This is the main tab of the spreadsheet. The user controls everything from the 'Input' section, where the wing profile (i.e. camber and number of elements) is selected from a drop-down list and the other parameters are keyed in.
Below this is the section where the calculations for lift and drag coefficient are carried out. The experimental data gave lift coefficient values varying with angle of attack for 4 different wing profiles with aspect ratios of 4, a proportionality formula between lift coefficient and aspect ratio, values that the lift coefficient would be multiplied by at different clearances from the ground, and experimental values of drag coefficient for different lift coefficients. Thus the calculation section starts by determining the lift coefficient due to specified angle of attack, then determines, based on specified aspect ratio and ground clearance, how much to multiply to determine the actual lift coefficient, which is then used to determine the drag coefficient.
This shows the top half of the supplementary tab which details the experimental data used for the spreadsheet, and the interpolation functions used to return lift coefficients for angle of attack values not given by experimental data.
As shown in the screenshot of the main spreadsheet, to determine any value from this experimental data, an IF function first checks if the relevant user parameter (e.g. angle of attack) matches the values given in experimental data. If it does not match, the interpolation function is used. If it does match, the excel VLOOKUP function is used to return the exact data point from the experimental data shown here.
The remainder of the supplementary tab, showing experimental data for determining drag coefficient from lift coefficient, and lift coefficient multiplier from ground clearance.
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Formula SAE Spoiler Aerodynamics Spreadsheet
A spreadsheet which predicts a Formula SAE racing car's drag and lift coefficients and forces,, using published experimental data for varying conditions (including camber, number of elements, ground clearance and angle of attack).
The spreadsheet returns the exact values of lift and drag coefficient given by the published experimental data and, when it cannot do so (i.e. lift coefficient values are generally only given for even values of angle of attack), it uses a cubic polynomial interpolation function to approximate the values.
This spreadsheet was completed in two hours as a timed challenge project for the university subject, "Design III."