AE 370 Airplane Performance Spreadsheet - Part III Stall Speed for S.L.F. Add the following to your previous spreadsheet or program. This section will use the results from the previous sections as well as some additional airplane specifications, to determine the maximum lift coefficient and steady level flight stall speed. Airplane Input Data . Maximum Airfoil Loft Coefficient (Cmax) Flapped Area (S flapped) Flap Effectiveness (ACmax) Fowler Flap Chord Extension (C'/C) Data Used from Previous Sections Planform Area (S) Weight (W) Wing Sweep (0.25, ^HL) Assume that the flap hinge line is at 70% chord (^0.70) Calculations Find CLmax for the wing. Find AC max for the flap system. Determine the S.L.F. stall speed with and without flaps in both ft/s and kts.