One of the kit built Dirty Birdy's from a Blue Jay kit. The design is an original Bridi and it is a old school build. No glass fuse, it's all built up. I did try to install a .91 four stroke but there was no room on the fire wall but I was able to manage to get an SK .90 two stroke in it. Low RPM and High Torque. It flew even better then my old Kaos. Due to the mid air the second time out I never got to see it's full potential but I could hold knife edge from end to end of our flying site. I was very impressed with this one. It landed so slow and stable it was easier then a trainer. I have so many planes in line for my building board right now otherwise I would be building another one. If I do build another one I will be using my spring air retracts though. Just for that clean look. I think anyone with enough trainer time could fly this plane. I haven't flown the ARF yet so can't say about how that one is?