I have been flying the 60UCD for about 7 or 8 mo with an FS Surpas II91 with no problems. Love the plane. I decided to go with a YS 110 and on the first flight the firewall broke in half when I landed. It was a dead stick landing and may have been a little on the hard side but not much. I had the cowl off because of breaking in the YS and the engine just fell off on the ground. Just wondering if anyone else has experienced this problem. I am in the process of making a much stronger firewall.