A structural panel for an aircraft nacelle may comprise a first skin, a second skin, and a core sandwiched between them. One of the skins may comprise regions of different thicknesses. The regions of different thicknesses may be separated by a ramp, in which the number of composite plies in the first skin varies. A slope of the ramp may vary across the ramp to prevent disbonding of the core from the skin at the base of the ramp.