My Visionaire developed a case of the wobblies where the ailerons would flutter at medium throttle. I suspected that the motor shaft was bent, so I pulled it out and checked it on a surface plate. Dead straight. I discovered that several magnets had broken loose and had shifted, causing the imbalance and ruining the motor. It was my fault, so I didn't pursue a warranty replacement.
After doing a lot of research, I decided to try a Hacker A30-10L motor. When it arrived, I found that the shaft placement is reversed and that the motor has to be "backmounted", with a bolt-on prop adapter.
Using the included cross-type mount, I mounted the motor in the VA, but the prop adapter was too short. I tried to build a mount out of plywood and carbon fiber, but it exploded in my hands as I mounted the motor. An aluminum mount didn't fit at all, and I could not find any suitable mounts, so my plane sat there.
A trip to my LHS yesterday led me to discover that the motor mount from a Parkzone T-28 works perfectly! It fits the Visionaire motor mount as if it were made for it, and the prop adapter now clears the cowl. It was necessary to enlarge the hole in the cowl to allow clearance for the can, but not much.
I still need to adjust the CG and wait for the rain to stop, and then I'm going flying!