carltonck,

I've been flying my UCD with the YS91FZ. I have a little over two gallons through it and it keeps getting stronger. When new, the engine turned a 16x4W APC at 9300 and would hover at half throttle. By the middle of the second gallon the engine was turning a 16x6 Bambula or 15x8 Menz-S at 9200+. It will hover at a little less than half throttle on either of these props. On the other hand, at full throttle, it doesn't leap from the hover. It does climb with some authority, and accelerates going up, but I could see where more power might be a good thing.

In my opinion, the extra weight won't hurt you. With the 91, and the CG back at 6" the plane feels VERY light in the air, so much so that I run spoilers for landing or it just floats forever. The plane is hard to stall, it's reluctant to snap and needs to be coaxed into a spin.

If I were to do it again, I'd go with something stronger, even if it were heavier. When I first heard of guys running the YS 1.40DZ in this plane I thought they were nuts, but I'm not so sure now. I'd sure love to try a DZ in mine.

As far as putting the tank on the CG goes... it doesn't cause a balance problem. I've got a 1000 mah 5 cell battery in the tail and the tank on the CG, and I'm still going to start sticking lead on the tail to move the CG back a bit more. I'm figuring two to three ounces will get it there.

David