I decided to fly my I1 today took off in an empty parking lot near my house. There was a tree about 15 feet away and when I took off, I had just calibrated my compass and had full gps. When I was about 7 feet in the air, my I1 immediatly, with no input from me, started drifting hard towards the right. I immediately recognized this as an error so I took control of the I1, but I hardly had time to react. I pulled back as hard as I could so as to avoid the tree and my left front prop clipped the trunk of the tree. After it clipped the tree, I set my I1 down and shut everything down. Thankfully, the only damage was too the left front prop and the I1 seems to be just fine as of right now. Has anyone else had any issues like this? I don't know what happened because at the height I was at, even if I didn't have gps lock, the ultra-sonic sensors and the camera on the bottom should have held it in place. I installed the software that was the latest version about one month ago.