Well I just had to reconstruct it: It must have been around 10-12cm back from the front edge, and that obviously explains why it behaved the way it did=) When I built it I must have assumed that the cg just has to be in the middle of the main wing, as it is what supports the weight in the air. I am sorry that I cannot provide any images since my camera broke a few weeks ago, and I haven't bought a new one yet.