Couple things I'm curious about after this week's trip.
I was sitting near the back of an MD88 (Delta) and i could see the fan inside the engine. When the pilot started up the engine, the fan didn't turn!!!! The engine also made a kind of high pitched loud whine until we started our takeoff roll then it got quieter (when you would think it would be louder at full takeoff power!). While inflight i noticed that the fan was spinning. Why doesn't the fan turn all the time that the engine is "on"??
I also flew on a 727. Let me tell you those hushkits really make it quiet inside!!!! But while we were at the gate, I could hear from outside a loud, deep roar (I sat in row 28). it could not be the engine running because they were still loading bags into the aft compartment. What causes that noise??