RotorWay 162F. Godawful bang and a smack into the bulkhead behind me. I put her into autorotation and picked out a spot to land. On the way down I noticed that the engine, while very low, wasn't quite dead. I was able to roll up enough to resume flight and headed for the barn when the student said, "hey - do you smell fire?"
Down goes the collective again and we're back into autorotation, only this time I curve the path so I can look behind to see if there's any smoke. There isn't and I start smelling what my student did - fried drive belt. Oh, good. We're not actually on fire in a fiberglass helicopter. I nursed the power back on and got us home, terminating in a 6" IGE hover taxi to the hangar.