That is cool, I like coax heli's!

So...Coax's cannot autorotate?

It's not the coax design but rather the fix pitch or variable pitch is the determining factor. Fix pitched rotors can NOT autorotate sufficiently. Of course being able to flatten the blades in an event of an engine out allows you to build up the speed and the kinetic energy in the rotor blades to have a successful flare and if necessary dampen the touchdown with a pull on the collective. It is not the coaxial design itself that can't do it. It is however very complex to build a coax with variable pitch!!!! And that's why experimentals build them fix pitched.
This heli the Diora has autorotation capability

Yes they have two 325 HP radials and that is pretty much the weakest point of the KA-26. Those engines suck!!! It is running 95% max at all times. I can't think of another helicopter that would run it's engines at the 95% max load mode! But.....it's Russian made so there is nothing surprising about that little nuance The usage for the coaxials is usually heavy lifting 900 KG about 2000 lbs. Crop dusting and crane comes to mind. Very stable machines though. 2x 13 meter rotors about 42-43 feet. When it's empty you can't kill the damn thing. There is another advantage of using coaxial rotors for crop dusting because the rotor creates an airflow which allows pesticides to settle underneath, rather than on top of, the leaves, this means a much more effective distribution of pesticides, as most pests and parasites do not live on the top side of foliage.