I have had exactly this same problem with my Ty3d. One day the motor just glitched on me in mid-flight, and luckily I managed to land it okay. Since I had servo control, I just assumed it was the motor and sent it in. After waiting for two weeks with no replacement, I just bought one, and lo and behold: exactly the same problem.

The glitch is that the prop chatters, and wobbles back and forth making a god awful noise while the motor, esc, and battery pack heat up exponentially. I actually melted the wrap on the stock battery diagnosing the problem. God help you if you use lipos, because my motor sparked and started smoking when I connected those.

The bottom line is this: THE STOCK ESC IS CRAP. Because it sits in that INSULATED foam tunnel with no air really rushing past, it overheats and melts the logic between the third and seventh flight. Motor problems and shorts ensue. I replaced mine with the Eflite 20A esc which includes a thermal cutoff (if the Ty3d does, it sucks/is set way too high) and soft-start for the prop and motor. I've had no issues with my 2100mAh 11.1 LiPo, the eflite 20A, and the stock brushless motor since the replacement. Oh, and I widened the ventilation holes leading in and out of the ESC "chamber", as well as positioned it for a maximum breeze. I also fly without the cowl; doesn't seem to harm it, as long as you don't crash the prop into something, and then what good is flimsy plastic going to do anyway?

On a related note, make sure you check your gearbox and see if the prop spins freely with the engine leads disconnected. When my Ty3d overheated because of the ESC, the heat from the motor warped the motor mount and was applying pressure between the rotor shaft gear and the pinion. All sorts of problems there...

Works great now though, but after buying replacement ESC, motor, LiPos, and new Hitec HS-81's, I may as well have bought a more quality ARF kit, powerplant, and radio...