Cyclic,
Check out http://www.spadtothebone.com/ and you will probably find out the name of your design. I built about 15 Defenders which sound similar to what you have and we flew full contact combat with them. They were disposable and I had lot's of extra parts for field repairs to keep everyone flying.

From your description of the flight charecteristics it sounds like you might have the throws to extreme or a rearward CG. While these things are not the greatest flyers some of them do very well for what they are.