grounded27
I have allways been taught that they are designed with the intent of producing minimal drag in operation and that a windmilling or locked engine esp creates allot of drag. An engine vibe failue is designed to shear the aft mount first creating an AOA to send the motor over the wing.
You have been taught an old wifs tale, or what some want to believe because it sounded about right.
Discard such thoughts because they are scientifically not correct.
With a windmilling engine the core will still compress air creating a pressure front, which is drag. With a locked engine most of the air finds it easier to pass between the fan blades. and since the fan is not creating a pressure front the drag goes down (of course so does the thrust)
Unfortunately the simulators that train pilots don't recognize this and perhaps fortunately only one or two flights in fan jets have ever locked a fan rotor above 150 kts.
The bottom line is that the inlet lip anular area is the major drag producer and not the engine fan face.
And relative to designed mount separations, the regulation do not permit a failure condition by design, they expect cascading failure conditions to be minimized, not allowed.