Always thought the Big Banana went thump-thump-thump. Well to my ears anyway, but thats usually after I've expended several hundred rounds, so maybe me ears are playing me up?
Sea Kings deffo. go wokka-wokka-wokka.......
Then again, the UH-1 has a very very distinctive sound, but nothing sounds as good as a Puma or Wessex back to the Grove when you're in your last week in the Emerald Khazi