by the manufacture.
> 
> Juha



as i understand the point there are discussion also on what power setting they are


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## Shortround6 (Apr 14, 2010)

tomo pauk said:


> Perhaps the P-40F (Merlin XX, two-speed supercharger vs. single speed in Allison) would've been the best solution? With 350 mph @ 20kft it would've been pretty speedy, not giving any advantage in horizontal speed category, and many of weight-reduction measures applied to the P-40N would have make it slightly faster, but also much more better climber.



It was supposed to be a bit faster than that, 364 at 20,000ft?

The "N" is a bit of a joke, it is also a collection of planes that vary quite bit from each other depending on block number. By the time you get to some of the last "N"s the speed is down to 343 mph at 15,000ft. Some of the weight saving tricks were reversed, like putting the electric starter and battery back in the plane. I have a feeling the the 378mph at 10,000ft is a misprint. 

Some of the other weight saving tricks were not only removing two .50cal MGs but cutting the ammo for the remaining guns from 281 rpg to 201rpg. 

An "F" with the lighter radiators and lighter wheels and 4 guns with full ammo might have been interesting.


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## Colin1 (Apr 15, 2010)

Another morsel I managed to dig up, Berlin went on post-war to work on the FH-1 Phantom and Boeing-Vertol Chinook programs


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## tomo pauk (Apr 15, 2010)

Shortround6 said:


> It was supposed to be a bit faster than that, 364 at 20,000ft?



Indeed 


> The "N" is a bit of a joke, it is also a collection of planes that vary quite bit from each other depending on block number. By the time you get to some of the last "N"s the speed is down to 343 mph at 15,000ft. Some of the weight saving tricks were reversed, like putting the electric starter and battery back in the plane.



Perhaps they've just given up making the P-40 fast, decided that good bomb load, good range durability was more useful than 10-20 extra mph, when really fast fighters were coming from production lines (something like RAF 'did' to Hurricane)?


> I have a feeling the the 378mph at 10,000ft is a misprint.



Perhaps it was achieved by WEP?



> Some of the other weight saving tricks were not only removing two .50cal MGs but cutting the ammo for the remaining guns from 281 rpg to 201rpg.



Guess that was not popular with pilots...



> An "F" with the lighter radiators and lighter wheels and 4 guns with full ammo might have been interesting.



Not only for Aussies; Ruskies would've loved it too I guess.


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## Milosh (Apr 15, 2010)

Has this P-40 been mentioned?


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## Colin1 (Apr 15, 2010)

Milosh said:


> Has this P-40 been mentioned?


Was it around in December 1941 or January 1942?


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## claidemore (Apr 15, 2010)

The 378 mph speed listed for P40-N's is with WEP.


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## Milosh (Apr 15, 2010)

Colin1 said:


> Was it around in December 1941 or January 1942?



Thread title:

* P-39 or P-40 for rest of war?*

War ended in 1945, did it not?


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## Colin1 (Apr 15, 2010)

Milosh said:


> Thread title:
> 
> * P-39 or P-40 for rest of war?*
> 
> War ended in 1945, did it not?





Jerry W. Loper said:


> Let's say the country is Australia and *the date is December 1941 or January 1942*


There's alot of fighting to be done before the XP-40Q shows up


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## Markus (Apr 15, 2010)

michaelmaltby said:


> Thanks Colin1 - I love the P-39 and read Lawrence Bell's biography for the same reasons - I got a couple of nuggets from the book. Larry Bell wanted to give Soviet pilots who flew P-39's ZIPPO Lighters  but that idea was vetoed. He once said that he might as well push all the P-39's Bell built into the lake for all the "feedback" he got from the Russians on how they actually USED his planes.
> 
> Did Berlin DO anything after WW2?
> 
> MM



He went to GM first, working on the XP-75. A website says he worked for McDonnell later.


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## tomo pauk (Apr 15, 2010)

Hmm, P-40Q vs. P-63 Knig Cobra...
The two underdogs 

Tnx for the table, Claidemore.


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## Milosh (Apr 15, 2010)

Colin1 said:


> There's alot of fighting to be done before the XP-40Q shows up



Jerry W. Loper also said in the same post:
_"The catch is, they'll be either P-39s or P-40s (all the different models of each main type will become available)."_


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## michaelmaltby (Apr 15, 2010)

Don Berlin died in 1982. His obituary in the NYT DON R. BERLIN, 83, A DESIGNER OF AIRCRAFT FOR WORLD WAR II - Free Preview - The New York Times is unfortunately behind subscription firewall. 

I've had better luck finding about him as "Don" rather than Donovan.

The XP-75 was truly a dog's breakfast .

M


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## Nikademus (Apr 15, 2010)

Continuing to read through Loza's "_Attack of the Airacobras_." I found this entry to be of particular interest given the subject of this thread. Ancedotal of course......but _interesting_ non the less:

_The differing technical and tactical characteristics of the P-39 and P-40 aircraft that made up the patrol [45th Fighter Regiment, 216th Fighter Division, 15aprl 43] made it necessary to fight the battle at two levels, the Kittyhawks at the lower level and the Airacobras above them. Petrov directed his Kittyhawks to go after the bombers and the Airacobras to engage the Messerschmitts. It would have been better of course, had the Soviet patrol been comprised entirely of the P-39, which performed better at altitude than the P-40. [patrol was at 15,700 - 16,100 feet approx] In the current situation, the group leader always had to monitor the location of the P-40's and be prepared to render assistance to them._


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## billswagger (Apr 16, 2010)

Shortround6 said:


> It was supposed to be a bit faster than that, 364 at 20,000ft?
> 
> Some of the weight saving tricks were reversed, like putting the electric starter and battery back in the plane.



That wouldn't surprise me, considering that delays getting into the air actually made it a slower plane from a tactical standpoint. 

i remember reading a pilot that mentioned the Es would start up, roll down the runway and climb to 10,000ft by the time an N could be hand started and get rolling down the runway. Kind of makes for a pressing issue for a front line fighter. 

Bill


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## Shortround6 (Apr 16, 2010)

Nikademus said:


> Continuing to read through Loza's "_Attack of the Airacobras_." I found this entry to be of particular interest given the subject of this thread. Ancedotal of course......but _interesting_ non the less:


Which model Kittyhawk and which model Aircobra and did the Aircobra's still have wing guns?


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## Nikademus (Apr 16, 2010)

Shortround6 said:


> Which model Kittyhawk and which model Aircobra and did the Aircobra's still have wing guns?



Believe they were Mk I's, (P40E equiv). The Soviets received several different marks of P-39 (C, D, N etc) but per Loza's book, the bulk of them were P-39Q's. All had wing guns as part of the orig design but the Soviets began removing them as a matter of policy and requested that future deliveries delete them for them. Another inovation introduced was the re-wiring of the flight stick so that the Cannon and MG's could be fired via one trigger. (Orig design had seperate triggers for the MG's and the Cannon)


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## MikeGazdik (Apr 16, 2010)

Hindsight being 20/20, I think that the P-39 would evolve into the P-63 is just another plus for going with the Bell product!


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## tomo pauk (Apr 16, 2010)

You got that right; the best production version of P-40 (either -F or -N, as one likes it) was clearly inferior to KingCobra.


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## Colin1 (Apr 16, 2010)

Trying to get to the bottom of why a P-39 would be any better than a P-40 at altitude

*Engine__________P-39_________P-40___________hp/rpm/alt (ft)*
V-1710-17_________XP-39__________________________1150/3000/SL
Block -E2_________________________________________1150/3000/25,000

V-1710-19_______________________XP-40____________1060/2950/SL
Block -C13________________________________________1150/2950/25,000

V-1710-33_______________________B,C,E,G___________1040/2800/SL
Block -C15________________________________________1040/3000/14,300

V-1710-35_________C,D,E,F_________________________1150/3000/SL
Block -E4__________G, Q___________________________1150/3000/11,800

V-1710-37_________YP-39A,B_______________________1090/3000/SL

V-1710-F3R______________________D,E______________1150/3000/11,800
_______________________________XP-46,XP-51,A

V-1710-D2A________YP-39A_________________________1090/3000/13,200

V-1710-47_________XP-39E_________________________1325/3000/SL

V-1710-59_________J______________________________1100/2800/SL
Block -E12________________________________________1100/3000/15,200

V-1710-63_________D,K,L___________________________1325/3000/SL
Block -E6__________________________________________1150/3000/11,800

V-1710-73________________________XP-40K___________1150/3000/SL
Block -F4R________________________K________________1150/3000/11,800

V-1710-81________________________M,N,R____________1200/3000/SL
Block -F20R_______________________P-51A____________1125/3000/14,600

V-1710-83__________L,M,N,Q________________________1200/3000/SL
Block -E18_________________________________________1125/3000/14,600

V-1710-85__________M,N,Q__________________________1200/3000/SL
Block -E19_________________________________________1125/3000/14,600

V-1710-99________________________N________________1200/3000/SL
Block -F26R_________________________________________1125/3000/15,000

V-1710-115_______________________N_________________1200/3000/SL
Block -F31R_________________________________________1125/3000/15,000

V-1710-121_______________________XP-40Q____________1425/3000/SL
Block -F28R_________________________________________1100/3000/26,000


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## tomo pauk (Apr 16, 2010)

That was neat


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## Colin1 (Apr 16, 2010)

tomo pauk said:


> That was neat


It was definitely tricky...


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## Nikademus (Apr 16, 2010)

The re-occuring theme in Loza's account is vertical maneuvering. Guards Captain Aleksandr Pokryshkin and others felt that the P-39 was "somewhat superior" to the 109F and G in maneuverability in that mode. In the past when i think "vertical maneuvering" the 109 comes to mind first as this was a primary Jagdwaffe method used over Malta and in North Africa when facing Commonwealth forces. They had it easiest against Hurricanes and Tomahawk/Kittyhawks. Spitfires were the toughest and considered equal to their mounts. The one no-no mentioned more than once re: 109 vs. "Curtiss" type fighters (p40) was never get into a turning fight with them, esp at low to med altitude. 

Comments like the above regarding P-40's from Shores were echoed in Bergstrom's Black Cross/Red Star. Russian recipiants of Lend-Lease Tomahawks from the UK commented unfavorably about the plane's abilities in general in comparison to the Yak-1, including the vertical plane but noted that it's turning characteristics were superior to enemy Messerschmitts. (like the Airacobra, they were very appreciative of the radio included and considered this the Tomahawk's best feature since Russian fighter planes at the time didn't have them)

What makes Loza's book interesting is that the 216th flew four types of planes simotaniously in the beginning of their operations in the Kuban (Kittyhawks, Spitfires, P-39's and a few Spitfires)


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## riacrato (Apr 16, 2010)

Sorry but Curtiss all the way. I don't know if it has been brought up, but don't you think eventually the Curtiss would've been powered by the R-2800?


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## Colin1 (Apr 16, 2010)

riacrato said:


> ...don't you think eventually the Curtiss would've been powered by the R-2800?


Presumably that would be normally aspirated?
Or are we thinking of secretly turning the P-40 into a P-47?


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## riacrato (Apr 16, 2010)

Yes I was thinking that would turn the Curtiss into something like a dirty F4U. Not quite as good but still capable enough and likely still better than any P-39 including the king cobra. Especially if a laminar profile is introduced later (which I don't see why it shouldn't).

The Curtiss probably had the strength to carry such a heavy engine too and it is already proven that it could take a radial.


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## tomo pauk (Apr 16, 2010)

They managed to produce the XP-60 (basically P-40 with R-2800 reworked landing gear), but it was just able to best 400 mph. While still decent speed, it was not enough to compete with what USAAF had in usage in pipeline.


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## riacrato (Apr 16, 2010)

Careful and exhaustive study at wikipedia tells me it managed 666 km/h or 414 mph, arguably good enough for most of the war. Sure it's worse than P-51 or P-47 but imo better than P-39/P-63.


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## tomo pauk (Apr 16, 2010)

As good as Kingcobra - and as fast as Japanese or German opposition.
OTOH, it was judged as not satisfactory by USAAF, proving further that speed was just one category of a plane.

Producing F4U for USAAF (fixed wings, with at least 500 lbs saved) would've been far better step (yet out of scope of this thread).


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## timshatz (Apr 16, 2010)

riacrato said:


> Yes I was thinking that would turn the Curtiss into something like a dirty F4U. Not quite as good but still capable enough and likely still better than any P-39 including the king cobra. Especially if a laminar profile is introduced later (which I don't see why it shouldn't).
> 
> The Curtiss probably had the strength to carry such a heavy engine too and it is already proven that it could take a radial.



Keep in mind the P40 was derived from the P36, which was a radial engined bird. In that respect, putting an R-2800 on it would kinda be a normal evolution...sorta.


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## Colin1 (Apr 16, 2010)

The P-40 being described is becoming Uncle Tom's old axe; three new heads and four new shafts.
I don't think there is an evolutionary line between R-1830 and R-2800 simply because both were radials, that's akin to taking the 12Y out of a MS.406 and dropping in a Sabre IIB; the P-40 fuselage would need significant work.

Where is this laminar flow going to exist? Everything directly aft of the prop disk is turbulent and that undercart arrangement is going to spoil everything else, unless we're only seeking it outboard of the main gear.

It's not a P-40 any more.


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## Shortround6 (Apr 16, 2010)

riacrato said:


> Sorry but Curtiss all the way. I don't know if it has been brought up, but don't you think eventually the Curtiss would've been powered by the R-2800?



Not a chance.

unless you turn it into a P-60.
New wing, new landing gear, new fuselage from cockpit forward, New tail. 

Yep, it's a P-40, you can tell because we kept the canopy


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## Shortround6 (Apr 16, 2010)

timshatz said:


> Keep in mind the P40 was derived from the P36, which was a radial engined bird. In that respect, putting an R-2800 on it would kinda be a normal evolution...sorta.



Kind of like putting a 7 litre ford V-8 in an old Ford Capri, they were both V engines...sorta....


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## Juha (Apr 16, 2010)

Hello Riacrato
if XP-60 proto was only 4mph faster than fully combat ready P-63, I'd say that when burdened with all those things that were needed to make a fighter combat ready P-60 would be at best as fast as P-63.

Juha


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## timshatz (Apr 16, 2010)

Shortround6 said:


> Kind of like putting a 7 litre ford V-8 in an old Ford Capri, they were both V engines...sorta....



Knew a guy who actually did that. Well, a four barrel 5 litre. Forgot about the tranny. BANG, no tranny.


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## Markus (Apr 16, 2010)

riacrato said:


> Sorry but Curtiss all the way. I don't know if it has been brought up, but don't you think eventually the Curtiss would've been powered by the R-2800?



It should have been powered by the R-2600 right away. The engine was from Wright, not from a competitor and the first version was 60% more powerful than the V-1170. Once the decision for the V-1170 had been taken the best course of action would have been to press for an earlier introduction of the 2-stage supercharger.


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## riacrato (Apr 16, 2010)

Shortround6 said:


> Not a chance.
> 
> unless you turn it into a P-60.
> New wing, new landing gear, new fuselage from cockpit forward, New tail.
> ...



It's not like they are no major differences between P-39 and P-63.

Juha, true, but I'm careful with the figures of prototypes in general. Early DB603 powered Fw 190 were only around 660 something km/h later versions with tweaks and more streamlined layout were at ~740 km/h. I don't think this particular conversion (P-60) was ever given a reasonable chance (it simply was unnecessary), but when in doubt (performance being about equal) I'd give the conventional layout the go over the P-39 layout.


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## Juha (Apr 17, 2010)

Hello Riacrato
On Fw 190 with DB 603, yes, but IIRC the development took years, at least partly because of low priority at times. 

Juha


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## Shortround6 (Apr 17, 2010)

Markus said:


> It should have been powered by the R-2600 right away. The engine was from Wright, not from a competitor and the first version was 60% more powerful than the V-1170. Once the decision for the V-1170 had been taken the best course of action would have been to press for an earlier introduction of the 2-stage supercharger.



We were going over it on another thread. First versions (1938?)were 1500hp. By 1940-41 it had gotten to 1600hp for take off but was only offering about another 300hp (30%) at 12,000ft or so over the Allison to counter it's greater weight and bulk.

By the way there was at least one plane if not two with 2 stage superchargers that competed in the 1939 Fighter trials. A Curtiss 75 with a two stage P&W R-1930 and Seversky derivative of the P-35 with the same engine but it did have inward retracting landing gear. Pictures of the Hawk show a rather large intercooler mounted below the fuselage under the wing trailing edge.


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## Markus (Apr 17, 2010)

Shortround6 said:


> We were going over it on another thread. First versions (1938?)were 1500hp. By 1940-41 it had gotten to 1600hp for take off but was only offering about another 300hp (30%) at 12,000ft or so over the Allison to counter it's greater weight and bulk.



What kind of supercharger? 1-stage, 1-speed I assume. When the war broke out Wright already had a 2-speed SC in production for the smaller R-1820. Worth a try.


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## Shortround6 (Apr 17, 2010)

Markus said:


> What kind of supercharger? 1-stage, 1-speed I assume. When the war broke out Wright already had a 2-speed SC in production for the smaller R-1820. Worth a try.



No, that is with a two speed single stage supercharger.


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## Markus (Apr 17, 2010)

Shortround6 said:


> No, that is with a two speed single stage supercharger.



Ahh, but I assume above 12,000ft the gap between the two engines widened. The critical altitude of the R-2600 must have been around 18,000ft. The V-1710-39 generated ~900hp up there.


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## Colin1 (Apr 17, 2010)

Markus said:


> The critical altitude of the R-2600 must have been around 18,000ft. The V-1710-39 generated ~900hp up there


There's alot of block numbers associated with the R-2600
The R-2600-8/A ran hp/rpm/alt (ft) figures of 1450/2400/21,000. Later marks, the -15, -17 and -19s ran 1750/2600/29,500


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## Shortround6 (Apr 17, 2010)

Markus said:


> Ahh, but I assume above 12,000ft the gap between the two engines widened. The critical altitude of the R-2600 must have been around 18,000ft. The V-1710-39 generated ~900hp up there.




No. the critical altitude for the early R-2600 (1600hp for take off) with two speed supercharger was 11,500ft in high gear. Military rating-1400hp.


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## Markus (Apr 17, 2010)

Shortround6 said:


> No. the critical altitude for the early R-2600 (1600hp for take off) with two speed supercharger was 11,500ft in high gear. Military rating-1400hp.



That and what Colin1 posted makes it look like the early versions were deliberately optimized for low/medium altitudes. Let´s see. The first plane that got the R-2600 was the Boeing 314 flying at 3,000 meters, the Havoc and Baltimore were so-called "attack" a/c. The TBF reached her top speed at 4,500m. None of these planes needed to be able to operate at high altitudes, so I think the reason for the low altitude rating was tactical not technical.


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## Colin1 (Apr 17, 2010)

Markus said:


> That and what Colin1 posted makes it look like the early versions were deliberately optimized for low/medium altitudes


That would make sense given the pre-war USAAC doctrine on air fighting and where (the altitudes) they imagined aircraft would be operating


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## Markus (Apr 17, 2010)

Colin1 said:


> That would make sense given the pre-war USAAC doctrine on air fighting and where (the altitudes) they imagined aircraft would be operating



More info pointing to tactics. The B-25 had the R-2600, the B-26 the R-2800 that was also used for many fighters but both planes reached their top speed at 15,000ft.


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## Shortround6 (Apr 18, 2010)

Markus said:


> More info pointing to tactics. The B-25 had the R-2600, the B-26 the R-2800 that was also used for many fighters but both planes reached their top speed at 15,000ft.




It also makes sense given the limitations of superchargers at the time. Wright started designing their own superchargers in 1937 because they were unhappy with the GE designs they were buying before then. The B-25 used a single stage supercharger vs the 2 stage supercharger used in the fighters. This saved hundreds of pounds of weight per engine (including intercoolers) and quite a bit of volume for the airducts, although bombers had more volume available than fighters. Adding an extra gear (3 speed) doesn't really do much for altitude performance because you are limited by the pressure ratio of the supercharger. If your supercharger can only deliver air at 2.3 times the pressure it takes in then that limits the amount of boost that can be supplied at altitude.


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## riacrato (Apr 18, 2010)

Juha said:


> Hello Riacrato
> On Fw 190 with DB 603, yes, but IIRC the development took years, at least partly because of low priority at times.
> 
> Juha



Hello Juha,
Fw 190 V13 flys in early april 1942 and reaches 663 km/h. V15 flys in may 1942 and reaches 696 km/h. V16 flys in august 1942 and reaches 724 km/h.

All of these have the same basic airframe and the same DB 603 A-0, BUT they differ significantly in the supercharger installation. Integration of the oil cooler à la Fw 190 Dora was supposed to give another 15 or so km/h. I'm not saying the same applies to the XP-60s, but it shows that the performance if measured in top speed can differ significantly from one prototype to another given the setup, conditions and the number of flights conducted, hence I only take them as a rough indication. A 4-10 mph top speed advantage in either direction is more or less meaningless anyway, it just shows the two were in about the same class speed wise and the P-40 is still the more forgiving and easier-to-fly bird.


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## billswagger (Apr 18, 2010)

tomo pauk said:


> They managed to produce the XP-60 (basically P-40 with R-2800 reworked landing gear), but it was just able to best 400 mph. While still decent speed, it was not enough to compete with what USAAF had in usage in pipeline.




Actually the story i read says Curtiss was attempting to build a P-60E, and had all the promise to be a competitive fighter. at a time when the USAAF had to make a decision on the contracts that it would either continue to hold or include as a production fighter. 

At the time of the test trial, the P-60E had suffered an engine glitch and in hopes of still receiving the funding to develop the aircraft they used their original P-60 prototype which offered lower than satisfactory performance compared to what was in the pipeline. 


Bill


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## Juha (Apr 19, 2010)

Thanks Riacrato
being not very well versed in Fw 190C development I only recalled the first proto flights in 42 and then the 603 production versions like 190D-15 or Ta-152C.

Juha


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## billswagger (Apr 19, 2010)

Vincenzo said:


> afaik P-40B was not faster of A6M3, and P-40E is closer to 50mph faster of A6M2 only if this don't go a max power (2550 rpm +250 mm Hg)



you and others may be interested in reading these. 


http://lend-lease.airforce.ru/english/articles/golodnikov/index.htm

http://lend-lease.airforce.ru/english/articles/kulakov/index.htm


These are russian interviews that include descriptions of the P-40 and P-39. 


Aircraft Profile 190 - Mitsubishi A6M3 Zero-Sen (Hamp). 

This article pegs the top speed of the A6m3 22 at 336mph, and model 32 at 338mph, and i'm aware later production models were a bit faster. 

It also says some interesting information concerning Australia's fight with Japan on page 9 in relation to the need for Spitfires, and on the following page there is brief yet direct comparison to a P-39D-1. 

It gives climb to the P-39 up to 12,000ft where the A6m surpasses it at 14,000ft and beats it to 25,000ft by five minutes. 
It also says the P-39D was faster than the A6m3 up to 17,000ft. 

Now what is interesting here is that the Russian pilots attest that the P-39Qs were of the fastest and lightest but were not decisively faster than the P-40, and that the early P-39s were some of the slowest and less reliable. 
This could be attributed to a few factors, a couple of which could be the notoriously cold climate and the lack of properly translated operating instructions. Afterall, these aircraft were originally to be sent to North Africa not Russia. 



Draw your own conclusions. 


Bill


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## Vincenzo (Apr 19, 2010)

the first two links don't works

i'll read the Francillon article when i can


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## billswagger (Apr 19, 2010)

oops

should be okay now.

Bill


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## Vincenzo (Apr 19, 2010)

i read the Francillon article it's sure informative but need to know that the comparisons in the end are with A6M2 (and the zero ever flying at the nominal power (and with a bit error in the setting).
the wep power in the table it's not the wep power but the nominal power, and probably the speed indicated are at the nominal power.

for the soviet pilots interviews i already knew one (shorter) they are informative but they are of the pilots point of view.


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## billswagger (Apr 19, 2010)

Vincenzo said:


> i read the Francillon article it's sure informative but need to know that the comparisons in the end are with A6M2 (and the zero ever flying at the nominal power (and with a bit error in the setting).
> the wep power in the table it's not the wep power but the nominal power, and probably the speed indicated are at the nominal power.
> 
> for the soviet pilots interviews i already knew one (shorter) they are informative but they are of the pilots point of view.



I can't seem to locate any evidences that validates what you are suggesting. 

There are several more articles posted that publish similar figures. 

saying words like "probably" and drawing conclusions outside of what the report shows requires more proof. 

For example. I provided Russian interviews that correlate that the P-39 was not decisively faster than the P-40, 
Both of these pilots flew these planes in combat for a number of missions. Its a pretty safe call to say that this particular element of their experience has some merit.

The Zero appears to be tested under proper conditions, unless you can site the page and paragraph that suggests it wasn't, your claim is empty. 

I'm very interested in knowing more about the A6m3, but i'm not able to locate any other speed information other than dive limits. If you have sources that can validate your claims please share. 

thanks


Bill


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## Vincenzo (Apr 19, 2010)

billswagger said:


> I can't seem to locate any evidences that validates what you are suggesting.
> 
> There are several more articles posted that publish similar figures.
> 
> ...



for the comparison they came on intelligenge summary n 85, can find on wwiiaircraftperformance with other allied report on zero.
for power setting of nakajima see in this forum the thread on japanese engine.


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## billswagger (Apr 19, 2010)

awesome can you post it here so i can look at it. 

I'm busy enough making my own assertions, 

i don't have the time to fish around proving yours, and i say that with the utmost respect for the forum. 



Bill


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## Juha (Apr 20, 2010)

I we speak on Soviet data.
According to Soviet tests, the speed difference between P-40E and P-39D-2 wasn’t marked but at max was appr. 20km/h at appr. 4500m and not significantly less under that altitude but from appr 5000-5500m upwards insignificant. P-39D-2 climbed clearly better to 5km, 6.4min vs. 7.8min.

Juha


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## Vincenzo (Apr 20, 2010)

intelligence summary 85 (A6M2) http://www.wwiiaircraftperformance.org/japan/intelsum85-dec42.pdf
23rd october '42 test (A6M2) http://www.wwiiaircraftperformance.org/japan/a6m2-oct2342.pdf
28th march '44 test (A6M3) Hamp Performance Test
6th february '43 test (A6M2) http://www.wwiiaircraftperformance.org/japan/p5016.pdf
TAIC report 17 (A6M5) http://www.wwiiaircraftperformance.org/japan/ptr-1111.pdf 
TAIC report 38 (A6M5) http://www.wwiiaircraftperformance.org/japan/zeke52-taic38.pdf

sakae nominal TO power and power setting http://www.ww2aircraft.net/forum/engines/data-base-japanese-aircraft-engines-19466-2.html


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## billswagger (Apr 20, 2010)

thanks Vincenczo




Vincenzo said:


> intelligence summary 85 (A6M2) http://www.wwiiaircraftperformance.org/japan/intelsum85-dec42.pdf



The magazine article appears to match the descriptions of this report almost word for word. There is nothing here that suggests it is not an A6m3, it just makes reference to a Type Zero mk1 model 2. 
Further description of the aircraft is found in Intelligence summary no59. That would probably tell us more about the plane and if it was indeed an A6m3 or A6m2. 



> 23rd october '42 test (A6M2) http://www.wwiiaircraftperformance.org/japan/a6m2-oct2342.pdf


It very clearly says that speeds are not adjusted for compressibility, so i'm not sure i can conclude anything about the M2's speed from this alone. 



> 28th march '44 test (A6M3) Hamp Performance Test



This describes the aircraft as a Japanese Mitsubishi Type 0 MK2 using the Nakajima Sakae 21 which is what the a6m3 used. 
The performance figures here appear to be a little slower than what the magazine published, perhaps because of engine/rpm settings. 

6th february '43 test (A6M2) http://www.wwiiaircraftperformance.org/japan/p5016.pdf

again, it shows the a6m2 max speeds under 300mph. Barring instrumentation error, i don't see how this helps prove your point. 




> sakae nominal TO power and power setting http://www.ww2aircraft.net/forum/engines/data-base-japanese-aircraft-engines-19466-2.html



I need help with this one, particularly the power settings and how they differ from what was mentioned in the magazine. 
"1130 hp at take off, 1100 wep at 2850m"

thanks again

Bill


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## Vincenzo (Apr 21, 2010)

billswagger said:


> thanks Vincenczo
> 
> 
> 
> ...



i hope you're not serious, mk I model 2 it's a A6M2

i never take a allied test for performance on axis planes this was for show that power setting of the engine was not correct.

same i want show the incorrect setting

not instrumental error the engine go only 2050 rpm so again trouble with engine or incorrect setting

the francillon article give 1100 wep at 2850 but for sakae 21 1100 at 2850 was nominal power (you can read on table in the this forum thread i've linked)so again missinterpretation of engine capability


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## billswagger (Apr 21, 2010)

Vincenzo said:


> i hope you're not serious, mk I model 2 it's a A6M2



I would like to know how you can tell, because that classification does not turn up any results. 
Pluss the report also mentions IS no 59 which would tell more about the aircraft and engine type. 
Its not to say it couldn't be an A6m2, but when you have conflicting sources i don't think assumptions can be made. 



> i never take a allied test for performance on axis planes this was for show that power setting of the engine was not correct.
> 
> not instrumental error the engine go only 2050 rpm so again trouble with engine or incorrect setting


Agreed, but what speeds do your tests show for the A6m3?
They look to be slower than 336mph, as explained by the lower power settings. 



> the francillon article give 1100 wep at 2850 but for sakae 21 1100 at 2850 was nominal power (you can read on table in the this forum thread i've linked)so again missinterpretation of engine capability



Well, the confusion is the translation of the terms used by the Japanese, not the outputs. 
The US has different power settings, continuous, military, and max. It does not appear that the Japanese made those distinctions, simply that they listed a "nominal power" setting that looks to be the equivalent of a max power setting. 

I can look at take off power which is listed at 1130 hp at 300mm boost, and whats listed as "nominal power in the air" at 1100hp with 200mm boost at 2850m altitude. 

If you aren't convinced these are max power settings for the A6m3, then show me the max power settings. 
They should be listed, right? or do you have another document that shows a higher manifold setting beyond whats listed here?
That should be listed somewhere if not on the chart you've provided. 
Otherwise, its just another assumption that needs to be validated. 



Bill


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## Shortround6 (Apr 21, 2010)

The US changed terminology with time.

In the early 1930s many engines were rated at MAX continuous. With fixed pitch props the engines sometimes couldn't rev high enough a low altitude/slow speeds to develop the power they could at higher altitudes (high for 1930-34) and higher speeds so there was no take -off rating. With the coming of variable pitch propellers and then constant speed propellers the load on the engine could be varied and the engines could hit full rpm on take-off and climb. 

Some engine charts in early WW II show a "emergency maximum" but no military power while later charts show a military power but no "emergency maximum" and from the ratings "emergency maximum" is NOT WEP.

Not all nations calculated climbing power the same either. 

Getting the manifold boost pressure AND the rpm at a given hight for a rated HP is a good start to figuring out what power "rating" is being talked about.


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## Vincenzo (Apr 22, 2010)

billswagger said:


> I would like to know how you can tell, because that classification does not turn up any results.
> Pluss the report also mentions IS no 59 which would tell more about the aircraft and engine type.
> Its not to say it couldn't be an A6m2, but when you have conflicting sources i don't think assumptions can be made.
> 
> ...



I'm sorry Bill but i think you've no intention to go to true only to do propaganda
so this is my last reply to you for this argument

it's well knew, if you don't know it's your trouble, that intelligenge summary 59 85 came to so told Akutan Zero that it's a A6M2

i've not japanese test on A6M3 i don't speak/read japanese, but the alone allied performance test i've read this one Hamp Performance Test, with very low speed and low power setting (as admit in the test they flying 2400 rpm at 36" Hg and they thinked that max emergengy was 2600 rpm at 40" Hg, we know that nominal power was 2700 rpm at 200mm Hg (~38"Hg) and a take off power was 2750 rpm at 300mm Hg (~42"Hg)) so it's largely explained the poor performance. there is a US intelligence report that give at 348 mph the speed (http://www.wwiiaircraftperformance.org/japan/japfighters-comp.jpg). 

for translation idk but Shinpachi know both the language, so i think it's ok him translation, also i think that war time intelligenge knew japanese so maybe it's not a translation trouble, there are also japanese pilots hisstory that talking to overboost and nominal power so i don't think they are the same.

i'm convinced that power setting of nakajima books tables are rights that not rights were of US test


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## billswagger (Apr 23, 2010)

Vincenzo said:


> I'm sorry Bill but i think you've no intention to go to true only to do propaganda



I'll try not to take that as an insult. I think having these kind of discussions only brings out the truth of what we are talking about. You obviously have different assertions, and so all i'm asking is to validate them with substance, so that any propaganda or misconceptions can be realized. 

If you find that challenging or difficult to resolve, then maybe you should ask yourself if your assertions are correct. I would also expect that there are things about ww2 that will never be answered, so the argument remains until more information is found,
I would ask that you not give up, and that if you really think there is more to the A6m3 then come back to this discussion at a later time. Maybe a year from now you read a book or an article that can tell you more about this plane and you will think of this thread again. That happens to me all the time.
I can't expect that you would have all the answers for what is known about Japanese aircraft. 



> it's well knew, if you don't know it's your trouble, that intelligenge summary 59 85 came to so told Akutan Zero that it's a A6M2



I was not able to find that intelligence summary no 59. The only reason why i ask is because we have conflicting sources. 

It is entirely possible the Japanese used higher boost pressures than what has been published, but you can't keep pointing to these sources because they don't support what you are saying. You need to find more information on it. That's not propaganda, that's called validity. 

I hope you also realize that i already conceded to the fact that the A6m3 was a faster plane later in the war in my original post. 

Bill


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## Juha (Apr 24, 2010)

Hello
a good Russian article on P-40 in Soviet service
The P-40 in Soviet Aviation

Juha


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## JoeB (Apr 24, 2010)

billswagger said:


> I was not able to find that intelligence summary no 59. The only reason why i ask is because we have conflicting sources.


The No. 85 report is definitely about the 'Akutan Zero'. Many other sources attest that trials of that a/c v various US ones were published at that time. So it was a 零式艦上戦闘機二一型, Zero Type Carrier Fighter21 Model, or some abbreviation of that, is how it would almost always be written in Japanese, and some variation of that on the a/c's namplate. 'A6M2' is also a Japanese designation, the so called short system, but much less commonly used, though elegant and natural for English speakers to use. This a/c would have been correctly called Zeke 21 under the Allied codename system. Some Japanese equipment was known was 'type' 'mark' 'mod' series of numbers but 'Type Zero Mark 1 Carrier Fighter Model 2' is just a mistake. It's 100% certain this a/c was a Zero Model 21, ie A6M2.

As far as true speed of the a/c, I agree these reports don't necessarily prove the speed of Zero Model 32, though it stands to reason if the Model 21 test was representative, the Model 32 was faster than that. And Lundstrom notes that F4F pilots with experience v the Zero did not believe the Akutan a/c's test results to be representative: in their experience the Zero was faster than shown in the test. Of course that was subjective, but trials of captured, possibly worn or extensively repaired (this a.c was) planes weren't 100% reliable. 

AFAIK it's fairly well established that Japanese official numbers tended to be conservative, so the most likely top speed (of well maintained a/c in good condition, of course) was probably at least equal to the official numbers of ~331mph for Zero Model 21, 338 for the Model 32. 

Joe


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## Vincenzo (Apr 25, 2010)

JoeB said:


> . This a/c would have been correctly called Zeke 21 under the Allied codename system. Some Japanese equipment was known was 'type' 'mark' 'mod' series of numbers but 'Type Zero Mark 1 Carrier Fighter Model 2' is just a mistake.
> 
> AFAIK it's fairly well established that Japanese official numbers tended to be conservative, so the most likely top speed (of well maintained a/c in good condition, of course) was probably at least equal to the official numbers of ~331mph for Zero Model 21, 338 for the Model 32.
> 
> Joe



just two notations

if i understand right, the codename so that A6M2 it's a Zeke 21 it's late of Summary 85 so it's can't applicate at that time.

do you have the japanese manual or thr english translation? it's know at what power setting they go a this speed?


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## Glider (Apr 25, 2010)

The title of the thread is the aircraft for the rest of the war. With that in mind you may want to consider which is best against the later versions of the Zero such as the A6M5 which is a lot faster than the Type 21 enough to worry the P40 and P39 and had an improved dive speed to reduce the difference.

Also these are land based fighters and the Ki44 would be a significant risk to the P39/P40, strong, fast, well armed and good in a dive.


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## billswagger (Apr 26, 2010)

Glider said:


> Also these are land based fighters and the Ki44 would be a significant risk to the P39/P40, strong, fast, well armed and good in a dive.




Most land based fighters and interceptors like the Ki-44 would pose little or no threat if the task of the P-39/40 is strictly to defend the country. 
The A6m5 was a very advanced plane but later model P-40s were still faster, and P-39Qs would have no problem out shining it in speed. 

I also think its somewhat of a myth about the A6M dive speeds. I know pilots were reluctant to dive beyond certain speeds in earlier variants, but versions of the A6m3 could actually exceed 400mph in a dive with little worry. The problem was in maneuvering at such high speeds which was still the case with the A6m5.


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## Vincenzo (Apr 27, 2010)

i find this http://warbirdsforum.com/archive/index.php/t-165.html idk if it's reliable
but talking of australian test of Hamp with a speed of 335 mph at fth with 2600rpm and +40" (this is less rpm of nominal power but with higher boost, but less boost of to power, and i remember this ever a captured plane)

down in the page there is also a US test of A6M2 (i don't read accurately but think ever akutan zero)


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## Nikademus (Apr 28, 2010)

If not already posted somewhere in this thread, this article on the captured A6M2 model 21 might offer additional insights.

Untitled Document


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## billswagger (Apr 28, 2010)

Nikademus said:


> If not already posted somewhere in this thread, this article on the captured A6M2 model 21 might offer additional insights.
> 
> Untitled Document




Interesting,

Most of what i've read says different and even Sabaru Saki is quoted as saying the top speed of the Model 21 was 309mph but what do pilots know. 

i actually think people confuse Model 21 and Sakae 21 and end up siting them as the same aircraft. 

There is a lot of obscurity with the US tests because they tested with higher octane gas which allows for higher boost pressures. 
Thats what the 44-1 summary is about. 

Furthermore, only the Sakae 31 engine had water-methanol injection for anti-detonation purposes. I suppose its possible that the A6M3 could've been retrofitted with these engines but we are talking at a time after the development of the A6m5c.

I still haven't found anything that supports a higher output than whats already been published and reiterated over several other sources. 

www.warbirdsresourcegroup.org - Imperial Japanese Aviation Resource Center - Mitsubishi A6M Zero-Sen

I still haven't seen anything else to suggest otherwise.


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## JoeB (Apr 28, 2010)

billswagger said:


> Interesting,
> 
> Most of what i've read says different and even Sabaru Saki is quoted as saying the top speed of the Model 21 was 309mph but what do pilots know.
> 
> .


That paper is deinitely correct that Sakai spoke as quoted in the source it refers to, "Samurai", where he said (it's pg 43 in my edition rather than 48 as the article says) "Under normal full power conditions the Zero was capable of 275kts [~316mph] and, when overboosted for short emergencies could reach its maximum speed of around 300kts [~345mph]". It's clear from the context he was speaking of the Model 21 (discussing preparation for war during 1941). That is just what he said as reported in that book, but if you have a source where he quoted a much lower speed, I think you'd have to cite it specifically.

Other sources beside that article also quote US pilots who had met the Zero in combat as saying the Akutan test results foir speed of the Zero seemed too low to them. And in general, that article gives all its sources, Rick Dunn is a reliable expert on the topic, and I don't think just saying 'that's not what I've read' is a very effective comeback to his conclusion, with all due respect.

Joe


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## billswagger (Apr 29, 2010)

Thats a very popular memoir but its also received a lot of criticism. http://www.warbirdforum.com/samurai.htm
There are some stories described in the book that never happened, and the author has been scrutinized for his mishandling of the facts. I would take that quote about the zero with a grain of salt. 

The zero reaching 345mph in level flight sounds like a misquote considering max dive speed nears 350mph depending on altitude. 

In another interview with Sakai, he mentions that the Zero gets very difficult to fly above 250 mph. 
http://www.warbirdforum.com/sakai.htm
There's even modern A6M3 pilots at airshows who fly using original parts. They confirm that flight above 250mph causes the controls to get really stiff and unresponsive. 

With that said, i only question speed figures on the basis that higher boost pressures would be necessary to obtain them. I also question the context they are reported under because the speed figures quoted are similar to other model numbers, obscure US military testing, or numbers that lack adjustment from compressibility. If higher boost pressures were obtained there should be published data on these settings, right? Published data also says water methanol (WEP) was not used on those engines. So the fuzziness for me is just determining what the max boost pressures were. 


Bill


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## JoeB (Apr 29, 2010)

billswagger said:


> Thats a very popular memoir but its also received a lot of criticism. http://www.warbirdforum.com/samurai.htm
> There are some stories described in the book that never happened, and the author has been scrutinized for his mishandling of the facts. I would take that quote about the zero with a grain of salt.
> 
> The zero reaching 345mph in level flight sounds like a misquote considering max dive speed nears 350mph depending on altitude.
> l


I know all about that book, am probably one of the ones criticzing it on the other thread, or have anyway pointed out specific errors in other threads on this forum. I'm simply pointing out here that Dunn is correctly quoting the book. You OTOH said Sakai was elsewhere quoted saying the Zero's max speed was 309mph: where? 

Dunn is also quoting a number of sources in that article all supporting his general conclusion that the Zero's speed was *probably* greater than what was shown in the Akutan Zero test. 

Joe


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## Nikademus (Apr 29, 2010)

Agree with JoeB on this one. I garnered a similar impression from reading Lundstrom regarding the Zero's real world speed as well as from Shores' accounts. The J-aircraft article seems solid in it's conclusions and well cites it's bibliography.


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## billswagger (Apr 29, 2010)

I guess for me, its not really enough until i see a document that specifies the actual boost pressures that were attainable. The rest is open to interpretation, and/or misinterpretation. 
It appears some of what Dunn is refering to can also be found on mike williams site, and that's where i garner most of my position from. I have a hard time reading into obscurities in a time when propaganda was rampant and the Japanese would have everyone believe the Zero was unbeatable. That's just my opinion on the matter. 
Its more a passion for the subject, and the reason why i'd like to know more about the boost pressures obtained by the aircraft. 

http://www.wwiiaircraftperformance.org/japan/a6m2-oct2342.pdf
Most people just look at the speed figures and move on, but there are couple things that pop out at me here. One is the lack of correction for compressibility, and standard conditions, which means these figures are going to be a little higher than actual speeds. 

The other thing this report says is that the plane had an automatic boost regulator that permitted a max of 35" . 

So tell me, how do you run higher boost pressures when it has a regulator to keep it from overboosting? 
In fact, its entirely possible that the 35" is a conversion error on the part of the USN and that max boost was obtained. 

http://www.wwiiaircraftperformance.org/japan/p5016.pdf
The more i look at this, the more i agree it is bogus. 
It shows 2050rpm at 120mm pressure, being at max throttle position. (120mm = ~35")
Of course pilots in combat are going to report higher operational speeds than whats found here. The top speed found was 289mph at 15,000ft at a boost of 2cm,(~31" max throttle) 
I would think not only would more speed be obtainable, but higher boost pressures would show with the proper RPMs. 

This is why i would like to see a document that specifies which boost pressures were used outside of what is already known. (200-300mm)
Requoting what's already been determined or getting someone else's take on it doesn't offer up any more incite to what boost pressures were actually achieved. 

BTW, the quote i am searching for, where i read the 309mph figure from Sakai, i don't agree with and probably needs the altitude to put it in better context.


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