i am currently building an great planes u-can-do 3-d. i was thinking about upgrading the control rods to carbon fiber, and i was wondering what size, and if it would be really worth it, thanks, randy.

Probably not worth the $ on that plane. The main reason to use CF pushrods is to lose weight and/or to increase precision with less rod flex. On something like a UCD3D, the weight savings isn't going to matter much and you don't need superfine precision. If you do decide to go CF, the size of the rod you need will depend on the lenght of the rod and how you support it mid span. I'd suggest looking at the CF rods and ends sold at www.centralhobbies.com. If you are looking for a useful control upgrade, consider getting some nice coreless digitals to run your controls and use low/zero slop linkages. That will cost more than the CF rod, but the performance benifits and reusability are greater.

Another good reason to upgrade is do to nylon rod
exspands and contracts with temperature change
which will cause you to re trim your plane from
time to time. Wood dowels and steel ends are
hard to beat in my opinion. I switched the contol
rods to carbon fiber on my LT-40 the nylon
one just exspands/contracts to much for me.

I was having trouble with thermal expansion/contraction which caused the rudder and elevator trim to be inconsistent on my 4*60. So I bought some carbon fiber control rods to replace the nylon rod type ones that came with the ARF.
The CF rods are very lightweight and have very low friction as they slide inside the outer tubes. The problem I had is that they are extremely flexible. So, if you choose CF rods for retrofit, be sure they are supported as close to their terminal ends as possible with the outer tube. If you don't, they will flex too much when you move a control surface when the servo arm pushes them (push-pull system).

Since I was experimenting, I ended up trying two different methods to replace the original nylon rods that came with the ARF. Both methods entailed using metal rod material. I cut 1/4" pieces of nylon rod from the original control rod and CA'd them every three inches along the metal rod. The nylon rod pieces work as bearings. This method worked fine, but you have to make sure the two end bearing pieces are long enough so they don't come completely out of the outer tube at maximum travel.

I used the Great Planes control rod for the second method. It's the same idea as the method above, but you cut "bearings" out of their low-friction material and glue them onto the rod in a similar fashion. Seems like the price of the Great Planes control rod was reasonable.

thx for the input fellas, i have decited to use the stock pushrods and upgrade the nylon clevice only. they are made by "tetra", here is the link were i found em, thx agian, randy. http://www.centralhobbies.com/contro...is/tettra.html