An Allison V-1710 with a two-speed supercharger in 1942 (3 Viewers)

[Engineman]

A suggestion for those who want to get more of an idea as to the reasoning behind a broad range of decisions made by the UK Government, Air Ministry, AIr Staff and various layers of RAF and other Commander and Command Organisations.

Go and have a look at the Royal AIr Force Air Historical Branch Second World War Campaign Narratives.

The Second World War: Campaign Narratives

The Second World War: Campaign Narratives

www.raf.mod.uk

These were researched and written to capture the learnings of the RAF's various air campaigns during the War and as such drew on a very wide range of at the time highly classified - including MOST SECRET and SECRET documents - held in official files in the UK, along with captured German documentation from the various Luftwaffe commands and intelligence organisations. In a couple of places the narratives do skirt around particular issues, that were still at the time even more highly classified than MOST SECRET or that still held some political at the time sensitivity. But in a number of the narratives, the lessons of aftersight, the understanding of what the real position at the time was, versus what they knew at the time decisions were made are identified and discussed. In particular, the balance between decisions made on operational grounds versus decisions made based on political or geopolitical influences do get a fair degree of analysis and coverage.

Following is an example of the types of sources used in just one of the volumes - in this case Air Defence of Great Britain, Volume V, The Struggle for Air Supremacy Jan 1942 - May 1945.


View attachment 880335

View attachment 880336


They also have available for download in addition to the Narratives, a series of Thematic Studies on particular aspects of the RAF's activities in WW2, translations of German documents (including some of those prepared post war by senior Luftwaffe personnel), as well as Depatches and Reports written during the War by Senior RAF Commanders regarding specific operations or campaigns.

AHB Narratives and Translations

Index of official histories, written by Air Historical Branch (RAF) .

www.raf.mod.uk

Well worth the effort to download, read and understand more about various aspects of the RAF's WW2 experiences, including aircraft choices and the like.

A good lead! However, I will give a little warning. Many "Official" histories are modified to omit embarrassing elements and to reflect policy in various ways. I do not suggest that all such histories are flawed but "the winners write the history". Original documents that were written as a situation occured and are not abridged to remove the bad bits, are very useful.

Eng

 

[MiTasol]

A good lead! However, I will give a little warning. Many "Official" histories are modified to omit embarrassing elements and to reflect policy in various ways. I do not suggest that all such histories are flawed but "the winners write the history". Original documents that were written as a situation occured and are not abridged to remove the bad bits, are very useful.

Eng

That is why there was so much official pushback over having the Official history of the RAF's war against Germany written by the man who revived the IWM. Cannot remember his name or the book name but i am sure someone will supply the answer very quickly.

 

[drgondog]

Thing is, you are overstating how quickly the P-39 was taken out of combat.

• 347th FG, 35th, 18th, and 8th FG still were at least partly still equipped with P-39s in the New Guinea / Solomons area through most of 1943 and some squadrons into 1944.
• There was still a whole Tactical Reconnaissance group (71st TRG) flying P-39s in New Guinea and the Bismarck islands in 1944, and several individual squadrons of mixed fighter groups were still using P39s, like the 72nd FS / 318 FG on Makin island 1944.
• The 343rd FG was flying P-39s in the Alaska / Aleutians zone.
• In the Med 81st, and 350th FG were flying P-39s in a host of oddball missions into 1944, which ended up being used in Italy with some success as fighter bombers.
• And of course, they were spoffing them off on our Allies like the Free French and Italians, resulting in the deaths of many of their notable pilots in accidents.

All in all something like 12-20 P-39 squadrons still flying for most of 1943 and maybe 6-10 still in early 1944.

As for when to do it, of course that's where it gets hard, but I'd say an optimal moment might be Q3 or Q4 1942. By then a lot more P-40s are available, P-38s and P-47s are starting to come out, and there are plenty of F4Fs around from the Marines and Navy in the Pacific to help take up the slack. If you came out of it with some 'improved' P-39s in say mid 1943 that might actually be helpful.

The 'intended' P-39 replacement was the P-63 which first flew in December 1942, just after the XP-51B; The airplane is plagued with major problems with V-1710-47 two stage engine. Also major issues with stability due to improperly sized empennage flight surfaces

The Production P-63A with V-1710-93 first flew May 1943, same time as the production P-51B-1 (of which 50 were awaiting Packard delivery of 1650-3 engines). Due to continued in-flight issues with engine the P-63A fails Operational Suitability testing at Eglin in March 1944.

In August 1944, with 300+ P-63A delivered, General Arnold decrees that USSR can have as many used P-39 and new P-63s as the US has and continues to produce - which saved Bell.

Many configurations of elevator and rudder sizes tested to improve stability of the P-63. Russians complain that the P-63 is structurally weak in aft fuselage frame causing kits to be designed for field installation on P-63D and F.

The P-63 had 126-gal internal fuel. It could carry the 150-gal tank but could not use all the fuel and still come home after combat at max combat radius of about 200 miles - which was less than P-47D with 305-gal internal plus 75-gal drop tank. The largest practical combat tank was the 75-gal drop tank - with same combat radius.

Summary, the P-39 (all versions) were inferior in all tactical comparisons to all versions of the current P-40, P-38, P-47, P-51/A-36, P-51B/D in 1943 and the P-63 was never going to be selected for operational deployment in AAF due to myriad gestation problems encountered in operational suitability testing.

Why speculate on the 'what if' when reality kills the dream?

 

[MikeMeech]

Hi
The changing over to different marks of types in factories and its effect on production is discussed in general terms by Ely Devons in 'Planning in Practice', extract below:

Of course the disruption to production would depend on the scale of changes between the marks. When changing to different a different type of aircraft, especially if it used different construction techniques, would generally cause more disruption with a loss in the numbers of aircraft produced. Gloster aircraft production below ('Gloster Aircraft since 1917' by Derek N James), the Audax through Hurricane production were using the basically the same construction techniques for the fuselage, the Typhoon did not:

With production of a certain type or mark many parts used in the particular type have to be ordered in advance from sub-contractors and component suppliers, so any 'premature' cancellation may result in surplus parts that cannot be used on other types, Devons also covers the decision making around this in other parts of his book.

Mike

 

[Shortround6]

You yourself have pointed out that they wasted a lot of resources on the P-46 and especially P-60 programs. I agree it's not as severe as building 1,000 Defiants but it was certainly wasted effort and maybe one of the fatal injuries that Curtiss inflicted on themselves.

Prototypes are costly per plane, in part because they don't use much production tooling. Tooling for production (jigs and fixtures) for interchangeable parts costs money. I don't know where the cross over is in terms of number of planes built for large investment in tooling.
Building 7-10 prototypes in not any mor costly in raw materials than building 7-10 production planes.
What killed Curtiss was that they were unable to come with a successor to the P-40 and contracts for new planes dried up. A better prototype might have lead to a new contract and the survival of the company.
Hawker was spending money on the Tornado and Typhoon in 1938 (design work) and actual construction in 1939 and was working on (getting the government to pay for?) a new factory in at Langley in Buckinghamshire that would be equipped for metal monocoque construction.

Failing to come up with a new product is what killed Curtiss.

 

[Shortround6]

P-39s were at Cactus and they did prove of some value there, mainly in close air support roles, but the issue here is whether they were necessary there or in New Guinea. There were some (US) P-40s in Theater, some were being used to refit existing units which were rotated out of the front lines for a rest, others were in rear area bases on the Pacific Islands like Espiritu Santo and the Hawaiian islands. There was also an RNZAF squadron forming up. I believe they (USAAF brass) were trying to see if the P-39s could settle-in and turn out to be effective during late 1942 and early 1943, even though they had a very rough run in New Guinea during the spring and summer of 1942.

It's one of those things we can see in hindsight was probably a mistake, though how the brass at the time could be sure about it is another matter. They knew the War Dept had bought a lot of these aircraft. They may have wanted to give them a really good test before writing them off.

The USAAF brass didn't have choice. They were not doing operational trials with P-39s in summer and fall of 1942. If they 'wrote off' the P-39s and didn't use them in combat it would have taken months (6-12) to retool and retrain the Bell factory to make even P-40s.
Look at the production numbers again, once Bell was making around 150-200 P-39s a month you just can't wave your fingers and swap them for P-40s in all units fighting on the front lines (or likely to). WW II aircraft had life span that was much shorter than many people realize. Assuming they are not shot down or crashed they start getting "tired" around 300-400 hours (and 2nd or 3rd engine) and this may be shorter on front line air strips, hundreds of take-offs and landings on bumpy airstrips means things get bent or vibrated loose and need more maintenance per hour of flight.
The Brass had to get better aircraft into production, get flight crews and ground crews trained and get the new planes and crews to the combat units before they could pull the old ones. In 1942 the P-47 was the great hope. They had tooled up two extra production lines starting in Jan 1942. These two new plants/lines don't actually start producing planes even n small until Sept and Oct 1942. The 2nd new plant is Curtiss with the P-47G and Curtiss flubs this. They never hit the production number planned for the P-47G.
What does the Brass do in the Fall of 1942?
What are their choices for planes to use the existing squadrons and planes for the future squadrons. P-38s and P-47s are wanted for the 8th Airforce and the European bombing campaign but nobody knows how bad that is going to be or what the actual problems are going be.

 

[Frog]

And much maligned as the P-39 was, Bell Marietta also managed to produce 663 B-29s...

 

[Steamed_Banana]

The 'intended' P-39 replacement was the P-63 which first flew in December 1942, just after the XP-51B; The airplane is plagued with major problems with V-1710-47 two stage engine. Also major issues with stability due to improperly sized empennage flight surfaces

The Production P-63A with V-1710-93 first flew May 1943, same time as the production P-51B-1 (of which 50 were awaiting Packard delivery of 1650-3 engines). Due to continued in-flight issues with engine the P-63A fails Operational Suitability testing at Eglin in March 1944.

Interesting. It sounds like at least half of the problems were with the kludgy engine Allison came up with. If a Merlin XX was substituted, or if Allison somehow made a viable copy of one, much of this might have been averted and Bell could focus on fixing the issues with the wing.

In August 1944, with 300+ P-63A delivered, General Arnold decrees that USSR can have as many used P-39 and new P-63s as the US has and continues to produce - which saved Bell.

Many configurations of elevator and rudder sizes tested to improve stability of the P-63. Russians complain that the P-63 is structurally weak in aft fuselage frame causing kits to be designed for field installation on P-63D and F.

The P-63 had 126-gal internal fuel. It could carry the 150-gal tank but could not use all the fuel and still come home after combat at max combat radius of about 200 miles - which was less than P-47D with 305-gal internal plus 75-gal drop tank. The largest practical combat tank was the 75-gal drop tank - with same combat radius.

Yeah that's a bit worse than some variants of the P-39. How much of that was due to fuel consumption of the V-1710-93? Wasn't the V-1710-93 a fair bit bigger and heavier than the older F3R type? The hope here would be to increase fuel capacity rather than add a quasi two stage supercharger. Maybe it's not viable I'm not an expert on the P-39 by any 'stretch' (pun intended! )

Summary, the P-39 (all versions) were inferior in all tactical comparisons to all versions of the current P-40, P-38, P-47, P-51/A-36, P-51B/D in 1943

Not for the Soviets, apparently. They had no use for the P-47 and didn't even consider it a fighter. They liked the P-40 somewhat but much preferred the P-39. They criticized the P-51 for it's weight and low altitude agility.

and the P-63 was never going to be selected for operational deployment in AAF due to myriad gestation problems encountered in operational suitability testing.

Why speculate on the 'what if' when reality kills the dream?

Some people really struggle with the concept of a "What If" discussion but this is literally what this thread is all about, and this whole section of threads on the site, and as you can see with this one, while no battles of WW2 are won, interesting discussions can indeed result. It's an interesting way to consider what actually happened.

 

[Geoffrey Sinclair]

"Geoffrey", I will once again advise you to keep your long-winded, gibberish posts directed at other forum users than myself,

Noted for if I ever write long winded and gibberish. Otherwise it comes across contradictions are not allowed.

you and I are never going to have a production discussion about anything online.

The difference between quoting primary sources and using search engine results.

Or are you just trying to derail this thread by turning it into a flame war?

Interesting given the insult laden message from the funny comment onwards.

None of your trollish questions are sincere,

You see the Internet long range mental state detector really does not work.

and most of your claims of alleged facts are clearly baseless and demonstrably false.

Sources are quoted, books like America's Hundred Thousand have things like production numbers for the USN fighters. Notice the lack of demonstration of error.

Now to veer off on a tangent.
The Darwin Spitfire losses (about which I made no specific claims, it's worth noting)
Rather it was claims about what Spitfires did and what they could have done in the Pacific, failing to note 79 RAAF squadron.

You'll notice that "Geoffrey"'s numbers for losses are well below all of the sources in those threads, such as those from Darwin Spitfires.

Apparently I now wrote the Australian Official History in 1957. The comments about running out of fuel seemed pertinent given range is being discussed.

Draw your own conclusions

We have someone desperate to invent things I am supposed to have wrong.

If the claimed Axis losses in the MTO are correct the allied fighters were collectively poor performers, disguised by major over claiming.

When it comes to captured on ground think of how many aircraft were in the boneyards of 8th Air Force bases in 1944.

Once they had 2 seat fighters in inventory bureaucracy said they had to come up with a replacement two seat fighter. Once they had them they would figure out what to do with them

As I understand it the turret fighter project was about the improvement in accuracy a turret gave, along with ideas of reduction in deflection shooting and modern speeds making it very hard to keep the enemy under fire, think 8 gun fighters to give killing blows in only a few seconds instead of needing prolonged hitting. The decision was taken to make the Defiant a bomber destroyer kept away from enemy fighters, meaning its use in 1940 in daylight was taking the aircraft outside its design limits, sort of like flying Wellingtons so their turrets could blast the Luftwaffe bomber formations. The Defiant reverted to its design use but at night rather than day and was only given until early May 1941 to show what it could do. The ideal time for non radar night fighters is summer and the ideal night fighter has its own radar. What we do not know is what the Defiant would have done had Battle of Britain 2 been fought in 1941, at the very least it meant less need for Hurricane and Spitfire night sorties. Yes the British had specified night flying instrument panels for their fighters and pre war did night training, it did not make the average fighter squadron a night fighter unit.

Some argument on this. At least 1 USN squadron deck qualified with the F4U in summer of 1943 but the USN decided to standardize on the F6F for carriers for logistics.

My comment was mostly about whether early F4U were combat worthy, the F4U made the F6F decision easier thanks to its landing characteristics. The F4U could be operated off carriers but the USN did not like the look of the expected accident rates using average pilots and decided not to do it as a rule. Changes were made to the F4U.

My dates about the shut downs of the Hurricane and P-39 lines relate to the continued claims they could have been stopped and a better liked aircraft built instead, the dates are when that would have to happen according to the latest ideas on waste.

I am not certain of the "trouble" you refer to in the new DB 605 AS supercharger?

Pilot reports indicated the new supercharger initially at least was not reliable. I believe one JG300 pilot noted the Russians were complaining about only getting 200 to 300 hours out of their US or British engines while the Germans were struggling to make 50 hours.

MW50 was indeed a great improvement for both the DB 605 A and the DB 605 AS in the early Summer of 1944.

Yes, as noted as a broad brush opinion the German fighter performance factors mentioned did not change much from early 1942 to Q4/44

Noble Frankland and Charles Webster wrote the official history of Bomber Command, when it was first published the criticism was it was too harsh, within a few years the criticism was it was too soft. Frankland wrote the book History At War about his experiences, including the pre publication "discussions" over content.

 

[yulzari]

Thanks for that Mike.
Your summary pretty much reflects the general situation I have read about. I feel that the RAF Top-Brass supported opinions were very much a driving force in most developments that found Ministerial support. Of course, the "RAF opinion" was in itself a distillation of experiences (both individual and as a fighting Force), results from investigations by specialist units and from the great undercurrents of promotional-ladder rivalry, the latter being a very strong force within the Service on which senior careers rose or fell.
The air-battle exercises did show that the biplane fighters had difficulty in intercepting incoming raids, they were slow to be alerted (by visual and sound observation), had relatively little speed overtake for manoeuvre into attack and used cumbersome formation attacks that were slow and unwieldy, no surprise that they were ineffective and might only make one pass, if they were lucky (many mock attacking formations were never intercepted)!
The concept of a Turret-Fighter being able to fly with the bombers and shoot at them with the same guns the bombers had was really nonsensical from the start.
The only bonus of the single seat fighter from that time was that it should have 8 guns to make a single pass effective. The lack of frontal armour was a weak point, but armour generally was minimal.

Of course, if the Turret Fighter concept had been successful, it would have been a good job that we had them! But here is the nub of the problem, it was obvious that the turret fighter was a bad joke, right from the start, its concept it was deeply flawed. That it was promoted to such a degree was a serious failure that should have been forseen. If anyone had seriously considered the engagement of bomber formations (with their own similar defence) in this way they would have realised the stupidity. The problem was not the Defiant aeroplane, it was those who promoted the turret fighter concept.

Eng

The turret fighter was built upon a not unreasonable assumption that the most powerful continental armed force would ensure that France would not fall and thus the war would be fought from France. Thus German bombers attacking would have to fly from bases from which á fighter escort could not accompany them. Á turret fighter could engage the enemy for far longer than the fleeting attack of the conventional fighters whose short fleeting bursts were feared to be inadequate. Hence doubling the number of guns on British single seat fighters. The only failings in the construction and operation of the Defiants in the intended rôle was the lack of a forward pilot sight to match the turret fixed forward inclined guns in a forward attack and the lack of a trained doctrine to use a turret fighter.

That latter could have been simulated with existing Hawker Demons and Gloster Gauntlets/Gladiators as well as with the newer RAF bombers. The former appears to have been lost in the routine churn of RAF postings of staff. Such sights existed and were used in assorted trials of inclined guns right up to the x3 20mm cannon of the Gloster F9/37.

The base assumption proved false but was not unreasonable. Had the Germans been held it would have been viable.As it was the Germans were held for nearly 8 months so was a case of the plan was proved correct. Right up until it wasn't……

When we look at Boulton Paul's production times they could have been making Spitfires which were well within their capabilities but not in crucial numbers at crucial times. All three services demanded á high speed target tug which simulated actual attack speeds so, whilst used thus opportunely filled á real need.

I feel that the whole concept could have been properly trialled with existing aeroplanes before creating a requirement and the base assumptions tested.

Had the turret fighter concept not been taken up then , from a 'what if' point of view it is not just Boulton Paul being put to making Spitfires but what would the Royal Navy acquire in lieu of the Blackburn Rocs, also made by Boulton Paul? The primacy of the Air Defence of Great Britain for Spitfire and Hurricane production would still apply unless the Foyal Navy can co opt Boulton Paul as their own manufacturer.

 

[Engineman]

The turret fighter was built upon a not unreasonable assumption that the most powerful continental armed force would ensure that France would not fall and thus the war would be fought from France. Thus German bombers attacking would have to fly from bases from which á fighter escort could not accompany them. Á turret fighter could engage the enemy for far longer than the fleeting attack of the conventional fighters whose short fleeting bursts were feared to be inadequate. Hence doubling the number of guns on British single seat fighters. The only failings in the construction and operation of the Defiants in the intended rôle was the lack of a forward pilot sight to match the turret fixed forward inclined guns in a forward attack and the lack of a trained doctrine to use a turret fighter.

That latter could have been simulated with existing Hawker Demons and Gloster Gauntlets/Gladiators as well as with the newer RAF bombers. The former appears to have been lost in the routine churn of RAF postings of staff. Such sights existed and were used in assorted trials of inclined guns right up to the x3 20mm cannon of the Gloster F9/37.

The base assumption proved false but was not unreasonable. Had the Germans been held it would have been viable.As it was the Germans were held for nearly 8 months so was a case of the plan was proved correct. Right up until it wasn't……

When we look at Boulton Paul's production times they could have been making Spitfires which were well within their capabilities but not in crucial numbers at crucial times. All three services demanded á high speed target tug which simulated actual attack speeds so, whilst used thus opportunely filled á real need.

I feel that the whole concept could have been properly trialled with existing aeroplanes before creating a requirement and the base assumptions tested.

Had the turret fighter concept not been taken up then , from a 'what if' point of view it is not just Boulton Paul being put to making Spitfires but what would the Royal Navy acquire in lieu of the Blackburn Rocs, also made by Boulton Paul? The primacy of the Air Defence of Great Britain for Spitfire and Hurricane production would still apply unless the Foyal Navy can co opt Boulton Paul as their own manufacturer.

Hi,
With no axe to grind, I feel that you are generous in your thoughts that the turret-fighter was ever a viable concept. I agree that the concept might have been trialed more effectively, but I do not think it even required that effort. The idea that an aircraft might engage another with a similar armament, effectively slug it out and win (the enemy having more guns, possibly of greater firepower and X-supported by other bombers in formation) was weak in the extreme.

Cheers

Eng

 

[Engineman]

Pilot reports indicated the new supercharger initially at least was not reliable. I believe one JG300 pilot noted the Russians were complaining about only getting 200 to 300 hours out of their US or British engines while the Germans were struggling to make 50 hours.

Hi Geoffrey,

The German fighter engines did have a lower "life" than some Allied fighter engines. There were many reasons for this, some were materials limitations and some were semi-historic and technology based operating concept. Very roughly, the German combat engines were expected to achieve a 50 hour part overhaul life and a 100hour Ground (Full) overhaul.
The achieved engine lives were often much lower than this. However, the German system to support this was robust, with overhaul workshops and back-up to achieve the flying task, subject of course to the vagaries of warfare! Nonetheless, the German combat engines in service did need support.
The Allied combat engines were not paragons of reliability virtue. Rolls-Royce Merlin "lives" were often quoted as the designed Full-overhaul life, with the part-overhauls unmentioned.
For instance with the Merlin, if a 240 life hrs fighter engine is considered, the best average life in service before failing or being rejected was 144 hours and only 33% of engines would reach the nominal 240 hours ie, 67% of engines would fail before 240 hours. These stats were tracked and if any Merlin type did better than the baseline, a life-extension for the type would be considered.

Specific figures for the "reliability" of German fighter engines in the last year of WW2 are not easy to define. However, I would say that the general trend was towards lower life expectancy, mainly due to the high power outputs that were traded for engine life.

Eng

 

[Steamed_Banana]

The difference between quoting primary sources and using search engine results.

Woah! Incredible!! You really nailed me here. I'm so ashamed, you caught me using quickly googled production numbers in my post from four pages back. What gave it away? Drat!! I should have known I couldn't pull one over on a swift you, and I therefore must clearly deserve your ponderous contempt!

Could it be when i wrote this bit ?

"Some production numbers here (just googling, so correct me if I'm wrong)"

Maybe that was low hanging fruit. You really did a great job though. I feel so put in my place.

Interesting given the insult laden message from the funny comment onwards.

You see the Internet long range mental state detector really does not work.

Oh, so it's not an attempted Troll? That's a good disguise!

Sources are quoted, books like America's Hundred Thousand have things like production numbers for the USN fighters. Notice the lack of demonstration of error.

One minor correction though - America's Hundred Thousand, while a great resource (and which I like many here have on my shelf) which does refer to primary sources, is not itself a primary source.

We have someone desperate to invent things I am supposed to have wrong.

Everyone makes mistakes "Geoffrey", as you have done repeatedly in this thread. It's ok to admit when you do, just own up! But you always ignore corrections, deny numbers that you don't like, and blatantly, ponderously, fudge numbers, omit data that (it turns out after you are called on it) you clearly had access to, simply because you are trying to paint a narrative that you prefer over whatever the data shows. This is why there is really no reason to ever read your posts.

If the claimed Axis losses in the MTO are correct the allied fighters were collectively poor performers, disguised by major over claiming.

So this isn't a clumsy, ponderous attempt at a Troll? Well I heard that British Commonwealth pilots were worse shots than the French. Seems legit, right?

 

[MikeMeech]

Hi,
With no axe to grind, I feel that you are generous in your thoughts that the turret-fighter was ever a viable concept. I agree that the concept might have been trialed more effectively, but I do not think it even required that effort. The idea that an aircraft might engage another with a similar armament, effectively slug it out and win (the enemy having more guns, possibly of greater firepower and X-supported by other bombers in formation) was weak in the extreme.

Cheers

Eng

Hi
When the turret fighter concept was being devised in the 1930s bombers generally had single MGs in their gun positions, indeed the German bombers in the BoB basically still had that armament. Combined fire from formation of bombers was dangerous, not just for turret fighters but single seat fighters as well. The Germans were quite late at putting powered gun turrets with multiple guns on their bombers it was the British doing that early in the war. Because France was occupied in 1940 allowing German single seat fighters to escort their bombers over the UK the whole tactic of using the turret fighter had ended, it was not designed for fighter v fighter combat. In the early war years individual German bombers were not that well armed and also had blind spots that an individual bomber's guns could not cover (this also applied to a bomber like the British Hampden) so a German bomber did not have an heavier armament in its individual gun positions than a Defiant, it would generally be one gun against four.

Mike

 

[MiTasol]

While I agree that the turret fighter was not a great concept in hindsight, based on the assumptions that it would only be fighting bombers, not "long" range fighters I can see the logic behind it as not unreasonable.

I can see no such depth of reasoning behind the concept of fitting massive armament to B-17s to create a defense against fighters or the Airacuda or ...

Every military had its brain farts.

 

[ColFord]

A good lead! However, I will give a little warning. Many "Official" histories are modified to omit embarrassing elements and to reflect policy in various ways. I do not suggest that all such histories are flawed but "the winners write the history". Original documents that were written as a situation occured and are not abridged to remove the bad bits, are very useful.

With the exception that these ones were not at the time they were researched and written "for public consumption". Hence why they were all classified as SECRET, they were intended to provide those within the RAF at the higher command or aspiring higher command levels a largely unvarnished account of the various aspects of the RAF's WW2 strategy and tactics. If the 'bad' were not also presented with the 'good' then the lessons learnt from the just concluded conflict could not be learnt by those who might have to potientially command and fight the next war. There is a small degree of 'political restraint' but for example decisions by Government to keep supply of Hurricanes to the Soviet Union at relatively high levels when urgent demands for the same Hurricanes in the Middle East and Far East could not be met is criticised. As another example, the considerable discrepancy between the claims being made by the Fighter Command units duing the campaigns in 1941 and 1942 "leaning into Europe" compared to the actual losses recorded in the captured Luftwaffe records and indications at the time that it was a flawed strategy being rejected, are sharply brought into focus in the Fighter Command narratives.

These are distinct from the official histories that were researched and written "for public consumption" post war, where the layers of review and vetting in both the senior layers of the Services and the political establishment did cause quite a few instances of tension between the authors and the reviewers/approvers and a general removal of anything that may have been contentious or potentially politically or reputationally damaging to some senior personages. (Having had the opportunity to see the set of files held in Archives regarding the preparation and publication of a particular set of official histories for public consumption, the evolution of the history from first draft to final published form through the review and vetting process was torturous and at times very interesting to see the minor and major changes being suggested/required and by whom and which were accepted, rejected, or modified.)

 

[Shortround6]

When the turret fighter concept was being devised in the 1930s bombers generally had single MGs in their gun positions, indeed the German bombers in the BoB basically still had that armament. Combined fire from formation of bombers was dangerous, not just for turret fighters but single seat fighters as well. The Germans were quite late at putting powered gun turrets with multiple guns on their bombers it was the British doing that early in the war. Because France was occupied in 1940 allowing German single seat fighters to escort their bombers over the UK the whole tactic of using the turret fighter had ended, it was not designed for fighter v fighter combat. In the early war years individual German bombers were not that well armed and also had blind spots that an individual bomber's guns could not cover (this also applied to a bomber like the British Hampden) so a German bomber did not have an heavier armament in its individual gun positions than a Defiant, it would generally be one gun against four.

While I agree that the turret fighter was not a great concept in hindsight, based on the assumptions that it would only be fighting bombers, not "long" range fighters I can see the logic behind it as not unreasonable.

I can see no such depth of reasoning behind the concept of fitting massive armament to B-17s to create a defense against fighters or the Airacuda or ...

Every military had its brain farts.

The thing with "trick" armament layouts is that they depend on the enemy to keep doing the same things.
Four guns in a power turret compared to single guns on unpowered mounts sounds like a good idea (it really wasn't) but it depends on your enemy to keep using single non-powered guns for defense 3-4 years (more?) in the future.
Meanwhile the British are sticking twin and quad gun power mounts in their newest bombers (Wellington a Whitley) and are installing twin non-powered guns in Hampdens.
French are putting 20mm cannon in power mounts in their better twin engine bombers.
That would be something to see, Defiants and LeO 451s exchanging broadsides like flying ironclads
For some reason the Germans, when it came to power turrets, got drunk in the pub, staggered down the dock, missed the ferry and fell in the harbor as the ferry steamed away.
Expecting your enemies to do that is poor planning.

It also tends to overlook the Bf 110, which was the most notable long range/heavy fighter of it's day but far from the only one. Assuming that your enemy would only have single engine short range escort fighters 3-5 years in future also seems like poor planning/wishful thinking.

110s actually worked when used as intended but then the plan also needed co-operation by the British. Get ahead of the bombers and attack the fighter fields as the interceptors were warming up or at low/mid altitude climbing (low energy). Radar warning tended to screw that one up. Making the 110s fly at the same speed as the bombers and nearly the same height (low energy) finished off any hope of the 110s acting as escort fighters.
Brisfits worked in WW I

Crew could touch each other and at 120mph had time to 'communicate', depending on the intercom and with things happening 3 times faster (300mph) and with no forward gun/s depending on crew co-ordination was a lot harder.
They knew in WW I that the DH 4 had problems with crew co-ordination compared to the Brisfits and DH-9s which did not stick a large fuel tank between the pilot and gunner.
British expected a lot from the intercom?

 

[Engineman]

Hi
When the turret fighter concept was being devised in the 1930s bombers generally had single MGs in their gun positions, indeed the German bombers in the BoB basically still had that armament. Combined fire from formation of bombers was dangerous, not just for turret fighters but single seat fighters as well. The Germans were quite late at putting powered gun turrets with multiple guns on their bombers it was the British doing that early in the war. Because France was occupied in 1940 allowing German single seat fighters to escort their bombers over the UK the whole tactic of using the turret fighter had ended, it was not designed for fighter v fighter combat. In the early war years individual German bombers were not that well armed and also had blind spots that an individual bomber's guns could not cover (this also applied to a bomber like the British Hampden) so a German bomber did not have an heavier armament in its individual gun positions than a Defiant, it would generally be one gun against four.

Mike

Are you a supporter of the Defiant contract then, or do you see that the concept was critically flawed and a waste of important effort?
The points you raise are simplistic ones. Despite the apparent bonus of a four-gun turret against single guns positions, the multiple bomber aircraft out gunned the turret fighter. Furthermore, aiming the unstabilised turret was difficult and the Defiant had an 80% restricted field of fire! The whole concept of flying in formation with a group of armed bombers and slugging it out was wrong. Remember, "The Bomber will always get through"? That was another fine example of muddled thinking.
The great advantage of a high performance agile fighter with heavy forward firing armament was that it could attack with manoeuvre and fast closure that made aiming defensive guns against it difficult, an important fact that the RAF almost missed and some argued against.

Eng

 

[drgondog]

Interesting. It sounds like at least half of the problems were with the kludgy engine Allison came up with. If a Merlin XX was substituted, or if Allison somehow made a viable copy of one, much of this might have been averted and Bell could focus on fixing the issues with the wing.

The basis for design leading to successful prototype and future production starts with wing attributes (CL, CD, low speed authority, stores, armament, etc), then moves to the general arrangement of fixed equipment within the fuselage for preliminary weights and balance, then tradeoffs with variables such as fuel and ammunition locations.

The General Arrangement is the required first step for design of the fuselage and serves as the foundation for modification considerations.

In the case of the P-39, it was specifically proposed and designed as a high-altitude capable, small point interceptor. Period. Due to multiple reasons, most importantly the flawed turbosupercharger system, it was a complete failure for the primary mission. It was then placed into competition with the P-40 and ultimately P-51 for all AAF mission profiles.

A Merlin XX, while attractive based on higher FTH, would probably have generated a better fighter for AAF doctrine but would not have been of much more benefit as a point interceptor and would have IMO required substantial and time-wasting changes for the benefits expected.

The Merlin was heavier than the Allison and the center of mass would have been further aft of the wing aerodynamic center plus required an updraft carb forcing a lower fuselage carb intake as well as radiator intake scoop below or more efficient ones imbedded in leading edge. Almost certainly the wing would have to move aft and a fuselage plug required to maintain static margins with existing empennage design.

In other words, even the concept of a Merlin XX was a non-starter due to War Production Board demands for production commitments. Additionally, Bell was never going to get a Merlin allocation from Packard production as AAF diverted their share of Packard Merlin 1650-1 to Curtiss. Very soon thereafter the priority for Packard Merlins was shifted to NAA for the new 1650-3 and the balance of 1943/Q1-44 for Packard production for AAF was divided for 1650-1 spares and 1650-3 for Mustangs.

The Soviets loved the P-39, AAF despised it. Problem solved, no changes - give all to USSR.

Yeah that's a bit worse than some variants of the P-39. How much of that was due to fuel consumption of the V-1710-93? Wasn't the V-1710-93 a fair bit bigger and heavier than the older F3R type? The hope here would be to increase fuel capacity rather than add a quasi two stage supercharger. Maybe it's not viable I'm not an expert on the P-39 by any 'stretch' (pun intended! )

No, 120-gal. was max internal fuel through the P-39M. So, the P-63 had only slightly more internal (126-gal.)

IIRC and would have to check the FAREP tables, the P39 was cited as using 50+ gal. solely for the combat requirement and 40 gal just to warm up, takeoff and climb to altitude. The drop tank would absorb some of the initial drain on internal fuel during climb but 25+ gal required of internal fuel for reserve. The 200 mile CR that I cited is for escort mission. A fighter strafing mission in SWP or Russia with a 75-gal tank might achieve more but recognize that the total straight line range on internal fuel only was 600 miles with no reserve. Slightly more for the P-63 but still under 700 miles for yardstick, straight line, no reserve, optimal cruise at 10,000 feet.

Not for the Soviets, apparently. They had no use for the P-47 and didn't even consider it a fighter. They liked the P-40 somewhat but much preferred the P-39. They criticized the P-51 for it's weight and low altitude agility.

Yes, the P-39 was in the center of the strike zone for VVS doctrine.

Some people really struggle with the concept of a "What If" discussion but this is literally what this thread is all about, and this whole section of threads on the site, and as you can see with this one, while no battles of WW2 are won, interesting discussions can indeed result. It's an interesting way to consider what actually happened.

Agreed.

That said, the 'what if' is usually accompanied without guardrails of practicality of lead times for major changes to existing designs as well as War Board/War Ministry demands for sustained production delivery commitments, as well as competing priorities for desired technologies (like the Packard 1650-3, desired by Lockheed and Curtiss - but denied in favor to the P-51B/D).

 

[yulzari]

Are you a supporter of the Defiant contract then, or do you see that the concept was critically flawed and a waste of important effort?
The points you raise are simplistic ones. Despite the apparent bonus of a four-gun turret against single guns positions, the multiple bomber aircraft out gunned the turret fighter. Furthermore, aiming the unstabilised turret was difficult and the Defiant had an 80% restricted field of fire! The whole concept of flying in formation with a group of armed bombers and slugging it out was wrong. Remember, "The Bomber will always get through"? That was another fine example of muddled thinking.
The great advantage of a high performance agile fighter with heavy forward firing armament was that it could attack with manoeuvre and fast closure that made aiming defensive guns against it difficult, an important fact that the RAF almost missed and some argued against.

Eng

Not to speak for MikeMeech, but I am not one who would support the Defiant and Roc contracts but I do understand the reasoning for the turret fighter. Founded upon inadequately tested theories and what became a flawed assumption it nevertheless had merits. Whilst, like all turrets of the time, the turret guns were unstabilised the gunner could choose aiming points independent of the general attitude of the aeroplane and give sustained fire impossible to the conventional fighter in a passing high speed attack. There was never a question of quasi wooden ships of the line 'slugging it out' in exchanged broadsides. The preferred approach was below and to one side. The aeroplane and gunner could move from one target to another without making new passes each time it engaged. Remaining within the enemy formation. In the nightfighter rôle it was actually similar to the much vaunted jazz fire of later German night fighters with better target acquisition and duration of fire and being able to manoeuvre and continue engaging with enemy target movements. Only being weaker in firepower with x4 7,7mm machine guns and not a pair of (fixed) inclined 20mm cannon.

A much missed aspect of the operational failings of the RAF with the Defiant as day turret fighters was the inadequate testing of the turret fighter concept in the air with contemporary fighters and bombers before issuing a formal requirement, the lack of tested and practiced doctrines for engagement and the curiously vanishing forward fire option of ' no allowance shooting' and the associated pilot gunsight.

Had the concept been properly simulated in practical trials it would have demonstrated the ability of the conventional fighter to make effective engagement without any need for a turret and being able to deal with the heavier turret fighter in the rôle of enemy fighter escort.

Another minor point is that not only was the model use of the Bristol Fighter one of using the pilot's front gun as the primary weapon and the gunners twin Lewis as the defence to the rear but the use of the contemporary Hawker Demon was also in the same manner. Had the original intention to give the pilot control of the turret in fixed inclined fire on a 'no allowance' basis been followed through the Defiant would have been able to be used in the same manner as the Bristol Fighter and Hawker Demon which at least would be following period successful models. As far as I can determine the pilot's forward fire option just vanished with changes of staff officers and disappeared somewhere in the program. Perhaps, just perhaps, a Defiant with a fixed forward firing option for the pilot may have made a useful improvement in the effectiveness of the Defiant. Whatever the theories Boulton Paul did a fine job of turning them into a working machine.