Yesterday I mounted a set of 600mm V Blades that I bought from someone on the net. Nice set of blades and looked new although he said they had been used. I had replaced a set of NHP blades and made no other change.

The heli almost shook it's self apart and I couldn't even get it off the ground. I brought the machine home, took the blades off and weighed them. They were 4 grams off but, the CG was ok. The NHP blades flew fine and I didn't bother the check the V Blades.

I have them balanced now and will give them another try weather permitting. That is the last time I will put any blades on a machine without putting them on the scale first. I always try to get my blades balanced to within .1 gram.

I supect that is what happened. I have them balanced now and will see how they fly when I get a chance.