External sounds audible in cockpit with engine running?

[droz]

So, there are several factors you have to think about in this situation.

1. Is the airplane pressurized?
2. What type of headset are you using?
3. Current day ANR headsets drown out external noise.
4. The list goes on.

The complicated answer to this is, back then, aircraft were not pressurized, engines may have been loud, but they did not drown out everything.

Sound waves move in a direction, and decrease or increase in intensity based on several factors.

As a real pilot, when I choose to, I can remove my headset, open the window, and I can hear all sorts of sounds outside of the cockpit. Many times I have opened the window and hear a plane passing by.

In the 1940's, they did not have ANR headsets, and typically, it was just a couple of small speakers inside earmuffs. It's that simple. No noise reduction, nothing to really keep the sounds out. In many ways, what was used was no better than wearing nothing.

So, to keep it simple, I'd prefer realistic. Realistic, in this case, is being able to hear the engines, the wind, and guns firing, you name it. Sound travels. It's more powerful than you think. This is not space. These are not pressurized aircraft. It's that simple.