It came back today, right over my house! Here you get a good view of the tail rotors (one sideways like a helicopter's, the other a vectored pusher-prop). The sound is similar to a small multi-engined plane, but with less Doppler effect; it just fades away.
It's longer than a 747, so try to imagine that floating over you!
For a better sense of the scale; at this point the Zeppelin is over the water.
