ORIGINAL: T. Defense

Recently purchased a Blade CP and love it. I have suddenly noticed however GREAT vibration whenever I run it up to about 50%. I put new blades on to no avail. I took off the blades and ran it up to full throttle to see if the main shaft was wobbling but it wasn’t. It seems to only happen when the blades are in place. There is no play in the head unit. Any suggestions??? Am I forgetting something? It’s so bad I can't even get it off the ground. Any advice would be greatly appreciated.