A method for producing a sector plate for a rotary heat exchanger is disclosed. The method includes defining overall dimensions of a sector plate. A number of a plurality of tapered ribs to be included on the top surface is determined based on a surface area of the sector plate and/or a sealing to be provided by the sector plate. Additionally, a root height of the plurality of tapered ribs is determined based on at least a plate thickness of the sector plate and the number of the plurality of tapered ribs. With the root height, the plurality of tapered ribs cause the sector plate to deform parabolically in response to an actuation. The plurality of tapered ribs also return the sector plate to a rest position and the sector plate supports its weight in a cantilevered fashion when in the actuated position and the rest position.