Groundhog Thread Part Deux - P-39 Fantasy and Fetish - The Never Ending Story (Mods take no responsibility for head against wall injuries sustained) (1 Viewer)

[pbehn]

Soviet removed 7.62 mm mgs pat of their P-39s but not from all, see my message XP-39 II - The Groundhog Day Thread, in June 44 clearly part of the P-39s of the famous 16 GvIAP still had their 7.62 mm mgs installed and loaded. That message was written over ½ year ago but for no good, it seems.

This is a requirement of groundhogism. A point of view is never disproved by facts, after a few months rest it can be brought back again. It cannot be accepted that any combat took place in the BoB at 30,000ft because that would undermine the argument that the British rejected the P-39 (and P-40) for UK based operations because of performance not cost and spite.

 

[P-39 Expert]

Some of you guys (not all) need to understand the difference between service ceiling and combat ceiling. WW2 fighters very seldom got anywhere near their service ceiling when the plane climbed at only 100fpm. Mainly theoretical, this figure wasn't normally reached even during official tests. It was projected based on climb tests at lower altitudes. In test conditions, not in combat. I believe the British started the term combat ceiling which is the altitude at which a plane will no longer climb at 1000fpm. That's about as high as a fighter will want to go in combat. Climb is at or near full power at around 150-175mph IAS. Crawling up to 30000ft at that speed is hazardous to one's health in combat. And hard on the engine to be at full power for that long.

I never said nobody ever got to 30000ft in the BoB, just that it was extremely uncommon. And like victory claims, probably not that accurate. Just my opinion.

 

[P-39 Expert]

You might be interested to know that the heating of the cabin of the P-39C and D was very good because they used a Stewart-Warner gasoline type heater.

This is stated in the pilots manuals.

So, NO, the British did NOT load the plane down with useless stuff like a fuel powered heater, it was already there.

Would like to see those pilot manuals. All the information I have ever seen shows heated air ducted from the coolant radiator exhaust up to the cabin. Rated as very efficient cabin heat in Eglin Field tests. The P-400 used the fuel powered heater, I have seen that manual. That fuel powered heater may have been efficient but it caused radio static feedback, making either the heater or the radio unusable.

 

[pbehn]

Some of you guys (not all) need to understand the difference between service ceiling and combat ceiling. WW2 fighters very seldom got anywhere near their service ceiling when the plane climbed at only 100fpm. Mainly theoretical, this figure wasn't normally reached even during official tests. It was projected based on climb tests at lower altitudes. In test conditions, not in combat. I believe the British started the term combat ceiling which is the altitude at which a plane will no longer climb at 1000fpm. That's about as high as a fighter will want to go in combat. Climb is at or near full power at around 150-175mph IAS. Crawling up to 30000ft at that speed is hazardous to one's health in combat. And hard on the engine to be at full power for that long.

I never said nobody ever got to 30000ft in the BoB, just that it was extremely uncommon. And like victory claims, probably not that accurate. Just my opinion.

And you need to understand that it makes no difference what you call the ceiling. The LW sent recon planes over UK at extremely high altitude dropping bombs, eventually a modified Spitfire shot one down at 42,000 ft. One gun was jammed and every time the other fired the plane stalled and dropped. After several attempts it made one hit with a cannon shell, that was enough to stop that type of raid. That is what it was all about, it doesnt have to be "common" it would have persisted until a successful interception happened. This is what happened in the dog days of the BoB, what began as a free shot, dropping bombs randomly on Kent and London started to cost pilots and planes and so was stopped. Can you remind us what you said makes you cringe?

Here you are, my bold.
Quote "BoB got nowhere near 30000ft. Spitfire and 109E combat ceilings (1000fpm climb) were a little above 25000'. 110s about 21000ft. He111 ABSOLUTE ceiling was 22000ft. Nobody going near 30000ft, much less over except possibly recon missions. I cringe when I hear 30000ft in WWII.

 

[buffnut453]

Some of you guys (not all) need to understand the difference between service ceiling and combat ceiling. WW2 fighters very seldom got anywhere near their service ceiling when the plane climbed at only 100fpm. Mainly theoretical, this figure wasn't normally reached even during official tests. It was projected based on climb tests at lower altitudes. In test conditions, not in combat. I believe the British started the term combat ceiling which is the altitude at which a plane will no longer climb at 1000fpm. That's about as high as a fighter will want to go in combat. Climb is at or near full power at around 150-175mph IAS. Crawling up to 30000ft at that speed is hazardous to one's health in combat. And hard on the engine to be at full power for that long.

I never said nobody ever got to 30000ft in the BoB, just that it was extremely uncommon. And like victory claims, probably not that accurate. Just my opinion.

We understand the difference.

As to your last statement, you're now trying to duck out of your incorrect statement without admitting you were wrong. You explicitly stated "BoB got nowhere near 30000ft." That's a pretty definitive statement. "Nowhere near" is not the same as "extremely uncommon."

You've been presented with actual pilot manuals citing that the Spitfire MkI and the Messerschmitt Bf109E-3 could get above 30,000ft. You have a contemporary account of a Spitfire pilot leading his squadron at 30,000ft and engaging Bf109s. And yet you persist that these data points are somehow not accurate?

Please provide data that you think is more accurate.

 

[P-39 Expert]

Well, since you've frequently quoted WW2aircraftperformance.org (Source: http://www.wwiiaircraftperformance.org/wade-ceiling.jpg), perhaps this table may help change your mind. It was originally published in The Aeroplane on 21 June 1946. Yes the Spitfire variants are much later than the MkI of BoB....but it would be a phenomenal increase to take an aircraft that, in 1940, couldn't best 25,000ft and then, just a few years later, attain 37,000ft (or thereabouts)...it's a big enough increase to go from 30K to 37K.

View attachment 630448

Can't you, for once, admit you are wrong about something? You're expressing an opinion and yet seem to be entirely unmoved by any evidence to the contrary. Again, you wonder why we call this the groundhog day thread.

Depends on how the magazine defined operational ceiling. Was it service ceiling, combat ceiling, or something else. And all those planes came well after the BoB with ceilings well above the Spit I and 109E. And it was a magazine, not an official test.

 

[buffnut453]

Depends on how the magazine defined operational ceiling. Was it service ceiling, combat ceiling, or something else. And all those planes came well after the BoB with ceilings well above the Spit I and 109E. And it was a magazine, not an official test.

So what about all the other data that's been presented related to Spitfire MkI and Bf109E-3. Are you going to ignore that as well?

 

[Shortround6]

Some of you guys (not all) need to understand the difference between service ceiling and combat ceiling.

Some people need to understand that there was also a 3rd ceiling, operational ceiling which was 500fpm, this was considered the climb rate needed for a small group of planes to maintain formation. The 109, Hurricane I and Spitifire I with constant speed props all had operational ceilings of over 30,000ft.
Source "The Merlin in Perspective-the combat years" 4th edition Rolls Royce Heritage trust. In Appendix V.

That's about as high as a fighter will want to go in combat.

There is also a difference between "combat" as in actual maneuver fighting and a combat patrol or flight in which the goal is to be above the enemy so they can use the advantage of height. The actual "combat" (firing of guns) may take place several thousand feet lower. Being the one's getting bounced from above was known not to be a good thing by about 1916

Would like to see those pilot manuals.

Try BELL P-39 AIRACOBRA - Flight Manuals

 

[pbehn]

Depends on how the magazine defined operational ceiling. Was it service ceiling, combat ceiling, or something else. And all those planes came well after the BoB with ceilings well above the Spit I and 109E. And it was a magazine, not an official test.

The important altitude is the altitude of the enemy aircraft coming into your space. Discussion of terms is just a distraction, as you know, that is why you are doing it.

 

[P-39 Expert]

Where you got the idea that "P-39s could match the LW fighters up to 8000meters (26400ft)" maybe even up to 17500 ft but after that P-39 N /Q began to run out of steam.

Conversations with N. Golodnikov, Part 3, P-39. Conversations with N.Golodnikov. Part Three. P-39 Airacobra and Yaks – Lend-Lease

 

[P-39 Expert]

You are confusing combat ceiling and service ceiling, you are also leaving out operational ceiling (climb is 500fpm). It was not uncommon for the British and German fighters to fly at around 30,000ft in the BoB. Not uncommon does not mean common or standard practice, it just means not uncommon.
The reason is at much over 20,000ft the fighters that had the altitude advantage had a major combat advantage. They did NOT FIGHT at 30,000ft but the planes with the altitude advantage could break contact/refuse combat easier. They could trade their altitude for speed (energy) by diving down on their opponents. They could keep going (boom and zoom) and since they were already flying faster in their dives (even if shallow) they were harder for the lower starting altitude fighters to follow. If the diving planes decided to turn they had more speed to burn in the turn before their airspeed fell too low.
For the British, if you know that some of the German fighters are coming in at around 30,000ft (certainly not all) do you just say "Oh well, we will continue to fly at 24-26,000ft and let them bounce us on occasion" or do you try to get some (not all) of your fighters up to 30,000ft to equal the high flying Germans and/or bounce the Germans that come in at 25,000ft or so?
A major part of the rational behind the Hurricane II with the Merlin XX engine (deliveries started in Sept 1940) was to improve it's altitude performance, They figured the Merlin XX engine would change the operational ceiling (500fpm climb) from 31,400ft to 34,900ft, They figured this would keep the Hurricane competitive with the 109.

BTW, the bomber ceilings are often given at full load. For some of the early twin engine bombers burning off several thousand pounds of fuel can change their ceilings by a few thousand feet. You are the one who keeps telling us that just cutting a few hundred pounds out of the P-39 will add hundreds of fpm to it's climb rate and thousands of feet to it's ceiling.

Not uncommon? But they did not fight at 30,000ft? Okay, whatever you say. I just believe that in the BoB planes actually getting to 30000' is extremely rare, which I would define as a lot less than not uncommon. Extremely rare does not mean never. My opinion.

And I am not confusing combat ceiling with operational ceiling. I almost always reference combat ceiling as climb at 1000fpm.

 

[wuzak]

Some of you guys (not all) need to understand the difference between service ceiling and combat ceiling. WW2 fighters very seldom got anywhere near their service ceiling when the plane climbed at only 100fpm. Mainly theoretical, this figure wasn't normally reached even during official tests. It was projected based on climb tests at lower altitudes.

From Spitfire Mk I K.9787 Trials Report

alt (ft) time (min) RoC (ft/min) 23,000 11.7 1135 26,000 14.8 790 28,000 17.8 555 30,000 22.4 325 32,000 32.9 95

Estimated absolute ceiling: 32,800ft
Greatest height reached: 32,400ft

That was with a fixed pitch wooden propeller (2 blade?).

 

[Shortround6]

Both sides in 1940-41 were working to improve the ceilings (all of them by whatever name) of their aircraft because it takes months if not years to get to get a new airplane or engine into service (variations of existing equipment takes less time but not instant), You can't wait for your opponent to show his improved capability. You have to be working on improving your own so you are ready when his improvement/s show up.
Reason for the Hurricane II was to improve the Hurricane so it was close to the Spitfire in capability so the total number of fighters being produced were altitude capable, making Spitfires with Merlin XX engines and continuing to make Hurricanes with Melrin IIIs or Melrin XIIs would have meant an overall less capable fighter force.
A wrench in the works was that cockpit heating, gun heating and oxygen equipment did not progress as fast as the engines so the engine improvements were harder to take advantage of.
The P-400/P-39 showed up at the wrong time. It showed up as the British were anticipating higher operational ceilings and the British were already getting low altitude P-40s and about to get low altitude Mustang Is.
In Mid 1941 to spring of 1942 the Bell fighter simply doesn't bring much to the table as production versions are much slower than promised and they can't do anything that can't be done by a number of fighters already in British service except complicate the supply situation.

 

[P-39 Expert]

Yep, real insanity, considering that the .30 cal ammo was used by the ground army tripod mounted Browning machine guns, both air and water cooled, the BAR, the M1 Garand, the 1903 Springfield (and variations) and the 1917 Enfield. In 1941 the standard mix of ammo for the ground machine guns was 10%AP, 20% tracer and 70% ball ammo. Getting .30 cal ammo might have been a much smaller problem than getting either 20mm or 37mm ammo. Might not be the preferred types but getting something seems to be pretty easy.

I would love to see a definition of "effective range" as used in AHT. The max range of a .30 cal Browning with M2 ammunition (150 grain flat based bullet) was about 3,500 yds and the max range using M1 ball (172 grain boat tail) of about 5,500 yds. effective range is certainly much shorter than max range.
However the US Army penetration tables show the M1 ball at 200yds going through an average of 7 in of gravel, 4 in of concrete, 13.8 inches of solid oak, 6.5in of dry sand. These are average penetrations, individual shots sometimes penetrated more.
I doubt the duralumin skin of most single engine planes is going to stop the .30 bullet.

A different table for the older 1906 load which was just about identical to the M2 ball ammo claims to would completely penetrate 1/4 low grade steel plate at 400yds. Low grade steel is not armor but then, depending on the angle of impact and deflection caused by the aircraft skin most aircraft structure and engine/cylinder blocks are not going to withstand that force of impact most of the time.

All penetrations are pretty much sea level and would improve at higher altitudes.

Not saying that the .30 cal (or .303) was anywhere near as effective as the .50 cal but the idea that the .30 cal bullets cannot inflict damage or are useless at anything beyond 200yds needs to go away and stay away.

AHT lists the 30calMG to have an effective range of 200yds in their gun table and talks about it in the text.

Yes there were lots of .30cal rounds available, since it was a standard round for the infantry. Are you advocating converting all seven guns in the P-39 to the .30cal? That makes about as much sense as your argument.

The .30cal MG was phased out of AAF/USN use before Pearl Harbor for all the American fighters except the P-39. I'm advocating it should have been phased out of the P-39 also.

 

[wuzak]

The .30cal MG was phased out of AAF/USN use before Pearl Harbor for all the American fighters except the P-39. I'm advocating it should have been phased out of the P-39 also.

Um, the P-40s at Pearl Harbor were fitted with the 0.30"mg.

 

[Shortround6]

Yes there were lots of .30cal rounds available, since it was a standard round for the infantry. Are you advocating converting all seven guns in the P-39 to the .30cal? That makes about as much sense as your argument.

Never said that did I?

Just saying that keeping the .30 cal was not the logistics problem you are making it out to be.

Now why don't you give the rest of the information in the tables and btw, the text includes NO definition of either "max effective practical range" or "max effective theoretical range"
For the .30 cal these ranges are the 200 yds you have said and 600yds, the 37mm cannon had ranges of 300yds and 600yds. The 50 cal has ranges of 300yds and 900 yds while the 20mm in the table has ranges of 1200 yds and 2400yds which is total nonsense.

I would also note that the heavier weight given for the 30 cal bullets like 220 grains is total nonsense. The US stopped putting 220 grain projectiles into 30 cal rifle ammo in 1906 when they changed from the .30-03 round to the .30-06. The .30-03 won't even chamber in a .30-06 gun.

AHT is very, very good. It is not infallible.

Have to go to work now.

 

[pbehn]

Not uncommon? But they did not fight at 30,000ft? Okay, whatever you say. I just believe that in the BoB planes actually getting to 30000' is extremely rare, which I would define as a lot less than not uncommon. Extremely rare does not mean never. My opinion.

And I am not confusing combat ceiling with operational ceiling. I almost always reference combat ceiling as climb at 1000fpm.

Are you saying that a plane shot down at 30,000ft was not actually in combat because it was above the "combat" altitude? What do you call firing guns at each other, other than fight or combat? This is taking groundhogism to a new height, or dare I say a new altitude of semantics.

 

[glennasher]

We might as well take a trip to Yosemite NP and try to educate El Capitan, it would be easier than trying to educate the "Expert".

 

[buffnut453]

The .30cal MG was phased out of AAF/USN use before Pearl Harbor for all the American fighters except the P-39. I'm advocating it should have been phased out of the P-39 also.

As others have pointed out, the e0cal was still in use in P-40s at Pearl Harbor.

Also the 30cal was REPLACED with the 50 cal. So to match other US fighters, you'd have to do the same. How will that affect the weight of your P-39 wonder-weapon?

 

[Peter Gunn]

Uhh... are you saying now that the P-39 was able to do the Mustang's job? And is it supposed to match the Mustang's performance at 26,400 feet? Which is basically RIGHT in the Mustang's wheelhouse.

Only difference between air combat in western Europe and eastern Europe was there were no high altitude bombers in Eastern Europe. And those weren't really a force in the west until mid '43. Soviets standard combat formation was the "Kuban Stairs" or "Flying Bookshelves" with a flight (4 planes) at 5000meters (16500ft), a flight at 6000meters (20000ft) and the top flight at 7000meters (23000ft). P-39s could match the LW fighters up to 8000meters (26400ft) with neither side willing to go much higher than that.

Turbocharged B-17s and B-24s flew at 25000ft with their escorts a little higher. Not much difference.