OK. After the canopy came off and took out the stock prop, I have had some issues. I figured that this was a good time to up to a 6x4e. The LHS did not have any so I did order some (just figured out that I ordered then from China. New order placed from US site with MUCH shorter delivery time). What I did get from LHS was some orange props. Markings say GWS ep-6030. Well, the center opening was not big enough. I drilled all 3 off them out to a sufficient diameter. Went to the field and put the plane up. At about 3/4 throttle the plane makes a gutt- wrenching sound that sounds like it is going to shake itself apart. I brought the plane down to investigate. When I ran the throttle up in my hand all was fine until about 3/4 throttle then WHAM! First the vibration then the prop self-destructed. Thinking that maybe I had somehow weakend the prop while drilling, I tried a second prop with the same results. The plane flies great at less than 3/4 throttle without any vibration. I did not balance the first 2 props. The third prop I did try to balance (I don,t have a balancer so I did the best I could) but still have the same results. I don't know the manufacturer of the props. I have posted a video of the issue. Any help would be appreciated.