Out of the Big Three WW2 bombers (B-17, B-24, Lancaster), was the Flying Fortress the most redundant?

pbehn said:

It just made it into service but not to any real effect and by the time Grumman started on the Bearcat it was their 3rd generation fighter, they really knew what they were doing. You could also include the Hawker Tempest, which went fairly well, because all the screw ups had been on the Typhoon.

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So you have moved the goalposts as I knew you would! You only took It to production in your last post. Now the objection is it it only just made it into service!

I thought about the Tempest, but it shared much of its fuselage structure with the Typhoon. You specified a clean sheet design. It began life as a "Typhoon Mark II" prior to the Dec 1941 timeline you set. So, to me, it doesn't qualify.

PStickney said:

I'd have to say that the utility of a warplane is measured by what happens to is when the war that it has been in is over. B-17s and Lancasters served into the late 1950s, B-24s left the inventory as fast as they could be ferried to the salvage depots - by the end of 1946, there are no B-24s in USAAF service. Yes, the Navy kept its PB4Y-2s, but a Privateer isn't a Liberator.
As for the performance differences - The '24 certainly did have longer range, but economical cruise speed (which for a bomber or transport is what counts) were actually pretty close - 165 mph for the B-17G and 170 for the B-24J - which is within the variation that you'll find in different airplanes of the same make and model. (Some are good, some are slugs)
The B-17 was better for excess power - it always has about a 5,000' advantage on the B-24 - all numbers from the Specific Flight Operation Charts of their Flight Operating Handbooks.

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Which charts for which models from what dates? Those charts for revised download fairly often during the early part of the war. Furthermore they're only a crude indication range. It is much better to use the long range cruise control charts. Which one has longer range really depends on the specific model and the specific operating conditions.

EwenS said:

So you have moved the goalposts as I knew you would! You only took It to production in your last post. Now the objection is it it only just made it into service!

I thought about the Tempest, but it shared much of its fuselage structure with the Typhoon. You specified a clean sheet design. It began life as a "Typhoon Mark II" prior to the Dec 1941 timeline you set. So, to me, it doesn't qualify.

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I havnt moved any goalposts because we are not playing a game, and I didnt specify anything, I thought we were just having a discussion, there is no point in producing something without the intention to use it, getting it into service is all part of getting it sorted, and it takes time. I agree with your point, but it also shows my point. To start with a clean sheet of paper and get a plane into production takes a long time, especially a complex new design like a four engined bomber. I mentioned the Tempest because that if you take it as a new design did well, its genesis as a Typhoon took an age, even though any non aviation minded person would struggle to tell them apart, much more alike than and early and late Spitfire.

The B-24 was designed as the B-17's replacement. It was better in every respect.
The claims it was 'harder' to fly' and had a higher loss rate? Nonsense.
It wasn't 'harder to fly', it just was a more modern plane that required higher skill from the pilot.
It had no higher a loss rate than the B-17 - while carrying a bigger bomb load further.
The B-17 quickly faded away except in the ETO where its short range and small bomb load wasn't much of an issue - after all, their prime purpose once the P-51 turned up in the NWETO was fighter bait.
The last batches made in early 1945 weren't even delivered as bombers, their days were done and they were converted to SAR planes etc.
The B-24 was the USAAF's 'big hitter' until the B-29 turned up, and it wasn't even going top be replaced by the B-29. It was going to stay in production right on past 1945 as the USAAF's mainstay medium bomber. The B-29 becoming the heavy.
5,000 much improved B-24N's were cancelled with the end of the war.
( Consolidated 32 XB-24N Liberator )
The B-24's last hurrah was raiding the Japanese home islands from Okinawa and Ie Shima in 1945. Many thousands were slated to be in on the invasion of Japans home islands, but no B-17's
The B-24's PBY Privateer brother served on to the mid 50's

And damage resistance?
The only reason the B-17 was apparently 'tougher' was its old fashioned fat airfoils meant its wings - the bits most often hit, were mostly air - most shells went through - and it was needlessly over engineered for a disposable warplane. The wings on a B-24 were much more advanced, had a much slimmer profile with much less empty space were actually doing something useful like carrying fuel.
And the claim the B-24 was 'flimsy' and 'more lightly built' than the 'sturdy' B-17? The B-17 was 20% lighter than a B-24 - yet the B-24 flew 50mph faster on the same 4 1200hp engines

The B-24 was a warplane designed to be built fast - everything was good enough, no better than necessary, just good enough.
A war winning strategy

Macandy said:

The B-24 was designed as the B-17's replacement. It was better in every respect.
The claims it was 'harder' to fly' and had a higher loss rate? Nonsense.
It wasn't 'harder to fly', it just was a more modern plane that required higher skill from the pilot.
It had no higher a loss rate than the B-17 - while carrying a bigger bomb load further.
The B-17 quickly faded away except in the ETO where its short range and small bomb load wasn't much of an issue - after all, their prime purpose once the P-51 turned up in the NWETO was fighter bait.
The last batches made in early 1945 weren't even delivered as bombers, their days were done and they were converted to SAR planes etc.
The B-24 was the USAAF's 'big hitter' until the B-29 turned up, and it wasn't even going top be replaced by the B-29. It was going to stay in production right on past 1945 as the USAAF's mainstay medium bomber. The B-29 becoming the heavy.
5,000 much improved B-24N's were cancelled with the end of the war.
( Consolidated 32 XB-24N Liberator )
The B-24's last hurrah was raiding the Japanese home islands from Okinawa and Ie Shima in 1945. Many thousands were slated to be in on the invasion of Japans home islands, but no B-17's
The B-24's PBY Privateer brother served on to the mid 50's

And damage resistance?
The only reason the B-17 was apparently 'tougher' was its old fashioned fat airfoils meant its wings - the bits most often hit, were mostly air - most shells went through - and it was needlessly over engineered for a disposable warplane. The wings on a B-24 were much more advanced, had a much slimmer profile with much less empty space were actually doing something useful like carrying fuel.
And the claim the B-24 was 'flimsy' and 'more lightly built' than the 'sturdy' B-17? The B-17 was 20% lighter than a B-24 - yet the B-24 flew 50mph faster on the same 4 1200hp engines

The B-24 was a warplane designed to be built fast - everything was good enough, no better than necessary, just good enough.
A war winning strategy

Click to expand...

The replacement for the B-17 was the B29 which ended the war. The B-24 was to augment the B-17. Obviously Boeing could have produced a better B-17, but that would have meant much fewer B-17s when they were needed.

Go Boeing!

SaparotRob said:

Go Boeing!

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Better than them there Grummans, a waste of blue paint if ever there was one.

I know, right?

Macandy said:

The B-24 was designed as the B-17's replacement. It was better in every respect.
The claims it was 'harder' to fly' and had a higher loss rate? Nonsense.

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Nonsense? How do you know? Have you flown one? I personally knew at least one pilot who flew both the B-24 and the Lanc operationally and he said the B-24 handled like a cow. Tough to escape a fighter attack if you're flying a cow. And…we know pilots struggled to fly the same tight formations that the B-17 was capable of flying, such that they had to use different formations in the European air war:



USAAF 8th Airforce Tactical Development 1942 1945, page 31:
World War II Operational Documents

I would like to see references for indicated air speeds and heights by type. I'm sure this info is available somewhere.

Note that Basil Dickens (Head, ORS RAF Bomber Command) contended the definitive statistic to evaluate the relative performance of aircraft types is "bomb tonnage dropped per aircraft lost". What do these comparisons between the B-17 B-24 indicate for this statistic? Best to do this calculation for 1945 uniquely.

I believe the B-24 had its role, particularly coastal command and it augmented the bombing campaign over Europe, but I'm not convinced it was a superior aircraft to the B-17, and certainly not the Lancaster.

Jim

Geoffrey Sinclair said:

The USSBS Bombing Accuracy report says

8th Air Force B-17 147.2 tons dropped for each loss, average mission lifetime 58.9 sorties. (average bomb load 4,998 pounds)
8th Air Force B-24 149 tons dropped for each loss, average mission lifetime 49.9 sorties. (average bomb load 5,972 pounds)
15th Air Force B-17 192.6 tons dropped for each loss, average mission lifetime 77 sorties. (average bomb load 5,003 pounds)
15th Air Force B-24 106.5 tons dropped for each loss, average mission lifetime 35.5 sorties. (average bomb load 6,000 pounds)

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I was wondering about the (my) bold part and why the 15th AF B-24 had worst loss rate and after that, the thread explains itself. Magic!!!

Geoffrey Sinclair said:

Turning to the 15th Air Force, it formed on 1 November 1943 with 4 B-17 and 2 B-24 groups, still that end December 1943, end January 1944 4 B-17 to 5 B-24, end February 4 to 8, end March 5 to 10, end April 6 to 13, end May 6 to 15. The Statistical Digest notes February 1944 was the peak loss to fighters, 106, with 105 in April, but losses June to August were 85, 94, 91, versus the 8th of 112, 80 and 61. Given the 15th was around half the size of the 8th it shows losses to enemy fighters was not driven down until September 1944, after the end of the Ploesti raids.

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I'm with SaparotRob , love this thread

Macandy said:

The B-24 was designed as the B-17's replacement. It was better in every respect.

Click to expand...

I think I'm just going to pick away at your nonsense.

"The Liberator originated from a United States Army Air Corps (USAAC) request in 1938 for Consolidated to produce the B-17 under license. After company executives including President Reuben Fleet visited the Boeing factory in Seattle, Washington, Consolidated decided instead to submit a more modern design of its own."

Reference: Taylor, John W. R. "Consolidated B-24/PB4 Y Liberator." Page 462

In January 1939, the USAAC, under Specification C-212, formally invited Consolidated to submit a design study for a bomber with longer range, higher speed and greater ceiling than the B-17. The specification was written such that the Model 32 would automatically be the winning design. The program was run under the umbrella group, "Project A", an Air Corps requirement for an intercontinental bomber that had been conceived in the mid-1930s. Although the B-24 did not meet Project A goals, it was a step in that direction. Project A led to the development of the Boeing B-29 and Consolidated's own B-32 and B-36.

THERE WAS NEVER ANY INDICATION BY THE AAF THAT THEY WANTED TO REPLACE THE B-17 WITH THE B-24!!!!

Specification C-212

Type Specification C-212

• Medium bomber.
• Multi-engine.
• 1 February 1939.
• Boeing Model 322.
• Boeing Model 333.
• Boeing Model 333A.
• Consolidated B-24 Liberator.

The B-24 NEVER fully met the C-212 requirement! Greater range, heavier bombload and faster, never had the ceiling of the B-17.

The only place where the B-24 "replaced" the B-17 was in the PTO and that decision was made because of it's range.

Beginning in the spring of 1943, the 43rd Bomb Group replaced its B-17s with B-24s, ending the combat career of the Flying Fortress in the Pacific.

The B-24 became a key factor in the plans of Generals Douglas MacArthur and Kenney as they sought to push the Japanese farther and farther north away from Australia and back toward Japan. The MacArthur/Kenney strategy was to isolate major Japanese installations with air power, while capturing terrain on which to construct airfields from which to launch B-24s on long-range missions that eventually were reaching all the way to the Philippines.

As the war moved northward, Far East Air Forces Liberators began attacking the Japanese homeland. Kenney and his bomber commanders worked to extend the range of the four-engine bombers until 2,400-mile round-trip missions were being flown routinely by B-24s. In comparison, the average mission flown by B-17s in Europe was less than 1,600 miles.

Missions by B-24 crews in the Pacific were considerably different from those of their peers in Europe. Much of the flying was over water, which reduced the exposure of the bomber crews to flak to a small percentage of mission time in comparison to the constant exposure faced by Eighth Air Force crews prior to the Normandy invasion. Kenney had no point to prove in regard to daylight bombing, and often his crews struck the most heavily defended targets at night, thus further reducing the exposure of the aircraft and crews. Consequently, B-24s in the Pacific flew missions at much lower altitudes than heavy bombers in Europe, and thus achieved much greater accuracy with their bombs.

The Boeing B-17 Flying Fortress, or the Consolidated B-24 Liberator?

The Consolidated B-24 Liberator was more advanced and versatile than the Boeing B-17 Flying Fortress, but we provide a fuller breakdown.

warfarehistorynetwork.com

Better in Every Respect?

"The B-24 bomber one of the most difficult planes to fly during WWII. It was unpressurized, underpowered and prone to explode on takeoff. Unlike the B-17, the B-24 could not maintain altitude if one engine was lost. If two engines were lost, the plane would drop pretty much like a rock." B-24 NAVIGATOR HARRY FORNALCZYK


I would suggest some research and reviewing some of the other references mentioned in this thread!!!!

Escuadrilla Azul said:

I was wondering about the (my) bold part and why the 15th AF B-24 had worst loss rate and after that, the thread explains itself. Magic!!!


I'm with SaparotRob , love this thread

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Thanks! I should have looked at Geoffrey's post more carefully. Still, I'd like to see this statistic for 3 month increments, which should be pretty robust for random effects.

Jim

Macandy said:

The B-24 was designed as the B-17's replacement. It was better in every respect.
The claims it was 'harder' to fly' and had a higher loss rate? Nonsense.
It wasn't 'harder to fly', it just was a more modern plane that required higher skill from the pilot.
It had no higher a loss rate than the B-17 - while carrying a bigger bomb load further.
The B-17 quickly faded away except in the ETO where its short range and small bomb load wasn't much of an issue - after all, their prime purpose once the P-51 turned up in the NWETO was fighter bait.
The last batches made in early 1945 weren't even delivered as bombers, their days were done and they were converted to SAR planes etc.
The B-24 was the USAAF's 'big hitter' until the B-29 turned up, and it wasn't even going top be replaced by the B-29. It was going to stay in production right on past 1945 as the USAAF's mainstay medium bomber. The B-29 becoming the heavy.
5,000 much improved B-24N's were cancelled with the end of the war.
( Consolidated 32 XB-24N Liberator )
The B-24's last hurrah was raiding the Japanese home islands from Okinawa and Ie Shima in 1945. Many thousands were slated to be in on the invasion of Japans home islands, but no B-17's
The B-24's PBY Privateer brother served on to the mid 50's

And damage resistance?
The only reason the B-17 was apparently 'tougher' was its old fashioned fat airfoils meant its wings - the bits most often hit, were mostly air - most shells went through - and it was needlessly over engineered for a disposable warplane. The wings on a B-24 were much more advanced, had a much slimmer profile with much less empty space were actually doing something useful like carrying fuel.
And the claim the B-24 was 'flimsy' and 'more lightly built' than the 'sturdy' B-17? The B-17 was 20% lighter than a B-24 - yet the B-24 flew 50mph faster on the same 4 1200hp engines

The B-24 was a warplane designed to be built fast - everything was good enough, no better than necessary, just good enough.
A war winning strategy

Click to expand...

Built fast, not meant to last.

at6 said:

Built fast, not meant to last.

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Indeed - very smart engineering.

'The perfect is the enemy of good enough'

FLYBOYJ said:

I think I'm just going to pick away at your nonsense.



"The B-24 bomber one of the most difficult planes to fly during WWII. It was unpressurized, underpowered and prone to explode on takeoff. Unlike the B-17, the B-24 could not maintain altitude if one engine was lost. If two engines were lost, the plane would drop pretty much like a rock." B-24 NAVIGATOR HARRY FORNALCZYK

Defying the Flying Coffin: The Combat and POW Experiences of B-24 Navigator Harry Fornalczyk - Daedalians

by Gary Fullmer, Pioneer Flight Harry was born in Erie, Pennsylvania on September 9, 1923. As a typical young boy of that period, Harry managed to stay out of serious trouble but was very active in several unexplained happenings around his neighborhood. In his high school years, Harry excelled...

www.daedalians.org

I would suggest some research and reviewing some of the other references mentioned in this thread!!!!

Click to expand...

Oh teh noes!
Warplane not designed to be failsafe handling like an airliner shock horror!
If only those stupid engineers at Consolidated hadn't used an efficient modern low drag airfoil and stuck with 20's high lift, high drag wing designs eh?
Next you'll be suggesting the B-29 should have been replaced by the B-17 because a B-29 that lost an engine on take off almost invariably crashed due to its modern wing design.


Underpowered?

Both, 4 x 1,200hp engines

B-17G : Max takeoff weight: 65,500 lb

B-24J: Max takeoff weight: 65,000 lb

Same power, same weight!



And loss rates?

I'll take a B-24!

Eight Air Force

B-17 - 60.38% of sorties - 69.75 percent of losses

B-24 - 29.77% of sorties - 26.1 percent of losses.

Macandy said:

And loss rates?

I'll take a B-24!

Eight Air Force

B-17 - 60.38% of sorties - 69.75 percent of losses

B-24 - 29.77% of sorties - 26.1 percent of losses.

Click to expand...

If those percentages are for the whole war, you should take in account that during much of the time (specially when the fight was hardest and bombers lack fighter escort) the 8th AF was a B-17 only force.

FLYBOYJ said:

I think I'm just going to pick away at your nonsense.

"The Liberator originated from a United States Army Air Corps (USAAC) request in 1938 for Consolidated to produce the B-17 under license. After company executives including President Reuben Fleet visited the Boeing factory in Seattle, Washington, Consolidated decided instead to submit a more modern design of its own."

Reference: Taylor, John W. R. "Consolidated B-24/PB4 Y Liberator." Page 462

In January 1939, the USAAC, under Specification C-212, formally invited Consolidated to submit a design study for a bomber with longer range, higher speed and greater ceiling than the B-17. The specification was written such that the Model 32 would automatically be the winning design. The program was run under the umbrella group, "Project A", an Air Corps requirement for an intercontinental bomber that had been conceived in the mid-1930s. Although the B-24 did not meet Project A goals, it was a step in that direction. Project A led to the development of the Boeing B-29 and Consolidated's own B-32 and B-36.

THERE WAS NEVER ANY INDICATION BY THE AAF THAT THEY WANTED TO REPLACE THE B-17 WITH THE B-24!!!!

Specification C-212

Type Specification C-212

• Medium bomber.
• Multi-engine.
• 1 February 1939.
• Boeing Model 322.
• Boeing Model 333.
• Boeing Model 333A.
• Consolidated B-24 Liberator.

The B-24 NEVER fully met the C-212 requirement! Greater range, heavier bombload and faster, never had the ceiling of the B-17.

The only place where the B-24 "replaced" the B-17 was in the PTO and that decision was made because of it's range.

Beginning in the spring of 1943, the 43rd Bomb Group replaced its B-17s with B-24s, ending the combat career of the Flying Fortress in the Pacific.

The B-24 became a key factor in the plans of Generals Douglas MacArthur and Kenney as they sought to push the Japanese farther and farther north away from Australia and back toward Japan. The MacArthur/Kenney strategy was to isolate major Japanese installations with air power, while capturing terrain on which to construct airfields from which to launch B-24s on long-range missions that eventually were reaching all the way to the Philippines.

As the war moved northward, Far East Air Forces Liberators began attacking the Japanese homeland. Kenney and his bomber commanders worked to extend the range of the four-engine bombers until 2,400-mile round-trip missions were being flown routinely by B-24s. In comparison, the average mission flown by B-17s in Europe was less than 1,600 miles.

Missions by B-24 crews in the Pacific were considerably different from those of their peers in Europe. Much of the flying was over water, which reduced the exposure of the bomber crews to flak to a small percentage of mission time in comparison to the constant exposure faced by Eighth Air Force crews prior to the Normandy invasion. Kenney had no point to prove in regard to daylight bombing, and often his crews struck the most heavily defended targets at night, thus further reducing the exposure of the aircraft and crews. Consequently, B-24s in the Pacific flew missions at much lower altitudes than heavy bombers in Europe, and thus achieved much greater accuracy with their bombs.

The Boeing B-17 Flying Fortress, or the Consolidated B-24 Liberator?

The Consolidated B-24 Liberator was more advanced and versatile than the Boeing B-17 Flying Fortress, but we provide a fuller breakdown.

warfarehistorynetwork.com

Better in Every Respect?

"The B-24 bomber one of the most difficult planes to fly during WWII. It was unpressurized, underpowered and prone to explode on takeoff. Unlike the B-17, the B-24 could not maintain altitude if one engine was lost. If two engines were lost, the plane would drop pretty much like a rock." B-24 NAVIGATOR HARRY FORNALCZYK

Defying the Flying Coffin: The Combat and POW Experiences of B-24 Navigator Harry Fornalczyk - Daedalians

by Gary Fullmer, Pioneer Flight Harry was born in Erie, Pennsylvania on September 9, 1923. As a typical young boy of that period, Harry managed to stay out of serious trouble but was very active in several unexplained happenings around his neighborhood. In his high school years, Harry excelled...

www.daedalians.org

I would suggest some research and reviewing some of the other references mentioned in this thread!!!!

Click to expand...

Great post. The links were very informative. I sort of knew a bit of it from scattered reading over the years. Nice reading a relatively impartial article on the two planes.

Macandy said:

Oh teh noes!
Warplane not designed to be failsafe handling like an airliner shock horror!
If only those stupid engineers at Consolidated hadn't used an efficient modern low drag airfoil and stuck with 20's high lift, high drag wing designs eh?
Next you'll be suggesting the B-29 should have been replaced by the B-17 because a B-29 that lost an engine on take off almost invariably crashed due to its modern wing design.

Click to expand...

And once again you ignore technical and historical FACTS, let alone pilot and crew reports FROM THOSE WHO ACTUALLY FLEW THE AIRCRAFT!!!! You last statement is ridiculous!

Macandy said:

Underpowered?

Both, 4 x 1,200hp engines

B-17G : Max takeoff weight: 65,500 lb

B-24J: Max takeoff weight: 65,000 lb

Same power, same weight!

Click to expand...

And the B-24 flew like a barn door - comment from a guy who FLEW ON THE AIRCRAFT!!!!

Macandy said:

And loss rates?

I'll take a B-24!

Eight Air Force

B-17 - 60.38% of sorties - 69.75 percent of losses

B-24 - 29.77% of sorties - 26.1 percent of losses.

Click to expand...

And what about the 15th AF??? What about the fact there were more B-17s in theater and it was there longer??? What you posted shows absolutely NOTHING new!

Please refer to this excellent post comparing the two aircraft:


And please take note!

USAAF Statistical digest, 1942 to 1945, accidents in continental US,
B-17 1,589 accidents, at 30 per 100,000 flying hours, 284 fatal accidents, 1,757 fatalities, 479 aircraft wrecked.
B-24 1,713 accidents, at 35 per 100,000 flying hours, 490 fatal accidents, 2,796 fatalities, 746 aircraft wrecked.
I read this as a higher chance of an accident in a B-24 but a much higher chance of fatalities and loss of aircraft. The B-24 crews in the 8th Air Force generally took higher casualties when shot down. Given safety generally improved during the war the yearly rates are instructive, B-17 versus B-24, were 1942 55 versus 75, 1943 39 all, 1944 25 versus 33, 1945 (January to August) 23 versus 29.

Please - spare us the rhetoric - it's obvious you're not only shooting from the hip and cherry picking facts but know little about the B-24, it's history and how it performed!!!!

More figures, note some of these contradict earlier reports, showing what is being measured and when is important.

Macandy said:

The B-24 was designed as the B-17's replacement. It was better in every respect.
The claims it was 'harder' to fly' and had a higher loss rate? Nonsense.
It wasn't 'harder to fly', it just was a more modern plane that required higher skill from the pilot.
It had no higher a loss rate than the B-17 - while carrying a bigger bomb load further.
The B-17 quickly faded away except in the ETO where its short range and small bomb load wasn't much of an issue - after all, their prime purpose once the P-51 turned up in the NWETO was fighter bait.
The last batches made in early 1945 weren't even delivered as bombers, their days were done and they were converted to SAR planes etc.
The B-24 was the USAAF's 'big hitter' until the B-29 turned up, and it wasn't even going top be replaced by the B-29. It was going to stay in production right on past 1945 as the USAAF's mainstay medium bomber. The B-29 becoming the heavy.
5,000 much improved B-24N's were cancelled with the end of the war.
( Consolidated 32 XB-24N Liberator )

And damage resistance?
The only reason the B-17 was apparently 'tougher' was its old fashioned fat airfoils meant its wings - the bits most often hit, were mostly air - most shells went through - and it was needlessly over engineered for a disposable warplane. The wings on a B-24 were much more advanced, had a much slimmer profile with much less empty space were actually doing something useful like carrying fuel.
And the claim the B-24 was 'flimsy' and 'more lightly built' than the 'sturdy' B-17? The B-17 was 20% lighter than a B-24 - yet the B-24 flew 50mph faster on the same 4 1200hp engines

Click to expand...

Most of the above is contradicted by the documents I have. The B-17 had a higher ceiling, important in Europe, the loss rates vary depending on time and place but overall the B-17 had the lower rates in Europe. Many reports indicate the B-17 was the easier to fly. The purpose of the bombers in Europe was to destroy ground targets, like the oil refineries, the wings of the B-17, like the B-24, had plenty of things in them, mostly fuel tanks. The B-24 fuel system, particularly in the fuselage, was prone to leaks. Over the course of the various models the B-17 and B-24 kept similar top speeds, even as each successive model tended to became slower. The B-17 was originally sold as hemisphere defence carrying the 1,600 AP bombs against approaching ships, the B-24 was meant as a heavy bomber, not a B-17 replacement but a second design in production. The B-17H, air sea rescue, with a radar set replacing the front turret. Apparently the plan was to convert 130 B-17G to H variants, but a smaller number were done. Officially the aircraft were accepted and delivered as B-17G, then modified. It looks like Cheyenne was where all the conversions to B-17H occurred then in mid July 1945 Cheyenne was ordered to shut by the end of the month so shutting down the B-17H program.

15th Air Force report,

B-24 86,838 effective sorties, 8,703 encounters, 1,374 enemy aircraft destroyed, 505 probable, 336 damaged, 803 B-24 lost to flak, 377 to enemy aircraft, 219 to mechanical and other reasons, 257 unknown, 2% loss rate, 7,538 damaged category I 1,346 category II

B-17 41,751 effective sorties, 4,531 encounters, 824 enemy aircraft destroyed, 265 probable, 124 damaged, 244 B-24 lost to flak, 179 to enemy aircraft, 108 to mechanical and other reasons, 93 unknown, 1.5% loss rate, 3,319 damaged category I 968 category II. The B-17 had 34.2% of encounters, for 32.2% of total B-17 and B-24 losses to fighters, the B-17 was 32.5% of total effective sorties but 23.3% of losses to flak, 25.3% mechanical/other and 26.6% of unknown losses.



Using Effective sorties, Mediterranean Theater, April to June 1944, selected targets,, Total bomb tonnage dropped, tons of bombs dropped per sortie, loss rates per 1,000 tons of bombs dropped, A loss rates per 1,000 effective sorties, all causes, B loss rates per 1,000 effective sorties, to enemy aircraft, C loss rates per 1,000 effective sorties, to flak.

Record Group 18 Entry 7 Box 5938, USAAF Mediterranean Theater for Operations 1 August 1943 to 31 January 1944, B-17 9.52 aircraft lost per 1,000 sorties, B-24 25.77. April to June 1944, B-17 14.5, B-24 17.9.

A reason I have heard for the difference in lifetimes between the B-17 and B-24 in the 15th air force was the smaller B-17 formations flying higher were often left alone for the bigger, lower B-24 formations. Things like the warning times and altitude performance of the Romanian fighter designs probably had a part as well.

The incomplete set of 15th Air Force target and duty sheets I have often record the altitude the bombs were released at, the maximum was 32,000 feet by a B-17 group, the highest recorded B-24 altitude was 27,000 feet, it is the only B-24 entry of 26,000 feet or higher, versus the 120 B-17 entries. Lowest bombing altitude, assuming no mistaken entries, was 2,300 feet, then one at 3,500 feet, all other entries are 11,000 feet or higher.

Now to where the USSBS is contradicted, the 15th Air Force figures say the B-17 dropped 104,877 tons of bombs January 1944 onwards, the B-24 192,113 tons, B-17 effective sorties from November 1943 onwards are 41,751, B-24 86,838. Even with the missing 1943 bomb tonnage it is clear the B-17 was carrying the heavier loads on average. The average bomb loads using the data in the "Target and Duty Sheets", which give a break down by bomb group, for the December 1943 to October 1944 period, noting the December 1943 figures do not include tonnage classified as jettisoned. For effective B-17 sorties December 1943 to October 1944 the average bomb load dropped was 5,400 pounds, for B-24 it was 4,690 pounds. These figures are a slight underestimate, as some sorties classified as effective have at least some of their bomb tonnage classified as jettisoned.

To the 8th Air Force, B-17 made up 70.2% of effective sorties, 72.2% of MIA, 65.2% Cat E, 5,139.4 pounds average bomb load, the B-24 29.8% of effective sorties, 25.3% of MIA, 34.8% Cat E, 5,321 pounds average bomb load, but the B-17 had the large 1943 losses the B-24 units largely avoided, for 1944 the B-17 had 66.1% of the effective sorties, 69.5% of MIA, 59.2% Cat E, B-24 33.9%, 40.8% and 30.5%

As of December 1944 the USAAF plan was to end B-17 production at Boeing in April 1945, and Douglas and Lockheed in January 1946, the B-24 was already down to 2 open production lines, San Diego scheduled to finish in July 1945 and Ford in June 1946, with 2,952 B-17 and 5,588 B-24 outstanding on current orders. End April 1945 the B-17 lines were to remain open until November and December 1946, delivering another 2,054 B-17, the B-24 lines were to shut in July 1945, delivering another 601 B-24. Actual B-24 end of production June 1945, B-17 end of production July 1945.

USN PB4Y-1 performance, all at 1,500 feet
2,814 gallons, 3,090 statute miles at 149 mph
3,214 gallons, 3,440 statute miles at 151 mph
3,063 gallons, 3,260 statute miles at 148 mph
2,019 gallons, 2,065 statute miles at 154 mph
1,272 gallons, 1,255 statute miles at 155 mph
3,614 gallons, 4,190 statute miles at 152 mph

USN PB4Y-2
3,020 gallons, 2,780 statute miles at 140 mph
2,764 gallons, 2,590 statute miles at 138 mph
2,868 gallons, 2,630 statute miles at 141 mph
1,881 gallons, 1,560 statute miles at 144 mph
3,050 gallons, 2,800 statute miles at 140 mph
3,716 gallons, 3,650 statute miles at 146 mph

The largest fuel loads are for ferry condition.

RAF Pilot's notes, Liberator III, IV and V, Maximum range cruise speeds, fully loaded, outward, 175 mph IAS, light loaded, homeward 155 mph IAS, if one speed it so be used throughout 165 mph recommended. If Special Coastal Command radio equipment is fitted reduce these speeds by 5 to 10 mph. For maximum endurance the optimum speed is about 125 to 130 mph IAS, but it may not be found to be easy to handle the aircraft for long periods below 145 mph IAS.

RAF Pilot's notes, Liberator III, VI and VIII, recommended cruising speeds for maximum range, 160 mph IAS with external ASV aerials, 170 mph IAS without external ASV aerials, 155 to 160 mph IAS at high altitudes on bomber version.

B-24D and J flight manual, 1,000 foot density altitude, revised per latest C.V.A.C flight tests 17 August 1943. P&W R-1830-43 engines 16:9 gearing, 11 foot 5 inch diameter wide blade prop. no. 6477A-O or narrow blade prop. No. 6353A-18. Ranges exclude allowances for wind, warm up and climb.

165 MPH TAS/163 IAS, 6,100 miles, 180 TAS,/177 IAS 5,875 miles, TAS 200 mph/IAS 197 mph 4,550 miles, TAS 220 mph/IAS 217 mph 2,750 miles, TAS 231 - 241 mph/IAS 228 - 238 mph 2,125 miles.

As above but for 20,000 foot density altitude, maximum range 6,150 miles speed not given, 220 MPH TAS/160 IAS, 5,750 miles, 240 TAS/175 IAS 4,525 miles, TAS 280 mph/IAS 190 mph 3,125 miles, TAS 269 - 292 mph/IAS 196 - 213 mph 2,475 miles.