Sciatica, Facebook, Aviation themed pages and a claim about B17 and Avro Lancaster...

[gruad]

Here's some background - the text which accompanied that photo on FB's 'PlaneHistoria' (I fianlly found it!)


'The incredible power of the German MK 108 30 mm autocannon is shown here on this Blenheim IV light bomber, which was hit by the weapon during British tests. Even the stoutly-constructed and rugged B-17 Flying Fortress was known to disintegrate when hit with as little as four MG 108 rounds, and the more lightly constructed RAF Lancaster and Halifax heavy bombers were even more susceptible to fatal battle damage from this weapon.'

To which I replied:

'can I see some evidence to back up the claim that the Lancaster was more lightly constructed than a B17? I find this slightly difficult to accept without clarification'

Reply
Rod Wylie
plenty of evidence around.
The Lanc was built light so as to carry large bomb loads.
Good read would be Lancaster Men by Peter Rees.


Me
Rod Wylie and yet it has an unladen weight almost the same as a B17 and is slightly smaller in all dimensions...? I'm crying BS


Jon Chapman
it was built differently, using a geodesic tubular steel design which had a very high strength/weight ratio, and was more spacious and could vary a higher volume as well as weight.


Rod Wylie
Or maybe'Big week' by James Holland

Me
Rod Wylie instead of digging yourself in even deeper, find me an extract from either book which refers to the Lancaster being 'lightly built' or more vulnerable to battle damage than contemporary four engined bombers.

Rod Wylie
Jeez , I'm a busy man.
Cant you read them yourself ?

Me
No, because there don't seem to be any [references online]. Someone with your self declared level of expertise and certainty should easily be able to dig those references out, eh?



... y'all know - the usual social media descent into snippy comments and replies (mea culpa!). But in all seriousness, has anyone ever heard anything to support this claim? As others have noted, Lancaster vulnerability would seem to be because of the nature of night fighting and context, NOT the airframe per se. As for 'lightly built', surely that is indeed just boll0c£s?

The difference between the US bombers and the British bombers was that the US bombers carried considerably more armor plates for protection of systems and the crew than the Lancaster where the only armor plate was behind the the pilot's head.

In the book "The Lancaster greatest heavy bomber" there is a description of how they converted an ordinary Lancaster to use more armor plate like the b17 so it could be used on daylight missions. They didn't upgrade the turrets to 0.5 in guns in this experiment which would also have meant even more weight for it to be effective against the German fighters.

However, once the idea was put to Harris he didn't like it and nothing went on further despite the fact it being extremely promising.

The Lancaster relied on stealth for its survival. Statistics I believe showed that once a night fighter got a sighting of a Lancaster it had about 50% chance of survival.

So yes, I believe the Germans were right when they said a Lancaster was less heavily built than a b17. Perhaps they should have said less protected by heavy armor.

 

[GrauGeist]

The Lancaster was also agile for it's size, too.

 

[ThomasP]

Not meaning to be picky, but saying that the Lancaster was more lightly built than the B-17 due to less armour is kind of a banana. It might be true (everything else being equal) that the Lancaster was more easily shot down due to the vulnerability of the crew via lack of equal armour.

But there are other odd factors to consider. For example:

The Lancaster and Halifax both flew night and day (admittedly much fewer than night) missions. I have not run across any particular mention that the Lancaster or Halifax were easier to shoot down than a B-17 or B-24 (which also had significantly more armour than the Lancaster).

British OR (Operational Research) reported that during night missions, the Lancaster was significantly more likely to be shot down during an attack than a Halifax. On the other hand, the Halifax was more likely to be attacked. So losses came out about the same in terms of per comparable sortie.

Also, during 1944-45 in Europe, the B-17 carried more of the mission load in terms of deep penetration raids (not bomb load) against heavily defended targets than the Liberator (this may have occurred with the Halifax also). This is per official period documents of the US 8th AF and at least hinted at in AM memos re the Halifax. The Stirling was definitely turned to easier targets as more of the Halifax and Lancaster became available, again this is per Air Ministry memos.

 

[gruad]

British OR (Operational Research) reported that during night missions, the Lancaster was significantly more likely to be shot down during an attack than a Halifax. On the other hand, the Halifax was more likely to be attacked. So losses came out about the same in terms of per comparable sortie.

Also, during 1944-45 in Europe, the B-17 carried more of the mission load in terms of deep penetration raids (not bomb load) against heavily defended targets than the Liberator (this may have occurred with the Halifax also). This is per official period documents of the US 8th AF and at least hinted at in AM memos re the Halifax. The Stirling was definitely turned to easier targets as more of the Halifax and Lancaster became available, again this is per Air Ministry memos.

Not sure I can agree with you on this. Typically what happened was when you had Lancaster's and Halifax s in the same stream the Halifax was given a lesser bomb load and the more favorable position in the middle of the stream.

This was deliberate to give the Halifax crews a chance, but once sufficient Lancaster's were available, they carried out the risky missions on their own, generally towards the end of 1944 having to compensate for the inferiority of the Halifax was not a good thing for Lancaster crews.

Again, not quite sure about your assertion that the b17 carried the heavier mission load than the b24.

Unlike the Lancaster and Halifax, the b17 and b24 were broadly equally capable aircraft with each having its own particular niche.

The b24 was faster and more versatile, but the b17 was more rugged hence the likelihood that the b17 was used on more dangerous missions.

 

[tomo pauk]

I remember my dad telling me what went into a 20 mm Canon shell for the aircraft of that time ( he was an aircraft technician in the RAF).

He said they were about £20 per shell mid seventies prices.

When I look at the construction of the various mine shells provided in the links with specialized detonators, I can see where that cost came from.

Comparing 1970s prices for small-run items vs. 1940's prices for mass-production items will not bring us close to truth. British were paying for millions of 20mm shells back in 1940s, the 'ideal set-up' being 4 cannons per a fighter.
Germans were of opinion that for destruction of a bomber, one 30mm shell was worth 4-5 20mm shells. Making one 30mm shells is far cheaper than making 4-5 20mm shells, and making one 30mm cannon is cheaper than making 4 20mm cannons.

So the decision by the USAAF to use the 0.5 in Browning throughout its fleet was also a good economic one.

USAAF was not faced with fleets of sturdy bombers flying over the USA, so the HMG battery was working for them. Americans were of opinion that it took 3 .50 BMGs to equal the fire power of a single Hispano, while 3 .50s will weight much more than 1 Hispano.

 

[pbehn]

From a discussion here years ago. The Blenheim was known as a light bomber because of its bomb load. When introduced it was a "fast lightweight design" but that was only by the standards of the day, it was actually quite heavy for what it was, something to do with the wing and fuselage construction turret etc. Also that picture seems to have been "cleaned up" to me.

 

[ThomasP]

Hey gruad,

This is a duplicate of one of my posts from another thread:

Here are 2 official write-ups of the B-17 vs B-24 that I think speak toward the qualities of the respective aircraft.

The first one addresses vulnerability - note that it was kept secret during the war. The other one addresses the myth of the superior performance of the B-24, and is available on the "http://www.wwiiaircraftperformance.org/B-17/B-17E_B-24D_Comparison.pdf" website.

________Vulerability_________________Performance

 

[gruad]

Comparing 1970s prices for small-run items vs. 1940's prices for mass-production items will not bring us close to truth. British were paying for millions of 20mm shells back in 1940s, the 'ideal set-up' being 4 cannons per a fighter.
Germans were of opinion that for destruction of a bomber, one 30mm shell was worth 4-5 20mm shells. Making one 30mm shells is far cheaper than making 4-5 20mm shells, and making one 30mm cannon is cheaper than making 4 20mm cannons.

You make a sound economic point here. I believe MK108 was of a simple pressed and electric actuated design, but at expense you had to get close to the bombers 50s (not such a problem for a night fighter)

But if you look at the complexity of the mine shell compared to 50 cal that's at least 10x possibly more. (Btw my Dad's £20 per 20mm shell equates to £200 in today's money).

As you say the dumb kinetic 50 did not need to do the bomber take down but was so much cheaper.

Surprisingly though US ground attack still used the 50 when you would think cannons would be more effective. I would love to hear you're thoughts on this as I am no expert.

 

[ThomasP]

Hey gruad,

I reread my post# and realized it was not clear. When I said:

"Also, during 1944-45 in Europe, the B-17 carried more of the mission load in terms of deep penetration raids (not bomb load) against heavily defended targets than the Liberator (this may have occurred with the Halifax also)."

I meant that the Halifax was treated like the Liberator, so in the above sentence substitute Lancaster for B-17 and Halifax for Liberator, thus:

"Also, during 1944-45 in Europe, the Lancaster carried more of the mission load in terms of deep penetration raids (not bomb load) against heavily defended targets than the Halifax (. . . "

I will see if I can find the British OR report referencing 1944-45, but I do not remember where I ran across it. Maybe someone else on the forum does?

Referenced below is an OR report that covers a 13 month period of time from 1 August 1941 - 31 October 1942 which gives a similar if exaggerated picture of what happened later in the war. This report covers the first 11 months of operations for the Lancaster, so is not quite representative.

"Operational Research Section, Bomber Command, Report 66, "Review of Sorties, losses, and interceptions of Bomber Command aircraft in night operations during the period 1st August 1941 – 31st October 1942" TNAPRO AIR 14/364"

During this period the Lancaster flew significantly fewer sorties than the Halifax, and both aircraft flew approximately the same mission profiles. The Halifax had ~4x the rate of attack as the Lancaster, but was shot down ~1 out of 6 times vs 1 out of 5 times for the Lancaster.

The OR report for the 1944-45 period indicates that the disparity in rate of attack lessened significantly, and the disparity in rate of shoot downs increased in favor of the Halifax (ie the shoot down rate went up for the Lancaster and down for the Halifax). I am sorry but I do not remember the exact numbers, but IIRC the loss rate was ~equal during the last 6 months of the war - partly due to improvements in the Halifax, and partly due to the Lancaster flying the more dangerous mission profiles.

 

[gruad]

Hey gruad,

This is a duplicate of one of my posts from another thread:

Here are 2 official write-ups of the B-17 vs B-24 that I think speak toward the qualities of the respective aircraft.

The first one addresses vulnerability - note that it was kept secret during the war. The other one addresses the myth of the superior performance of the B-24, and is available on the "http://www.wwiiaircraftperformance.org/B-17/B-17E_B-24D_Comparison.pdf" website.

________Vulerability_________________Performance

Hmmm that goes against my understanding they were broadly comparable, but facts are facts.

UK OR showed 1Lanc the equivalent of 3 Halifax mk 3s.

Does the B17 have such an advantage over the B24?

 

[ThomasP]

Hey gruad,

There is an analysis of the 'efficiency' of the different US 4-engine bombers along with the B-25 and A-20 for comparison. In effect it measures the different aircraft's comparative logistical effort per ton of bombs dropped. If you combine this with the B-17 vs B-24 USAF Analysis report posted above I think it gives a fairly good feel for what's what. IMO the B-17 comes out at between 1.7:1 and 2.5:1 vs the B-24 - with the B-24 being the 1 (though possibly I am interpreting things wrongly ).

edit: sorry, typo - the 2:1 should be 2.5:1 - changed it

 

[tomo pauk]

You make a sound economic point here. I believe MK108 was of a simple pressed and electric actuated design, but at expense you had to get close to the bombers 50s (not such a problem for a night fighter)

But if you look at the complexity of the mine shell compared to 50 cal that's at least 10x possibly more. (Btw my Dad's £20 per 20mm shell equates to £200 in today's money).

As you say the dumb kinetic 50 did not need to do the bomber take down but was so much cheaper.

Germans went in extremes with their 30mm cannons. A simple, compact and lightweight MK 108 was saddled with the heavy shell from the MK 101, thus ballistics were poor. The powerful MK 101 and 103 were big weapons, ill suitable to fit within the confines of the small fighters the 109 and 190 were.
There was no in-between weapon, so the MK 108 was mostly picked for installation. The MK 103 suitable for motor-cannon installation was too late, so was the attempt to use it as a synchronized gun on the Ta 152 (that itself was too late to matter)

Complexity level of the 30mm mine shell was same as complexity level of the 20mm mine shell, while having 4-5 times the destructive power. Leaving out the fuses for the time being, both were cheaper and less wasteful to make than the 'normal' shells that required drilling a solid piece of steel rod.
.50 cal ammo will not cut it for Lutwaffe past 1941 kill-power wise, each .50 round will require tripling the number of weapons vs. 20mm that were carried - impossible on small fighters like the Bf 109 or 190. Installed weight, price and complexity goes overboard, with eg. Fw 190 now required to lug a dozen of HMGs while being not just heavier but also draggier than it was before.

Surprisingly though US ground attack still used the 50 when you would think cannons would be more effective. I would love to hear you're thoughts on this as I am no expert.

Unless one needs to kill tanks or fortifications, 6-8 HMG batteries will work just as good against the ground targets.

 

[gruad]

Hey gruad,

There is an analysis of the 'efficiency' of the different US 4-engine bombers along with the B-25 and A-20 for comparison. In effect it measures the different aircraft's comparative logistical effort per ton of bombs dropped. If you combine this with the B-17 vs B-24 USAF Analysis report posted above I think it gives a fairly good feel for what's what. IMO the B-17 comes out at between 1.7:1 and 2.5:1 vs the B-24 - with the B-24 being the 1 (though possibly I am interpreting things wrongly ).

edit: sorry, typo - the 2:1 should

That makes sense B17 is roughly twice an effective bomber as the B24, but not upto Lancasters superiority of 3:1 over Halifax.

Other info:

1.Lanc better cockscrew but some Halifax had mid under.

2. Crew escape when shot down Lancaster 1 in 7 vs Hx 2 in 7. Simply because escape hatch too small.

I am sure that B17/24 crew loss was anything like this. Stats anyone, please?

Lancaster vs B17 is a whole new kettle of fish as different roles.

This doesn't even take in the fact Lancaster was cheaper to make and to run.

ThomasP, thank you for taking the time to share your knowledge with me and the forum.

 

[33k in the air]

1.Lanc better cockscrew but some Halifax had mid under.

Some Lancaster II (the all but forgotten mark) also had a ventral turret. I can even give you serial numbers for some of those so equipped.

 

[33k in the air]

Surprisingly though US ground attack still used the 50 when you would think cannons would be more effective. I would love to hear you're thoughts on this as I am no expert.

The 500-lb bomb was the most commonly dropped ordnance by U.S. ground attack fighters; fragmentation bombs were frequently used against infantry. The 100-lb phosphorous-filled bomb was found to be highly effective in demoralizing enemy troops. (Phosphorous was nasty stuff.)

 

[gruad]

Some Lancaster II (the all but forgotten mark) also had a ventral turret. I can even give you serial numbers for some of those so equipped.

Thanks 33k. You are correct about Mk2 which used the Hercules engine and some had ventral 0.5.

Another thing IIRC was the exhaust flame trap on the Merlin worked well, but I think the Hercules was easier to spot by Lw NF.

Was that an 14 into 1 exhaust pipe? Did the pipe glow?

Thanks if anyone knows.

 

[33k in the air]

Thanks 33k. You are correct about Mk2 which used the Hercules engine and some had ventral 0.5.

As far as I'm aware, the Lancaster II used the FN64 ventral turret with two .303" MGs; the Preston Green turret with a single .5" MG was used on some Halifax bombers.

 

[Greyman]

The FN64 wasn't a Mk.II-specific thing. All Lancasters could mount one -- provided the H2S didn't get there first.

If I remember correctly the Lancasters with the Martin mid-upper weren't able to mount the under turret either.

Both Halifaxes and Lancasters were getting ad-hoc .5-inch under-defence positions just as H2S numbers were allowing widespread fitment in Bomber Command, and the preference was for the radar.

 

[wuzak]

The FN64 wasn't a Mk.II-specific thing. All Lancasters could mount one.

Some Manchesters also had the under turret IIRC.

 

[Geoffrey Sinclair]

The Bristol Blenheim came from the civil Britain first design. When it comes to agility anyone seen a roll rate chart for the various allied heavy bombers, maximum dive speeds, turning circles etc.?

It is possible, given the knowledge of the time, the B-17A was over engineered, like the DC-3 and Empire State Building are reported to be, stronger than they needed to be to meet the specifications. The B-17A came in at around 26,520 pounds empty and up to around 45,650 pounds full. The B-17E mated a new fuselage to the existing wings. The B-17G came in at 36,135 pounds empty 65,500 pounds full, was the wing strengthened around 50% A to G to keep the original safety margins?

Unless the USAAF specifications changed between B-17 and B-24 and/or were significantly different to the RAF ones the allied heavy bombers should have been designed to roughly the same strength factors. Armour protecting the crew is very good from the humane point of view and the military cost of training crew, unless that armour was engineered to increase structural strength it was not going to contribute much to surviving damage, while there are plenty of stories about dead pilots meaning the loss of the aircraft, has anyone gone through the reports to figure out exactly what damage shot down heavy bombers actually took? Along the lines of the returning F-105 study in Vietnam, which showed no damage to one particular part of the aircraft as damage there was invariably fatal.

The B-17 carried up to 2,810 US gallons of fuel, the Lancaster carried 2,154 imperial gallons, the B-17 had around 9% more fuel capacity, putting aside which design had the better fuel economy the 8th AF tactics required lots more fuel, so the average B-17 had more fuel on board than the Lancaster, with the same amount of fuel protection. An extreme case the B-17F required around 1,760 US gallons less a 115 gallon reserve to hit a target 320 miles away, the Lancaster around 900 imperial gallons less a 200 gallon reserve. The best way to bring down an aircraft is to start a fire, the more fuel on board the greater the chance of fire. As far as I know there is curve starting at little chance of starting a fuel fire in a full fuel tank, to a peak when partially filled to no chance when empty. One issue for crews was that meant emptying each tank in turn reduced that risk, but a leak in the remaining tanks could mean not being able to make it home.

Under the conditions they operated in the 8th AF said the B-17 was better than the B-24, while Bomber Command said the Lancaster was the best British heavy. That is not the same as the airframe was harder to shoot down and both benefitted from having lower performance bombers around attracting the defenders. Using empty weight the Stirling at around 43,000 pounds empty should have required a higher amount of damage, it was the first of the RAF 4 engine types to be withdrawn.

10 March 1942 first Lancaster bomb operation
29 April 1942 last Whitley operation (ignoring 1,000 plane raids), final strength return 5 May
25 June 1942 last Manchester operation (1,000 plane raid) final strength return 9 June.
14 September 1942 last Hampden operation, final strength return 14 September.
8 October 1943 last Wellington bomb operation, final strength return 6 March 1944.
23 November 1943 Stirling withdrawn from attacks on Germany
20 February 1944 Halifax II and V withdrawn from attacks on Germany, about a third the Halifax force.
July 1944 last Halifax II and V operations, the last reported II/V on strength was 12 July 1944.
8 September 1944 last Stirling bomb raid, final strength return 13 September.

Fun with numbers time, with the point be sure to know what and how is being measured. In particular what time periods are being used, as losses, tactics, defences etc. varied. Operation Varsity 24 March 1945, 8th AF airfield attacks, 700 B-17 two MIA 2 damaged, 300 B-17 three MIA, 1 Cat E, 100 damaged, 58 B-24 no casualties, 180 B-24 sixteen damaged, 114 B-17 two damaged, 150 B-17 twenty damaged, rather variable loss rates but the big one was 240 B-24 low level resupply to paratroops, 14 MIA, 4 Cat E, 103 damaged. How the B-24 losses are counted matters, they had a significantly higher risk that day.

Why the B-17 was considered better, April 1945 8th AF report, after deducting diversions, spares and recalled aircraft 85.6% of B-17 and 79.2% of B-24 sorties attacked, the B-24 was more prone to mechanical aborts, "other" aborts and particularly weather aborts. The USSBS bomb accuracy report found the B-24 less accurate. Against that the downside to flying higher is lower accuracy and more chance of cloud between the aircraft and ground, further reducing accuracy. The 8th AF bombers had little fighter opposition after May 1944 making flak density and average altitude an important factor in survival. The period roughly January to August 1944 with the V weapon and Overlord missions gave the 8th AF a large number of less well defended targets, there does not seem to be any report, published or unpublished, that breaks the bomb tonnage down by B-17/24 except the March 1944 8th AF report, for February 1944 80% of B-17 effort to Germany, 48% of B-24, March 72.5% and 63.7%.. Counting the entries in Mighty 8th War Diary might be the answer. If there was a systematic bias of B-24 to softer targets that should have been noticed at the time and later, but remember as of end December 1943 the 8th had 18 operational B-17 and 7 operational B-24 groups, on D-Day 21 and 19, newer formations tend to be given easier operations for a while.

The 8th AF reports 1,957 MIA and 502 Cat E B-17 in 1944, along with 858 and 346 B-24. In terms of credit sorties 1.6% MIA and 2.0% overall loss for the B-17 1.3% and 1.8% for the B-24, a higher percentage of badly damaged B-24 seem to have made it back to friendly territory than B-17. For the war the B-17 had 3 times the MIA as the B-24 but only twice the Cat E. The tough B-24 and fragile B-17? Time to look at the accident report statistics which include things like being hit while parked, the ground crew setting the aircraft on fire as well as things like take off accidents, collisions, etc. The USAAF usually classified the damage taken between 1, minor, and 5 salvaged/write off. As far as I can tell some level 3 and most level 4 damaged aircraft were scrapped. The B-17 accident list I know of has 4,021 accidents, 3,632 of which have a 1 to 5 damage level recorded, 27% level 4, 23% level 5. For the B-24 3,653 accidents, 3,288 of which have a damage level recorded, 35% level 5, 30.4% level 4. So 50% of B-17 accidents probably meant scrapping versus 65% of B-24 accidents. It strongly suggests the B-17 was more crash worthy, taking less damage in a crash landing. Back to fragile B-24 and tough B-17? I have little doubt more returning damaged B-24 than B-17 went from damaged to write off in crash landings, or were abandoned in the air. Whether that means overall a higher percentage of badly damaged B-17 than B-24 made it back? Range also makes a difference, in the period to 31 August 1944 some 2.7% of 8th Air Force B-17s listed as lost to fighters made it back to allied territory, versus 6.4% of those listed as lost to flak. For the period 1 September 1944 to the end of the war the figures become 5.8% and 16.6%.

The Luftwaffe fighter pilots thought the B-24 was easier to shoot down, they over claimed B-17 at 2 to 1, B-24 at about 1.8 to 1, a higher percentage of B-24 crews were killed when shot down by flak and also fighters.

US Archives Record Group 18 Entry 7 Box 5695, Month of May 1944 8th AF Heavy bombers damaged by cause and category

B-17 A	B-17 AC	B-17 B	B-24 A	B-24 AC	B-24 B	Bomber and damage
2831​	648​	21​	447​	147​	23​	Total damaged
2488​	743​	28​	465​	178​	31​	total damage incidents
1.04​	1.15​	1.33​	1.04​	1.21​	1.35​	Incidents per damaged aircraft
2267​	600​	20​	431​	131​	19​	caused by flak
39​	57​	3​	6​	24​	6​	caused by fighter 20mm
12​	20​	0​	2​	2​	0​	caused by fighter small calibre
34​	19​	1​	9​	11​	6​	machine gun unknown origin
1​	4​	0​	2​	0​	0​	fire from other US aircraft
8​	7​	1​	0​	1​	0​	self inflicted
104​	16​	1​	11​	4​	0​	empty shell cases or links
4​	3​	0​	2​	1​	0​	unknown
19​	17​	2​	2​	4​	0​	other

Just a snap shot showing how flak tended to wound, not kill. For May 1944, the bombers claimed 377-115-170 in the air and 265 destroyed on the ground. 260 B-17 lost, 59 flak, 6 enemy aircraft, 140 flak & enemy aircraft, 11 accidents, 58 unknown, 23 cat E, 101 B-24 lost, 18 flak, 0 enemy aircraft, 33 flak & enemy aircraft, 4 accidents, 18 unknown, 28 cat E, B-17 2.5% of sorties missing, 0.2% Cat E, B-24 1.1% and 0.4%. For the previous 6 months, missing and Cat E rates of 3%, 0.5% B-17, 3%, 0.7% B-24.

US Archives Record Group 18 Entry 7 Box 5678, 8th AF bomber crew survival rates, at February to May 1944 loss rates 763 out of every 1,000 men would still be alive at the end of their tour, this steadily increases until the February to April 1945 numbers were 909 survived. At February to May 1944 loss rates, 419 complete tour, 21 relieved for medical or administrative reasons, 23 Escape & Evade, 16 seriously wounded, 284 PoW/Interned, 28 KIA/DoW, 205 reported or presumed dead, 4 non combat deaths. The fighters had 300 hour tours, in the period November 1944 to February 1945 the average P-51 sortie was 4.5 hours, requiring 60 sorties to complete a tour, the P-47 4.7 hours and 57 missions, losses meant 52% of P-51 and 60% of P-47 pilots could expect to complete their tour. There was almost no difference in B-17 and B-24 crew survival rates for these 4 months.

Air 22/204 Bomber Command War Room Manual 1942. Night bomb raids, 1 January to 31 December 1942.

Lancaster 4,377 sorties sent, 3,943 attacking (90%) all cause losses 160 (4%, 18 not enemy action), all cause damaged 67, 10,953 long tons of bombs (41% incendiary, 6,272 pounds per attack)

Halifax 3,271 sorties sent, 2,786 attacking (85%) all cause losses 241 (8.6%, 36 not enemy action), all cause damaged 68, 7,263.4 long tons of bombs, (44% incendiary, 5,824 pounds per attack)

Air 22/205 Bomber Command War Room Manual 1943. Night bomb raids, 1 January to 31 December 1943.

Lancaster 27,577 sorties sent, 25,558 attacking (92.7%) all cause losses 1,060 (4.1%, 106 not enemy action), all cause damaged 534, 100,512.9 long tons of bombs (41% incendiary, 8,809 pounds per attack)

Attrition rates, aircraft losses per operational squadron for the year, Stirling 55.9, Halifax 60.8, Lancaster 39.6, Manchester 98.2.

Halifax 14,685 sorties sent, 13,311 attacking (85%) all cause losses 786 (5.9%, 67 not enemy action), all cause damaged 248, 33,479.9 long tons of bombs, (55.2% incendiary, 5,634 pounds per attack)

Air 22/206 Bomber Command War Room Manual 1944. Night bomb raids, 1 January to 31 December 1944.

Lancaster 56,259 sorties sent, 51,851 attacking (92.2%) all cause losses 1,752 (3.4%, 106 not enemy action), 235,939.7 long tons of bombs (22% incendiary, 10,193 pounds per attack)

Halifax II&V 2,355 sorties sent, 2,098 attacking (89.1%) all cause losses 122 (5.8%, 12 not enemy action), 7,806.2 long tons of bombs, (13.3% incendiary, 8,355 pounds per attack)

Halifax III&VII 24,106 sorties sent, 22,210 attacking (92.1%) all cause losses 610 (2.7%, 77 not enemy action), 79,888.3 long tons of bombs, (11.4% incendiary, 8,057 pounds per attack)

Day bomb raids, 1 January to 31 December 1944.

Lancaster 26,551 sorties sent, 23,242 attacking (87.5%) all cause losses 225 (1%, 26 not enemy action), 125,065.9 long tons of bombs (4.9% incendiary, 12,054 pounds per attack)

Halifax III&VII 16,288 sorties sent, 14,459 attacking (88.8%) all cause losses 114 (0.8%, 29 not enemy action), 58,411.2 long tons of bombs, (2.2% incendiary, 9,049 pounds per attack)

1944 day and night, Lancaster 90.7% attacked, 10,769 pounds of bombs, 2.6% loss rate, Halifax III & VII 90.8% of sorties attacked, 8,448 pounds of bombs, 2% loss rate,

B-17 vs B-24 analysis

US Archives Record Group 18 Entry 7 Box 5695 8th AF monthly reports February and March 1944.

January 1944, 175 bombers lost in action.

February 186 B-17 lost in action (plus 28 cat E), 60 B-14 lost in action (plus 15 Cat E), plus 4 pathfinders. 1 B-17 lost per 32.6 sorties, B-24 per 40.3 sorties. 2,052 incidents of B-17 damage, including 1,626 to flak, 353 incidents of B-24 damaged including 284 to flak, 5,249 B-17 and 1,822 B-24 attacking sorties. B-17 units claimed 222 kills, B-24 113.

March, 211 B-17 lost in action (plus 28 Cat E), 86 B-24 (plus 19 cat E), plus 4 pathfinders. 1 B-17 lost per 34.6 sorties, B-24 per 38.8 sorties. 2,517 incidents of B-17 damage, including 2,106 to flak, 469 incidents of B-24 damaged including 452 to flak, 6,050 B-17 and 2,351 B-24 attacking sorties. B-17 claimed 303 kills, B-24 44.

Over 4,500 B-17 damaged in February and March 1944, around 400 lost in action, over 800 B-24 damaged, around 150 lost in action. The report has 4,233 B-17 lost or battle damaged January to March 1944 (566 lost), plus 1,006 B-24 (210 lost). The contents of tab A would be useful

B-17E versus B-24D comparison,

The charts go up to 60,000 pounds yet as I understand it the early B-24D limit was 56,000 pounds, the B-17E was 53,000 pounds. Also the B-24D came with tanks for 2,814 gallons of fuel, the B-17E 1,730. The fuel loads used are 1,500, 2,000 and 2,500 gallons. The chart says at 70% power the B-17 has 1.66 times the air miles per gallon of the B-24, at 60% power about 1.25 times, the two 50% power examples say about 1.1 times. The B-24 range figures at 40% power are about the same or less than the 50% power except with 2,500 gallons of fuel, when it is 10 to 20% longer.

The 16 July 1943 B-24D range prediction chart, assuming someone tows the aircraft to 10,000 feet after which engines are started, gives ranges from 2,300 miles at around 250 mph to 6,300 miles at 156 mph. Deduct 75 gallons for warm up and around 160 gallons to climb to 10,000 feet starting at 65,000 pounds.