BalsaDust
Moderator
Hatches are easy. No thought involved really the way I do them. Just center it between R1 and R2. I like the front of it to be about 1/2” back from the main spar and on a plane that size I like it to be at least 3” square if not 4” square so there’s plenty of room to reach my hand inside. So with all that said literally draw it out on the sheeting after the wing is framed up. Cut out what you have just drawn. On the removed hatch sand all the edges down slightly so it will fit once covered and then on the front of it glue some 1/8” balsa on the bottom to act as a catch. Then use some more 1/8” balsa to go all around the opening in the wing to frame it out and have a ledge for it to sit on. Easy peasy. Normally takes me about five minutes from start to finish on doing a hatch.