I just test flew mine last week with a YS .63 in it and apart from a little engine trouble it flew great. I ended up with a dead stick landing off the end of the runway but everything held up fine. I'm using a 13x4W APC prop so the plane will slow down nicely with the engine. I also found that I had to open the cowl up quite a bit to get the airflow to the engine and back out again. Going to fly it with the mods today. Video of the 1st flight is in members videos.