GP CG Machine = Junk? UCD 60 Problem
 

Check this out, I am trying to balance my UCD 60. First of all, this is the first time I have tried to use this thing, second as you can see by the photo the arms flop all over the place making moving the plane and getting them to sit accurately impossible, and third the UCD 60 has NO supportive balsa on the wing near the CG to support the plane for CG checking. I am hanging this plane on the monokote, which does not make me feel very good.

Is this thing supposed to work like this? Am I the only one who is complaining about the UCD and checking the CG on the monokote?

RE: GP CG Machine = Junk? UCD 60 Problem
 

Just got one myself. Heres my experance with it. Using the old finger balancing method almost every plane i have flowen came out nose heavy. I used the COG machine the first time on a TF P47 Using the fingers the cog was on the money. With the cog maching it was a little tail heavy. After talking to a few people i went (nervesly)with what the cog machine said was right. Plane maidened great and made me a beliver in the tool. I did have to make some different arms that hold it apart tho as its to narrow otherwise for 99% of the planes i have. The arms are kind of a pain but after a little use you can balance the plane on your hands and hold both arms out straight.

RE: GP CG Machine = Junk? UCD 60 Problem
 

Thats the problem. The spread is not wide enough for the UCD. You gotta go to the first rib out in either direction. Longer spreader bars are needed, or if you have a board, you can measure the stance needed to put you under the ribs and just screw them down to the board. The CG machines are acurate, but the arms are floppy. Joe

RE: GP CG Machine = Junk? UCD 60 Problem
 

NOVAflier...
Went round this the other day..... I realy had to force those ball and socket ' pivot ' things home under the round pad thingys...after that i just whizzed a 7" length of 1/8 balsa from the fuze side to just past the first rib.....the centre of the balsa is @ about 5" from L/E.... the rest is a walk in the park...;)...Dave

RE: GP CG Machine = Junk? UCD 60 Problem
 

Good idea. I notice that your pivot arms stay pretty stationary, which would make life alot easier, whereas mine just flop around..I may have to contact GP about it... It's really bothering me..

I have an unrelated question though...How did you get your Slimline pilot to fit under the canopy? I have the same one I picked up in Toledo and the shoulders are a little too wide, it bows out the sides of the canopy. Doesn't look like you had this problem. I didn't want to slice up the pilot to fit under the canopy..

RE: GP CG Machine = Junk? UCD 60 Problem
 

NOVAflier..
Yeah, old " Joe Pilot "..:)I carefully cut a " V " out under him then re- glued him back together ...but with slightly narrower shoulders ...so to speak..! he's not actually got his bum nailed down in the photo :)...i was using his position to " Fine tune " the C of G...he weighes over an ounce.....if i'd not have put the Voltwatch where it was, thier would have been even more room for 'adjustment..'!... but.... the Voltwatch covers the hatch used to strengthen the landing gear area... :) Dave.

RE: GP CG Machine = Junk? UCD 60 Problem
 

I have had very good luck with the CG machine. The arms on my do flop around a bit until the plane is on them. If it didn't it wouldn't be so sensative to balance though. Anyway I just went to Home Depot and got 2 36" rods, 3/16" diameter I think. Cut then in half and now I have 18" worth of space between the arms. I needed more as well for my DPM Ultimate 40.

After using the CG Machine I won't fly without using it. However, it can be a bit tough to get the planes on the balancer. Small price to pay for near perfet balance IMO. My fingers are truely lousy at being accurate for balancing.

RE: GP CG Machine = Junk? UCD 60 Problem
 

I've balanced alot of planes with mine. Yeah its a pain having the arms flop around but every plane I've balanced turned out perfect. I just finished my Edge 540 and it flew perfect. I think that dealing with the flopping arms is better than guessing with the old finger balancing.