A separate issue for the R22 to think about(copied from the web)....
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Due to its light weight and low inertia rotor system, the R22 is not forgiving of pilot error or sluggishness. After an engine failure, real or simulated, you and the instructor will have 1.6 seconds to lower the collective and enter an autorotation. Any delay beyond 1.6 seconds will be fatal as the rotor speed, once decayed below 80 percent, cannot be recovered. Frank Robinson did not design the R22 to be a trainer; he designed the R22 for a fast cruise speed and fuel efficiency. The R22 thus has a fast cruise speed, high fuel efficiency, and is a terrible trainer. Why do so many flight schools use the R22 for training? It is cheap to operate.If you are looking for a trainer, consider the
Robinson R44 instead. The R44 has about 4 seconds of rotor inertia rather than 1.6. That gives a pilot time to hear the low rotor RPM warning horn, look at the gauges, come up with a plan, and implement the plan (i.e., lower the collective and enter the autorotation). Count out 4 seconds to yourself and then count out 1.6."
Robinson R22 (with some comparisons to the R44) (greenspun.com)