I am on my second GB Ultimate. The first had an OS 1.20 Surpass 2 that flew awesome right off the board. It had amazing unlimited vertical and would lamchavac (spelling?) easily from a 45 degree knife edge entry.

The mods I made at the time were some as those already stated above and as recommended to my by someone who talked to Dave Patrick about it. I don't know if that was all true or not but I followed the advise given to me and it all came out good. I replaced the firewall with 5ply birch. Left in all the lightening holes around the firewall, behind the aft end of the wing on the bottom, and around the tail. I believe I also left in some/alot/all of the lightening holes in the wing ribs too. The cabanes come with a balsa vertical stiffiner and replaced it with some spruce of the same size. All of the 2-56 rods were replaced with 4-40 rods. I also strengthened areas requiring it by installing tristock balsa like the firewall and the landing gear plate and the wing bolt plate.

My second one I just purchased the ARF kit about 6 weeks ago and am fighting more than I remember on my first. I just assembled it and didn't replace the 2-56 rods. It has a YS .91AC for power and while strong and offering unlimited vertical (no other .91 besides the new YS .91's will do this I believe) it is a real slow vertical climb to out of site - not quite the power of the 1.20 in the first one. I cannot get this one to lamchivac for me. I have moved the CG back to somewhere around 1/4 - 1/2 inch behind the ARF's plans called for aft CG range. The tail kicks around 1/2 way then stops and will not complete the tumble. I am afraid of moving the CG aft further. I think I will next try replacing the tail's 2-56 rods with 4-40 ones first as maybe they are bending under that load and flattening out the elevators. I do have one repair to make to the kit. I found out after flying the last weekend that one side of the wing hold-down plate in the fuse has come free - thank god it was a bipe and the other wing helped hold the lower wing on. I need to reglue it and put some tri-stock there.