… but to answer the question, the new Brantly B2B was flight-tested for Pilot magazine in the UK by Derek Jones in March 1999. He wrote: “Entering autorotation is no problem as you just lower the lever and keep straight with about half right pedal. The throttle correlation split the needles and there was only a small nose-down pitch. Rate of descent stabilised at a reasonable 1,600 fpm at 55 mph, with the rotor rpm at 460. The maximum allowed is 472. Rolling into moderate turns resulted in a slow rise in rpm, without any collective lever correction required to stay within the limit. It is recommended that the engine is maintained at 2,000 rpm during these manoeuvres, to avoid embarrassing silences.
“The rotor inertia on the Brantly is somewhat greater than that of the Robinson R22, and therefore gives a bigger margin for error during engine-off landings. However, you do have to roll off the throttle as the lever is raised for the touchdown, to prevent the engine re-engaging the freewheel. For practises, it is recommended to run onto the ground at 15 – 20 mph on smooth surfaces, following a flare initiated at 50 – 60 feet. The well-sprung undercarriage is forgiving of errors, although the closeness of the blades to the tailcone would concentrate the mind in the event of a tail-down arrival. Powered go-rounds just require raising the collective to join the needles and co-ordinating the throttle slightly to prevent overspeeding, then settling the speed again at 60 mph for the climb. A happy by-product of the fuel injected engine is not having to remember the carb heat at low power settings.”
Hope this helps. Incidentally, it's not the inner portion of the blade that drives the outer during autorotation. Only the centre section provides an autorotative force.