Nitro2bass I put a zdz 40 in mine and they are about the same size. I didn't cut the firewall down I cut a hole in the wall for the carb. With the right thrust in the firewall I ran a string from the tail to the noes held my motor out at 6" and marked a hole then went and found center with the exciting holes and did some measuring and found new holes and drilled and then cut the hole for the carb and installed and it came out great. It wasn't quit as easy as it sounds, it will take a little time but it worked. Talked to chip about it and he said I did it the right way. And wanted a pic of it so he could have it to show people. But I don't have a digital camera. Im purity sure the DA 50 would work much the same because like I said they are close the same size I got the dimension of both before I even bought the motor. because I was going to go with a DA but a few people told be they thought a zdz might be better, so I trusted them. I have only been able to fly it once because of the weather here and it flew great, Im around 4700'