I built one about 3 years ago. I dont remember any problems and the instructions were very good. Mine was powered with an os 91 fx and later a ys 91ac. If I was going to build it again today I would do a lot of lightening. It is a very strong airframe but a bit on the heavy side as compared to some of todays ligter models. It will get snappy if you have too much elevator throw so be careful on first flights. You do have to land with a bit of speed or it can tip stall, but then again so will just about any other 60 size cap. Overall mine flew pretty well and took a lot of abuse for the almost 2 years I had it. I was not very happy with the abs cowl.I bought a fiberglass cowl for it