Some thoughts on "combat effectiveness/performance" factors that are often hidden.

[Steamed_Banana]

I think gunnery in general is one of those major issues which tends to be overlooked in analysis of the war. If you look at the Wildcat fighter on paper, it really has very few advantages over the A6M Zero. And yet they held their own, as we can now see in the operational histories, going about 1 for 1 with the Zero, and sometimes a little better, not just early on at Coral Sea when you had the (performance wise, superior) F4F-3, but all the way through 1943 when the USN was still flying the rather lumbering F4F-4 (with a roughly 1500 fpm initial climb rate and half the ammunition per gun), while both the Zero and Hayabusa had been upgraded (to A6M3 and Ki-43-II respectively) so they performed better at higher altitudes, rolled better in the case of the A6M3, and had more ammunition.

By 1943 the Allies had some new fighters in Theater in increasing numbers - USMC F4Us, USAAF P-38s, but these as we know took a while to sort out flaws and minor problems until average pilots could do well with them. The Army had the P-40 which did fairly well by this time but these were limited by range and could not move around on carriers like the Navy planes. It was really the Wildcat units which blunted the impact of the elite IJN fighter units and ground them down in the attrition war. What made them work was the very good gunnery training of the USN pilots in particular. They were just much more likely to hit their targets, in part because most of them had practice shooting at aerial targets and had been thoroughly briefed on best practices.

So just to make up a random example- if during a combat between two squadrons, one side gets 7 opportunities to shoot and the other (with better fighters) gets 12 opportunities, but the side with only 7 shooting opportunities hits at an average 20% rate* of hits while the other side is more like 10%, you'll get 1.4 victories vs 1.2 victories. A slight advantage which will add up over time in an attrition war.

Those percentages are just made up, but anecdotally, the USN pilots were better shots. I think this is basically what allowed the Wildcat units to hold their own. Tactics like the Thach Weave were designed around this specific advantage.

Needless to say a device like the gyro gunsight which makes this kind of accuracy possible for much less well-trained pilots makes a big difference. I think it was close to an order of magnitude? I know there were some studies on this which have some numbers.

(I almost said 'game changer' but I'm trying not to use degraded Corporate slogan-speak)

* this number is pulled out of an area of my body best not mentioned in polite company, just for sake of analogy to make the point.

 

[Shortround6]

The F4F had to be good enough to survive against the Zeros.
It's main job was to shoot down dive bombers, torpedo bombers, twin engine bombers and recon planes of various types, land based and water based (float planes/flying boats).

It did this rather well, helped by the large ammo capacity. F4F-3s carried up to 516lbs of ammo. F4F-4s carried up to 432lbs of ammo. Even with less than full ammo boxes the WIldcats could shoot for a longer period of time than the Zeros. At least until the Zero got the 2nd ammo increase. The first increase from 60 rounds to 100 rounds was significant.
The F4F was aided in this by the not very good protection of most Japanese aircraft in 1942 and early 43 and the general light construction.

The downside for the Wildcats is that they were carrying around 800-870lbs worth of guns and ammo and the entire plane had been designed to do that. Like do arrester landings with that load in the wings. This means heavier wing structure and heavier landing gear and even a little more weight in the fuselage and all this weight means less performance and the extra structural weight cannot be gotten rid of. You can pull a couple of guns and some of the ammo but the structural weight stays.
The ability to shoot for longer periods of time may have helped some novice pilots get kills when lower ammo capacity might have resulted in only damaged planes or no damage at all while the novices figured out why they were missing.

 

[Steamed_Banana]

The F4F had to be good enough to survive against the Zeros.
It's main job was to shoot down dive bombers, torpedo bombers, twin engine bombers and recon planes of various types, land based and water based (float planes/flying boats).

This was probably 60-70% off their job. Another 25%-35% or so was to protect Allied and especially the USN carrier based bombers from enemy fighters like the A6M and the Ki-43, (or in British use, the Bf 109 and MC 202). Maybe 5% was to participate in strikes themselves (for example strafing enemy AAA during bomber attacks, or carrying bombs themselves) and various other tasks for which they weren't super well suited but still also had to do, like ASW and recon etc.

It did this rather well, helped by the large ammo capacity. F4F-3s carried up to 516lbs of ammo. F4F-4s carried up to 432lbs of ammo. Even with less than full ammo boxes the WIldcats could shoot for a longer period of time than the Zeros. At least until the Zero got the 2nd ammo increase. The first increase from 60 rounds to 100 rounds was significant.

Yes. The F4F-4 as I'm sure you know, went from 4 to 6 guns, but carried a lot less rounds per gun. F4F-3 had a really impressive 450 rounds per gun (34 seconds of trigger-time), while the F4F-4 carried only 240 rounds per gun (19 seconds). So really just about half.

This was still decent, mind you, especially considering these were heavy machine-guns. But given that their job may be to intercept multiple waves of enemy bombers while also contending with enemy fighters, carrying more ammunition really mattered.

For comparison:

F6F3- 400 rounds per gun for 12.7mm heavy machine guns.

A6M2 - 60 rounds per gun (for 20mm cannon), 680 rounds per gun (7.7mm machine guns)
A6M3 - 100 rounds per gun (for 20mm cannon), 500 rounds per gun (7.7mm machine guns)
Ki-43-II - 250 rounds per gun (for 12.7mm in nose)
Ki-61 Ko - 250 rounds per gun (12.7mm nose)
Ki-61-i Hei - 150 rounds per gun (20mm cannon), 250-400 rounds per gun (12.7mm nose guns)
P-400 - 60 rounds (20mm nose gun), 200 rpg (12.7mm nose guns), 1,000 rpg (7.62mm in wings)
P-39Q - 30 rounds (for 37mm cannon), 200 rpg (12.7mm nose guns), 1,000 rpg (7.62mm in wings)
P-38F - 150 rounds (for 20mm cannon in nose), 500 rounds per gun (12.7mm nose guns)
P-40B - 235 rounds per gun (12.7mm in nose), 500 rounds per gun (7.62mm in wings)
P-40E - 240-312 rounds per 12.7mm wing gun (different guns had different amounts)
P-40F - 295 rounds per 12.7mm wing gun
F4U-1 - 375-400 rounds per 12.7mm wing gun
P-51B - 280-350 rounds per 12.7mm wing gun
P-51D - 400 rounds per gun (inboard 12.7mm), 270 rounds per gun (center and outboard 12.7mm)
Bf 109F2 - 200 rounds (15mm motorkanone), 500 rounds per gun (7.92mm nose guns)
Bf 109F4 - 200 rounds (20mm motorkanone), 500 rounds per gun (7.92mm nose guns)
Bf 109G6 - 200 rounds (20mm motorkanone), 300 rounds per gun (13mm nose guns), 135 rounds per gun (optional under wing 20mm gun pods)
Fw 190A5 - 250 rounds (20mm wing guns), 900 rounds per gun (2 x 7.92 mm nose guns)
Fw 190A8 - 250 rounds (20mm inner wing guns), 140 rounds (20mm outer wing guns), 400 round per gun (13mm nose guns)

So the Wildcat went from one of the largest ammunition capacities for any WW2 fighter (for the size of the gun) to slightly below average. The folding wings on the F4F-4 was supposed to double the number of fighters per carrier, but it didn't work out that way. IIRC the actual increase was more like 40%, which is significant, but it's hard to say if it's worth it due to the diminished rate of climb causing major problems intercepting enemy air strikes on a few occasions.

I personally think they should have continued to manufacture F4F-3 for the USMC for operation from islands. Would have helped a lot around Guadalcanal and some of the other Pacific islands, might have even saved some USN ships.

The F4F was aided in this by the not very good protection of most Japanese aircraft in 1942 and early 43 and the general light construction.

Somewhat. But I think this tends to be overstated a fair bit, to be honest. The Zero in particular made up for the protection of the Wildcat with it's 20mm cannons.

The downside for the Wildcats is that they were carrying around 800-870lbs worth of guns and ammo and the entire plane had been designed to do that. Like do arrester landings with that load in the wings. This means heavier wing structure and heavier landing gear and even a little more weight in the fuselage and all this weight means less performance and the extra structural weight cannot be gotten rid of. You can pull a couple of guns and some of the ammo but the structural weight stays.
The ability to shoot for longer periods of time may have helped some novice pilots get kills when lower ammo capacity might have resulted in only damaged planes or no damage at all while the novices figured out why they were missing.

The Wildcat was also quite stout compared to equivalent period fighters, only the Brewster F2A Buffalo looks more portly. All that width created a lot of drag.

The difference in fuselage width with the Ki-43 is particularly glaring

But the A6M is also quite slim in comparison. The A6M2 was also carrying quite a bit of fuel and two big 20mm guns.

 

[yulzari]

This recent discussion raises, for me, the question of the relative effectiveness of the gunsights, both between air forces but also over time. Our period is too late for radar gunsights but deflection shooting saw great steps forward.

 

[Steamed_Banana]

Worth considering. In broad strokes the types I know of are: none, 'ring and bead', periscope (seemingly on most early WW2 fighters), reflector gun sight, and the gyro mentioned above. Today of course we moved into HUD and then helmet based sights.

I suspect there were different grades of the reflector sights with different features but I don't really know all the details.

One thing I know was an issue with the periscope type sights in the early war was that they sometimes fogged up, which was a major issue for a while on SBD Dauntless dive bombers in the Pacific.

They also seem to me likely to diminish situational awareness somewhat during use. A problem as one way fighter pilots were constantly getting shot down was while trying to shoot down another aircraft...

 

[MikeMeech]

Worth considering. In broad strokes the types I know of are: none, 'ring and bead', periscope (seemingly on most early WW2 fighters), reflector gun sight, and the gyro mentioned above. Today of course we moved into HUD and then helmet based sights.

I suspect there were different grades of the reflector sights with different features but I don't really know all the details.

One thing I know was an issue with the periscope type sights in the early war was that they sometimes fogged up, which was a major issue for a while on SBD Dauntless dive bombers in the Pacific.

They also seem to me likely to diminish situational awareness somewhat during use. A problem as one way fighter pilots were constantly getting shot down was while trying to shoot down another aircraft...

Hi
For types of gunsights, the book I mentioned previously is useful, however, if you go to the RAF Air Historical Branch website and look at the document AIR 41-82 SD 737 'Armament Vol. II, Guns, Gunsights, Turrets, Ammunition and Pyrotechnics' you will find a summary on different gunsights between pages 61-89. This is useful and free.

Mike

 

[RCAFson]

This was probably 60-70% off their job. Another 25%-35% or so was to protect Allied and especially the USN carrier based bombers from enemy fighters like the A6M and the Ki-43, (or in British use, the Bf 109 and MC 202). Maybe 5% was to participate in strikes themselves (for example strafing enemy AAA during bomber attacks, or carrying bombs themselves) and various other tasks for which they weren't super well suited but still also had to do, like ASW and recon etc.



Yes. The F4F-4 as I'm sure you know, went from 4 to 6 guns, but carried a lot less rounds per gun. F4F-3 had a really impressive 450 rounds per gun (34 seconds of trigger-time), while the F4F-4 carried only 240 rounds per gun (19 seconds). So really just about half.

This was still decent, mind you, especially considering these were heavy machine-guns. But given that their job may be to intercept multiple waves of enemy bombers while also contending with enemy fighters, carrying more ammunition really mattered.

For comparison:

F6F3- 400 rounds per gun for 12.7mm heavy machine guns.

A6M2 - 60 rounds per gun (for 20mm cannon), 680 rounds per gun (7.7mm machine guns)
A6M3 - 100 rounds per gun (for 20mm cannon), 500 rounds per gun (7.7mm machine guns)
Ki-43-II - 250 rounds per gun (for 12.7mm in nose)
Ki-61 Ko - 250 rounds per gun (12.7mm nose)
Ki-61-i Hei - 150 rounds per gun (20mm cannon), 250-400 rounds per gun (12.7mm nose guns)
P-400 - 60 rounds (20mm nose gun), 200 rpg (12.7mm nose guns), 1,000 rpg (7.62mm in wings)
P-39Q - 30 rounds (for 37mm cannon), 200 rpg (12.7mm nose guns), 1,000 rpg (7.62mm in wings)
P-38F - 150 rounds (for 20mm cannon in nose), 500 rounds per gun (12.7mm nose guns)
P-40B - 235 rounds per gun (12.7mm in nose), 500 rounds per gun (7.62mm in wings)
P-40E - 240-312 rounds per 12.7mm wing gun (different guns had different amounts)
P-40F - 295 rounds per 12.7mm wing gun
F4U-1 - 375-400 rounds per 12.7mm wing gun
P-51B - 280-350 rounds per 12.7mm wing gun
P-51D - 400 rounds per gun (inboard 12.7mm), 270 rounds per gun (center and outboard 12.7mm)
Bf 109F2 - 200 rounds (15mm motorkanone), 500 rounds per gun (7.92mm nose guns)
Bf 109F4 - 200 rounds (20mm motorkanone), 500 rounds per gun (7.92mm nose guns)
Bf 109G6 - 200 rounds (20mm motorkanone), 300 rounds per gun (13mm nose guns), 135 rounds per gun (optional under wing 20mm gun pods)
Fw 190A5 - 250 rounds (20mm wing guns), 900 rounds per gun (2 x 7.92 mm nose guns)
Fw 190A8 - 250 rounds (20mm inner wing guns), 140 rounds (20mm outer wing guns), 400 round per gun (13mm nose guns)

So the Wildcat went from one of the largest ammunition capacities for any WW2 fighter (for the size of the gun) to slightly below average. The folding wings on the F4F-4 was supposed to double the number of fighters per carrier, but it didn't work out that way. IIRC the actual increase was more like 40%, which is significant, but it's hard to say if it's worth it due to the diminished rate of climb causing major problems intercepting enemy air strikes on a few occasions.

I personally think they should have continued to manufacture F4F-3 for the USMC for operation from islands. Would have helped a lot around Guadalcanal and some of the other Pacific islands, might have even saved some USN ships.



Somewhat. But I think this tends to be overstated a fair bit, to be honest. The Zero in particular made up for the protection of the Wildcat with it's 20mm cannons.



The Wildcat was also quite stout compared to equivalent period fighters, only the Brewster F2A Buffalo looks more portly. All that width created a lot of drag.

View attachment 872893

The difference in fuselage width with the Ki-43 is particularly glaring
View attachment 872894

But the A6M is also quite slim in comparison. The A6M2 was also carrying quite a bit of fuel and two big 20mm guns.
View attachment 872895

Fulmar Mk1: 750RPG x 8, Mk2, 1000RPG x 8.

 

[Steamed_Banana]

Hi
For types of gunsights, the book I mentioned previously is useful, however, if you go to the RAF Air Historical Branch website and look at the document AIR 41-82 SD 737 'Armament Vol. II, Guns, Gunsights, Turrets, Ammunition and Pyrotechnics' you will find a summary on different gunsights between pages 61-89. This is useful and free.

Mike

Sounds like a good source, but without fully coming up to speed on the subject, do you know the differences well enough to say whether there were functionally different grades of reflector gunsights?

 

[MikeMeech]

Sounds like a good source, but without fully coming up to speed on the subject, do you know the differences well enough to say whether there were functionally different grades of reflector gunsights?

Hi
Depends what you mean by different 'grades'? Reflector sights were being experimented with at the end of WW1 and we see various designs from around the world being tried out during the 1920s and 1930s. These were in use both for fixed guns (fighters) and free/turret guns. An interesting piece reference US use of reflector sights can be found in Roger Freeman's 'The Mighty Eighth War Manual':

A couple of images of reflector sights being used on free guns, from 'British Aircraft Armament' are below:

Fixed sights were being improved and adapted to do different tasks, for example rocket firing Typhoons altered the sight to use with that weapon. Below, also from 'British Aircraft Armament', are images of the Mk.II and Mk.II*:

It was also tried with removing the reflector screen totally and use the inside of the windscreen for that purpose, but there were some problems with 'double images' I believe. It appears that the USAAF and the USN did benefit from having access to British Reflector Sight (and Gyro Sight) technology.

Mike

 

[Steamed_Banana]

Great post! Even here there is an amazing story. German designed gunsights!

 

[MikeMeech]

Great post! Even here there is an amazing story. German designed gunsights!

Hi
"German designed gunsights!"? If you are referring to the Goerz company (Austria) they were not German design but British sights being manufactured on a British contract. The company also produced the German Revi gunsight. Austria was not part of Germany when the contract was initially done, the Anschluss (55 delivered before this event) was a worry but the contract was fulfilled (700) before the outbreak of war. I should add a caveat as according to the AHB RAF Document source The sights manufactured by Goertz consisted of a "Barr and Stroud body with the firm's own optical system installed." As the firm also produced Revi sights for Germany one wonders if their same optical system was installed on a Revi body?

Mike

 

[Steamed_Banana]

Hi
"German designed gunsights!"? If you are referring to the Goerz company (Austria) they were not German design but British sights being manufactured on a British contract. The company also produced the German Revi gunsight. Austria was not part of Germany when the contract was initially done, the Anschluss (55 delivered before this event) was a worry but the contract was fulfilled (700) before the outbreak of war. I should add a caveat as according to the AHB RAF Document source The sights manufactured by Goertz consisted of a "Barr and Stroud body with the firm's own optical system installed." As the firm also produced Revi sights for Germany one wonders if their same optical system was installed on a Revi body?

Mike

Ah my bad I misread, late at night .. I was also thinking of the glass used for gunsights / optics for the early US tanks, which were prior to WW2 initially of German manufacture which was suddenly unavailable right as tank production ramped up. The US optics were not as good, especially early on.

 

[Dr. Odendahl]

there was a reason that the US 4 engine bombers used a "flight engineer"
View attachment 850655
B-29 flight engineer's panel.

Forecasting wartime spare parts levels is sort of like forecasting your requirements for rally driving unknown distances based on your regular work commute travel on good roads. The easiest way to up production numbers was to reduce the number of components set aside for spares.

The general rule was everyone was caught short the first times they encountered heavy combat and some made deliberate choices, the US had more warning time but had some trouble believing the numbers required (So did Churchill). Not only spare parts but the personnel to do the repairs, including moving the damaged aircraft as required. Going into largely unknown environments was another factor, like the tropics and flying at greater heights. The US published the two volume official history Global Logistics and Strategy looking at things from higher levels, it had more distances to cover during internal movements but the USN versus IJN plans aside not a lot about major expeditionary forces, the islands the navies were going to fight over did not have a lot of room and no one was forecasting how good you could make a wartime construction system. The merchant ships needed were not being built. The US had a much bigger civil than military aviation industry, which had different objectives and requirements, like reliability and economy versus absolute performance.

If anyone was building long range aircraft as standard requirement it was the IJN.

The US was heavier idea needs the usual qualifications, the B-17/24 ended up around the same weights as the Halifax/Lancaster, the US mediums were built on the assumption they would be intercepted and so went for survivability, the heavyweight P-47 started out about 600 pounds heavier than the Typhoon. Some of the extra weight is due to when the aircraft was designed, the later the more powerful the engines available, amongst other things those engines needed more airframe strength to stay attached, some early Merlin Mustangs did not have the engine bearer strength of the Spitfires, add more fuel as well. The Hellcat had a 2,000 HP engine but on specifications did not have much performance over the Zero with half the power, the weight went into other features, including pilot safety and good carrier landing characteristics.

The British could put forward the Stirling as a much more rugged design than the US heavies based on empty weights, how much of the P-40 weight is Curtiss or the way it is an update of an older design instead of then current US practice? The Empire State Building is over strength compared with later designs.

Always remembering there were people on the other side putting holes in your equipment. The Luftwaffe thought it took around 20x20mm or 2 to 3x30mm. hits to bring down a heavy bomber if no fire was started.

Given the USAAF reports its aircraft losses as 1/3 in USA, 1/3 non combat/war weary and 1/3 combat it is clear accident rates had a big impact on the maintenance system and those rates went up as average crew experience went down. RAF, end August 1939 75 out of 475 delivered Hurricanes had been Struck Off Charge, 27 out of 305 Spitfires, 38 out of 210 Gladiator I. The site Martin's Aviation Pages lists British non training unit all causes aircraft casualties September 1939 to March 1940 as 584 losses and 897 damaged, by end August 1940 that was up to 2,794 lost and 3,585 damaged plus 233 abandoned.

The Narrow Margin by Wood and Dempster have a cumulative battle casualties table fr the RAF at home presumably for the war, to 1 July 1940 82 bombers category 2, 358 lost, 56 fighters category 2, 517 lost, other types 16 category 2, 104 lost, as of 31 October 1940 it was bombers 198/725, fighters 766/1,657, others 66/200.

According to the Ministry of Aircraft Production aircraft awaiting spares as a percentage of all aircraft within the RAF, end of month June 1941 to February 1942 was 8.5%, 9.7%, 10.2%, 9.9%, 9.4%, 8.2%, 8.4%, 8.0%, 7.0%. End June 1941 RAF Home Commands had 932 aircraft awaiting spares of which 611 were trainers, end February 1942 1,090 aircraft, 602 trainers. October 1941 to March 1942 spares requested in the month, around to over a third there was no stock and a similar number had over 10 month's stocks. Drill down and Hurricane spares were more plentiful than Spitfire, engine spares had under 15% no stock, propeller generally over 40% no stock, airframes varied between 13 and 48%, usually closer to the lower figure. We know any functioning repair system at a given date is going to have under repair and not under repair for <reason>, the question being what is an acceptable level of not under repair.

March 1942, aircraft storages, front line combat types, 212 aircraft needing engines (all but 2 Merlins), 479 needing propellers, 346 needing constant speed units, 193 (all Blenheim) needing turret, total 1,240, though some needed more than 1 component. January 1945, of the 8,949 aircraft and 512 airframes in storage units 1,292 had equipment deficiencies. (Top 5 were 121 Oxford I, 76 Anson, 71 Beaufighter TF.X, 60 Stirling IV and 45 Martinet.)

When introduced into RAF service the Merlin had an engine failure rate of 1 per 500 hours of flying, as of the December 1941 to May 1942 period it was 1 per 1,000 hours, the Sabre was 1 per 340 hours.

Some of the 15th Air Force 1945 monthly reports have Engine Change Reports, graphs of average running time per aircraft engine changed. generally speaking the R-1830 radials in the B-24 and the R-1820 radials in the B-17 had at least an average of 300 hours running when changed, few had 400, with the R-1820 ahead, most having 350 or more hours. Overhauled engines usually had around half the average hours of new engines. The V-1650 Merlins and the V-1710 Allisons usually averaged over 200 hours, few made it to 300 until March/April. Overhauled Allisons were around half the new engine hours, overhauled Merlins more like a quarter. In civil service the radials lasted several times longer between overhauls.

You find WWII history in some interesting places. Journal of the American Statistical Association, V 41 no. 234, June 1946, pages 190 to 203. "Actuarial Analysis of the operating life of B-29 aircraft engines", by O L Altman and C G Goor. Lots of obvious and not so obvious points.

1) R-3350's were in critical supply in 1944 and the first half of 1945. This is despite usually the number of R-3350 built to date being twice the number needed for B-29 built to date. Supply problems were easing around the end of the war.
2) Air transportation was used to fly R-3350's to the US for overhaul, at best 2 R-3350's would fit in a cargo plane.
3) Overhauled engines had around 10% lower "life" before the next overhaul.
4) The -23 was the carburettor and the -57 the fuel injected versions. The -23 was modified to improve reliability.
5) The statisticians noted the standard USAAF methodology for forecasting engine life was only suitable for a reasonably static population. Not where there was a steady arrival of more strength with new aircraft.

In terms of engine life, operations in India were the worst, since each combat sortie required three reasonably rapid climbs, India to China, China to Japan, China to India. Next came training in the US, finally the best were the units in the Marianas.

Expected life prior to first overhaul, early operations from India, 163 hours, -23 engines. Using modified -23 engines this had risen to 280 hours by February/March 1945 for aircraft operating from India and 304 hours from the Marianas. The figures for B-29s used in training were 221 hours and 310 hours versus the 163 and 280 hours figures above.

Operating from India a comparison between the modified and unmodified -23 engines showed 80% of the unmodified and 95.3% of the modified engines survived to over 100 hours, 33.9 of the unmodified and 81.5% of the modified engines survived to over 200 hours, 0.2% of the unmodified and 47.3% of the modified engines survived to over 300 hours.

In the Marianas, as of 20 November 1944 the average hours on each -23 engine removed was 91, by 20 January 1945 it was 151, as of 30 April it was 234. These figures include removals for engine model changes, modifications, accidents and battle damage. They are also under estimates of the normal engine lifetime because so many of the engines were new. The figures include new and overhauled engines, so it is either the number of hours since the engine was built for new engines or since overhaul for the overhauled engines.

Engine hours before removal as of 31 May was 259 hours, and 31 July 272 hours. These figures are for engines removed because of mechanical problems only. Even in July the steady number of new B-29s arriving drove down the average engine hours per removed engine.

A study as of 31 July 1945 noted in the Marianas the -23 engines 96.8% of new and 92.5% of overhauled logged more than 100 hours before replacement, 87.5% and 75.7% respectively logged over 200 hours, 62.7% and 43.4% logged over 300 hours, 19% and 8% logged over 400 hours, none logged over 500 hours.

As noted above the training schools in the US went through R-3350 engines quicker than the combat units in the Marianas, for example 57.9% (new) and 36.4% (overhauled) logged over 300 hours, but once this mark was passed the engines in the US held up more, so 24.6% and 10.4% logged over 400 hours, and 1.2% and 0.2% managed over 500 hours.

The fuel injected -57 engine had a higher time between overhauls, so in the above study 31.2% used in training logged over 400 hours, and 4.9% logged over 500 hours.

The USAAF Statistical Digest has the 20th Air Force flying between 10 and over 14 hour missions per the monthly averages, 621,975 hours of which 479,113 were on combat missions, at 200 hours per engine that is around 12,500 engines.

The US statistics on spares production indicate says airframe plants might not be making any, which makes some sense if they were assembly plants, or some plants were more dedicated to spares, it clearly varied, an example, Consolidated, San Diego in 1943, 25,656,000 hours making B-24, 3,185,000 making B-24 spares, Fort Worth no spares made for knock downs assembled, for other B-24 18,949,000 hours for assembly, 907,000 for spares.

The Spitfire and Bf109 undercarriage attached to the fuselage.

Thanks. This was a fascinating discussion. I hope to reread it later to see if I understood most of it. This is why I keep coming back to this forum.

 

[Writer]

Apart from any of the other topics, (maintenance, gunnery etc; mentioned above), there is also the aspect of how many controls the individual pilots had to operate. The Focke-Wulf 190 of 1941 on had only a single throttle lever to bother about, this operating the "Kommandogerat" Mechanical computer, which combined the operations of mixture control, aircrew pitch, supercharger use, throttle settings and indeed just about everything that pilots had to operate with individual controls on other aircraft. So the German pilots had much less to bother about in combat. That must have made an enormous difference. Of course there's also the fact that as the war progressed, Allied pilots received more flying trains hours and German/Japanese pilots less....

 

[wrathofatlantis]

Apart from any of the other topics, (maintenance, gunnery etc; mentioned above), there is also the aspect of how many controls the individual pilots had to operate. The Focke-Wulf 190 of 1941 on had only a single throttle lever to bother about, this operating the "Kommandogerat" Mechanical computer, which combined the operations of mixture control, aircrew pitch, supercharger use, throttle settings and indeed just about everything that pilots had to operate with individual controls on other aircraft. So the German pilots had much less to bother about in combat. That must have made an enormous difference. Of course there's also the fact that as the war progressed, Allied pilots received more flying trains hours and German/Japanese pilots less....

That was a problem, but the fact that the Japanese Navy (to a lesser extent the Army) and the Germans still tried to stick with Hit and Run all the way into 1944, when everyone turned at the first sound of "break!" on the radio, was probably their biggest problem...:

"On October 21, 1943, the Group launched eight aircraft along with four Mustangs from the 530th on a big Japanese supply dump at Kamaing in Burma. The 530th squadron's P-51As met numerous Mitsubishi Zeros when they accompanied B-24s and B-25s on bombing missions. On the way down, I came up behind Lt. Geoffrey Neal, who was chasing a Zero [Mitsubishi A6M] down to the deck! I latched on to their formation and watched as he drove the enemy fighter right into the ground. The pilot of the Zero had tried everything to get rid of Lt. Neal except to circle fight. At this point, Lt. Arasmith had two confirmed kills, but the fight wasn't over…"-311th Fighter Group Unit history

-Drachinifeld, YT, "Zero or Hero?" (Interview with Justin Pyke, UCalgary MA in Military and Intelligence History, @CBI_PTO_History) 59:07 "Intelligence reports assumed that these tactics (hit and run) indicated the Zero lacked maneuverability." 59:22 "Judging from their apparently long fuselage, these planes do not have a small turning circle, and are not very maneuverable." 59:33 "The Chinese report in question noted the reluctance of the Japanese Navy pilots to dogfight." 1:00:05 "Chinese pilots report that the Japanese will not engage in a turning duel." 1:01:42 USN pilot comment (1942): "In my opinion, they [Zero pilots] had generally poor fighter tactics: Zeros could not be shaken by us if they would chop their throttles and sit on our tails."


View: https://youtu.be/ApOfbxpL4Dg?si=CmDMLXUcmKUxmt76

Me-109 pilots in particular only started to finally understand the importance of turning at reduced power in late 1944: In mid 1944 many 100 kill Eastern front aces still had to learn that lesson (a 136 kill experience in that regard was just a terrible thing):

-"Defenders of the Reich" JG 1 p. 247: Ofhr. Hubert Heckmann (5 kills, survived the War): "I became wingman to the new Kommandeur, Hptm. Karl-Heinz Weber (136 kills). His only experience was from the Eastern Front, and from time to time he used the words "pull up during air combat". I assumed that he would make use of this method in the West, and I warned him about doing so. As his "Kaczmarek", I did not want to lose my "protégé" on his first mission- that would be a bad omen. But he cast all my well-meant recommendations to the wind on our first mission. Weber had a highly polished aircraft (thus emphasizing speed) and whereas we all looked like gray mice, he differed from the rest of the formation. Besides he had Methanol on board (again, emphasis on speed in every option: Me-109G-6AS with MW-50)—7th June Flying at 1000 m. about 30 P-51s showed up some 500 meters above us. After passing us they made a downward turn. Weber didn't turn in, but pulled up steep into the sky, dragging a Methanol cloud behind him. I yelled "turn in!" but he did not listen. I saw 4 P-51s coming down on me, and pulled into a slight left bank (meaning he reduced his turn to entice them to him) to distract them from Weber. My self-sacrifice was of no use; two P-51s stayed behind me, and the other two went after Weber. I fought my two opponents for more than 30 minutes. They moved off when, eventually, they lost much of their speed. That evening we were informed Hptm. Weber (136 kills) was dead."

Ofhr. Heckmann

Hptm. Weber

 

[Steamed_Banana]

There are reasons for the German emphasis on vertical maneuvering - a Bf 109 could turn with a P-51 or a P-47, but a 109G especially will be easily out-turned by an I-16, I-153, LaGG-3, Yak-1, Yak-7, Hurricane, Spitfire V, P-39, P-40, though it can in turn out-climb and out-run all of these easily enough. Which strategy is optimal depends on the opponent.

The Japanese emphasized energy fighting in their doctrine but they clearly figured out early on that they could out turn Allied fighters early-on. Saburo Sakai notes this by 1942 over New Guinea in his memoirs.

 

[Greg Boeser]

That was a problem, but the fact that the Japanese Navy (to a lesser extent the Army) and the Germans still tried to stick with Hit and Run all the way into 1944, when everyone turned at the first sound of "break!" on the radio, was probably their biggest problem...:

"On October 21, 1943, the Group launched eight aircraft along with four Mustangs from the 530th on a big Japanese supply dump at Kamaing in Burma. The 530th squadron's P-51As met numerous Mitsubishi Zeros when they accompanied B-24s and B-25s on bombing missions. On the way down, I came up behind Lt. Geoffrey Neal, who was chasing a Zero [Mitsubishi A6M] down to the deck! I latched on to their formation and watched as he drove the enemy fighter right into the ground. The pilot of the Zero had tried everything to get rid of Lt. Neal except to circle fight. At this point, Lt. Arasmith had two confirmed kills, but the fight wasn't over…"-311th Fighter Group

So, a panicked, probably green pilot gets shot down.
Already in the second half of 1942 front line commanders were complaining about the low hours and lack of training on type of new replacements coming into theater.

 

[wrathofatlantis]

There are reasons for the German emphasis on vertical maneuvering - a Bf 109 could turn with a P-51 or a P-47, but a 109G especially will be easily out-turned by an I-16, I-153, LaGG-3, Yak-1, Yak-7, Hurricane, Spitfire V, P-39, P-40, though it can in turn out-climb and out-run all of these easily enough. Which strategy is optimal depends on the opponent.

The Japanese emphasized energyi fghting in their doctrine but they clearly figured out early on that they could out turn Allied fighters early-on. Saburo Sakai notes this by 1942 over New Guinea in his memoirs.

No, the 109 will easily out-turn the Spitfire in prolonged circles, even as the Spitfire has the harder initial high speed turn... (Emil vs Spit I, 880 feet to 1025 feet, true circles in the RAf's own testing), and the 109 at least matched the P-40, P-39, LaGG-3 and the Yaks in circles.

Read Spitfire Encounter Reports: All high speed, all dives. Many tried circles, not just turns but circles, and we don't have their writings now for a reason, as Clostermann explains... "Those who tried the Spitfire "turn legend" did not come back to complain about it."

Could it be any plainer than that?

Yes the I-16 will out-turn the 109 by a wide margin, but that was pretty much it in the European monoplanes. There is a reason the numerous 109 "replacements" failed.

Yes, the Zero's pilots figured out it could turn, but in reality they didn't sustain the turns (by doctrine) and did not lower power while doing these brief turns, as the USN pilot above rightfully excoriates them for it, particularly the not cutting the throttle part....

Again read Zero combat accounts: Turns, loops, but never circles.
Do you think these guys went against their doctrine?

Circles is the key. Cir-cles.

 

[wrathofatlantis]

So, a panicked, probably green pilot gets shot down.
Already in the second half of 1942 front line commanders were complaining about the low hours and lack of training on type of new replacements coming into theater.

When doctor takes your blood, does he take all of it?

Just face it: Zeros turned but hardly ever made circles. Ki-43s did. Lots of Ki-43 pilots were walking around post-war saying: "We owe our lives to the Ki-43."

Sakai owes his life to having spent the worst years in the hospital.

Boomer historians went with what US pilots said of flying captured Zeros, and what they said THEY would do with it...

Read first hand accounts of actual Zero encounters, and you will see circles are rare to non-existent. Sakai's duel with a Wildcat was one of the rare ones I can recall: He was getting so much nowhere after 3 circles (the Wildcat had a bigger wing than the Ta-152H, try to out-turn THAT), that he had to quit his turn and loop to finally nail it... It did loop great.

If you think the Zero made circles... Man o man... Boomer historians did their number on you.

 

[Thumpalumpacus]

Personal attacks are beneath this discussion, don't you think?