April 1943 - May 1944: Luftwaffe's answer to the long range escort in the ETO?

[33k in the air]

A concentrated allied attack increases the effectiveness of the defences, as the raids become more predictable and even with day fighter escorts the bombers were taking significant losses historically, similar for the night bombers. In 1943 the allies lack the bomb lift and the accuracy to hit even the historical oil targets hard enough. The USAAF was a visual bomber force only until 27 September 1943 (H2S) and 3 November 1943 (H2X), and through lack of equipment and training still largely visual to end 1943, with a radar bombing accuracy comparable to the 1942 night bombers. Bomber Command was still mostly thinking in terms of marking a city, not a specific target in the city, as it would change over to in France in early 1944.

Varying the targets enough to not be too predictable is a challenge, certainly, but on the other hand, forcing the Luftwaffe to come up and defend the Ruhr is getting the fight for air superiority to happen sooner than it did historically, if proper fighter support can be mustered. That Bomber's Command campaign against the Ruhr in the first half of 1943 was having a deleterious effect on German war production is clear.

If most oil targets are not yet in range, many transportation targets are. The German electrical supply was not hit in any substantive way historically, so pushing those up the list would pay some dividends.

 

[Geoffrey Sinclair]

forcing the Luftwaffe to come up and defend the Ruhr is getting the fight for air superiority to happen sooner than it did historically, if proper fighter support can be mustered.

The Luftwaffe was fighting for air superiority in early and mid 1943 mostly in the south and east, and in fact was being forced to do so for the first time in a while (that is countering allied moves versus supporting German ones), while similar was starting to happen in the west, the emphasis switched to the west after mid 1943. The allied Mediterranean air forces defeated the Luftwaffe units in the area in the first half of 1943 and over Sicily.

That Bomber's Command campaign against the Ruhr in the first half of 1943 was having a deleterious effect on German war production is clear.

Bomber Command was doing real damage in mid 1943, Hamburg is estimated at costing 1% of Reich economic output for 1943 but the damage was diffuse and could not compete with the Germans switching more effort to war production and removing inefficiencies, so war production was not as effected. Raids like that of 22/23 November 1943 on Berlin where the Alkett works were heavily hit were rarities, that raid costing maybe 2 to 3% of German AFV production for 1943.

Certainly forcing the Luftwaffe to fight earlier in the west helps but that requires escort fighters as well as a credible bomber force, which largely did not exist until the historical shift in Luftwaffe fighter forces. The Eighth had 6 operational bomber groups in mid May, 10 by the end of May, 13 by end June (all B-17), 15 end July (again all B-17), 20 in early October when the B-24 groups had returned, 25 end December. It is having enough fighters to help cover the May to September operations to Germany where the RAF can play its biggest part and then remain useful until early 1944. In 1943 ignoring things like the B-24 groups sent to the Mediterranean the Eighth had to build its maintenance systems and stock spare parts, it had to take crews trained using pre war theory and apply that to combat, then hopefully report and so later obtain better trained personnel. It had to find out how many hours a crew and aircraft could effectively fly in a given period. The result was things like the 92nd Bomb Group being turned into a training unit for around 6 months. The USAAF had 21 raid days on Germany January to July 1943, including 1 that was against a convoy, take away the strikes on ports as well and you are left with 9 raid days. January to July 1943 the USAAF thinks 2,624 heavy bombers attacked targets in Germany or ships just offshore. In October it was 1,719 bombers, in November 2,079, in December 3,576

From the Statistical Summary of Eighth Air Force Operations, figures include 24 credit sorties by light bombers in September and 12 in October 1942 versus 106 and 157 by heavy bombers for those months. Also 23 credit sorties in May, 245 in July, 996 in August, 2,344 in September and 485 in October 1943 by medium bombers versus 1,340, 2,334, 2,058, 2,561 and 2,159 by heavy bombers for those months, hence the drop in average sortie length in August and September.

Table is month \ operational hours per sortie \ sorties per crew assigned \ sorties per aircraft on hand tactical units \ operational hours per crew \ operational hours per aircraft. For bomber aircraft.

Aug-42​	n/a	2.4​	2.9​
Sep-42​	n/a	1.4​	1.6​
Oct-42​	n/a	2​	2.2​
Nov-42​	4.8​	2.5​	2.5​	12​	12​
Dec-42​	4.3​	2.4​	2.1​	10.3​	9​
Jan-43​	4.7​	2.4​	2.3​	11.3​	10.8​
Feb-43​	4.3​	3.7​	3.6​	15.9​	15.5​
Mar-43​	4.1​	6.3​	5​	25.8​	20.5​
Apr-43​	4.4​	2.4​	1.9​	10.6​	8.4​
May-43​	3.7​	5.2​	4.8​	19.2​	17.8​
Jun-43​	4.1​	5.1​	4.7​	20.9​	19.3​
Jul-43​	5​	6.1​	4.8​	30.5​	24​
Aug-43​	3.5​	4.5​	3.9​	15.8​	13.7​
Sep-43​	3.9​	5.2​	5.2​	20.3​	20.3​
Oct-43​	5.6​	3.3​	3.6​	18.5​	20.2​
Nov-43​	5.2​	4.2​	5.1​	21.8​	26.5​
Dec-43​	5.9​	4.1​	6.1​	24.2​	36​
Jan-44​	5.2​	4.2​	6.4​	21.8​	33.3​
Feb-44​	6.2​	6.2​	7​	38.4​	43.4​
Mar-44​	6.5​	7.4​	8.1​	48.1​	52.7​
Apr-44​	5.8​	8.3​	8.9​	48.1​	51.6​
May-44​	6.2​	9.2​	9.7​	57​	60.1​
Jun-44​	5.6​	10.2​	11.5​	57.1​	64.4​
Jul-44​	6.4​	7.7​	10.2​	49.3​	65.3​
Aug-44​	6.3​	7.1​	9.7​	44.7​	61.1​
Sep-44​	6.7​	6​	8.8​	40.2​	59​
Oct-44​	6.3​	5.5​	7.6​	34.7​	47.9​
Nov-44​	6.5​	4.9​	6.9​	31.9​	44.9​
Dec-44​	6.6​	5.1​	8​	33.7​	52.8​
Jan-45​	6.6​	4.7​	7.7​	31​	50.8​
Feb-45​	7.4​	6​	10.5​	44.4​	77.7​
Mar-45​	6.9​	8​	13.8​	55.2​	95.2​
Apr-45​	7.9​	5.4​	8.7​	42.7​	68.7​

Note how the aircraft could be used more than the crews and what sort of flying hours were required if concentrating on German targets. For the 8th Air Force's heavy bomber units the number of crews assigned to the combat units was around the same as the number of aircraft August 1942 to February 1943, for March to August 1943 the units generally had 10 to 20% more aircraft than crews, then the ratio rapidly shifted so crews outnumbered aircraft by nearly 1.5 to 1 in January 1944 which seems to be a surge of crews arriving before aircraft, by May there were about 5% more crews than aircraft, in June the 8th hit peak average aircraft strength in the units, 2,547, while average crew strength went from 2,180 in May to 3,213 in July, stabilised at around 3,400 to 3,500 for most of 1944, then jumped to 3,835 in February 1945 for 2,230 aircraft.

From July 1943 on most day raids on Germany were being escorted most of the way, after mid October 1943 all and all. A Luftwaffe that concentrates on defending German day airspace will outnumber any allied escort force during most of 1943, often heavily. The USAAF had 3 P-47 groups April to August, 6 by end September. Even assuming the RAF could double this plus do insert and withdrawal cover the Luftwaffe can over match if desired.

Tactics matter, it seems clear the published combat radius figures in books like Mighty Eighth War Manual are inconsistent because they depend on the tactics used. Radius at bomber speeds when staying with slow bombers will be different to that for fast bombers, radius at fighter speed but staying with the bombers different again, staying at fighter speeds but protecting a section of sky rather than a specific bomber formation is another radius. Next comes whether any evasive routing is used, fighters that fly direct to their patrol zones tell the enemy where the bombers are going to be.

If most oil targets are not yet in range, many transportation targets are. The German electrical supply was not hit in any substantive way historically, so pushing those up the list would pay some dividends.

The transportation targets are all around Germany, all those city marshalling yards.

The electricity industry was never seriously attacked from the air but there is a steady amount of speculation about doing so, I know there are studies but have not really read any. Start with how easy were the targets to hit and for the hits to damage. How wide was the German grid, enabling power to come from distant sources if required. What was the German repair and replacement capacity, normal and emergency. Many large factories had boilers which means they could generate their own electricity if desired, some were probably already doing so. How much of the supply went to war industry versus domestic etc. use? How easy to use the repair and replacement capacity of the French etc. grids, or simply strip them of required items? Before that, taking power from their grids, including buying from Switzerland.

From early 1943 western allied operations meant the Luftwaffe day fighter force was being forced to engage or give up areas to the allies. In the east there was still the Manstein counter attack and Kursk before response to the enemy became the rule. Putting more range into the P-47 and Spitfire and sending them to Western Germany with enough bombers would have helped the allies increase the pressure but in the first half of 1943 the USAAF was having trouble mounting enough bomber operations thanks to supply and training issues before considering the limits of visual only bombing. In the second half of 1943 Germany and the west became the Luftwaffe day fighter priorities, getting more range into more allied fighters would clearly help the allies as the day bomber force grew and the supply system enabled a higher operational tempo.

 

[delcyros]

An feasable and early technical answer could be a wide refitting of MW-50. With it, the performance gap of Fw-190A and Bf-109G shrinks considerably.

 

[tomo pauk]

An feasable and early technical answer could be a wide refitting of MW-50. With it, the performance gap of Fw-190A and Bf-109G shrinks considerably.

American bombers were flying at 25000 ft, their escorts between 25000 ft and 28000 ft? MW 50 provides less and less benefits as the altitude is increased, and already at 18000-19000 ft on the BMW 801D and DB 605A it is of no use (had everything to do with their superchargers).
BMW being allowed/supported to go with BMW 801E solves a good deal of 801's high altitude problems; the 801E was not produced due to the changes needed in production lines that would've decreased the production of 801Ds. Some nip and tuck will be also required on the Fw 190, like the deletion of cowl guns, and better intakes.
DB 605 requires curing the problems with valves' coting and oil system in 1943, it is still derated in Spring and Summer of 1943. Similar problems were probably the ones badly hurting the DB 603A in 1943. DB 605 will also require a better/bigger S/C, ie. something like what DB 605AS got, but in 1943 (1944 is too late to matter).

By early 1944, Luftwaffe will require jet-powered fighters in hundreds...

 

[Shortround6]

DB 605 will also require a better/bigger S/C, ie. something like what DB 605AS got, but in 1943 (1944 is too late to matter).

There was nothing to really stop putting the bigger supercharger on the 605 was there?

I thought it was pretty much a 603 supercharger mounted on the 605 engine?

However you don't get something for nothing and the bigger supercharger took about 50 more HP to drive at low altitude.
Perhaps the bigger supercharger would have fit (bolted on) just fine, however the if the 605 pistons won't stand up to the airflow they did have then increasing the airflow at higher altitudes might have fried even more engines.

 

[tomo pauk]

There was nothing to really stop putting the bigger supercharger on the 605 was there?

I thought it was pretty much a 603 supercharger mounted on the 605 engine?

Agreed all the way.

However you don't get something for nothing and the bigger supercharger took about 50 more HP to drive at low altitude.
Perhaps the bigger supercharger would have fit (bolted on) just fine, however the if the 605 pistons won't stand up to the airflow they did have then increasing the airflow at higher altitudes might have fried even more engines.

(my bold)
Trick was improving the high-atitude power, the big S/C does exactly that. If that means sacrificing 50 HP down low, so be it.
Bolded part is a key here - the 'basic' DB 605A needs to be sorted out before it was asked to do more.

 

[delcyros]

While the fights do start at high altitude, they tended to transgress towards lower altitudes in prolonged action. At high altitude GM-1 helps and actually provides superior performance, but it is limited to above full pressure height. One needs MW-50 to provide a performance boost at below full pressure height in order to get on equal performance footing with Bf-109G and Fw-190A in late 1943 and early 1944. In early 1944, the performance gap between USAAF and the Luftwaffe fighter force was probably more pronounced than at any other time before or thereafter. GM-1 and MW-50 provide a stopgap.

 

[tomo pauk]

While the fights do start at high altitude, they tended to transgress towards lower altitudes in prolonged action. At high altitude GM-1 helps and actually provides superior performance, but it is limited to above full pressure height. One needs MW-50 to provide a performance boost at below full pressure height in order to get on equal performance footing with Bf-109G and Fw-190A in late 1943 and early 1944. In early 1944, the performance gap between USAAF and the Luftwaffe fighter force was probably more pronounced than at any other time before or thereafter. GM-1 and MW-50 provide a stopgap.

In 1943, the gap will not be as pronounced. GM-1 is surely a very interesting suggestion, especially for the Fw 190, where the over-boosting can be used to help out under the rated altitude. Avoids the need to carry additional MW 50 tank, too.

Here is the (draggy & heavy) Fw 190A-8 doing 50-70 km/h more with GM-1 above the rated altitude: