Bending of the fuselage mid side skins and fitting to the fuselage skeleton. This was not as hard as I thought it would be but it does take a lot of elbow grease. The sharp bend at the forward part of the skin was actually very easy to do and lined up perfectly with the pre-drilled holes. The aft part of the bend is more difficult as you need it to be gradual and it is easy to kink the skin if you aren't careful
