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

pbehn said:

You said it NEVER happened, when shown that it did you opine on frequency and how many you think took place.
From wiki
The Luftwaffe decided to expand its fighter bomber force and an additional group equipped with modified Bf 109s became operational in August. On 2 September Hermann Göring, the Commander-in-Chief of the Luftwaffe, directed that one squadron of each Bf 109 group was to be equipped with fighter-bombers and that these aircraft were to be used to attack the British aircraft industry and other industrial facilities.[6]​

Despite Göring's directive, only 19 fighter-bomber operations were conducted against the UK during September 1940. These operations involved 428 sorties, of which 264 were conducted against London. Four fighter-bombers were lost, one by fighters and the others to anti-aircraft guns.[7]​ On 26 September, a force of fifty fighter-bombers and medium bombers attacked the Supermarine aircraft factory at Woolston, Southampton; this raid stopped all production at the factory for a period and killed more than thirty people. The Royal Air Force (RAF) shot down three of the raiders but lost six fighters. The next day, ten Bf 110 fighter-bombers escorted by other fighters attempted to attack either RAF Filton or another target near Bristol. This force was intercepted by No. 504 Squadron RAF and the Bf 110s dropped their bombs on Bristol, causing little damage.[8]​

Later in autumn, the Luftwaffe conducted a series of attacks on London using Bf 109 fighter-bombers.[8]​ These operations represented the majority of German attacks on Britain in October 1940, and the British defences had difficulty detecting and intercepting the high-flying and fast fighter-bomber formations. Due to their speed British radar stations usually provided less than 20 minutes warning before the aircraft arrived over London.[9]​ The Luftwaffe conducted 140 attacks involving 2,633 fighter-bomber sorties against London during October. Losses were light, with 29 Bf 109s being destroyed.[10]​ October marked the peak of fighter-bomber operations in 1940 but attacks continued until late in the year. The rate of effort decreased during November and December as the Bf 109s needed to be used to counter RAF fighter sweeps over France and the onset of winter weather reduced flying opportunities.[11]​

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This same wiki article said the 109E fighter bombers came in over 20000'. Carrying a 550lb bomb they couldn't have flown much over 20000'. A long way from 30000'.

The LW switched to night attacks from September 15, were these flown at 30000'? I just don't see much at all about 30000' in the BoB.

pbehn said:

Where in my post did I mention the BoB, the BoB as an event was over, the RAF still had to defend its airspace which in 1942 meant interceptions at 42,000ft and low level tip and run raiders all along the south coast, again the P-39 would be useless at this, which is why the British sent the malfunctioning rubbish away. I no longer care what you are convinced of because nothing convinces you of anything. What is serious and consistent? Isnt 2,600 in a month serious and consistent? The link if you read it says "and the British defences had difficulty detecting and intercepting the high-flying and fast fighter-bomber formations. "

High flying means high altitude, that is not low or medium but high. 10,000ft isnt high, 20,000ft isnt high 25-30000ft is high.

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Exactly how many interceptions at 42000' did the RAF achieve? One?

High flying and fast fighter bomber formations? Those 109Es were carrying 550lb bombs which severely limited any high altitude operations. Wiki said they cam in over 20000', not 30000'. And how did they bomb with any accuracy? In formation? As dive bombers?

P-39 Expert said:

Exactly how many interceptions at 42000' did the RAF achieve? One?

High flying and fast fighter bomber formations? Those 109Es were carrying 550lb bombs which severely limited any high altitude operations. Wiki said they cam in over 20000', not 30000'. And how did they bomb with any accuracy? In formation? As dive bombers?

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As per my previous post, Chain Home couldnt accurately tell altitude at those altitudes so they had to send up planes to look, the subject of discussion is whether an RAF interceptor in the BoB and later had to get up to 30,000ft and whether they did that, the answer to both is YES. If a Bf109E could get to 32,000 how do you know how much a 550lb bomb would affect it? You claim the P-39 could get close to that with half a ton of extra junk.

They only had to achieve one to stop the game, how many sorties were done before that one interception? Twelve, one of them dropped a 550LB bomb in a bus station killing 48 people and wounding 56, how may more would they have done? As many as they wanted until stopped.

P-39 Expert said:

This same wiki article said the 109E fighter bombers came in over 20000'. Carrying a 550lb bomb they couldn't have flown much over 20000'. A long way from 30000'.

The LW switched to night attacks from September 15, were these flown at 30000'? I just don't see much at all about 30000' in the BoB.

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You said it never happened, I pointed out the high altitude attacks in October which were fighter bombers and fighters, now you exclude fighters why? The subject is the altitudes planes met not the exact altitude a plane carrying a bomb flew. You also bring in frequency, why? It happened and the RAF needed planes to get there and that wasnt the P-39 so they were sent away.

You are now side tracking into specific altitudes on specific dates and giving your thoughts on their significance, it didnt matter if they had a bomb on them, if they were there they had to be intercepted and the P-39 was useless at it, completely utterly useless especially since they only got 4 in squadron service in 1941.

Any more groundhoggery?

Shortround6 said:

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.

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The British specified the gas heater in the P-400.

The P-39D ducted warm air from the rear of the coolant radiator up under the pilot's seat for cabin heat. Standard arrangement from the D model onward. No gas heater for the P-39D onward.

P-39 Expert said:

The British specified the gas heater in the P-400.

The P-39D ducted warm air from the rear of the coolant radiator up under the pilot's seat for cabin heat. Standard arrangement from the D model onward. No gas heater for the P-39D onward.

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Did the British specify taking out a ducted air system and putting in an American suppliers gasoline heater for the cabin?

P-39 Expert said:

Exactly how many interceptions at 42000' did the RAF achieve? One?

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Enough that Ju86s were withdrawn from service by July '44

P-39 Expert said:

The British specified the gas heater in the P-400.

The P-39D ducted warm air from the rear of the coolant radiator up under the pilot's seat for cabin heat. Standard arrangement from the D model onward. No gas heater for the P-39D onward.

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And what about the P-39C? Did that use a gas heater? S Shortround6 stated it was both the P-39C and D that had the gas heater. You've made the claim that the D didn't have one...so what about the C? The P-39C was the Bell Model 13 while the P-400 was the model 14, hence the P-39C design came first. If the C had the gas heater, then it was "standard" for the type at that stage, which means the British didn't specify the gas heater as an exception.

From page 4 of the Flight Operating Instructions for the P-39D-1 and P-39D-2 aircraft, dated Nov 10th 1942.

I. Heating and Ventilation.
The Cockpit is heated by a Stewart-Warner gasoline type heater. The heater control toggle switch(fig 6-17) is located on the main control switch panel. A heater warning light
(fig 6-33), located on the right auxiliary instrument panel, will light if the heater is not getting sufficient fuel, if the exhaust line to the supercharger is leaking or if the heater system gets too hot.

Don't believe everything you read.

P-39 Expert said:

Every one of you guys are masters at taking a general statement and finding a very small number of exceptions and then stating that I'm wrong. It was a big war with lots of exceptions to every rule.

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And, in return, you either ignore responses and refuse to answer questions, or you ignore evidence that contradicts your general statements....or you continue to restate opinions that have been debunked.

Here's two penn'orth of free advice for you:

1. Stop making general comments that aren't backed up by facts. For example, you said that no fighters got up to 30,000ft during the BoB. That's patently untrue and no amount of dissembling (e.g. making (again) unsupported claims about the number of sorties at that altitude) will change the fact that your statement was just plain wrong.

2. Stop viewing every engagement on this forum as an argument that you have to win. This thread would be much more productive if you would demonstrate a willingness to learn new facts rather than clinging to old opinions. You criticize others for not accepting your arguments and yet any view contrary to yours is met with the responses listed above. Rather than simply dismissing the contributions of others, maybe occasionally you might try a different tack...for example, perhaps thanking them for making you aware of something that you didn't know.

Your knowledge about the P-39 is impressive and I've learned a lot from your posts. In particular, some variants did have better performance than I'd previously accepted. But (and it's a BIG BUT) those better-performing variants arrived after other designs were already in service with at least as good if not better performance.

Shortround6 said:

From page 4 of the Flight Operating Instructions for the P-39D-1 and P-39D-2 aircraft, dated Nov 10th 1942.

I. Heating and Ventilation.
The Cockpit is heated by a Stewart-Warner gasoline type heater. The heater control toggle switch(fig 6-17) is located on the main control switch panel. A heater warning light
(fig 6-33), located on the right auxiliary instrument panel, will light if the heater is not getting sufficient fuel, if the exhaust line to the supercharger is leaking or if the heater system gets too hot.

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Since the early P-39Ds started out as P-39Cs, I suspect the gas heater was a carry-over from the C-variant.

My guess is the client specified that the cabin should be heated and the gasoline heater was what Bell proposed until they had sorted out a ducted system. The resulting agreed specification doesnt mean that the British specified anything, clients specify requirements and accept or reject proposals. If the British had this requirement (like instruments or guns) it is a global requirement and it would have been the same for the P-40 and Mustang MkI + all British made fighters. Did any other military plane use these heaters? Or is this added to the many other myths about what the eccentric British got up to, trying to screw Bell up?

from the Operation and Flight Instructions for the YP-39 and P-39C pursuit airplanes, dated Feb 15th 1941. Page 6.

"d. heating and ventilating equipment. - A Stewart-Warner Cabin heater is provided. A ventilator is installed in the left side of the cabin enclosure. A shutter, installed in the ventilator, is operated by a control located at the pilot's left. "

This is pretty basic and does not say the Stewart-Warner is a combustion (fuel) heater. But why designate it by brand name unless it was well known? If it was a car type heater core and duct why use the Brand name of a combustion heater company?
Stewart-Warner built combustion heaters for A-20s and other aircraft and also built ground heaters for warming up engines prior to starting.

P-39 Expert said:

BoB got nowhere near 30000ft.

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Umm, yes it did. Bf 109s carried out fighter sweeps from higher altitudes while escorting bomber formations. RAF fighters had difficulty intercepting them, but the German tactic was to dive down upon the attacking RAF aircraft then climb back to height. Dog fights, which is what usually broke out once the Bf 109s dived among the RAF fighters tended to descend with altitude, but yes, altitudes of over 30,000 ft were flown by the Bf 109s. And wot Pbehn said.

P-39 Expert said:

I just have a hard time believing those accounts. With the altitude statistics of the day.

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This is because you get all your information from charts and not from things like combat reports, historical accounts etc. Charts don't tell the whole story and are not always representative of real-world conditions. They are produced from test operations under controlled conditions for the purpose of recording standard performance data, but don't always represent every single aircraft, nor do they represent specific combat arenas, where conditions were frequently different on a daily basis.

P-39 Expert said:

Okay, how many P-40s with .30calMGs served in the AAF after Pearl Harbor?

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In an active war zone? Or just in the AAF.
Those based in the PI were mostly wiped out on December 8.
The 23rd FG, the successor to the AVG, took over the aircraft of the AVG, predominantly H-81s, on July 4, 1942, and continued to fly them in combat during the later half of 1942
Other units in the US and the Canal Zone continued to operate them for defensive or training purposes, but did not see combat.
But you bring up an excellent point. By the end of 1941, the USAAF and USN were equipping with fighters that were armed with 4-6 wing mounted .50 caliber MGs. Fighters with nose mounted, synchronized MGs were considered obsolete. The P-39, still armed with synchronized MGs and wing mounted .30 caliber guns was therefore obsolete before it entered combat. Why didn't Bell put .50 cals in the wings? There wasn't room. In the Q they slung a single .50 under each wing. Still wasn't good enough

P-39 Expert said:

Okay, how many P-40s with .30calMGs served in the AAF after Pearl Harbor?

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Can't give you a number but here are some P-40Cs still in front line service defending the Panama Canal in 1943:

P-39 Expert said:

Where did you see the 600yds range for the .30cal? Edit: Oh, sorry, I see it now. AHT lists 200yds as the max practical range. Why would we want the max theoretical range?

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Without knowing the criteria or method of figuring out either the practical range or the theoretical range we are simply speculating.

As I have said, AHT is a very good source but that table has a number of errors and inconstancies.

One might define practical range as the range that has some combination of probability of hitting plus the potential to do a certain amount of damage. It may have something to do with the amount of rounds fired to get a certain amount of damage.
Max theoretical range may be the range at which a golden BB hit will still do something? but a hit from a 37mm doesn't need to be golden BB, it just needs to hit.

Without having any idea of the criteria used it is impossible to critique.


I would also note that both the practical range and theoretical range will change with altitude. Higher altitudes with thinner air mean less drag, shorter times of flight and more impact energy.

Germans figured the MG 131 had an effective range of 400 meters against bombers but a max range of 700 meters at 3000 meters altitude and a max range of 1000 meters at 6000 meters altitude. The 15mm MG 151 is listed as having a 600 meter effective range, max range of 800 meters at 3000 m altitude and 1,100 meters amx range at 6000 meters altitude.

However this is complicated by the fact that the 13mm MG 131 was a pretty crappy long range gun/cartridge. At sea level it lost 55% of it's velocity by the time it had gone 600 meters and the time of flight was 1.22 seconds. The much higher velocity MG 151 lost 39% of it's velocity and and a time of flight of just 0.816 seconds to the same distance.
For a real head scratcher the AP round out of the MG 17 was rated as having an effective range of just 200 meters. But it lost57% of it's initial velocity in 600 meters but since it started faster than the MG 131 it's time of flight to 600 meters was 1.159 seconds, not really much better than the MG 131 but since it is going to arrive at pretty much the same time and have about the same drop why does it have such a short effective range? Granted it won't do as much damage but it's chances of hitting would seem to be as good.

BTW the .50 cal loses less velocity and has shorter times of flight to given distances than the 20mm Hispano which really calls into question the numbers in the AHT chart.

buffnut453 said:

Can't give you a number but here are some P-40Cs still in front line service defending the Panama Canal in 1943:

View attachment 630621

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FWIW the fighter ORBAT in Hawaii on 7 December 1941 comprised:

14 x P-26
39 x P-36A
87 x P-40B
12 x P-40C

So...none of the fighters present had 50cals in the wings.

In addition to the above there were 71 x P-40Bs and 26 x P-35s in the Philippines on 7 December 1941. Some 20 x P-40Es had arrived shortly before the Japanese attacked.

P-39 Expert said:

And you're telling me Spitfire I and 109E in 1940 routinely got over 30000ft?

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According to trials done by the Aircraft and Armament Experimental Establishment (A&AEE) in November 1939 with Spitfire Mk.I N3171 fitted with a Merlin III engine, its maximum altitude recorded was 34,700 ft. To put that into perspective, the first Airacobra I tested by the A&AEE in August 1941 recorded a maximum altitude of 29,000 ft.

The Airacobra's performance overall was poorer than that of the Spitfire VC AA873 with a Merlin 45, on which performance trials was carried out in October 1941, the Airacobra recording a maximum speed of 365 mph at 15,600 ft and a rate of climb of 1,845 ft/min to 12,500 ft, taking 12.4 minutes. The Spitfire VC recorded a maximum speed of 374 mph at an altitude of 19,000 ft and a rate of climb of 2,900 ft/min to 13,400 ft, taking 7.4 minutes.