kfir2

I have just acquired a new white/red and blue extra ( similiar to the extra special)with built up wings and the instrustion manual says balance on forward half i.e front edge to middle of wing tube and shows a picure with a ruler on the wing tip showing 3 3/4" from tip to tip. This puts the c of g @ the back edge of the tube. If the plane is balanced on the front edge to the middle of the tube the wing skin deforms so much that it is starting to crack. (in fact I have fitted a cross grain piece in between root and first rib)Which one is right. I have had a extra special until a recent mid air and loved it

Tired Old Man

My Feedback: (1)

Anywhere in the width of the wing tube is acceptable. The position that best suits the way you fly and prefer in balace dictaes the final position. C/G is adjustable. One specific location is not "The One" that it has to be balanced at. 3-3/4" is only a starting point.

As for cracking the skin at a given location, ever thought of using something to span a couple of ribs when balancing a plane? Works when all you have between you and the wing is plastic covering as well....

kfir2

Thanks for info I guess I am a bit parinoid about the first flight, and wanted to get everything about right so as not to have to move too much about. I have got a zdz60 with a can muffler and it has come out a bit nose heavy especially as I use pull pull rudder. I dont like adding weight. Praying for better weather to get her in the air.

Tired Old Man

My Feedback: (1)

Move the rudder servo to the tail and use it as a push pull. Nose heavy and it lands too fast. Balanced center of the wing tube and it's extremely docile. It can be heavy and not matter if the balance point is right. I've flown one as heavy as 21 pounds and it flew well. Nogt a great 3d plane at that weight but serobatically sound. Balance is everything.