Helicopter noise level

[God Bless USA]

The CH-47 Chinook has a twin rotor system and two engines.  The CH-53E Super Stallion has one rotor system and three engines.  Yes I know we all know this!   But I was wondering which helicopter you would hear approaching you first?
 

[iluveagles]

Well, heres the thing though. You won't hear the engines at all until the helo passes you, goes for jets as well...............

In my expierence(I have flown on a 47), you'll probably here them in a fairly equal amount of time. The 47 may be a bit louder, but I doubt there is much difference.............

[God Bless USA]

I agree jets are here and gone.  But these two helicopters are slower than a jet, so lets say they are going to go past you, which one would you hear first?

CH-47F two rotors and two engines
CH-53E Super Stallion one rotor and three engines

[iluveagles]

*sigh* the point is, that regardless the since they are jet engines(or w/e the technical name is) you won't hear the engine until after they pass you.............and even then the rotor wash will pretty much silence the engine noise.

What I'm trying to say is that there really isn't that big of a difference..............

[God Bless USA]

I think we beat this dog dead!  Thanks for the info, it answered my question.

[Globetrotter]

Maybe it also depends on the engine type.

Suppose, B-737-200 (long thin engines) vs B-737-800 (shorter, fatter engines). Or KC-135 vs KC-135R. They had their engines replaced, among many other things, to reduce noise, I believe...

Hope to have summed up somehting

[tigershark]

CH-47s are faster then out Apaches I saw that on Wing's not bad for a big helicopter.  Noise wise neither will sneak up on you but both are proven platforms and glad we have them. (smile face)

[iluveagles]

Yes, the dog is long long dead.......