The key is NOT to add any dead weight to any airframe.

what sort of auw are you guys at?

Mine GW 50cc Sbach came in at 18.3 pounds, dual recvr batteries, nimh for ignition...Mine flies near perfect at the front third of the wing tube. I bet its close to 6". I added no weight and my engine was moved back with shorter standoffs to obtain 1/8 gap at the spinner. I can not figure for the life of me how they had to add weight. My 2100 life batteries are mounted up against the firewall, and nimh is on the engine box opposite of ignition. The plane flies great. Mine is a V3 with all the carbon goodies.

Brian

do you guys think my maiden will be fine ? kinda nervous.... CG at 6"(just on the aft edge of wing tube) WITH 9 oz wieght up front. ?

Balance it on the wing tube and fly it. Adjust to your flying style from there. The manual on my GW MX2 didn't even have a recommended CG, so I Balanced it on the tube and have been flying it that way for 2 years now. It's a little on the tail heavy side, but that's the way I like it. No joke....13 pounds AUW

I have a GW Edge 540 30c. The recommended CoG is at 100mm from the leading edge at the root. I maidened it with the CoG at 130mm from the LE at the Root.
Why?
Becuase I calculated where the Cog is in relation to the MAC and as long as you're ahead of 35% it will fly without porpoising.

There way to much focus on achieving the recommended CG than there is on determining what the wing plan form allows for.

27%MAC for my peakmodel 30% sbach is 6 1/16".... That's what I went with but did have to add 9 oz of weight. Think it'll be good enough to maiden ?

Originally Posted by TimBle

I have a GW Edge 540 30c. The recommended CoG is at 100mm from the leading edge at the root. I maidened it with the CoG at 130mm from the LE at the Root.
Why?
Becuase I calculated where the Cog is in relation to the MAC and as long as you're ahead of 35% it will fly without porpoising.

There way to much focus on achieving the recommended CG than there is on determining what the wing plan form allows for.

You mean anything 35% or less and it will be ok to fly ?

yip. Sorry I realise my post wasn't clear. The closer to 35% the more expo you need on elevator, it's going to be twitchy but still flyable. My .60 Edge is set up with the CG at 35%. it \s a real handful to others but it flies really great with a soft touch and enough expo.
My 30cc has it at about 32% and its fine. holds an inverted 45 upline and then gradually begins to fall after about 4-5sec.
The piot has to know his/her limitation on what they can handle.
Another thing to consider is that every arf is going to have variances in where the CG comes out after construction. Bespite being mostly preconstructed there are significant variances in wood and amount of glue used to build the subassembies.
As long as the CG is ahead of the neutral point its flyable. Further forward just makes it easier to fly

I have mine at 27% as per the manual... But it is on the aft side of the wingtube... Normally I start off on the wingtube... But I'd have to add a crazy amount of weight for that... It's an sbach, I hear they are usually tail heavy... I did add 9 oz. balances at 27% mac

I build a 30cc gw sbach last year and had to add 9oz to the nose to get it to balance on the center of the tube. I ended up taking about 2 and a half oz off and it's better, but a little on the tail heavy side. I don't like this plane, it's my beater and only gets flown every now and then. Has a dle 30 up front and a 3200 life bat on the firewall. I got everything I can get as far forward as I can and still had to add lead. I have many other planes, and no have had to have any lead added. My 100cc slick needed nothing, 30cc pilot edge, no lead either. I'll never buy another gw.

I have a 30cc gw sbach it weights 4,7kg(8,8 pounds) the a123 2300 battery is just before
The servo tray and it s a bit nose heavy for me I will set it backer as soon as I come back home after my holidays and it flies very floatie

I switch to the solar D770's on the elevator and boy what a differences. That really lighten the tail up

Originally Posted by kerwin50

I switch to the solar D770's on the elevator and boy what a differences. That really lighten the tail up

how long have you been using the 770's,what do you think of them,any gear slop, and how do they center.
they look good in the vedio on HobbyPartz.com and the price is almost to good to be true.

I've been using them since early may. They center really well and don't seem to have any gear slop in them.
I have them on my elevators and they track really well.