Altitude of a Mixed Bomber fleet

[kitplane01]

Suppose one is doing a bombing with both B-17s (service ceiling 35,600 feet, or pick a different large bomber) and B-25s (service ceiling 24,000 feet, or pick a different medium bomber). What altitude does one use?

(I'm envisioning some of the vary large, city busting bombing runs.)

 

[pbehn]

There are many considerations. First you don't want them all at one altitude, that is a gift to AA defences and not what a defensive box wants. From 35,000 ft even if you can get there with a loaded B-17 you are lucky to hit a city.

 

[Shortround6]

service ceiling 35,600 feet

That is the ceiling that ONE test plane maybe reached during a test (and be very very careful of test weights. B-17s often took off thousands if not tens of thousands pounds over normal gross weight) and was still able to climb at 100fpm. The actual altitude that a small formation (squadron or less) of planes could maintain was several thousand feet lower and the altitude that large formation (bomber group or wing) was several thousand feet below that.
You also have to careful about timing the attacks as you don't want the higher bombers dropping their bombs through the lower bomber formations. Happened all too often just with All one type of bomber in the formations.

 

[kitplane01]

That is the ceiling that ONE test plane maybe reached during a test (and be very very careful of test weights. B-17s often took off thousands if not tens of thousands pounds over normal gross weight) and was still able to climb at 100fpm. The actual altitude that a small formation (squadron or less) of planes could maintain was several thousand feet lower and the altitude that large formation (bomber group or wing) was several thousand feet below that.
You also have to careful about timing the attacks as you don't want the higher bombers dropping their bombs through the lower bomber formations. Happened all too often just with All one type of bomber in the formations.

But what I'm asking is ... The optimum altitude of a one type is different from another. In a mixed bomber attack, what altitude does one pick.

 

[pbehn]

But what I'm asking is ... The optimum altitude of a one type is different from another. In a mixed bomber attack, what altitude does one pick.

Bomber command of the RAF frequently (usually) had mixed aircraft on raids. The altitude was varied to avoid collisions and minimise Flak damage, When Stirlings were involved in the raid they were generally lower because they couldn't go higher. The optimum altitude is generally as close as possible to the target, it is ground defence and need to cover the distance that increases the altitude. At 35,000 ft you can be flying in air currents that make you almost stand still or fly sideways.