I once saw a 3D pilot performing a maneuver that looked like a flat spin, but was climbing. I was wondering if anyone would be so kind to describe how such a maneuver is accomplished? I am new to 3D, and have the big GP Ultimate bipe, with a DLE 55 engine. It has plenty of power, which I am sure is required for this task. Thanks for any tips, ideas.

Only seen a few planes that would ever do it. You need at least 2.5:1 power to weight ratio. Your bipe may have plenty of power but not that kind of power. Most of the planes that will do a climbing flat spin are profiles.
To get into one enter a normal flat spin. (full down , full left aile , full right rudder, idle) Find the sweet spot by moving the ailes toward the center while slowly increasing power. Once you find this spot with the plane in a good flat spin start to increase throttle and reduce the amount of elev. Too much elev and the plane will start to flip and many times go into a knife edge spin. It's a delicate balancing act to find the right spot in the sticks. make sure you have a bunch of ALT.

I think it may have been one of those Morris hobbies profiles. Thanks for the info, I will give it a try.

Some planes [most planes?] seem to climb inverted better than when right side up.

Go to 2:18 appears to be a climbing flat spin maybe?

http://www.youtube.com/watch?v=q1OfG33Rr9Q

The old Magic would do this quite well, daveopam pretty well described how to do it. On my Magic I go into a full stall at idle, full left rudder, left ail and full back on the elevator. As it starts to wrap up I start feeding in right aileron while increasing throttle slowly. As it starts to stabilize with little to no altittude loss I actually back off of the elevator some and kind of find a sweet spot where it will begin to climb slowly.

Several years back I showed another guy at our field how to do it with his Magic and he actually landed it doing a full out flat spin. He just let it very slowly sink until it touched down on the grass, it kind of tipped over and drug a wingtip but the engine was still going and he was able to take back off after everything settled! Normal takeoff of course....

My Morris Hobbies Sledge with a West 50 and Genesis Throttle pipe running a APC 13x4 W would do both upright and inverted climbing flat spins. It was the only 3D model I have had that I could flip it from an upright to an inverted climbing spin and back. Quite a party piece.

My OMP Yak the 65 with a OS 120 AX would do both but not the flip between at least I could not get it right.

If you are exploring 3D I would recommend a profile. http://www.swanyshouse.com/primo60/primo60.aspx this one is about as state of the art as it gets.