We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember (Steve Firth)
saying something like:

http://www.liveleak.com/view?i=cdd_1203701257

Why did it collapse?

I think the explosion may have contributed to that.

Stop motion revealed a blade split first, very rapidly followed by
disintegration of the whole assembly. I suppose the rate it was whirling
around meant the slightest failure leading to unbalance would pitch
everything else over the failure limit.
--

Dave