Gun sounds vs. engine sounds on different aircraft

[spamRoast]

Probably dumb questions but curious.

 

I've read here that pilots in WWII couldn't hear their gun's sounds over their engines which seems logical but I watched a recent helicopter video where you could clearly hear both cannons and rockets over their engine (the sounds seem real). Obviously a modern chopper is entirely different from a plane, and an 80 year old plane at that, but I still assumed a chopper would have a very loud engine that similarly blocks out its weapon's sounds. Genuinely curious if this just due to the engine's location relative to the pilot or perhaps it's due to modern engines (I know nothing about engines)? And what about modern jets, can they hear their fired weapons?

[Art-J]

It's probably more about location of engine exhaust system vs gun muzzle - two primary sources of noise on any combat aircraft, irrespectively of type and age (closely followed by propellers/rotors, although that depends on their design as well). That will affect sound propagation a lot - after all, sound is just a pressure wave.

 

In that Ka-52 vid you've got turboshaft engines nozzles located way behind the crew compartment, but that 30 mm cannon muzzle is just beside pilot's right foot, so that's going to be more prominent source of sound. There's a cockpit vid out there with one of Flanker-family jets firing its 30 mm gun - same thing. Rockets will also be clearly audible when their exhaust passes in front of the cockpit. 

 

Exactly opposite case is Spit/Mustang/Warhawk etc. where engine exhaust stacks are in front of and pointing towards the pilot, but gun muzzles are located in wings.

 

Then there's a myriad of in-between cases, like turbocharged piston planes being much quieter because of exhaust being muffled by the turbo system, or fighters with some guns literally mounted in the cockpit (A6M anyone?). So I would say some WWII pilots most likely couldn't hear their guns, but some could, depending on plane.

[Yogiflight]

5 hours ago, Art-J said:

or fighters with some guns literally mounted in the cockpit (A6M anyone?).

Bf 109s with the 20 (30)mm gun's rear between the rudder pedals just covered by a thin metal box.

[spamRoast]

@Art-J, I figured it was something similar to your answer but the specifics make more sense now. Thanks.