For those who are wishing to learn from these threads it may be a good idea to relate a bit about the whirlmode RPM as well.
60% and 132% RRPM are the relevant numbers in the R22 according to RHC. (The first number is, of course, far less dangerous, although this is the reason for the yellow arc on the tachs).
There are cases where the entire tailboom separated during a severe overspeed.