USAAF - Around the clock bombing

[wuzak]

After D-Day, did the USAAF have enough aircraft and crews that they could run a day and night campaign concurrently?

I ask, because the 8th AF had their idea of targets, and BC (ie Harris) had theirs.

Would running day and night be too difficult, and weaken the day bomber effort?

Could the USAAF have effectively adopted the RAF techniques for night marking and bombing?

Or would it have been easier to get Harris and Spaatz on the same page?

 

[drgondog]

Wusak IMO - no. At least not until post D-Day did the 8th AF have the number of experienced aircrews and bombers to split their mission and join the RAF at night while maintaining daylight ops.. The attrition of August 1, 17 and October 14, 1943 bled the 8th AF of perhaps 30% of its experienced crews - many of them lead crews. Only the success of Operation Pointblank in drastically whittling down Germany's day fighter capability enabled the 8th to re-build experience and capability.

The 8th did prepare for switching to night bombing in October/November but arrived at a couple of conclusions:

1. The re-training and re-skilling by experience in the transition would take several months, but yes it could be done.
2. The losses of the RAF at night didn't give Spaatz any comfort that the 8th would fare any better.
3. The bomb loads of the B-17 were far less than all the RAF counterparts, and any precision advantage envisioned/gained during daylight would have been lost at night.
4. Arnold/Spaatz would not have accepted the loss of face IMO

In hindsight the combined Planning for Operations would have been more effective if they reported directly to Eisenhower and priorities/conclusions regarding which targets to hit day and night should have been enforced - or fire the footdraggers.
harris is the one I had in mind. Spaatz, when told to stand down on the Oil Campaign to focus on tactical targets, did so with a salute and a 'Yes Sir".. Harris, wellllllllll.

 

[wuzak]

Bill, I was suggesting after D-Day.

 

[rank amateur]

After D-Day, did the USAAF have enough aircraft and crews that they could run a day and night campaign concurrently?

I ask, because the 8th AF had their idea of targets, and BC (ie Harris) had theirs.

Would running day and night be too difficult, and weaken the day bomber effort?

Could the USAAF have effectively adopted the RAF techniques for night marking and bombing?

Or would it have been easier to get Harris and Spaatz on the same page?

I understand that the standard B17 wasn't adoptable to nightbombing because of the exhaust flames. This could be mended with exhaustdampers but I do not know if these were readily available. Im sure the USAAF could adopt British methods but i guess it would have cost a few months

 

[Shortround6]

The planes were not going to do more than one mission in 24 hours so any night missions would have resulted in that many fewer day missions or that many fewer bombers over a target in day time. Total bombs dropped per week might be about the same.
Effects of 24 hr bombing (lack of sleep for defenders and morale) vs usually poorer accuracy at night (fewer bombs actually on target) ???

As mentioned, night bombing needs special training and different tactics if anything is to be achieved.

 

[krieghund]

In hindsight the combined Planning for Operations would have been more effective if they reported directly to Eisenhower and priorities/conclusions regarding which targets to hit day and night should have been enforced - or fire the footdraggers.
harris is the one I had in mind. Spaatz, when told to stand down on the Oil Campaign to focus on tactical targets, did so with a salute and a 'Yes Sir".. Harris, wellllllllll.

Fortunately through the 20-20 hindsight eyes with the available documents today the Oil campaign may have been a viable strategy. Its easier to strafe planes on the airfield or hit non-moving tanks. Could the war have been shortened? IMO

 

[drgondog]

Bill, I was suggesting after D-Day.

Wuzak - Sorry about that.

Well, splitting the force after D-Day complicates night ops and simplifies daylight bombing for USAAF. In addition the daylight activities get much better fighter escort coverage. Offhand I see no real value in throwing more aircraft into the night war when the daytime freedom of action as well as loss reductions had been achieved at such high cost.

Does the USAAF night bombing campaign help the war effort?

I don't know, don't see net positive advantage in 8th AF bombing accuracy; don't see net positive advantage in losses (believe German fighters will be effective against B-17s and B-24s and moreso than German daylight fighters because of lack of escorts); don't see any advantages in forming up yet another large force to fly in airspace conflict over England.

Sorry I missed the point of your question the first time.

 

[JoeB]

After D-Day, did the USAAF have enough aircraft and crews that they could run a day and night campaign concurrently?

I think we could say the USAAF always had 'enough' a/c and crews to fly both day and night missions, but the day missions would have had to have been smaller than they were in actual history if the same command had pursued night missions at the same time. I don't see any reason or point in time where this would not have been true, ie there was never AFAIK any bottleneck besides available number of planes/crews in the process of conducting day raids that would allow the day campaign to be just as big if some of the a/c and crews were assigned to night missions instead.

That said, I'm not sure there were any insurmountable bottlenecks to having US and RAF a/c both operate at night without getting too much in one another's way, if it were coordinated.

But it seems the premise of the question is some good reason why the USAAF should have operated night raids as of ca. mid 1944. I don't see what this would be, given the basic belief that daylight raids were a viable way to degrade German war making potential. And while that might have been a highly questionable belief as it applied to the earlier smaller USAAF efforts ca 1943, it was becoming quite a reasonable belief right around mid 1944. The size of the effort had grown alot, it was clear that excessive losses could be avoided (something that *wasn't* clear wrt RAF night bombing in the same period, the German nightfighters were gaining the upper hand until the latter part of that year) and accuracy and target selection were growing more effective.

Although, to take a contrasting example, the USAAF did adopt a mixed day and night campaign against Japan with B-29's. The well known initial part of that story was (believed to be) ineffective daylight precision bombing in Nov 1944-Feb 1945 by the Marinas based B-29's (plus earlier pinprick raids, basically, by China based B-29's) followed by a series of night fire raids in March. But thereafter it was a mixture with some day and some night bombing raids, plus night mining raids, and towards the end of the war true night precision radar raids by 'Eagle' equipped B-29's, at least against high radar-contrast targets. There was day and night 'concurrently', but of course the day effort had to be smaller than if it would have been with all a/c flying day missions all the time.

It seems to me two key elements were absent in the ETO/MTO case compared to the B-29 case. First the USAAF didn't believe it was failing in day precision bombing ca. mid 1944 (and arguably was not, in fact arguably the B-29's weren't either, the Japanese a/c industry was actually seriously damaged in the latter part of the Nov-Feb B-29 raids, and damaged itself further by poorly executed plan to disperse its activities in response to the bombing). And secondly it didn't see a political/military rationale to adopt night area bombing v Germany (was there one? I guess we could reconsider this), and the USAAF lacked true night precision bombing at that time, though RAF possessed it to a limited degree, and USAAF would have it by mid-1945 over Japan.

Joe

 

[wuzak]

I asked because sometime after D-Day the 8th AF had 2000+ heavy bombers on strength, and 2 crew for each bomber. Did they ever send all bombers on one mission?

I believe that 1000 bomber raids were quite common in early-mid 1944.

Could some of the remainder - say 500+ bombers have been used in follow up night raids.

For example, if the 8th bombed an oil facility during the day it might be worth following up with a night raid - disrupting cleanup, repair and firefighting efforts. Sometimes BC would follow up, but usually Harris was following his own agenda. The 8th could do the follow up themselves.

I think Drgondog is correct - it would have better to get Harris on board with the campaign.

 

[drgondog]

Wuzak - the Maximum effort 8th BC missions occurred on June 20, 1944 and March 24 1945. 1965 bombers/1111 fighters resumed the Oil Campaign, and 1749 dispatched (1375 fighters) to support the Airborne Operations past the Rhine. The next day 1009 bombers were dispatched. Interestingly after June 20 most of the bombers dispatched were under 1000 on the average for several months - certainly not capacity related

The typical March efforts were in the 1200-1300 bomber range with occasional 1400 bomber missions. After March they dwindled down to typical 1100-1300 through April 10 (April 7 had 1314/898 fighters), then most below 1000 as the 8th wound down bomber missions and prepared to go to the PTO.

The missions were 9 to 10 hours, with mandatory multiple hours of post strike maintenance. I do not believe the airplanes or the ground crews could do two missions per day, so the force would have to be split. I also do not believe the crew to a/c ratio was 2:1. I suspect March 24 gives you a pretty good look at maximum number of aircrews ~ perhaps 1800 in March? but I don't have a sense for June-July, 1944 TO&E in comparison.

If the 8th (and 15th) were directed to perform 2 missions per day per Bomb Group it would have had some significant impact on the operatonal rythms - (aircraft launching when returning crews trying to sleep, etc) so the force structure of 8th BC probably would have a % dedicated to single mission per day, and the others to single mission per night.

Looking at the numbers dispatched that could average 500 for daylight and 500 for night bombing through 1944. I question the relative effectiveness when weather permitted good visibility over the target, but the night trained bomber crews would probably do better than day crews when visibility was 10/10 over the targets.

 

[Milosh]

I asked because sometime after D-Day the 8th AF had 2000+ heavy bombers on strength, and 2 crew for each bomber. Did they ever send all bombers on one mission?

I believe that 1000 bomber raids were quite common in early-mid 1944.

The Army Air Force Statistical Digest has 1786 B-17s and 2440 B-24s on hand (first line) vs Germany at the end of June 1944. (Table 88 )

Wuzak, look at this link The USAAF in WWII for the number of a/c in USAAF missions.

 

[drgondog]

The Army Air Force Statistical Digest has 1786 B-17s and 2440 B-24s on hand (first line) vs Germany at the end of June 1944. (Table 88 )

Wuzak, look at this link The USAAF in WWII for the number of a/c in USAAF missions.

Milosh - at the end of the war the 8th AF still had ~ 50% more B-17s and B-17 BG's than B-24. The above number must include 15th AF to reach those totals.

 

[Milosh]

Milosh - at the end of the war the 8th AF still had ~ 50% more B-17s and B-17 BG's than B-24. The above number must include 15th AF to reach those totals.

Yes it is the combined total of a/c in the ETO and MTO.

At the end of June 1944 in the ETO there was 1471 B-17s and 1458 B-24s on hand. In the MTO, it was 315 B-17s and 982 B-24s.

End of May 1945
ETO - 2707 B-17s, 1988 B-24s
MTO - 529 B-17s, 811 B-24s

Tables 89 and 90

 

[JoeB]

1.I asked because sometime after D-Day the 8th AF had 2000+ heavy bombers on strength, and 2 crew for each bomber. Did they ever send all bombers on one mission?

I believe that 1000 bomber raids were quite common in early-mid 1944.

Could some of the remainder - say 500+ bombers have been used in follow up night raids.

2. For example, if the 8th bombed an oil facility during the day it might be worth following up with a night raid - disrupting cleanup, repair and firefighting efforts. Sometimes BC would follow up, but usually Harris was following his own agenda. The 8th could do the follow up themselves.

1. Again, I don't see any evidence the USAAF ever left bombers idle just because there were 'too many'. Thus a night effort would always subtract from a day effort. This was clearly the case with B-29 round the clock operations against Japan from ca. April 1945. If a full effort or certain groups were night bombing or mining, they weren't available for a day mission till next cycle (of crew rest, maintenance and preparation of the plane etc). Night operations weren't a way to send more bombers in total, but rather night tactics were more cost effective against particular targets using particular methods: again mainly mining and area bombing. Neither of those mission/targets were on the menu for USAAF ETO/MTO in 1944.

And again night 'precision' bombing was a limited commodity. The Oboe system only worked over certain areas of Germany and was ultimately a Rube Goldberg method, of a few Oboe equipped a/c (the system was interactive between a/c and ground station so only a few a/c at a time could use it) dropping markers with relative precision and other bombers trying to drop on the markers. Making that work, to a degree, also relied on the cumulative wealth of night experience in Bomber Command lacking in 8th/15th AF's at the time. The US answer to night precision bombing (for highly radar reflective targets anyway) of APQ-7, which eventually achieved accuracy on real night missions on order of 30+% bombs in 1000' circle, comparable to practically attainable results with bombsights in reasonable visibility (though still much worse than than theoretical/trial results with visual bombing) was a year away.

2. That seems like a reasonable idea, but USAAF bombers at night in mid 1944 would have been able to achieve accuracies, with Gee radio nav and H2X radar, at best similar to what that actually did achieve with those systems in heavy cloud conditions in the daytime hours, order of 1% of bombs in 1000' circle, only enough to create a nuisance to cleaning or firefighting crews at a particular point target. In many cases Bomber Command missions also still relied on similar systems. They had achieved by late in the war the consistent ability to hit cities at night rather than sprinkle bombs semi-randomly across the German countryside as they often had ca. 1940-1. But night precision bombing capability was a limited commodity in the RAF, and absent in USAAF, ca. mid 1944.

Joe

 

[Balljoint]

One possible advantage to more night bombing would be the limited, even dismantled, night fighter LW capacity. Kammhuber's plan was rejected early on and even limited support was diminished in favor of offensive bombing by Hitler.

 

[Juha]

IIRC BC had ability to usually hit a synthetic oil plant, not always but usually, in later part of 44, and when they hit the results tended to be damages more difficult to repair than those after USAAF raids because of BC used generally heavier bombs.

Juha

 

[JoeB]

IIRC BC had ability to usually hit a synthetic oil plant, not always but usually, in later part of 44, and when they hit the results tended to be damages more difficult to repair than those after USAAF raids because of BC used generally heavier bombs.

Juha

BC had from the end of 1942 the ability with Oboe to achieve comparable accuracy at night to the practical capability of bomb sights in daylight in some circumstances but with two key limitations:
-the system could only guide a handful of a/c at a time, so either a few Oboe equipped Mosquito's would drop bombs themselves, or more often against major targets they's drop target markers for the main bomber force to drop on. But the pathfinder/marker system introduced the possiblity of low cloud obscuring the markers, and sometimes the Germans managed to lay out correctly colored decoy markers in time to confuse the main force.

-the range was practically limited to around 270 miles from the Oboe ground stations in Britain, so basically Ruhr targets.

But it was used against all kinds of point targets in that area, and was by far the most accurate method of night bombing widely used in the European war. However at longer ranges methods like Gee and LORAN radio navigation and picking up ground targets with H2S radar were still only really good for hitting a city-size target.

The US SHORAN system was conceptually somewhat similar to Oboe, with a similar range limitation, but more a/c could use the same ground stations at the same time. It saw limited use by B-26's in Italy from late 1944, and was the main system used by B-29's to bomb at night in Korea, again yielding CEP's similar to the practical results with bomb sights in daylight.

The mid-1945 WWII B-29 night precision capability was via a high resolution radar (Eagle) and associated bombing system, and each plane could find a (high radar-contrast target) and bomb it with accuracy comparable to practical results in day light. The 'catch' in that case was limitation to high radar contrast targets. It was mainly used v Japanse refineries and synthetic oil plants whose reactor towers could be seen on the radar scope. Again it gave way to SHORAN in Korean War B-29 night operations, which were relatively near friendly territory and often featured targets lacking any prominent radar return. Later still USAF heavy bombers used radar offset bombing, where the bombing system could accurately compute release parameters for a target at a known location in reference to some other high radar contrast point, as B-52's used in Vietnam with usually good accuracy by WWII day bombing standards.

Joe

 

[wuzak]

BC had from the end of 1942 the ability with Oboe to achieve comparable accuracy at night to the practical capability of bomb sights in daylight in some circumstances but with two key limitations:
-the system could only guide a handful of a/c at a time, so either a few Oboe equipped Mosquito's would drop bombs themselves, or more often against major targets they's drop target markers for the main bomber force to drop on. But the pathfinder/marker system introduced the possiblity of low cloud obscuring the markers, and sometimes the Germans managed to lay out correctly colored decoy markers in time to confuse the main force.

They also used sky marking flares when cloud was going to be a problem.

 

[Juha]

...But it was used against all kinds of point targets in that area, and was by far the most accurate method of night bombing widely used in the European war. However at longer ranges methods like Gee and LORAN radio navigation and picking up ground targets with H2S radar were still only really good for hitting a city-size target...

IMHO H2S was adequate if there weres high radar contrast areas near the target, for ex coastline, lake, river etc, so BC could bomb fairly accurately certain targets well outside the Oboe range, as was shown for ex in Peenemünde raid in Aug 43. I recall from BC War Diaries that BC made a number of effective attacks on oil targets during the Allied oil campaign in 44, some raids however were complete failures. I cannot remember exact targets, so I cannot say, how many of the oil targets were outside Oboe-range.

And as wuzak noted, not surprisingly, knowing weather in UK, British had developed sky marking systems.

Juha

 

[wuzak]

IMHO H2S was adequate if there weres high radar contrast areas near the target, for ex coastline, lake, river etc, so BC could bomb fairly accurately certain targets well outside the Oboe range, as was shown for ex in Peenemünde raid in Aug 43. I recall from BC War Diaries that BC made a number of effective attacks on oil targets during the Allied oil campaign in 44, some raids however were complete failures. I cannot remember exact targets, so I cannot say, how many of the oil targets were outside Oboe-range.

And as wuzak noted, not surprisingly, knowing weather in UK, British had developed sky marking systems.

Juha

Some daylight raids were also complete failures.

Many of the oil facilities had smokescreen defences, which obscured the target and made bombing more inaccurate.

On occasion the 8th bombed decoy installations near some of the facilities.

And low cloud screwed up visual bombing too.