Don't forget, the B17 added armor and extta machine guns at the expense of a substantially smaller payload. So you're sacrificing bombing capability (the whole point of the plane) in exchange for the ability to somewhat "fight" off enemy fighters (something bombers shouldnt be doing by themselves in the first place and even with armor and more guns stood a minute chance of success). Perhaps the British/commonwealth were wise to use strategy instead of extra armor and guns to protect bombers (read: night bombing)
Point is its impossible to really compare them as one was designed for night and stealthier missions and the other for brazen daytime bombing.
I think sure different variants had different payloads. I'm pretty sure that even with the reduced payload it had a similar payload to the Lancaster.
Even without the added guns and armor it had a sturdier frame.
About bombing at night.
It reminds me about the air war in Korea.
Soviets had denied airspace to the U.S. Their bombers would get wrecked in the sky. Hence they had to bomb at night to take advantage of the mig-15's poor night vision technology.
This makes you limited and predictable. The DPRK-Chinese forces would advance during the day. Also night bombing is less accurate and
It's a great way of missing a tank factory and killing civilians.
