Question on RX battery. I run a Hitec 6 channel dual conversion rx in my Arrow. There are a total of 5 servos. I use a 4 cell nimh pack to power the system. 4.8 volts, 720 mah. I am going to run the same rx in my U Can Do 3D. However, there are 6 standard size servos in it. Will I need to use a 6 volt rx battery pack? I do have another 4 cell rx pack that has 1200 mah cells that I can use also. Not sure but I think the hitec rx's can use either 4 cell or 5 cell packs. So I am wondering which I should use, a 4 cell or 5 cell pack.

Dave...

No, the 4 cell pack will work just fine.

A 6 cell pack will give faster servo travel and increase the torque of the servos a little, but it will also drain the pack quicker. You want larger mAH capacity when going to 6 cells.

For your U Can Do the 1200 mA pack should be fine.
Dennis-

Thanx for the info! I hope to maybe finish it today. The U Can Do is sorta weird in that the CG range is from 2 to 4 inches from the LE.
Where the D-tube ends (you can feel it thru the covering) is at about 3 inches. I am gonna try and make the CG on this part or a tad forward of it. Of course when I really get used to this plane, a Saito 72 will go in it and I will move the CG back some. But first, I have to get used to the huge control surfaces it has. I'm thinking of roughly 3/4 to 1 inch travel on the elevator and ailerons. Nothing worse than a squirrely model on its maiden flight!

Dave...

Hi!
Hitec equipment will run fine on either 4 or 5 cell battery packs. If you have long extension leads, say longer than 12-15 in., for servos mounted in the tail or in the wings you may be better off with a 5 cell Rx battery.
The reason is that when the servos draw current there will be a voltage drop in the leads because of its resistance, meaining that the voltage delivered to the servo will be slightly less than the voltage supplied by the battery.
In practice I don't think it will matter much with a model such as the UCD-3D.
Since I suppose that you will be doing some hot-dogging with your new aircraft the 6 servos will be drawing quite a lot of current. If it is O.K. from a weight point of view I therefore suggest that you use the 4-cell 1200 mAh pach that you have already got.

/Red B.