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

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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.
 
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.
Click to expand...

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
 
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.

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
Click to expand...

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.
 
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.

:D

Bill
 
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
 
 
thanks Vincenczo


Vincenzo said:
intelligence summary 85 (A6M2) http://www.wwiiaircraftperformance.org/japan/intelsum85-dec42.pdf
Click to expand...

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
Click to expand...
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
Click to expand...

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
Click to expand...

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
 
billswagger said:
thanks Vincenczo




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.


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.



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.




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
Click to expand...

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
 
Vincenzo said:
i hope you're not serious, mk I model 2 it's a A6M2
Click to expand...

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
Click to expand...
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
Click to expand...

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
 
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.
 
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.


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.



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
Click to expand...

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
 
Vincenzo said:
I'm sorry Bill but i think you've no intention to go to true only to do propaganda
Click to expand...

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
Click to expand...

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
 
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.
Click to expand...
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
 
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
Click to expand...

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?
 
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.
 
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.
Click to expand...


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.
 
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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