Here is the "Hobo Queen." The only B-29 deployed to the ETO during WW2. She was displayed at several airbases in Britain for morale purposes and also to alarm German Intelligence. But perhaps things should have been different. In retrospect considering the high loss rates among the B-17 and B-24 heavy bombers that were deployed in OTL maybe B-29s should have been used instead. At least as far as production numbers would allow. Which brings up other considerations.
Boeing began their initial design work on what would become the B-29 in 1938. However it didn't enter service until mid-1944. How could've the development and large scale production of the B-29 be sped up?
One of the major problems with the B-29 was the Wright R-3350's troubled development. Overheating and fires being a serious danger that caused the loss of many airplanes. Eventually after a few years the R-3350 was improved but not in time for WW2. So for use in WW2 the Pratt and Whitney R-2800 would have been a better choice. As shown in the P-47 the turbocharged R-2800 could produce at least the same, if not somewhat more, power as the 1944 versions of the R-3350 and it was also a more reliable engine. The R-2800 would have been available for mass production of B-29s in 1942.
Another big development hurdle the B-29 faced was the remotely operated gun turrets. These type of turrets were the only practicable method to fit guns in a pressurized airplane before radar or TV sighting were developed. It was an electro-mechanical system that was complex, expensive and took 3 years to get to a working state. But avoiding this developmental delay would require a much larger POD then the much easier one where someone chooses a different
engine. This requires a huge change in AAF policy.
What Boeing and the USAAF would have to do is abandon fitting defensive armament to the B-29 at that time. This would result in a much simpler, lighter and more aerodynamically clean airplane. A plane that could cruise at 35K to 40K feet at better then 300MPH TAS. And could push close to 400 TAS at those altitudes using emergency power and after dropping the bombload. This kind of performance put the airplane out of reach of most of the Luftwaffe's fighters. It would also have made it a much more difficult target for Flak.
But this approach goes directly against the Air Force's belief that a heavily armed bomber "will always get through." What could possibly change that belief?
Could the massive losses RAF Bomber Command experienced earlier in the War before they abandoned daytime bombing have made the Americans reconsider? If the British had proceeded with Barnes Wallis' Victory Bomber concept would that have changed a few minds? What if the decision was made to start producing the B-29 in large numbers early in 1942 and the remotely operated gun system would be added later? Go with with what they got?
Producing the B-29 in 1942 to equip the 8th Air Force with unarmed B-29 bomber groups in 1943 is a radical idea it's true. But consider what they would be facing. Almost all the Luftwaffes' fighters are going to struggle to intercept B-29s that are clipping along at better then 35K feet and more then 300MPH TAS.
I'm not sure how much this would degrade German Flak guns capabilities but it would be considerable.
This alternative B-29 would be carrying a crew of only 6 men. Without the weight of and the drag of gun turrets and ammunition. Loaded with about 30 to 40 percent of the fuel load that was needed to reach Japan from the Marianas this B-29 can hit any target in Germany while carrying, I think, a 10,000 pound bombload. All this and the R-2800 engines would give it the performance needed to avoid the Jagdwaffen. For the most part. The Germans had recon planes that could reach these altitudes and they would have surely have embarked on a crash program to develop more planes that could. But this would've taken time, resources, and production resources from other uses.
The Allies would need to provide escorting fighters for these ATL B-29s right from the get-go. This was also true in OTL though it wasn't acknowledged until after the heavy losses of the early bombing campaign. Sending unarmed bombers at the beginning would have expedited the use of escort fighters. For their high altitude performance the P-47 and P-38 are already in service by 1943. A well designed pressure oxygen system would be needed for long duration flights at those altitudes in an un-pressurized fighter.
Even a partial pressure suit might prove necessary for flights approaching 40K feet. In the ETO escorting fighters proved essential in OTL. That would also be needed in TTL even if the Luftwaffe fighter threat is diminished by the difficulty of interception and the smaller numbers of German fighters with that capability.
One wonders about the accuracy of bombing from 35K to 40K instead of 25K feet but would that be remediated by the larger bombloads and the less disturbance by Flak?
Would the 8th Air Force have benefited from having the B-29 available in force in 1943? To supplement the B-17 and B-24 groups? To be used for the more dangerous long distance raids deeper into Germany while the B-17s and B-24s are reserved for shorter ranged missions in France, Benelux or the Rhur escorted by the shorter legged fighters?
By the time that Tinian and Saipan are available in late 1944 for the bombing campaign against Japan the remotely operated gun turret system should be ready for fitting to the production B-29s earmarked for use in the Pacific. These planes will need that defensive armament because they are flying missions that are too long ranged for fighter escort and they'll be flying lower and slower then their European sisters. They'll still be a difficult and dangerous intercept problem for the Japanese air forces same as OTL. And in this TL a few thousand B-29s would have been built by late 1944 with most of the bugs worked out and also using the Pratt and Whitney R-2800 engines.
