Yes, I see..... it's what I didn't know, I just thought that softer = better, but in my short flying experience it has given me some trouble, I hadn't tried on concrete because I am scare of destroying my t-rex in a hard landing, but I am gonna start trying to see what happens.... do u think that crashing against grass or crashing against concrete makes the same damage??? or there will be way more damage on concrete????? to give you an idea, I always fly 2 feet above the ground so, when I have a hard landing it's at that distance, normally all what I have to replace are the main blades, main shaft, feathering shaft and once the main gear, that is it..... what about on concrete????? I have a 450 SE