With our 714 engines, we have a max gross weight of 50,000 lbs. Our engines burn on an average 2000 lb/ hr during cruise flight. You know, when you see a chinook flying by and you see a trail of smoke coming out the back, don't think that it's on fire. They're just barbecueing!!
About the drive shaft...the engines have a nosebox transmission which rotates the driveshaft 90 degrees to the center of the aircraft which meet in the middle to a combining transmission. This transmission then distributes the power down a long drive shaft which links the forward and aft rotors and keeps them in sync. This is why we inspect our drive shaft so closely!