I flew my new Fox 60 Eagle III on a Hangar 9 Cap using 10% nitro fuel after breaking it in on a test stand for 15 minutes. It has backfired on the ground a few times and threw the prop/spinner in the air twice. This last time it threw the prop, it sped up in a high pitch scream and I shut it down within 1-2 seconds.

After landing the plane, I was extremely lucky to find the spinner (Dubro) still held on to the prop with the washer and nut inside it. I reinstalled them on the Fox and tried to start it. It spun easily like there was no compression. It ran but only on high and died as soon as I retarted throttle. It sounded like a loud sewing machine, i.e., no compression. When I rotated it by hand backwards, at TDC it felt like there was a rough bump. I have not disassembled it to take a look. Any suggestion, help, or solution will be appreciated.