How did B-17 and B-24 formations avoid shooting each other?

[Admiral Beez]

heavy armament, the YB-40's increased weight and drag significantly reduced its performance, making it less effective in practice.

Surely someone at Boeing told the Air Force chaps that more weight and drag without an engine upgrade beyond the B-17's 9-cylinder 1,000 hp Wright R-1820 Cyclone was not going to be able to keep up. In that light, was the 2,000 hp Pratt & Whitney R-2800 Double Wasp considered?

 

[Frog]

Surely someone at Boeing told the Air Force chaps that more weight and drag without an engine upgrade beyond the B-17's 9-cylinder 1,000 hp Wright R-1820 Cyclone was not going to be able to keep up. In that light, was the 2,000 hp Pratt & Whitney R-2800 Double Wasp considered? The R-2800 is heavier and longer, but narrower than the R-1820. I believe its first four engine application was the Boeing B-29, but it looks like it could be modified to fit the B-17. There were many twin engined R-2800 applications.

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R-2800 on a B-29 ?
You would have needed 6 per plane...

 

[Admiral Beez]

R-2800 on a B-29 ?

Sigh. I abhor the pedant; so have edited the post, hopefully to your satisfaction.

 

[EwenS]

Surely someone at Boeing told the Air Force chaps that more weight and drag without an engine upgrade beyond the B-17's 9-cylinder 1,000 hp Wright R-1820 Cyclone was not going to be able to keep up. In that light, was the 2,000 hp Pratt & Whitney R-2800 Double Wasp considered? The R-2800 is heavier and longer, but narrower than the R-1820. I believe its first four engine application was the Boeing B-29, but it looks like it could be modified to fit the B-17. There were many twin engined R-2800 applications.

View attachment 798699

From Joe Baugher's site about the YB-40 with my emphasis.

"In the spring of 1943, the 327th BS of the 92nd BG based at RAF Alconbury were issued 12 YB-40s foroperational combat tests. The first operational YB-40 sortie took place on May 29, 1943 against St. Nazaire. Eight other missions were later flown, the last one taking place on July 4, 1943. Five kills and two probables were claimed during these missions, with the loss of one YB-40. Very early on, it was found that the net effect of the additional drag of the turrets and the extra weight of the guns, armor, and additional ammunition was to reduce the speed of the YB-40 to a point where it could not maintain formation with the standard B-17s on the way home from the target once they had released their bombs. The YB-40 could protect itself fairly well, but not the bombers it was supposed to defend. Consequently, it was recognized that the YB-40 project was an operational failure, and after less then ten missions the YB-40s were withdrawn from service, and the surviving YB-40s were converted back to standard B-17F configuration or used as gunnery trainers back in the States."

Boeing YB-40

There was only a single XB-41 based on the B-24 built. So many problems were encountered that the results of the YB-40 programme became available and the project was cancelled.