You got a good amount of blur on the first two photos. I used to shoot helicopter shots, whenever choppers flew over the house, and such situations were one of the very few times I ever deliberately chose shutter priority automatic, to ensure that the shutter speed will be slow enough to get the needed degree of motion blur.
I was worried I was shooting too fast, but 1/250 seemed to work perfectly, and with the IS, I was able to snap tack sharp shots. I was thinking about what shutter speed I wanted to use, and I thought 1/250 would create way more blur than it ended up doing. It's actually surprising how slowly the rotors are turning!