For those building the 4 (3 also, maybe). Iif you haven't built your flaps yet, you may want to consider the following. Yesterday when I tried to mate my flaps to the wings and fuse I found that the inboard end of the flaps was too close to the fuse. Not by much, but it does rub in the up position. I measured the heck out of things back when I built the flaps and fuse, so I don't feel like anything is out of spec. However, the plans call for the tops of the inboard ends of the flaps to be canted outward by 1/4 inch. I think this is to roughly match the fuse sides, which also slant out as they go up. The problem seems to be that the fuse sides lean out more than the flap ends. I'm making a new set of flaps and this time I'm gonna angle the ends by 3/8 instead. I'm also gonna move the entire flap outboard by about 1/16. This should fix it just fine. I'd be curious to hear form others who've run into this.