Good thing this topic came up. I've been having the same problem with a TT 46 on an Ultra stick. It destroyed one plane before I found out what all was going on. I rebuilt the plane and found that the original problem was due to the glow plugs burning out. I went through 3 of them in one day and still didn't figure out why it was happening. These were all different types and ranges of plugs too. I still don't know what's causing it.......[>:]