B24 ceiling vs. B17 ceiling

[JDCAVE]

In RAF Bomber Command, the increase in "Main Force" Lancaster crew size to 8 crew members typically occurred with an experienced crew taking a second pilot on a combat operation for him to gain battle experience prior to going out with his "sprog" crew. They were referred to as "Second Dickie" trips. In most cases pilots in training did one of these. In some cases two. In other cases, the Main Force Crew carried someone from "Group". Air Vice Marshall McEwen, did at least 3 trips as a "2nd pilot" on operations.

Pathfinder Crews might carry a 2nd navigator/bomb aimer on regular occasions. The 7 Squadron ORB records some crews included 8 crewmen in February 1945 with an extra crewman called a "Visual Bomber", in addition to an "Air Bomber" and a Navigator. I surmise that the task of the Visual Bomber was in the standard role, using a bomb sight, whereas the role of the "Air Bomber" was as a H2S Mk III set operator for blind bombing. More research is required to verify this, however we do know that on most crews, the Bomb Aimer was "Set Operator". Pathfinders also carried a 2nd pilot on occasion, again, probably a pilot training for Pathfinder Force.

Jim

 

[James Heddon]

"Brevity is the soul of wit." -- Oscar Wilde

"Brevity is the soul of Lingerie." -- Dorothy Parker

 

[Reluctant Poster]

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

I have looked at that and similar articles and as the saying goes "There are three kinds of lies: lies, dammed lies and statistics" The claim is that the B-24 had the same loss rate as the B-17 and on the surface its seems true but the reality is that the B-24 actually didn't fly that many missions to Germany during the dark days of 1943 when the 8th Airforce suffered terribly proving that unescorted bombers were not a viable concept.
I went through the missions from January to October when the 8th AF was flying unescorted missions into Germany and found that the B-24 didn't actually fly on most of them and certainly didn't fly on the deep penetration ones. In order to compare apples to apples I took the data for the missions that both the B-17 and the B-24 flew together and this is the result:

If you tally up only the missions where both aircraft went to the same target, The B-24 rate increases to 12.1% whereas the B-17 rate drops to 5.3%.

Here are the missions where only B-17s flew:

One of the striking things about this data is that is shows that the B-24 barely flew any missions into Germany during this time frame. In fact the B-17 flew 98% of the missions. This obviously slews the overall statistics for the entire war which is what B-24 defenders like to quote.
While not shown in the tables the B-24 stats in this time frame are padded by the diversion missions they flew over the North Sea after they returned from Ploesti. Also note that Ploesti is included in MTO stats.
If you take the period from January 27 to October 14 when missions to Germany were unescorted the overall loss rate is 10.1% for the B17 and 10.2% for the B-24 indicating that the loss rates were virtually identical. This conveniently ignores the fact that the B-24s did not participate in any of the extremely difficult missions (Blitz Week, Schweinfurt -Regensburg, Stuttgart, Munster, second Schweinfurt) and that in general participation by the B-24s was minimal.
If you tally up only the missions where both aircraft went to the same target, The B-24 rate increases to 12.1% whereas the B-17 rate drops to 5.3%.

 

[EwenS]

The reason that there were not many B-24 sorties in the 8th AF in 1943 was twofold:-

1. There were not many B-24 BG present in the early / mid part of 1943; and
2. The earliest arrivals were transferred to the MTO to support Operation Husky & later operations against Northern Italy & southern Germany from North Africa

So we start with:-
93rd BG which was transferred to the MTO between Dec 1942 & 22nd Feb 1943 and again between 26th June & 27th Aug
44th BG in MTO between 28th June 1943 & 25th Aug and again from 17th Sept to 4th Oct.
389th BG arrived in Britain in June/July 1943 and was almost immediately sent to the MTO 3rd July & 23rd August and again 19th Sept to 3rd Oct

These 3 BG all participated in the ill-fated Ploesti mission, Operation Tidal Wave, on 1 Aug 1943.

The next B-24 BG in the 8th AF were:-
482nd BG (Pathfinder) (2 squadrons with the other 2 B-17 equipped). First mission 27 Sept 1943
392nd BG first mission 9 Dec 1943.
445th BG first mission 13 Dec 1943
446th BG first mission 16 Dec 1943
448th BG first mission 22 Dec 1943

Other 8th AF B-24 BG arived later and began to fly missions in 1944.

 

[JDCAVE]

I have looked at that and similar articles and as the saying goes "There are three kinds of lies: lies, dammed lies and statistics" The claim is that the B-24 had the same loss rate as the B-17 and on the surface its seems true but the reality is that the B-24 actually didn't fly that many missions to Germany during the dark days of 1943 when the 8th Airforce suffered terribly proving that unescorted bombers were not a viable concept.
I went through the missions from January to October when the 8th AF was flying unescorted missions into Germany and found that the B-24 didn't actually fly on most of them and certainly didn't fly on the deep penetration ones. In order to compare apples to apples I took the data for the missions that both the B-17 and the B-24 flew together…

That's exactly right. Best to examine paired observations, if they can be obtained and analyzed using analysis of variance.

Jim

 

[Reluctant Poster]

Regarding the B-17 versus B-24 debate, I'll offer these quotes from the book The B-24 Liberator — A Pictorial History by Allan G. Blue:


There were certain other contrasts between the two aircraft which were becoming apparent to men who were acquainted with both. For example the overall impression one got from the Fortress interior was that it was, like its exterior, round and smooth — with its equipment built-in rather than added-on. Each B-17 crew member had a place to sit down and strap himself in — a small point, perhaps, but psychologically important. On the other hand the Liberator fuselage, while of larger dimensions than the Fortress, offered little in the way of comfort for the crew. There seemed to be draughts everywhere, and of such magnitude that they were far more than the troublesome spot heaters could contend with. Movement throughout the ship was awkward and difficult in full flight gear, and more often than not resulted in jarring collisions with various sharp-edged and unyielding structural members and/or installed equipment. Idle gunners sat on the floor — if they sat — and likely as not pondered possible fates for the design engineer who was responsible for a fuel-transfer system that required any prudent B-24 pilot to crack open the bomb bay doors in flight to disperse the petrol fumes. Or perhaps the ball and tail gunners thought about the greater speed with which their B-17 counterparts could exit their stations in a emergency. (p.184)


Inevitably the Liberator continued to be compared with the Flying Fortress and, as far as the later versions of the two bombers were concerned, suffered by the comparison. This was due not so much to short-comings of the Liberator — although it certainly had them — as to the fact the B-17 was in many respects an exceptional aircraft, with many of its merits having particular — and personal — appeal to the men who flew it and flew in it. From the beginning the Fortress was an honest aircraft, easy to fly in formation, with a low landing speed and with no major vices. 'A four-engined Piper Cub' was the popular and rather apt description. Most important, the Fortress retained its original characteristics throughout its development, while the Liberator did not. (p.186)


Actually the Liberator never did lose its performance edge over the B-17, as a series of tests run at Elgin Field demonstrated conclusively late in the war. Rather, the areas in which the B-24 excelled became less important in the European and Mediterranean theatres. The range of the Fortress was adequate for Europe, and individual aircraft speed became academic because of formation requirements. Altitude, however, became paramount and here, literally, the B-17 remained on top. In addition, with over 70% of Eighth Air Force mission failures being attributed to navigational errors, the superior accommodations of the B-17 nose were highly desirable. General Doolittle, in fact, considered poor visibility the number one fault of the B-24.

In the Pacific theatre there was no vocal contest between the two aircraft, for although B-24's were originally requested by Pacific theatre commanders because they felt there was a better chance of getting them than the more popular B-17, the Liberator's longer legs soon demonstrated that it was a natural choice for an air war conducted for the most part at extreme range. The European requirement for tight formation flying was not as severe, and the typical maximum-range mission allowed Pacific Liberators, when necessary, to approach the target at adequate altitude because of the large amount of fuel burned on the way. (p.186-187)

The B-24s edge in range was actually gone by the end of the war at least according to the USAAF

 

[ThomasP]

Based on the chart posted above by Reluctant Poster, and the linked document below from 30 May 1942, the USAAF never considered the B-24 to have a greater range than the B-17:

"http://www.wwiiaircraftperformance.org/B-17/B-17E_B-24D_Comparison.pdf"

I think the superior range of the B-24 over the B-17 is another candidate for the "Greatest aviation myth this site "de-bunked"" thread.

 

[EwenS]

Based on the chart posted above by Reluctant Poster, and the linked document below from 30 May 1942, the USAAF never considered the B-24 to have a greater range than the B-17:

"http://www.wwiiaircraftperformance.org/B-17/B-17E_B-24D_Comparison.pdf"

I think the superior range of the B-24 over the B-17 is another candidate for the "Greatest aviation myth this site "de-bunked"" thread.

I don't think it is a candidate for "Greatest Aviation Myth". The report is dated May 1942 and is for a specific set of circumstances. But what about the fuel load? Max shown is 2,500 US gallons.

From Joe Baugher's site, max fuel loads
B-17E normal 2490 gal
B-17F normal 2,520 gal
B-17G normal 2,520 gal

At some point in the B-17F run Tokyo Tanks began to be installed but I'm not sure how much they added. And bomb bay fuel tanks could be fitted to increase the capacity to 3,612 gals.

The B-24D began with an internal fuel capacity of 2,343 gals. But from the D-1 model introduced in mid-1942 extra auxiliary tanks were added in the outer wings with a capacity of 450 gals to take total internal capacity to 2,790 gals. On top of that 2 bomb bay tanks each with a capacity of 345 gals could be fitted in the forward bomb bay, taking the capacity to 3,483 gals. At that max fuel load the aft bomb bay was still available for weapons while the B-17 was reduced to external carriage only.

So what does that extra potential 300 gals do to the range of the B-24? In the Pacific by late 1942 B-24D aircraft were regularly flying with either one or both of the bomb bay tanks installed. What was being achieved with the B-24 in the Pacific was a different ball game from that being achieved by the 8th & 15th Air Forces in Europe.

What is not mentioned in this is the potential bomb loads of the aircraft at each weight.

We had a discussion about this last year.

W/Cdr Blackburn and very long-range Liberators

The following passages come from www.weaponsandwarfare.com, specifically an article entitled 'The Consolidated Liberator in RAF Service': ' First squadron to serve in the Burma theatre was No. 159, whose Middle East detachment was mentioned earlier. This squadron began operations in November...

ww2aircraft.net

 

[ThomasP]

B-17F/G carried 1080 USgal in the 'Tokyo tanks', so a maximum of 3600 USgal.

 

[EwenS]

B-17F/G carried 1080 USgal in the 'Tokyo tanks', so a maximum of 3600 USgal.

But is that correct?

The Wiki article on these (yes I know, it's Wiki) says the Tokyo tanks for the B-17 were 1,080 gals as you state, but to add to the 1,700 gals in the main tanks to give a total of 2,780 gals plus the bomb bay tanks of 820 gals to give a total of 3,600 gals. Wiki says factory fitted Tokyo tanks from Boeing built B-17F-80 that reached the 8th AF in April 1943.

The B-17E transferred to Britain in the early part of 1942 as Fortress IIA are described as having 1,416 Imp Gal (1,700 US gals) main tanks plus a then hypothetical 600 Imp Gal (720 US gal) bomb bay tank. Some of the later deliveries of B-17F/Fortress II were noted to have the Tokyo tanks fitted but they were all delivered Aug-Oct 1942 and were Boeing Block 30 aircraft.
"Boeing B-17 Fortress in RAF Coastal Command Service" by Rob Stitt.

So just what was the normal fuel tankage for a B-17E in May 1942? 1,700 US or 2,490 US?

When did Tokyo tanks begin to be fitted other than on the production line?

I'll admit now that I have more knowledge about the B-24 than the B-17. Can anyone enlighten me further?

 

[Reluctant Poster]

I don't think it is a candidate for "Greatest Aviation Myth". The report is dated May 1942 and is for a specific set of circumstances. But what about the fuel load? Max shown is 2,500 US gallons.

From Joe Baugher's site, max fuel loads
B-17E normal 2490 gal
B-17F normal 2,520 gal
B-17G normal 2,520 gal

At some point in the B-17F run Tokyo Tanks began to be installed but I'm not sure how much they added. And bomb bay fuel tanks could be fitted to increase the capacity to 3,612 gals.

The B-24D began with an internal fuel capacity of 2,343 gals. But from the D-1 model introduced in mid-1942 extra auxiliary tanks were added in the outer wings with a capacity of 450 gals to take total internal capacity to 2,790 gals. On top of that 2 bomb bay tanks each with a capacity of 345 gals could be fitted in the forward bomb bay, taking the capacity to 3,483 gals. At that max fuel load the aft bomb bay was still available for weapons while the B-17 was reduced to external carriage only.

So what does that extra potential 300 gals do to the range of the B-24? In the Pacific by late 1942 B-24D aircraft were regularly flying with either one or both of the bomb bay tanks installed. What was being achieved with the B-24 in the Pacific was a different ball game from that being achieved by the 8th & 15th Air Forces in Europe.

What is not mentioned in this is the potential bomb loads of the aircraft at each weight.

We had a discussion about this last year.

W/Cdr Blackburn and very long-range Liberators

The following passages come from www.weaponsandwarfare.com, specifically an article entitled 'The Consolidated Liberator in RAF Service': ' First squadron to serve in the Burma theatre was No. 159, whose Middle East detachment was mentioned earlier. This squadron began operations in November...

ww2aircraft.net

The chart I posted clearly shows the B-17 carrying 6,000 lbs. of bombs for 1,800 miles whereas the B-24 only carries 5,000 lbs. of bombs for 1,600 miles. I have attached the study I took it from.
Range is not solely a function of fuel capacity. As the B-24 grew heavier and less aerodynamic it only makes sense that the MPG suffered. Here is another excerpt from the study adding the fuel consumption:

The maximum range without bombs favors the B-24 but that is a different role.

 

[pbehn]

I have looked at that and similar articles and as the saying goes "There are three kinds of lies: lies, dammed lies and statistics" The claim is that the B-24 had the same loss rate as the B-17 and on the surface its seems true but the reality is that the B-24 actually didn't fly that many missions to Germany during the dark days of 1943 when the 8th Airforce suffered terribly proving that unescorted bombers were not a viable concept.
I went through the missions from January to October when the 8th AF was flying unescorted missions into Germany and found that the B-24 didn't actually fly on most of them and certainly didn't fly on the deep penetration ones. In order to compare apples to apples I took the data for the missions that both the B-17 and the B-24 flew together and this is the result:
View attachment 711811
If you tally up only the missions where both aircraft went to the same target, The B-24 rate increases to 12.1% whereas the B-17 rate drops to 5.3%.

Here are the missions where only B-17s flew:

View attachment 711813

One of the striking things about this data is that is shows that the B-24 barely flew any missions into Germany during this time frame. In fact the B-17 flew 98% of the missions. This obviously slews the overall statistics for the entire war which is what B-24 defenders like to quote.
While not shown in the tables the B-24 stats in this time frame are padded by the diversion missions they flew over the North Sea after they returned from Ploesti. Also note that Ploesti is included in MTO stats.
If you take the period from January 27 to October 14 when missions to Germany were unescorted the overall loss rate is 10.1% for the B17 and 10.2% for the B-24 indicating that the loss rates were virtually identical. This conveniently ignores the fact that the B-24s did not participate in any of the extremely difficult missions (Blitz Week, Schweinfurt -Regensburg, Stuttgart, Munster, second Schweinfurt) and that in general participation by the B-24s was minimal.
If you tally up only the missions where both aircraft went to the same target, The B-24 rate increases to 12.1% whereas the B-17 rate drops to 5.3%.

I dont have any dog in this fight. As far as I can see it they both had 4 engines with the same amunt of power, the same defensive armament, crew size and bombing design brief (give or take a little). They were very similar in performance with the differences down to minor issues of weight and aerodynamics. The stats you posted show (in my opinion) mainly the difference that use and chance make. To me it was lucky for the USA that they were different, they could be sent to where their strength were most useful. The nightmare scenario for the USAAF would be only having one or the other in bigger numbers.

 

[ThomasP]

'Tokyo tanks' were fitted from blocks B-17F-25-DL, B-17F-30-VE, B-17F-80-BO. These were all ordered with 42-xxxxx SN and some were delivered in 1942, but I do not know how many were delivered in 1942 as opposed to 1943. There were quite a few F models with the 'Tokyo tanks' in service in early-1943.

There were some airframes retrofitted with the 'Tokyo tanks' after delivery to modification centers, but I do not have any specific data as to how many or when.

B-17 bomb bay tanks were self-sealing as of early-1943 and contained 410 USgal each.

 

[ThomasP]

After looking through the various data I have on the B-17 and B-24, I think the ranges listed in the chart Reluctant Poster posted above are for maximum internal fuel - without the bomb bay fuel tanks. So the fuel loads would be:

B-17_____2780 USgal
B-24_____2793 USgal

 

[Geoffrey Sinclair]

I went through the missions from January to October when the 8th AF was flying unescorted missions into Germany and found that the B-24 didn't actually fly on most of them and certainly didn't fly on the deep penetration ones

Interesting, where does the B-17/24 split data come from? The Richard Davis spreadsheets only have bomb tonnages.

Pre Torch there were 7 B-17 and 2 B-24 groups in England, that dropped to 5 B-17 (1 non operational) and 1 B-24 in the first week of December 1942. The 93rd group returned and resumed flying missions on 25 February 1943. By the time of the June detachment to the Mediterranean it was 15 B-17 (13 operational) to 3 B-24 (2 operational). The 8th flew no B-24 combat sorties 27 June to 7 September. 16 B-17 to 4 B24 groups on 9 September but down to 1 B-24 group for the second half of September due to the second Mediterranean deployment. The next B-24 groups arrived in early November, which started the B-24 build to end up at 21 B-17 to 19 B-24 on D-Day. Conversions made that 26 to 13 in late August, finally 26 to 12 on 10 November. At the other end of the war all the B-24 groups were gone by end July 1945, leaving 19 B-17 groups. It means in 1943 the 8th reports 107 B-24 MIA, 20 Category E and 23 non operational salvage while operating out of England, versus 863 MIA, 136 Category E and 68 non operational salvage B-17.

Officially the Mediterranean deployments were 93rd group 13 December 1942 to 20 February 1943, 44th, 93rd, 389th groups 2 July to 21 August 1943, and the same groups 21 September to 1 October 1943. 47 strike days, 1,453 sorties, 1,288 effective, 3,365 tons of bombs on targets, 69 aircraft MIA. The 8th flew 28,115 heavy bomber sorties from England in 1943.

8th Air Force Heavy Bomber losses on operations for 1944, percentage of effective sorties

A/c	MIA	Cat E	credit sorties	effective sorties	MIA %	MIA+CAT E %	Cat E/MIA
B-17	1957​	502​	121882​	109736​	1.78​	2.24​	0.26​
B-24	858​	346​	66154​	56300​	1.52​	2.14​	0.40​
Total	2815​	848​	188036​	166036​	1.70​	2.21​	0.30​

The bomber efficiency report in message 151 has the B-17 taking off at 65,000 pounds, the B-24 at 61,500 pounds, yet both types were cleared to 65,000 pounds by 1945, another 1,000 pounds of bombs on the B-24 would still leave 3,500 pounds for fuel, at 5.84 pounds per gallon that is around 600 gallons. (100 Octane Fuel density is just under 5.8 pounds per US gallon at 30 degrees C, to just over 6.2 pounds per gallon at -30 degrees C).

Roger Freeman quotes the B-17G at 65,500 pounds, 6,000 pounds of bombs, 2,810 gallons of fuel range 2,000 miles at 182 mph at 10,000 feet, with no bombs and 3,630 gallons of fuel range 3,400 miles at 180 mph at 10,000 feet. For the B-17E at 51,000 pounds, 4,000 pounds of bombs, 1,730 gallons of fuel, range 2,000 miles at 224 mph at 15,000 feet, with no bombs at 53,000 pounds, 2,520 gallons of fuel, range 3,200 miles at 180 mph at 10,000 feet.

Extra wing fuel tanks. B-17F-80-BO production starting with 42-29932 began in mid March 1943, B-17F-30-VE starting with 42-5855 began in late March 1943, B-17F-25-DL starting with 42-3074 began in mid January 1943, first reports 8th AF losses for all three versions is May 1943. The first Douglas Tokyo tank versions began emerging from the modification centres in mid/late February 1943. Boeing 2,300 B-17F (1,200 in blocks 1 to 75), Douglas 605 (110 in blocks 1 to 20), Lockheed/Vega 500 (150 in blocks 1 to 25)

USN PB4Y-1 as of 1 November 1944

Gross Weight Pounds	62,900​	63,000​	63,000​	63,000​	62,000​
Fuel Gallons	3,214​	3,063​	2,019​	1,272​	3,614​
Bomb load No. x Pounds	0​	2x500	8x1,000	8x1,600
Bomb Bay Tanks Droppable No. x Gallons	1x400	1x400	0​	0​	2x400
Max Range Statute Miles	3,440​	3,260​	2,065​	1,255​	4,190​
Max Range Average Speed MPH	151​	148​	154​	155​	153​
Max Endure./Range Altitude Feet	1,500​	1,500​	1,500​	1,500​	1,500​

USN PB4Y fleet from new production, built at San Diego unless noted, was 233 B-24D (4 from Fort Worth), 1 G (North American), 367 J, 186 L and 145 M, with the M versions accepted October 1944 to January 1945.

RAF pilots notes have B-24 fuel as 2,354 US gallons (1,960 imperial gallons) normal internal fuel, plus 450/374 wing cells plus 800/670 bomb bay. It indicates non bomb bay tankage was about the same for the B-17 and B-24. The B-24 tended to cruise faster than the B-17, the question being how much of that was due to the Davis wing living up to its promise of being lower drag.

The B-24D range and endurance chart, which has all fuel available for cruise (The notes say deduct 75 gallons for warm up plus the fuel used in the climb and also allocate reserves), take off at 65,000 pounds, cruise at 1,000 feet range is between 2,125 miles at 231 to 241 mph to 6,100 miles at 165 mph, at 5,000 feet between 2,200 miles at 239 to 251 mph, to 6,250 miles at 171 mph, at 10,000 feet between 2,300 miles at 248 to 253 mph to 6,250 miles at 159 mph, at 15,000 feet between 2,355 miles at 258 to 276 mph to 6,300 miles at 193 mph, at 20,000 feet between 2,475 miles at 269 to 292 mph to 5,750 miles at 220 mph, at 25,000 feet between 2,600 miles at 280 to 311 mph to 5,300 miles at 240 mph, at 30,000 feet between 3,650 miles at 280 mph to 5,100 miles at 260 mph. The 20,000 feet and higher charts have a longer range curve but the speed is not specified.

Service ceilings at gross weight, 23,000 feet at 65,000 pounds, 26,900 feet at 60,000 pounds, 29,400 feet at 55,000 pounds, 31,900 feet at 50,000 pounds, 34,100 feet at 45,000 pounds, 36,300 feet at 40,000 pounds, 38,900 feet at 35,000 pounds.

Fuel consumption 4 engines running, military power 2,700 RPM, 630 gallons per hour at sea level 670 gallons per hour at 26,500 feet when the turbo limit of 23,400 RPM is reached, 100% power 2,550 RPM, 575 gallons per hour at sea level, 595 gallons per hour at 27,000 feet when the turbo limit is reached (21,300 RPM?), 90% power 2,490 RPM 505 gallons per hour at sea level, 530 gallons per hour at 29,500 feet when the turbo limit of 21,300 RPM is reached, 80% power 2,400 RPM 425 gallons at sea level, 445 gallons per hour at 30,000 feet, 75% power 2,325 RPM 385 gallons per hour at sea level, 405 gallons per hour at 30,000 feet, 70% power 2,400 RPM 345 gallons per hour at sea level, 360 gallons per hour at 30,000 feet, 65% power 2,200 RPM 305 per hour gallons at sea level, 320 gallons per hour at 30,000 feet. Above is "Power-AR" setting, remainder are "Power-AL" setting, 65% power 2,200 RPM 250 gallons oer hour at sea level, 265 gallons per hour at 30,000 feet, 60% power 2,050 RPM 205 gallons at sea level, 215 gallons per hour at 30,000 feet, 55% power 1,900 RPM to 25,000 feet then 2,000 RPM, 175 gallons per hour at sea level, 190 gallons per hour at 30,000 feet, 50% power 1,750 RPM to 15,000 feet, 1,850 RPM to 25,000 feet then 2,000 RPM, 175 gallons per hour at sea level, 190 gallons per hour at 30,000 feet. At 35% power the maximum height is 24,000 feet, at 30% power 12,000 feet.

RAAF aircraft performance summaries, Appendix 1 – British, American, German, Italian and French Service Aircraft, 1939–45

RAF Fortress I/B-17C, 7,400 pounds of bombs, 1x0.30 inch, 6x0.50 inch, 1,415 gallons of fuel, 1,900 miles range at 240 mph at 30,000 feet. No bombs, 2,075 gallons of fuel, 3,000 miles at 240 mph at 30,000 feet. The ranges deduct a 150 gallon allowance for warm up, take off, climb, time over target, navigational errors and other emergencies.

 

[33k in the air]

B-17F/G carried 1080 USgal in the 'Tokyo tanks', so a maximum of 3600 USgal.

B-17: 1,700 gallons + 1,080 gallons in 'Tokyo Tanks' = 2,780 gallons (plus up to two 410 gallon auxiliary fuel tanks carried in the bomb bay)
B-24: 2,343 gallons + 450 gallons in aux. wing tanks = 2,793 gallons (plus up to two 391–425 gallon auxiliary fuel tanks carried in the bomb bay)

These figures come from the Pilot's Flight Operating Instruction manuals.

 

[ThomasP]

Hey 33k in the air,

?

I know

That is what I posted in my post#154 "B24 ceiling vs. B17 ceiling". The fuel loads I listed in my post#154 are the ones that work for the ranges listed (assuming reserves) and associated bomb loads in the chart Reluctant Poster provided in his post#146.


I posted the maximum for the B-17 with 'Tokyo tanks' and bomb bay tanks here "B24 ceiling vs. B17 ceiling"

1700 + 1080 + 820 = 3600

EwanS posted the maximum for the B-24 with 'Tokyo tanks'/long range aux. wing tanks and bomb bay tanks here "B24 ceiling vs. B17 ceiling"

2343 + 450 + 820 = ~3614

From the B-24D manual dated September 1942

B-24 and B-24A manual says 3000 USgal in wing if non-SSFT, or 2480 USgal if SSFT - no bomb bay fuel tanks noted.

B-24C/D/E manuals say 2343 or 2344 USgal in wing SSFT.

A Weight & Balance sheet for the B-24J lists 2360 USgal in wing SSFT.

Liberator Mk II/LB-30 manual lists 1890 Impgal (2268 USgal) in wing SSFT (different number and arrangement of tanks than on US B-24 series with SSFT) - no mention of bomb bay tanks.

Liberator Mk III/V/VI manual lists 2334 Impgal (2801 USgal) in wing SSFT, with 670 Impgal (804 USgal) in 2x 335 Impgal (402 USgal) bomb bay SSFT.

Liberator Mk III/V/VI Pilot's Notes list the self-sealing bomb bay tanks as "approximately 335" Impgal (402 USgal) each and not droppable.

Liberator Mk VI Aircraft Data Sheet lists 2350 Impgal (2820 USgal) in wing SSFT, and 3010 Impgal (3612 USgal) with 2x 330 Impgal (396 USgal) bomb bay SSFT.

B-24, PB4Y-1/-2 bomb bay SSDT are listed as 400 USgal in a 1945 supply catalog, and fuel loads listed on post-war SACs reflect this volume as correct (probably?).

<edit> added the following

B-17F December 1942 manual lists the fuel load as 1732 USgal without 'Tokyo tanks' or bomb bay tanks.

B-17F January 1943 manual lists the fuel load as 3612 USgal with 'Tokyo tanks' and bomb bay tanks.

B-17F August 1943 manual lists the fuel load as 3600 USgal with 'Tokyo tanks' and bomb bay tanks.

 

[Reluctant Poster]

Interesting, where does the B-17/24 split data come from? The Richard Davis spreadsheets only have bomb tonnages.

I started a spreadsheet years ago. I believe the original source was Freeman, but the latest version is based on this:

Search Missions | American Air Museum

www.americanairmuseum.com

The numbers from this website seem to match up with other data I have collected .

 

[33k in the air]

Hey 33k in the air,

?

I know

I saw that later. But I had already posted, so I thought I'd let it stand.

There always seems to be some small variation in fuel capacity between different sources. Part of that may have to do with the amount of trapped fuel which can't actually be drawn from the tanks for use, or it just be may be natural fluctuations in measuring equipment, etc.

 

[ThomasP]

I just ran across a couple more B-17F fuel load numbers that vary a little bit, added them to my my previous post