Boulton Paul Defiant

[Shortround6]

Yes and no. It was sort of an admission that the self defending bomber idea wasn't working. While "escort bombers" are sort of an extension of the self defending bomber in terms of hardware they are an attempt to cobble together some sort of escort in a short period of time using existing bits and pieces. First operational use of the YB-40 was in May of 1943 which is before the P-47 got drop tanks. Only 10 (?) operations/missions were flown before the idea was discarded vs hundreds of Defiants built after the basic idea was shown not to work.

 

[swampyankee]

Yes and no. It was sort of an admission that the self defending bomber idea wasn't working. While "escort bombers" are sort of an extension of the self defending bomber in terms of hardware they are an attempt to cobble together some sort of escort in a short period of time using existing bits and pieces. First operational use of the YB-40 was in May of 1943 which is before the P-47 got drop tanks. Only 10 (?) operations/missions were flown before the idea was discarded vs hundreds of Defiants built after the basic idea was shown not to work.

I think -- and this is, rather obviously, benefiting from hindsight -- that a serious analysis of data would have shown that the bombers' self-defense armament was much less effective than it had been considered pre-war (in this, the USAAF came to the same sort of optimistic conclusion as did most navies about the effectiveness of their ships' anti-aircraft armament) , and that increasing armament did not reduce casualties or even aircraft losses. The YB-40 was a logical extension of the flawed idea that bombers with defensive armament could effectively defend themselves from serious fighter opposition.

I think the utility of bomber defensive armament is pretty clear from its near complete abandonment post-ww2.

 

[tyrodtom]

If the massed firepower of the bomber formations was so ineffective, the Luftwaffe sure went to a lot of trouble to develop weapons that enabled them to attack the formations while staying out of the range of that ineffective firepower.
R4M, 40 mm cannons and bigger, mortar tubes mounted on the wings, bombs dropped from above the formations, and fighters so fast ( Me 163 & 262 ) no gunner could would likely get a sight on them .

One bomber by itself, no matter how heavily armed was dead, but a massed formation of armed bombers was a problem of a whole different level.

I think the heavily armed bomber fell out of favor after WW2 because with nuclear weapons, massed formations was a thing of the past.
Though a lot of the early generation jet bombers still retained a tail gun.

 

[Shortround6]

I think -- and this is, rather obviously, benefiting from hindsight -- that a serious analysis of data would have shown that the bombers' self-defense armament was much less effective than it had been considered pre-war

B-17D The Earlier C had four .50s and one .30

B-17E in production before Pearl Harbor.

Double the number of guns, two power turrets. 10 .50 cal guns ?
The "G" had 13 guns and 3 powered twin mounts.

The self defense armament increased considerably from what it was prewar. The fighters just got a lot better too.

I think the utility of bomber defensive armament is pretty clear from its near complete abandonment post-ww2.

That took quite number of years. granted the B-36 was essentially a WW II design but a tail position was used on the B-45, B-47, B-48, B-52. B-58. Russian TU-16 had 3 gun positions on early versions.

 

[buffnut453]

If the massed firepower of the bomber formations was so ineffective, the Luftwaffe sure went to a lot of trouble to develop weapons that enabled them to attack the formations while staying out of the range of that ineffective firepower.
R4M, 40 mm cannons and bigger, mortar tubes mounted on the wings, bombs dropped from above the formations, and fighters so fast ( Me 163 & 262 ) no gunner could would likely get a sight on them .

One bomber by itself, no matter how heavily armed was dead, but a massed formation of armed bombers was a problem of a whole different level.

I think the heavily armed bomber fell out of favor after WW2 because with nuclear weapons, massed formations was a thing of the past.
Though a lot of the early generation jet bombers still retained a tail gun.

The defensive firepower of USAAF heavy bombers was ineffective in that it didn't provide sufficient protection to enable sustained operations. USAAF heavy bomber losses prior to the advent of long-range fighters were deemed unsustainable, as evidenced by the active consideration of switching to night bombing. Thus it seems pretty self-evident that the defensive firepower of the B-17 and B-24 were, indeed, ineffective.

The Me163 and Me262 were both in development long before the US entered the war so you can't argue that they were a specific response to the defences of USAAF heavy bombers. The Me262 concept had been around since before the outbreak of war in 1939 while the Me163 design started that year and first flew in early 1941.

As to the other developments you cite, some were desperation measures while the heavier cannon and R4M align with the general thrust of air-to-air weapon development that continues to this day - hit the enemy at longer range with fewer munitions. Given that Germany was, by 1944, struggling to defend itself, efforts to kill bombers more efficiently are just a logical evolutionary step.

 

[swampyankee]

I think that the USAAF was worried about the efficiency of bomber defense before WWII, as evidenced by the complex FCS of the B-29.

I wonder, though, if they analyzed the casualty rates as the bombers got more and more heavily armed. For example, getting rid of the waist gunners would probably free up 750 lb of payload, probably a fifth of the bomb load of a B-17, so fewer bombers would be needed for the same effect on the target and there would be fewer casualties, as the aircrew would be smaller. Indeed, unless the loss rate increased by as much as 10% there would be fewer casualties of all kinds.

 

[stona]

I wonder, though, if they analyzed the casualty rates as the bombers got more and more heavily armed. For example, getting rid of the waist gunners would probably free up 750 lb of payload, probably a fifth of the bomb load of a B-17, so fewer bombers would be needed for the same effect on the target and there would be fewer casualties, as the aircrew would be smaller. Indeed, unless the loss rate increased by as much as 10% there would be fewer casualties of all kinds.

I think the issue with this perfectly logical argument can be summed up in two words...maximum effort. The mirror of the argument is that, If the waist gunners had been deleted, then more ordnance could have been carried to the targets by the same number of aircraft, but that losses may have risen due to the reduction in protective firepower. I don't think the idea that the USAAFs would have operated fewer bombers is tenable.
The British removed just about everything they could from their bombers in order to maximise the bomb/fuel load, and were loathe to add anything (like extinguishing systems for fuel tanks) without convincing evidence that they would substantially lower losses.
Cheers
Steve

 

[tyrodtom]

While the Me 163 and Me 262 might have been in development before American entered the air war, the armament they chose to arm the Me 262 with was surely chosen with bombers in mind.
And the point defense capability only of the Me 163 , ( short range, very limited endurance) made it useful for what else but against massed bombers ?

 

[stona]

And the point defense capability only of the Me 163 , ( short range, very limited endurance) made it useful for what else but against massed bombers ?

This is what it became, because of those limitations, though the endurance was more limited than the engine developers had led the RLM to believe. There was, as you say, nothing else it could do.
The early versions, that is those built prior to US involvement in the war (and after), were experimental aircraft. They were not designed to fulfill a particular role.
The ultimate point defence interceptor, designed and built specifically to target bomber formations in daylight, was the Ba 349. The programme for this was only approved after the Me 163 was axed, leaving a surplus of HWK 509 bi-fuel motors with no obvious use.

Cheers

Steve

 

[buffnut453]

While the Me 163 and Me 262 might have been in development before American entered the air war, the armament they chose to arm the Me 262 with was surely chosen with bombers in mind.
And the point defense capability only of the Me 163 , ( short range, very limited endurance) made it useful for what else but against massed bombers ?

The Me262's armament wasn't vastly superior to what was being fitted to Spitfires, Tempests and Typhoons and even the Meteor in 1944. Yes the Mk108 was a heavier calibre but it had a slower muzzle velocity and a lower rate of fire than the Hispano 20mm cannon fitted to RAF aircraft. Those aircraft weren't intercepting massed bomber formations.

As previously stated, the armament of the Me262 simply shows a standard evolution of aircraft armament rather than any specific development effort driven by your alleged effectiveness of USAAF heavy bomber defensive weapons.

 

[stona]

The reason that the Germans were fitting heavier calibre cannons to all their fighters, including the Me 262, was because of the need to destroy American bombers. The evolution of the armament of the Luftwaffe's daylight fighters, all of them, was driven by this imperative. Some of them were fitted with even larger flak cannon. Despite the limitations of the 30mm cannon it was possible to score the few hits required to down a bomber, though hitting a smaller, faster, manoeuvring fighter might be tricky. It's also why the Me 262, and other aircraft, were fitted with R4M rockets and other exotic systems.
The lack of any such need was why the Americans stuck with heavy machine guns and the British with various combinations of machine guns and 20mm cannon, or 20mm cannon. The Anglo-Americans never saw the need to fit something like the 50mm BK 5 cannon to any of their fighters, what would they have used it for?
Cheers
Steve

 

[Shortround6]

Well, there was a tendency to develop bomber killing armament. Now we can argue about wither it was developed to combat single bombers/small formations or large formations.
The MK 108 was a compromise weapon. It didn't have the range to "stand off' and trade shots with bombers But then even the MK 103 couldn't even do that with any real chance of success. That is to say the chances of scoring hits or enough hits at such range with amount of ammo the plane could carry would be less than one bomber shot down per fighter (or several fighters) intercepting.
The Move to the 30mm cannon came when the Germans concluded (rightly or wrongly) that it would take 750-1000 rounds of 20mm ammo fired by an average pilot to bring down a 4 engine bomber since it took 15-20 20mm hits. and such ammo capacity was pretty much beyond the capacity of a single engine fighter. 30mm guns needed 2-3 hits and with a similar hit percentage (2%) the ammo needed was within the capacity of a single engine fighter.

Even the big German guns only were rated as having an effective range of 800 meters while max ranges went beyond that. Ratings were for use against bombers and while the .50 cal may NOT have had an effective range of 800 meters against aerial targets it rather depends on the definition of effective. With dozens of guns firing from a formation the total amount of projectiles in air was large, luck (statistics) played a part.

The only weapon to see service that I can think of, for use against formations, was the German 21cm rocket. It was fired from beyond the effective (or at least practical) range of the .50 cal guns with the intention of breaking up the formation so the fighters could attack single aircraft or at least small groups.

BTW even the 5cm BK 5 was rated at an effective range of 800 meters. Sighting problems may have as much to do with max ranges as ballistics.

 

[swampyankee]

I think the issue with this perfectly logical argument can be summed up in two words...maximum effort. The mirror of the argument is that, If the waist gunners had been deleted, then more ordnance could have been carried to the targets by the same number of aircraft, but that losses may have risen due to the reduction in protective firepower. I don't think the idea that the USAAFs would have operated fewer bombers is tenable.
The British removed just about everything they could from their bombers in order to maximise the bomb/fuel load, and were loathe to add anything (like extinguishing systems for fuel tanks) without convincing evidence that they would substantially lower losses.
Cheers
Steve

Then they could have operated the same number of bombers for greater effect. The question, which may be unanswerable, is whether loss rates would increase without the waist gunners, and, if so, how much.

 

[Shortround6]

The waist gunners were often left home in the last year of the war or fall of 1944 through spring of 45. But that was long after the escort fighters were flying the whole distance and after the Luftwaffe presence in the air had diminished considerably.

 

[pbehn]

True SR but by the spring of 1945 Lancasters were performing daylight missions.

 

[tyrodtom]

The B-17 and B-24 armament wasn't ineffective IMO, it just wasn't effective enough to be the bomber's only means of protection.
All that added crew and weight weren't just there for morale of the pilots and bombardier.

The Luftwaffe wasn't decimated by any means by their return fire, but you don't have to read many pilot's accounts to find out most dreaded exposing themselves to all those .50 cals.

I think I remember a chart shown on this forum that showed that the waist gunners were the least effective gun position, while being the most likely wounded and killed.

 

[pbehn]

On the unescorted raids I think the LW suffered 10% complete losses and 20-30% damaged in some way, it was enough to stop unescorted dayliht raids by the USAAF but also for the LW to think about their equipment and tactics.

 

[stona]

On the unescorted raids I think the LW suffered 10% complete losses and 20-30% damaged in some way, it was enough to stop unescorted dayliht raids by the USAAF but also for the LW to think about their equipment and tactics.

Not as bad as that. The raids generally cited as those that changed American perceptions of the ability of unescorted (or partially escorted) bombers to defend themselves are usually the Schweinfurt-Regensburg raid of 17th August 1943, and it's follow up to Schweinfurt on 14th October.

The 17th August raid was a two part affair. Luftwaffe losses on the first raid (Regensburg) were 9 fighters of the 404 that sortied. As a percentage of those that made contact with the Americans, 197 fighters, this is about a 4.5% loss rate. 27 B-17s were destroyed or damaged beyond repair.

Losses on the second raid (Schweinfurt) were c.38 aircraft of the 468 which sortied. 244 made contact with the Americans, losses as a percentage of that number were about 15% BUT two factors influenced this number. First the US escort fighters had intervened, they claimed 16 Luftwaffe fighters, (which was a bit optimistic) and secondly 21 of the aircraft lost were night fighters operating by day, a role in which they proved very vulnerable. Losses of day fighters to US escorts and bombers were only about 7%. 39 B-17s were lost or damaged beyond repair, 17% of the total sorties

On the 14th October raid the Luftwaffe destroyed or fatally damaged 67 B-17s. 882 Luftwaffe fighters sortied and 672 made contact with the Americans. Of that number 53 were lost, about 8%, but this represents a stunning victory for the Luftwaffe and both sides knew it. It could have been worse, the weather saved the bombers from a further mauling as they withdrew.

Cheers

Steve

 

[stona]

I'll just add that, as I've said before, the destruction of Luftwaffe fighter forces in Europe and the establishment of Allied air superiority, prior to 'Overlord' was the one unequivocal victory of the combined bomber offensive and though many from all Allied nations contributed, the lion's share of the credit must go to the Americans. Whilst in no way diminishing the contribution of the bomber crews, without whose sacrifices there would have been no victory, it was the US fighter forces that delivered the victory. It was they that destroyed the vast majority of the Luftwaffe fighters, shot down in their efforts to attack the bombers, and harried anywhere else they could be found.
Cheers
Steve

 

[stona]

"It was a bomber destroyer and in 1935/36 when the idea was produced, no one thought that Germany would invade France and be able to use single seat fighters to escort bombers into British airspace."

This is of course total nonsence.

It was predicted that France will be attacked by Germany and when Defiant will be used it could probably be attacked by enemy fighters. Defiant supporters predicted that it will be successful.
.

Here we have someone expressing his opinion, which he is entitled to do, but confusing it with facts.

In 1933, when the new FO1 (Williams) who replaced Maund (who left the Air Staff to take command of the A and AEE) pointed out that the aircraft selected by the committee reviewing the Novel Fighter competition did not meet the requirement to be

"...able successfully to engage fighters as well as bombers, in as much as they are somewhat restricted in rear defence."

Geoffrey Salmond took a different view. Writing in support of a turret fighter concept submitted by ADGB he stated

"Defence, however, should not be allowed to play too important a role in the design of home defence fighters, since enemy fighters are not likely to operate frequently or in force over our defended zones. In addition defence against enemy fighters is provided by the 'interceptor' class of fighter."

My bold.

At the time (February 1933) Salmond was Deputy Chief of the Air Staff, he would become Chief of the Air Staff in April, not only did his opinion reflect the prevailing view of the RAF, it carried some considerable weight.

The turret fighter was not expected to be attacked by enemy fighters in the areas in which it would operate. It was also somehow to be defended by the interceptor fighters. All the turret fighter concepts were to be zone fighters. By the time the war started the interceptor/zone fighter categories had been blurred into one, but the Spitfire and Hurricane were the resulting aircraft. In 1940 these fighters were not likely to escort the Defiants

Cheers

Steve