I'm glad you started this thead! Finding info like this in the old thread was too time consuming.

I'm assuming the 2-56 rods you're having trouble with are the aileron rods, right? I haven't had any problems with the 2-56 on the elevators, but I went with 4-40 on the ailerons. Rudder is a pull-pull with the servo on the bottom of the fuselage.

My UCD came with about 1 degree of left thrust built into the firewall. A 3 degree Ernst thrust plate was used to get back to 2 degrees of right thrust.

For now my UCD is flying with a ST 90. The only props I've tried so far are the APC 14x6, Zinger 14x6, Rev-Up 14x6, and Zinger 15x6. Out of these props, the Zinger 14x6 is my favorite due to the faster spool up time of the wooden prop. I've got some APC 15x4 props on order, but I'm concerned that the slower spool up time of the 15x4 might be unacceptable. I sure wish APC made wood props!!!

Experimentation with a MCP on the ST 90 is still ongoing. The best results so far have the ST 90 spinning an APC 14x6 at 11,700 which gives the UCD pretty good acceleration out of a hover. The MCP has improved the power, transition, and fuel draw over the stock muffler, but transition and fuel draw issues still need some tinkering. Pehaps an OS 7D carb might cure these problems.

I'm debating on trying a Perry ocillating pump to see if that helps the fuel draw, but once the MCP gets dialed in, that might not be necessary.

CG is now at 6.5" and I like it much better than the 5.5" and 6.0" that I started with. But to get back this far, I had to replace the 120 size motor mount in the kit with a GP 60 size motor mount, and then push the ST 90 back as far as possible. And I don't even have the cowl installed yet, which would add more nose weight.

I'm wondering if a Saito 100 would be better than the ST 90 w/MCP in a UCD. I think the Saito 100 would be about the same weight as the ST 90 w/MCP, and maybe even lighter. But my buddy's Saito 91 falls way short on power compared to my ST 90 w/MCP. This has me worried that the Saito 100 still might not be enough power once you start to really throw the UCD around.

I've also considered an OS 108 or a TT 120 since their weights are identical to each other. But these two engines would add about another 1/2 pound of dead nose weight to the already too nose heavy UCD. The power and throttle response would sure be nice, but I'm not so sure the weight penalty would be worth it.