Greg of Auto and Airplanes has asked for a Debate

[Low Battery]

Remember, we (and the debate) was referencing bombers that are relying on their armament as their primary defence - not their superior altitude or speed

#1. Well, it was pretty obvious to the RAF by early 1940 that it would not work in general (and that was backed up by post BoB operational experience over the continent). It was equally obvious to the Luftwaffe too by the end of the same year: Unless your opponents had insufficient fighters or fighters of particularly poor performance, armament and organisation, daylight unescorted raids by large numbers of bombers would result in unsustainable losses.

#2 Touch of strawman there, the issue isn't about bombers not making it though to their target at all, is it? Very few raiding forces were ever completely annihilated by defending fighters. The issue was unsustainable, impractical attrition through combat damage or losses, regardless of how many aircraft you're fielding. When Schweinfurt 1 and 2 were undertaken in strength and the loss percentage was some of the highest ever seen. If the AAF had started its war with a full compliment of contemporary B17b or B17c, and undertook unescorted raids, they would have been absolutely hacked out of the sky. These lacked power operated turrets, even a tail position and would have been utterly easy meat for the experienced Luftwaffe and a Germany that had not yet started to see its fortunes reversed on the Eastern Front.

#3 It took two years, grim experience, ESCORTS and the lives of thousands of aircrew to reduce that level of attrition down to strategically acceptable and then highly favourable levels. But the odds of victory to loss in direct unescorted air combat was almost never in the favour of the bombers in the ETO. To have matched airframe to airframe in manufacturing time , materiel and aircrew, it would have needed to be a loss ration of something like at least 3 fighters for every 1 B17.

No amount of extra turrets and .50s were ever going to achieve that (and never did).

1. Under different conditions with different equipment and different altitudes and formations etc. Tweaking various aspects produces different results. Just as was the case with B-29s vs Japanese fighters. The proof in the pudding as well because clearly the Americans even at the beginning were doing daylight raids with far more success than others who thought it was suicidal. Mind you I am not arguing that escorts were not needed. What I am pointing out is that it was closer than than imagined and hardly as insane as people judging today with the benefit of hindsight seems to presume.

2. This was perhaps poorly worded. I am not merely talking about just reaching the target. Attrition is a multi variate street. Whether your losses are too high and whether or not you take them in the first place is dependent on many factors. More bombers increases their defenses, diffuses the attack, increases the damage they do to the target per run etc. And I also am not talking about the specific types of B-17 being fielded in any case. My point is that if you have sufficient mass of an organically well defended bomber it changed the game. If you launch 1000 or more bombers per mission it's a completely different challenge compared to the paltry sub 300 or less bombers a available at first. Correspondingly, without enough bombers even escorts would be useless since if there are too few the fighters won't be able to sufficiently interfer with the attackers to stop them from shooting down the smaller force.

3. But it took barely any escorts to tip the balance. The facts are that a tiny handful of fighters were available in 1944 to escort to the target, and that was all it took to make the campaign viable again.

 

[Low Battery]

Even if unescorted bombers were feasible, they wouldn't have been decisive. During the bombing campaign against German aircraft plants, despite significant initial destruction, production actually increased. ( https://www.airuniversity.af.edu/Po...B_0020_SPANGRUD_STRATEGIC_BOMBING_SURVEYS.pdf )

The bulk of the irreparable damage to the Luftwaffe was done by the escorts:

That campaign enabled the later largely unopposed attacks on oil and transportation, along with widespread fighter bomber interdiction and harassment, and marked a sharp rise in the effectiveness of ground operations.

The strategic bombing did in fact have significant deleterious effects on German production. The problem isn't the Strategic Bombing Survey is they failed to properly consider knock on effects.

For one that actually do point out that the oil campaign was decisive. It dropped German oil production by 75 percent and this has major secondary effects on things like ammunition production due to other byproducts of those plants also being affected.

The transportation campaign was also effective, and basically nullified the advantages of spreading factories out to avoid attack.

But critically the only reason the Germans were able to do things like increase airframe production was because they robbed peter to pay Paul. It is suspected that possibly 30 percent of the increase in airframes was due to recounting repaired to modified planes. The Germans also maint3ned these dramatic increases at the expense of other industrial efforts.

For example, while tank production was not halted this was in large part achieved by not making spare parts or other systems like trucks. For much of the war the Germans put aside about a third of a all engines made for spares. By the end of 44 this was down to less than 8 percent.

Germany did not magically operate at exceptional economic output despite having millions of tons of TNT dropped on it.

 

[Shortround6]

The first RAAF as in Australian Air Force, not RAF as in Britain, were definitely Hudsons and Catalinas and the US had to almost force the first batch of P-40s on the Australians. The USAAF wanted to give them lots of P-40s but only enough pilots to train the RAAF pilots. Instead they took a small number of P-40s and the 49th USAAF Pursuit Group were sent here.

Thank you for the Correction. I did miss-read it.

Unfortunately RAAF orders immediately post PH may have as much to do with what they could actually get delivered in short order rather than what they may have wanted or thought lined up with any doctrine/policy. Given the large area of Australia Recon may have had a high priority.

 

[wuzak]

The Bomber raids they undertook actually had high loss rates. Perhaps the individual raids were worth the losses, but a more widespread application might have lead to even higher losses and it was hard to scale up.

Loss rates in raids with a small number of aircraft will always look worse.

If you lose 1 out of 6, that's a 16% loss rate.

IMO, the number of aircraft lost is a reflection on the defender's capacity to shoot down aicraft, the loss rate is the based on how many aircraft the attacker can send.

In the second half of 1943 and the first few montsh of 1944 the number of B-17s shot down was similar. But the loss rates went down because the number of bombers sent was increased significantly.

 

[Thumpalumpacus]

Even if unescorted bombers were feasible, they wouldn't have been decisive. During the bombing campaign against German aircraft plants, despite significant initial destruction, production actually increased. ( https://www.airuniversity.af.edu/Po...B_0020_SPANGRUD_STRATEGIC_BOMBING_SURVEYS.pdf )

The bulk of the irreparable damage to the Luftwaffe was done by the escorts:

That campaign enabled the later largely unopposed attacks on oil and transportation, along with widespread fighter bomber interdiction and harassment, and marked a sharp rise in the effectiveness of ground operations.

Doolittle's change, of directing for advanced escort, and the permission to strafe on the way home, allowed 8th AF fighters a great advantage in seizing air control. The bombers in a sense became the bait for a broader mission than just bombing the Reich.

 

[Thumpalumpacus]

Loss rates in raids with a small number of aircraft will always look worse.

If you lose 1 out of 6, that's a 16% loss rate.

IMO, the number of aircraft lost is a reflection on the defender's capacity to shoot down aicraft, the loss rate is the based on how many aircraft the attacker can send.

In the second half of 1943 and the first few montsh of 1944 the number of B-17s shot down was similar. But the loss rates went down because the number of bombers sent was increased significantly.

60 bombers lost on 17 Aug 43, 69 lost on 6 Mar 44. About 16% losses for the former, 10% for the latter. First raid had 376, the latter over 700. Note that both 16% and 10% are unsustainable, but these are max efforts. Most are below this loss-rate.

Bottom line: attacking numbers rising greatly, defending shoot-downs lagging. More escorts, more bombers (meaning the defenses are strained), target-rich environment means flak and fighters can clip more numerically but statistically that's not a graph you want to look at.

 

[EwenS]

The first RAAF as in Australian Air Force, not RAF as in Britain, were definitely Hudsons and Catalinas and the US had to almost force the first batch of P-40s on the Australians. The USAAF wanted to give them lots of P-40s but only enough pilots to train the RAAF pilots. Instead they took a small number of P-40s and the 49th USAAF Pursuit Group were sent here.

You might like this article about the first P-40 deliveries to the RAAF. I'm not seeing much "force" being applied to the RAAF. If anything it is RAAF requests to both Britain & the US going unfulfilled in the first half of 1942. I do note the comment about Gen Marshall insisting on many of the early deliveries going to Java and the lack of deliveries between Jun & Oct 1942.

http://www.adf-serials.com.au/research/Part1-P40.pdf

The first of an entire series of articles on the P-40 in RAAF service in the ADF Serials newsletters began in the May 2003 edition. The initial series dealing with the P-40E/E1 deliveries ran to June 2004. The above was in the July 2003 edition. March 2004 Part VII also dealt with the earliest deliveries.

ADF Serials Newsletters

 

[MiTasol]

I got my information two sources
1 - from the historical files at https://www.naa.gov.au/, and
2 - from the historical files at https://www.afhra.af.mil/. I got about 20 rolls of microfilm that had been converted to PDF and went through them.

I was researching all aircraft and units that came to Aus up until 1 July 1942. From memory one RAAF doc dated late 41 early 42 dismissed the need for fighters. I will try find that one again.

I did not strip out the records I am referring to from either source so cannot instantly post them but the NAA files index will find the RAAF orders quickly if the NAA put the right date on the files. Given the large number of ww2 files that are dated as opening and closing in the year 1800 the accurate dating, and naming, of files is not one of their requirements or priorities.

 

[MiTasol]

Here is one of the RAAF files. Decision to expand RAAF to include 15 fighter squadrons made but no suggestions of aircraft needed. In the pre PH programme the RAAF only needed its existing two squadron of Hawker Demons.

http://raafdocumentary.com/wp-content/uploads/sites/10/2022/02/12-SQN-NEG-050-260-scaled.jpg

 

[Geoffrey Sinclair]

At the start of 1935 the RAAF had 2 Army Co-Operation squadrons, 1 Fleet Co-Operation flight (for the aircraft carried by RAN cruisers), 1 flying training school (with fighter flight), a seaplane training unit and 1 aircraft depot, total 6 units in 3 locations, personnel strength of 817 on 1 April 1934 was rising to 966 a year later, there were 69 aircraft with the units.

As of 1 September 1941 the RAAF plan was expand the home based force to 32 squadrons, 17 General Reconnaissance (including 4 torpedo carrying and 3 flying boat), 9 General Purpose, 3 Army Co-Operation, 2 Fighter and 1 Fleet Co-operation. The Hawker Demons had been removed from squadrons by mid 1940, there were 54 Beaufighters on order.

RAAF in the Pacific, December 1941
4 squadrons in Malaya
7 squadrons in Northern Australia, New Guinea etc.
6 squadrons (1 a cadre) plus 3 flights in Southern Australia
2 squadrons in Western Australia
All listed as either Army Co-Operation, Bomber, General Reconnaissance or General Purpose.

In March 1942 War Cabinet approved a home based 73 squadron plan for the RAAF. The force would be 9 transport, 11 General Reconnaissance (medium and torpedo bomber), 12 dive bomber, 7 flying boat, 24 fighter, 4 heavy bomber, 5 Army Co-Operation and 1 Fleet Co-operation. The fighter orders were 771 P-40 and 362 Beaufighter. Lack of aircraft would see this plan modified to 45 squadrons by end 1942, then 35 by April 1943. Heavy bombers were not delivered until 1944, de Havilland built 87 DH.84 October 1942 to June 1943 to help overcome the lack of transport aircraft, the first from the US arrived in February 1943. The transport units were meant to give the air force mobility, able to quickly move units to where they were needed.

RAF 2 Group lost its 2 Mosquito squadrons end May 1943. Then gained 5 Mosquito fighter bomber squadrons by end 1943, including 2 new units and 3 ex Ventura, it had 8 Mosquito Fighter Bomber units by May 1945, most sorties were flown at night.

RAF 8 Group had 3 Mosquito Bomber/Pathfinder squadrons as of early June 1943, a fourth in December, a fifth in February 1944. As of June 1944, 5 group had 1 and 8 group 5 Mosquito Bomber/Pathfinder, while 100 Group had 4 Night Fighter and 1 Fighter Bomber squadrons.

 

[MiTasol]

As of 1 September 1941 the RAAF plan was expand the home based force to 32 squadrons, 17 General Reconnaissance (including 4 torpedo carrying and 3 flying boat), 9 General Purpose, 3 Army Co-Operation, 2 Fighter and 1 Fleet Co-operation. The Hawker Demons had been removed from squadrons by mid 1940, there were 54 Beaufighters on order.

You are correct that the Demons were officially removed from squadrons by mid 1940 although a number remained in service as squadron hacks.

I was deliberately omitting the fact that the RAAF had no actual fighters of any sort scheduled to enter service between mid 1940 and 11 June 1942 when the first Beaufighters were issued to squadrons. From memory the scheduled entry date was somewhat later but the outbreak of the Pacific war hastened their arrival significantly.

Fortunately the NEI, RAF and USAAF all threw modern, or relatively modern, aircraft in to the RAAF before the Beaufighters arrived otherwise the only "fighters" available would have been the semi-retired 182mph Demons or the 220mph Wirraway trainers, or maybe the Beauforts which had a maximum dive speed of 350mph and more guns than both the Demon and Wirraway.

As you know it is always difficult finding data within the Australian Archives because of the endless misspelling and misdating of their records.

file closed

 

[Low Battery]

Does anyone have any information on the fuel pumps Greg brought up in the debate?

 

[drgondog]

Does anyone have any information on the fuel pumps Greg brought up in the debate?

Yes - all modern aircraft of passenger type have imbedded pressure pumps. Gerg went off on a tangent when I was pressing him on the drop tanks - which until the C-9 pump mounted on drop tank,were all slaved from engine vacuum pump.

 

[Low Battery]

Yes - all modern aircraft of passenger type have imbedded pressure pumps. Gerg went off on a tangent when I was pressing him on the drop tanks - which until the C-9 pump mounted on drop tank,were all slaved from engine vacuum pump.

I know very little about fuel pumps. He seemed to imply during his tangent that the two P-47 pumps he mentioned the G something and K something, were so powerful that they could pump fuel in spite of the lack of pressurization in the tank. While I dont know much about this, it would seem that if it were this easy, everyone would have just put mega pumps on all planes. Also as per the previous part of this thread I would think you would get vapor lock if the drop tank were not pressured no matter how strong the pump?

 

[MiTasol]

Does anyone have any information on the fuel pumps Greg brought up in the debate?

Go back to post #170. It covers all the options then (suction from an electric pump or pressure from the vacuum pump or both) and the submerged pumps used in modern aircraft starting with the P-47 (unknown sub model) and P-51D or earlier (but not early Allison powered one) and gives diagrams of the various layouts.

The P-39 and P-41 and early P-38 and P-51 had non pressurised drop tanks. Late P-51 were pressurised and late P-38 MAY have been pressurised. May manuals are not clear on that.

What I missed on that post is that the Hawker Hurricane had submerged pumps in their long range external fuel tanks though I am not confident those could be dropped in flight. I need to find my manual to be sure and cannot at present.

 

[MiTasol]

I know very little about fuel pumps. He seemed to imply during his tangent that the two P-47 pumps he mentioned the G something and K something, were so powerful that they could pump fuel in spite of the lack of pressurization in the tank. While I dont know much about this, it would seem that if it were this easy, everyone would have just put mega pumps on all planes. Also as per the previous part of this thread I would think you would get vapor lock if the drop tank were not pressured no matter how strong the pump?

Again post #170 - and you will see that not only did the P-47 have PRESSURISED drop tanks but the manual also covers how to recover from drop tank vapour lock

 

[Engineman]

Yes - all modern aircraft of passenger type have imbedded pressure pumps. Gerg went off on a tangent when I was pressing him on the drop tanks - which until the C-9 pump mounted on drop tank,were all slaved from engine vacuum pump.

IMO, video gerg is often talking rubbish, he introduces some facts then obfuscates and conflates the subject to add his own incorrect details.
The "C-9" pump is actually the G-9 mechanical engine driven pump (EDP) that can only by itself draw fuel in under low pressure in its inlet. This is a common method of supplying critical pressurised fuel flow to a WW2 Aero-engine. However, it has an essential weakness that is very important to low-vapour pressure fuels like aviation gasoline, if the drop in pressure at the inlet of the pump drops to the vapour pressure of the fuel, vapour-lock may occur and the pump will cease to provide fuel flow and the engine stops. For this reason, you find the important reference in MiTasol's #170 that describes the possible recovery from "drop tank vapour lock", which is actually EDP vapour lock. In fact this illustrates the weakness of the P-47 EDP fuel feed design and actually shows that the G-9 pump COULD NOT just lift fuel from drop tanks reliably. Furthermore, the P-47 EDP could not even reliably lift fuel from the aircraft internal tanks! It had to have electrical immersed booster pumps in the sump of each main tank, with rheostat pilot control to adjust the booster pump output (fuel pressure and flow to the EDP inlet).
You can read on my attached internet sourced pic below, how the drop tanks were pressurised with air to assist fuel flow to the EDP.

Eng

 

[Engineman]

I know very little about fuel pumps. He seemed to imply during his tangent that the two P-47 pumps he mentioned the G something and K something, were so powerful that they could pump fuel in spite of the lack of pressurization in the tank. While I dont know much about this, it would seem that if it were this easy, everyone would have just put mega pumps on all planes. Also as per the previous part of this thread I would think you would get vapor lock if the drop tank were not pressured no matter how strong the pump?

See my #217 above.
Also, you will see on MiTasol post #170 that several of the aircraft types there relied on uplift by their EDP, with just vented drop tanks!

Eng

 

[SplitRz]

The proof in the pudding as well because clearly the Americans even at the beginning were doing daylight raids with far more success than others who thought it was suicidal. Mind you I am not arguing that escorts were not needed. What I am pointing out is that it was closer than than imagined and hardly as insane as people judging today with the benefit of hindsight seems to presume.

#1 Far more success than others who thought it was suicidal? Rhetoric aside, what's your actual benchmark for success, when comparing heavy losses to strategic achievement?

The losses were demonstrably large and unsustainable - and that was the 8ths own assessment. The only way to limit them was to keep raids to within the then limited range of the available fighter cover and to keep flight times over occupied Europe short. When they eventually ventured further forth over the Reich proper in 1943 under 'Pointblank', the losses were so high (something like 20% of aircrew killed or wounded) that the 8th had to suspend operations. I'm struggling to think of very much which could be deemed a 'success' to offset that before escorted raids in '44, can you?

As for 'suicidal'? I suppose it depends on your personal appetite for risk and sense of mortality. But an airman serving in the 8th in the 1943 period knew that statistically, the odds were against them surviving even a single tour of operation. Thats a pretty close comparison, I would have said.

Raids only recommenced when fighter escort became available. And no, this critique is NOT with the 'benefit of hindsight'. The USAAF only had to look at what happened to the Luftwaffe during the BoB. And it could have looked at (and listened to) the two and a half year's worth of direct war experience of the RAF - who advised them at the time of the capability of the Luftwaffe and had long since been on the receiving end of it. Instead, political, doctrinal and material limitations lead them to relearn those lessons again. Maybe that was worth-while in itself, but it cost a lot of arguably avoidable lost-lives for what looked and still looks like little return for that sacrifice.

#2 The Kassel raid on 1-2 April 44 where a raid went in without its escort due to a series of errors showed exactly how unescorted raids remained horribly vulnerable. Indeed the USAAF suffered its worst proportional losses of the entire bombing campaign on this raid. It merely underlined the lesson: strategic bombing by aircraft with a significantly lower speed and overall performance than defending fighters CANNOT 'slug it out' in a box formation and inflict enough losses to favourably attrite any enemy equipped with modern fighters in any number (and especially when operating under good radar direction). Adding yet more .50s eventually drops speed (meaning the aircraft is an easier target which is spending more time under threat), lowers bombload (meaning its less likely to achieve its bombing objective) and simply puts more flesh in the path of concentrated groups of 13, 15, 20 and 30mm shells. And in the grim economics of war, those are also human beings into whom a large amount of expensive and time consuming training has also been invested.

As envisaged and promoted by the designers and strategists, the self-defending daylight strategic bomber was a proven bogus philosophy. Underlined, proven unambiguously and in triplicate - a lesson evidenced that, aside from early B36 models, western bombers designed post-war concentrated on speed, altitude performance (be that high or low), counter-measures and offensive load.

Why unescorted raids over Germany were suspended

 

[Low Battery]

#1 Far more success than others who thought it was suicidal? Rhetoric aside, what's your actual benchmark for success, when comparing heavy losses to strategic achievement?

The losses were demonstrably large and unsustainable - and that was the 8ths own assessment. The only way to limit them was to keep raids to within the then limited range of the available fighter cover and to keep flight times over occupied Europe short. When they eventually ventured further forth over the Reich proper in 1943 under 'Pointblank', the losses were so high (something like 20% of aircrew killed or wounded) that the 8th had to suspend operations. I'm struggling to think of very much which could be deemed a 'success' to offset that before escorted raids in '44, can you?

As for 'suicidal'? I suppose it depends on your personal appetite for risk and sense of mortality. But an airman serving in the 8th in the 1943 period knew that statistically, the odds were against them surviving even a single tour of operation. Thats a pretty close comparison, I would have said.

Raids only recommenced when fighter escort became available. And no, this critique is NOT with the 'benefit of hindsight'. The USAAF only had to look at what happened to the Luftwaffe during the BoB. And it could have looked at (and listened to) the two and a half year's worth of direct war experience of the RAF - who advised them at the time of the capability of the Luftwaffe and had long since been on the receiving end of it. Instead, political, doctrinal and material limitations lead them to relearn those lessons again. Maybe that was worth-while in itself, but it cost a lot of arguably avoidable lost-lives for what looked and still looks like little return for that sacrifice.

#2 The Kassel raid on 1-2 April 44 where a raid went in without its escort due to a series of errors showed exactly how unescorted raids remained horribly vulnerable. Indeed the USAAF suffered its worst proportional losses of the entire bombing campaign on this raid. It merely underlined the lesson: strategic bombing by aircraft with a significantly lower speed and overall performance than defending fighters CANNOT 'slug it out' in a box formation and inflict enough losses to favourably attrite any enemy equipped with modern fighters in any number (and especially when operating under good radar direction). Adding yet more .50s eventually drops speed (meaning the aircraft is an easier target which is spending more time under threat), lowers bombload (meaning its less likely to achieve its bombing objective) and simply puts more flesh in the path of concentrated groups of 13, 15, 20 and 30mm shells. And in the grim economics of war, those are also human beings into whom a large amount of expensive and time consuming training has also been invested.

As envisaged and promoted by the designers and strategists, the self-defending daylight strategic bomber was a proven bogus philosophy. Underlined, proven unambiguously and in triplicate - a lesson evidenced that, aside from early B36 models, western bombers designed post-war concentrated on speed, altitude performance (be that high or low), counter-measures and offensive load.

Why unescorted raids over Germany were suspended

1. I did say that escorts were needed. In the specific context of 1943-44 Europe with the bombers the US was fielding and the numbers of bombers vs attackers and all other factors considered. The point is that it didnt take very much escort to shift this scale. A tiny number of escort fighters fielded in early 44 allowed the 8th to resume operations. This is simply a fact.

Large formations of well defended bombers moving at high enough speed are not easy targets. The reason I give the Japan example is that whether this works or not totally unescorted is simply a factor of the specific conditions. Once a formation of fighters passes through the formation from the front, it takes a relatively long time to catch back up and the lower rate of closure makes the fighters much more vulnerable to the defensive guns and applied formation. If the bombers are well armed enough and the fast enough, this CAN be enough. Given these factors, whether escorts are strictly necessary and how much escort will be needed varies. While an argument could have been made at the time that escorts MIGHT be needed, it was not irrefutably obvious until the autumn of 1943.

Its also not a straight comparison to look at any of the preceding campaigns as if they were tit for tat comparable to what was planned by the Americans. The American bombers were faster at higher altitudes than contemporary designs and far better armed. Its not that wild to understand why some might have reasonably thought they would succeed where other failed.

Whether this would be successful or not depended on a many intertwined factors. The performance of the planes, the effectiveness of the raids, the losses inflicted on the opposing force. All of these can be broken down even further. And given that perfect information was unavailable, what was and was not obvious in in large part hindsight. For example it was thought that Luftwaffe losses were much higher than actual and also not known just how much damage had actually been done in some of the raids, which from the German perspective was sometimes perilously close to disastrous.

Especially pre-war and early war it was CERTAINLY not obvious that self defending bombers were a totally bogus idea. As time went on there was more evidence that this might not be the case, but hardly 100 percent damning.


2. Are you not referring to the 27th September raid and not April? I cannot even find a mission in the ETO to Kassel on that date.